[PATCH v1 2/2] i2c: npcm7xx: add i2c controller master mode only

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Nuvoton NPCM7XX I2C Controller
NPCM7xx includes 16 I2C contollers. THis driver operates the controller.
This module also includes a slave mode, which will be submitted later on.

Any feedback would be appreciated.  


Signed-off-by: Tali Perry <tali.perry1@xxxxxxxxx>

---
 drivers/i2c/busses/Kconfig       |   11 +
 drivers/i2c/busses/Makefile      |    1 +
 drivers/i2c/busses/i2c-npcm7xx.c | 2574 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 2586 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-npcm7xx.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 4f8df2ec87b1..692ce1568fb0 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -742,6 +742,17 @@ config I2C_NOMADIK
 	  I2C interface from ST-Ericsson's Nomadik and Ux500 architectures,
 	  as well as the STA2X11 PCIe I/O HUB.
 
+config I2C_NPCM7XX
+	tristate "Nuvoton I2C Controller"
+	depends on ARCH_NPCM7XX
+	select I2C_SLAVE
+	help
+	  If you say yes to this option, support will be included for the
+	  Nuvoton I2C controller.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-npcm7xx.
+
 config I2C_OCORES
 	tristate "OpenCores I2C Controller"
 	help
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 5a869144a0c5..80d4ec8908e1 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_I2C_MT65XX)	+= i2c-mt65xx.o
 obj-$(CONFIG_I2C_MV64XXX)	+= i2c-mv64xxx.o
 obj-$(CONFIG_I2C_MXS)		+= i2c-mxs.o
 obj-$(CONFIG_I2C_NOMADIK)	+= i2c-nomadik.o
+obj-$(CONFIG_I2C_NPCM7XX)	+= i2c-npcm7xx.o
 obj-$(CONFIG_I2C_OCORES)	+= i2c-ocores.o
 obj-$(CONFIG_I2C_OMAP)		+= i2c-omap.o
 obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o
diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
new file mode 100644
index 000000000000..442b23aacaaf
--- /dev/null
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -0,0 +1,2574 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NPCM7xx SMB Controller driver
+ *
+ * Copyright (C) 2018 Nuvoton Technologies tali.perry@xxxxxxxxxxx
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/jiffies.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/clk/nuvoton.h>
+#include <linux/bitops.h>
+#include <linux/bitfield.h>
+
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/dma-mapping.h>
+
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+static struct regmap *gcr_regmap;
+static struct regmap *clk_regmap;
+
+#define	 I2CSEGCTL_OFFSET 0xE4
+
+#define NPCM7XX_SECCNT		(0x68)
+#define NPCM7XX_CNTR25M		(0x6C)
+
+#define	 I2CSEGCTL_VAL	0x0333F000
+
+#define ENABLE	1
+#define DISABLE	0
+
+#define _1Hz_		(u32)1UL
+#define _1KHz_		(1000 * _1Hz_)
+#define _1MHz_		(1000 * _1KHz_)
+#define _1GHz_		(1000 * _1MHz_)
+
+#ifndef ASSERT
+#ifdef DEBUG
+#define ASSERT(cond)  {if (!(cond)) for (;;) ; }
+#else
+#define ASSERT(cond)
+#endif
+#endif
+
+#define ROUND_UP(val, n)	(((val)+(n)-1) & ~((n)-1))
+#define DIV_CEILING(a, b)	 (((a) + ((b)-1)) / (b))
+
+#define I2C_VERSION "0.0.2"
+
+#define I2C_DEBUG2(f, x...)
+
+
+
+
+// HW module supports TO. in Linux, we choose to use SW TO to avoid conflicts
+// However this code is still available in this driver:
+// #define SMB_CAPABILITY_TIMEOUT_SUPPORT
+
+#define SMB_RECOVERY_SUPPORT
+
+// override HW SMBus may fail to supply stop condition in Master Write operation
+#define SMB_SW_BYPASS_HW_ISSUE_SMB_STOP
+
+// slave mode: if end device reads more data than available, ask issuer or
+// request for more data:
+#define SMB_WRAP_AROUND_BUFFER
+
+#define SMB_QUICK_PROT	 0xFFFF
+#define SMB_BLOCK_PROT	 0xFFFE
+#define SMB_EXCLUDE_BLOCK_SIZE_FROM_BUF	0xFFFD
+
+
+enum smb_mode {
+	SMB_SLAVE = 1,
+	SMB_MASTER
+};
+
+/*
+ * External SMB Interface driver states values, which indicate to the
+ * upper-level layer the status of the
+ * operation it initiated or wake up events from one of the buses
+ */
+enum smb_state_ind {
+	SMB_NO_STATUS_IND = 0,
+	SMB_SLAVE_RCV_IND = 1,
+	SMB_SLAVE_XMIT_IND = 2,
+	SMB_SLAVE_XMIT_MISSING_DATA_IND = 3,
+	SMB_SLAVE_RESTART_IND = 4,
+	SMB_SLAVE_DONE_IND = 5,
+	SMB_MASTER_DONE_IND = 6,
+	SMB_NO_DATA_IND = 7,
+	SMB_NACK_IND = 8,
+	SMB_BUS_ERR_IND = 9,
+	SMB_WAKE_UP_IND = 10,
+	SMB_MASTER_PEC_ERR_IND = 11,
+	SMB_BLOCK_BYTES_ERR_IND = 12,
+	SMB_SLAVE_PEC_ERR_IND = 13,
+	SMB_SLAVE_RCV_MISSING_DATA_IND = 14,
+};
+
+// SMBus Operation type values
+enum smb_oper {
+	SMB_NO_OPER = 0,
+	SMB_WRITE_OPER = 1,
+	SMB_READ_OPER = 2
+};
+
+
+// SMBus Bank (FIFO mode)
+enum smb_bank {
+	SMB_BANK_0 = 0,
+	SMB_BANK_1 = 1
+};
+
+// Internal SMB states values, which reflect events which occurred on the bus
+enum smb_state {
+	SMB_DISABLE = 0,
+	SMB_IDLE,
+	SMB_MASTER_START,
+	SMB_SLAVE_MATCH,
+	SMB_OPER_STARTED,
+	SMB_REPEATED_START,
+	SMB_STOP_PENDING
+};
+
+// Module supports setting multiple own slave addresses:
+enum smb_addr {
+	SMB_SLAVE_ADDR1 = 0,
+	SMB_SLAVE_ADDR2,
+	SMB_SLAVE_ADDR3,
+	SMB_SLAVE_ADDR4,
+	SMB_SLAVE_ADDR5,
+	SMB_SLAVE_ADDR6,
+	SMB_SLAVE_ADDR7,
+	SMB_SLAVE_ADDR8,
+	SMB_SLAVE_ADDR9,
+	SMB_SLAVE_ADDR10,
+	SMB_GC_ADDR,
+	SMB_ARP_ADDR
+};
+
+
+
+// Common regs
+#define NPCM7XX_SMBSDA(bus)		(bus->base + 0x000)
+#define NPCM7XX_SMBST(bus)		(bus->base + 0x002)
+#define NPCM7XX_SMBCST(bus)		(bus->base + 0x004)
+#define NPCM7XX_SMBCTL1(bus)		(bus->base + 0x006)
+#define NPCM7XX_SMBADDR1(bus)		(bus->base + 0x008)
+#define NPCM7XX_SMBCTL2(bus)		(bus->base + 0x00A)
+#define NPCM7XX_SMBADDR2(bus)		(bus->base + 0x00C)
+#define NPCM7XX_SMBCTL3(bus)		(bus->base + 0x00E)
+#define NPCM7XX_SMBCST2(bus)		(bus->base + 0x018)  // Control Status 2
+#define NPCM7XX_SMBCST3(bus)		(bus->base + 0x019)  // Control Status 3
+#define SMB_VER(bus)			(bus->base + 0x01F)  // SMB Version reg
+
+// BANK 0 regs
+#define NPCM7XX_SMBADDR3(bus)		(bus->base + 0x010)
+#define NPCM7XX_SMBADDR7(bus)		(bus->base + 0x011)
+#define NPCM7XX_SMBADDR4(bus)		(bus->base + 0x012)
+#define NPCM7XX_SMBADDR8(bus)		(bus->base + 0x013)
+#define NPCM7XX_SMBADDR5(bus)		(bus->base + 0x014)
+#define NPCM7XX_SMBADDR9(bus)		(bus->base + 0x015)
+#define NPCM7XX_SMBADDR6(bus)		(bus->base + 0x016)
+#define NPCM7XX_SMBADDR10(bus)		(bus->base + 0x017)
+#define NPCM7XX_SMBADDR(bus, i)	(bus->base + 0x008 + \
+	(u32)(((int)i * 4) + (((int)i < 2) ? 0 : \
+	((int)i - 2)*(-2)) + (((int)i < 6) ? 0 : (-7))))
+
+#define NPCM7XX_SMBCTL4(bus)		(bus->base + 0x01A)
+#define NPCM7XX_SMBCTL5(bus)		(bus->base + 0x01B)
+#define NPCM7XX_SMBSCLLT(bus)		(bus->base + 0x01C)  // SCL Low Time
+#define NPCM7XX_SMBFIF_CTL(bus)		(bus->base + 0x01D)  // FIFO Control
+#define NPCM7XX_SMBSCLHT(bus)		(bus->base + 0x01E)  // SCL High Time
+
+// BANK 1 regs
+#define NPCM7XX_SMBFIF_CTS(bus)		(bus->base + 0x010)  // FIFO Control
+#define NPCM7XX_SMBTXF_CTL(bus)		(bus->base + 0x012)  // Tx-FIFO Control
+#define NPCM7XX_SMBT_OUT(bus)		(bus->base + 0x014)  // Bus T.O.
+#define NPCM7XX_SMBPEC(bus)		(bus->base + 0x016)  // PEC Data
+#define NPCM7XX_SMBTXF_STS(bus)		(bus->base + 0x01A)  // Tx-FIFO Status
+#define NPCM7XX_SMBRXF_STS(bus)		(bus->base + 0x01C)  // Rx-FIFO Status
+#define NPCM7XX_SMBRXF_CTL(bus)		(bus->base + 0x01E)  // Rx-FIFO Control
+
+
+
+// NPCM7XX_SMBST reg fields
+#define NPCM7XX_SMBST_XMIT			BIT(0)
+#define NPCM7XX_SMBST_MASTER			BIT(1)
+#define NPCM7XX_SMBST_NMATCH			BIT(2)
+#define NPCM7XX_SMBST_STASTR			BIT(3)
+#define NPCM7XX_SMBST_NEGACK			BIT(4)
+#define NPCM7XX_SMBST_BER			BIT(5)
+#define NPCM7XX_SMBST_SDAST			BIT(6)
+#define NPCM7XX_SMBST_SLVSTP			BIT(7)
+
+// NPCM7XX_SMBCST reg fields
+#define NPCM7XX_SMBCST_BUSY			BIT(0)
+#define NPCM7XX_SMBCST_BB			BIT(1)
+#define NPCM7XX_SMBCST_MATCH			BIT(2)
+#define NPCM7XX_SMBCST_GCMATCH			BIT(3)
+#define NPCM7XX_SMBCST_TSDA			BIT(4)
+#define NPCM7XX_SMBCST_TGSCL			BIT(5)
+#define NPCM7XX_SMBCST_MATCHAF			BIT(6)
+#define NPCM7XX_SMBCST_ARPMATCH			BIT(7)
+
+// NPCM7XX_SMBCTL1 reg fields
+#define NPCM7XX_SMBCTL1_START			BIT(0)
+#define NPCM7XX_SMBCTL1_STOP			BIT(1)
+#define NPCM7XX_SMBCTL1_INTEN			BIT(2)
+#define NPCM7XX_SMBCTL1_EOBINTE			BIT(3)
+#define NPCM7XX_SMBCTL1_ACK			BIT(4)
+#define NPCM7XX_SMBCTL1_GCMEN			BIT(5)
+#define NPCM7XX_SMBCTL1_NMINTE			BIT(6)
+#define NPCM7XX_SMBCTL1_STASTRE			BIT(7)
+
+// NPCM7XX_SMBADDRx reg fields
+#define NPCM7XX_SMBADDRx_ADDR			GENMASK(6, 0)
+#define NPCM7XX_SMBADDRx_SAEN			BIT(7)
+
+// NPCM7XX_SMBCTL2 reg fields
+#define SMBCTL2_ENABLE				BIT(0)
+#define SMBCTL2_SCLFRQ6_0			GENMASK(7, 1)
+
+// NPCM7XX_SMBCTL3 reg fields
+#define SMBCTL3_SCLFRQ8_7			GENMASK(1, 0)
+#define SMBCTL3_ARPMEN				BIT(2)
+#define SMBCTL3_IDL_START			BIT(3)
+#define SMBCTL3_400K_MODE			BIT(4)
+#define SMBCTL3_BNK_SEL				BIT(5)
+#define SMBCTL3_SDA_LVL				BIT(6)
+#define SMBCTL3_SCL_LVL				BIT(7)
+
+// NPCM7XX_SMBCST2 reg fields
+#define NPCM7XX_SMBCST2_MATCHA1F		BIT(0)
+#define NPCM7XX_SMBCST2_MATCHA2F		BIT(1)
+#define NPCM7XX_SMBCST2_MATCHA3F		BIT(2)
+#define NPCM7XX_SMBCST2_MATCHA4F		BIT(3)
+#define NPCM7XX_SMBCST2_MATCHA5F		BIT(4)
+#define NPCM7XX_SMBCST2_MATCHA6F		BIT(5)
+#define NPCM7XX_SMBCST2_MATCHA7F		BIT(5)
+#define NPCM7XX_SMBCST2_INTSTS			BIT(7)
+
+// NPCM7XX_SMBCST3 reg fields
+#define NPCM7XX_SMBCST3_MATCHA8F		BIT(0)
+#define NPCM7XX_SMBCST3_MATCHA9F		BIT(1)
+#define NPCM7XX_SMBCST3_MATCHA10F		BIT(2)
+#define NPCM7XX_SMBCST3_EO_BUSY			BIT(7)
+
+
+// NPCM7XX_SMBCTL4 reg fields
+#define SMBCTL4_HLDT				GENMASK(5, 0)
+#define SMBCTL4_LVL_WE				BIT(7)
+
+// NPCM7XX_SMBCTL5 reg fields
+#define SMBCTL5_DBNCT				GENMASK(3, 0)
+
+// NPCM7XX_SMBFIF_CTS reg fields
+#define NPCM7XX_SMBFIF_CTS_RXF_TXE		BIT(1)
+#define NPCM7XX_SMBFIF_CTS_RFTE_IE		BIT(3)
+#define NPCM7XX_SMBFIF_CTS_CLR_FIFO		BIT(6)
+#define NPCM7XX_SMBFIF_CTS_SLVRSTR		BIT(7)
+
+// NPCM7XX_SMBTXF_CTL reg fields
+#ifdef SMB_CAPABILITY_32B_FIFO
+#define NPCM7XX_SMBTXF_CTL_TX_THR		GENMASK(5, 0)
+#else
+#define NPCM7XX_SMBTXF_CTL_TX_THR		GENMASK(4, 0)
+#endif
+#define NPCM7XX_SMBTXF_CTL_THR_TXIE		BIT(6)
+
+// NPCM7XX_SMBT_OUT reg fields
+#define NPCM7XX_SMBT_OUT_TO_CKDIV		GENMASK(5, 0)
+#define NPCM7XX_SMBT_OUT_T_OUTIE		BIT(6)
+#define NPCM7XX_SMBT_OUT_T_OUTST		BIT(7)
+
+// NPCM7XX_SMBTXF_STS reg fields
+#ifdef SMB_CAPABILITY_32B_FIFO
+#define NPCM7XX_SMBTXF_STS_TX_BYTES		GENMASK(5, 0)
+#else
+#define NPCM7XX_SMBTXF_STS_TX_BYTES		GENMASK(4, 0)
+#endif
+#define NPCM7XX_SMBTXF_STS_TX_THST		BIT(6)
+
+// NPCM7XX_SMBRXF_STS reg fields
+#ifdef SMB_CAPABILITY_32B_FIFO
+#define NPCM7XX_SMBRXF_STS_RX_BYTES		GENMASK(5, 0)
+#else
+#define NPCM7XX_SMBRXF_STS_RX_BYTES		GENMASK(4, 0)
+#endif
+#define NPCM7XX_SMBRXF_STS_RX_THST		BIT(6)
+
+// NPCM7XX_SMBFIF_CTL reg fields
+#define NPCM7XX_SMBFIF_CTL_FIFO_EN		BIT(4)
+
+// NPCM7XX_SMBRXF_CTL reg fields
+// Note: on the next HW version of this module, this HW is about to switch to
+//	 32 bytes FIFO. This size will be set using a config.
+//	 on current version 16 bytes FIFO is set using a define
+#ifdef SMB_CAPABILITY_32B_FIFO
+#define NPCM7XX_SMBRXF_CTL_RX_THR		GENMASK(5, 0)
+#define NPCM7XX_SMBRXF_CTL_THR_RXIE		BIT(6)
+#define NPCM7XX_SMBRXF_CTL_LAST_PEC		BIT(7)
+#define SMBUS_FIFO_SIZE				32
+#else
+#define NPCM7XX_SMBRXF_CTL_RX_THR		GENMASK(4, 0)
+#define NPCM7XX_SMBRXF_CTL_LAST_PEC		BIT(5)
+#define NPCM7XX_SMBRXF_CTL_THR_RXIE		BIT(6)
+#define SMBUS_FIFO_SIZE				16
+#endif
+
+// SMB_VER reg fields
+#define SMB_VER_VERSION				GENMASK(6, 0)
+#define SMB_VER_FIFO_EN				BIT(7)
+
+
+
+// stall/stuck timeout
+const unsigned int DEFAULT_STALL_COUNT =	25;
+
+
+// Data abort timeout
+const unsigned int ABORT_TIMEOUT =	 1000;
+
+// SMBus spec. values in KHz
+const unsigned int SMBUS_FREQ_MIN =	10;
+
+const unsigned int SMBUS_FREQ_MAX =	1000;
+const unsigned int SMBUS_FREQ_100KHz = 100;
+const unsigned int SMBUS_FREQ_400KHz =	 400;
+const unsigned int SMBUS_FREQ_1MHz =	1000;
+
+
+
+// SCLFRQ min/max field values
+const unsigned int SCLFRQ_MIN =		10;
+const unsigned int SCLFRQ_MAX =		511;
+
+// SCLFRQ field position
+#define SCLFRQ_0_TO_6		GENMASK(6, 0)
+#define SCLFRQ_7_TO_8		GENMASK(8, 7)
+
+// SMB Maximum Retry Trials (on Bus Arbitration Loss)
+const unsigned int SMB_RETRY_MAX_COUNT = 2;
+
+const unsigned int SMB_NUM_OF_ADDR = 10;
+
+
+
+// for logging:
+#define NPCM7XX_I2C_EVENT_START	  BIT(0)
+#define NPCM7XX_I2C_EVENT_STOP	  BIT(1)
+#define NPCM7XX_I2C_EVENT_ABORT	  BIT(2)
+#define NPCM7XX_I2C_EVENT_WRITE	  BIT(3)
+#define NPCM7XX_I2C_EVENT_READ	  BIT(4)
+#define NPCM7XX_I2C_EVENT_BER	  BIT(5)
+#define NPCM7XX_I2C_EVENT_NACK	  BIT(6)
+#define NPCM7XX_I2C_EVENT_TO	  BIT(7)
+#define NPCM7XX_I2C_EVENT_EOB	  BIT(8)
+
+#define NPCM7XX_I2C_EVENT_LOG(event)   (bus->event_log |= event)
+
+// Status of one SMBus module
+struct NPCM7XX_i2c {
+	struct i2c_adapter		adap;
+	struct device			*dev;
+	unsigned char __iomem		*base;
+	spinlock_t			lock;
+	struct completion		cmd_complete;
+	int				irq;
+	int				cmd_err;
+	struct i2c_msg			*msgs;
+	int				msgs_num;
+	int				num;
+	u32				apb_clk;
+
+	// Current state of SMBus
+	enum smb_state		state;
+
+	// Type of the last SMBus operation
+	enum smb_oper			operation;
+
+	// Mode of operation on SMBus
+	enum smb_mode			master_or_slave;
+
+	// The indication to the hi level after Master Stop
+	enum smb_state_ind			stop_ind;
+
+	// SMBus slave device's Slave Address in 8-bit format -for master xfer
+	u8				dest_addr;
+
+	// Buffer where read data should be placed
+	u8				*rd_data_buf;
+
+	// Number of bytes to be read
+	u16				rd_size;
+
+	// Number of bytes already read
+	u16				rd_ind;
+
+	// Buffer with data to be written
+	u8				*wr_data_buf;
+
+	// Number of bytes to write
+	u16				wr_size;
+
+	// Number of bytes already written
+	u16				wr_ind;
+
+	// use fifo hardware or not
+	bool				fifo_use;
+
+	// fifo threshold size
+	u8				threshold_fifo;
+
+	// PEC bit mask per slave address.
+	//		1: use PEC for this address,
+	//		0: do not use PEC for this address
+	u16				PEC_mask;
+
+	// Use PEC CRC
+	bool				PEC_use;
+
+	// PEC CRC data
+	u8				crc_data;
+
+	// Use read block
+	bool				read_block_use;
+
+	// Number of retries remaining
+	u8				retry_count;
+
+	// int counter
+	u8				int_cnt;
+
+	// log events, fir debugging
+	u32				event_log;
+
+	// The indication to the hi level after Master Stop
+	u32				clk_period_us;
+	u32				int_time_stamp[2];
+};
+
+
+static bool NPCM7XX_smb_init_module(struct NPCM7XX_i2c *bus,
+				    enum smb_mode mode, u16 bus_freq);
+
+static bool NPCM7XX_smb_master_start_xmit(struct NPCM7XX_i2c
+					  *bus, u8 slave_addr,
+					  u16 nwrite, u16 nread,
+					  u8 *write_data, u8 *read_data,
+					  bool use_PEC);
+static int  NPCM7XX_smb_master_abort(struct NPCM7XX_i2c *bus);
+
+static int  NPCM7XX_smb_recovery(struct i2c_adapter *_adap);
+
+
+static void NPCM7XX_smb_set_SCL(struct i2c_adapter *_adap, int level);
+static int  NPCM7XX_smb_get_SCL(struct i2c_adapter *_adap);
+static int  NPCM7XX_smb_get_SDA(struct i2c_adapter *_adap);
+
+
+
+typedef void(*SMB_CALLBACK_T)(struct NPCM7XX_i2c *bus,
+			enum smb_state_ind op_status, u16 info);
+
+static inline void NPCM7XX_smb_write_byte(struct NPCM7XX_i2c *bus, u8 data);
+static inline bool NPCM7XX_smb_read_byte(struct NPCM7XX_i2c *bus, u8 *data);
+static inline void NPCM7XX_smb_select_bank(struct NPCM7XX_i2c *bus,
+						enum smb_bank bank);
+static inline u16  NPCM7XX_smb_get_index(struct NPCM7XX_i2c *bus);
+static inline void NPCM7XX_smb_master_start(struct NPCM7XX_i2c *bus);
+static inline void NPCM7XX_smb_master_stop(struct NPCM7XX_i2c *bus);
+static inline void NPCM7XX_smb_abort_data(struct NPCM7XX_i2c *bus);
+static inline void NPCM7XX_smb_stall_after_start(struct NPCM7XX_i2c *bus,
+						 bool stall);
+static inline void NPCM7XX_smb_nack(struct NPCM7XX_i2c *bus);
+static	void NPCM7XX_smb_reset(struct NPCM7XX_i2c *bus);
+static	void NPCM7XX_smb_int_enable(struct NPCM7XX_i2c *bus, bool enable);
+static	bool NPCM7XX_smb_init_clk(struct NPCM7XX_i2c *bus, enum smb_mode mode,
+					  u16 bus_freq);
+static	void NPCM7XX_smb_int_master_handler(struct NPCM7XX_i2c *bus);
+static	void NPCM7XX_smb_int_master_handler_write(struct NPCM7XX_i2c *bus);
+static	void NPCM7XX_smb_int_master_handler_read(struct NPCM7XX_i2c *bus);
+
+
+static inline	void NPCM7XX_smb_eob_int(struct NPCM7XX_i2c *bus, bool enable);
+
+static		void NPCM7XX_smb_write_to_fifo(struct NPCM7XX_i2c *bus,
+					       u16 max_bytes_to_send);
+static inline	bool NPCM7XX_smb_tx_fifo_full(struct NPCM7XX_i2c *bus);
+static inline	bool NPCM7XX_smb_rx_fifo_full(struct NPCM7XX_i2c *bus);
+static inline	void NPCM7XX_smb_clear_tx_fifo(struct NPCM7XX_i2c *bus);
+static inline	void NPCM7XX_smb_clear_rx_fifo(struct NPCM7XX_i2c *bus);
+
+
+static		void NPCM7XX_smb_set_fifo(struct NPCM7XX_i2c *bus,
+				int bytes_read, int bytes_write);
+static		void NPCM7XX_smb_calc_PEC(struct NPCM7XX_i2c *bus, u8 data);
+static inline	void NPCM7XX_smb_write_PEC(struct NPCM7XX_i2c *bus);
+static inline	u8   NPCM7XX_smb_get_PEC(struct NPCM7XX_i2c *bus);
+static		void NPCM7XX_smb_callback(struct NPCM7XX_i2c *bus,
+					enum smb_state_ind op_status, u16 info);
+
+
+
+static inline void _npcm7xx_get_time_stamp(u32 *time_quad0, u32 *time_quad1);
+static inline u32  _npcm7xx_delay_relative(u32 us_delay, u32 t0_time0,
+						u32 t0_time1);
+
+
+static inline void _npcm7xx_get_time_stamp(u32 *time_quad0, u32 *time_quad1)
+{
+	u32 seconds, seconds_last;
+	u32 ref_clock;
+
+	regmap_read(clk_regmap, NPCM7XX_SECCNT, &seconds_last);
+
+	do {
+		regmap_read(clk_regmap, NPCM7XX_SECCNT, &seconds);
+		regmap_read(clk_regmap, NPCM7XX_CNTR25M, &ref_clock);
+		regmap_read(clk_regmap, NPCM7XX_SECCNT, &seconds_last);
+	} while (seconds_last != seconds);
+
+	*time_quad0 = ref_clock;
+	*time_quad1 = seconds;
+}
+
+#define EXT_CLOCK_FREQUENCY_MHZ 25
+#define	 CNTR25M_ACCURECY  EXT_CLOCK_FREQUENCY_MHZ  // minimum accurecy
+
+
+
+// Function:	 _npcm7xx_delay_relative
+// Parameters:
+//		 us_delay -  number of microseconds to delay since t0_time.
+//				  if zero: no delay.
+//
+//		t0_time	      - start time , to measure time from.
+// get a time stamp, delay us_delay from it. If us_delay has already passed
+// since the time stamp , then no delay is executed. returns the time elapsed
+// since t0_time
+
+static inline u32 _npcm7xx_delay_relative(u32 us_delay, u32 t0_time0,
+			u32 t0_time1){
+
+	u32 iUsCnt2_0, iUsCnt2_1;
+	u32 timeElapsedSince;  // Acctual delay generated by FW
+	u32 minimum_delay = (us_delay * EXT_CLOCK_FREQUENCY_MHZ)
+		+ CNTR25M_ACCURECY;
+
+	// this is equivalent to microSec/0.64 + minimal tic length.
+	do {
+		_npcm7xx_get_time_stamp(&iUsCnt2_0, &iUsCnt2_1);
+		timeElapsedSince = ((EXT_CLOCK_FREQUENCY_MHZ*_1MHz_)*
+				    (iUsCnt2_1 - t0_time1)) +
+				    (iUsCnt2_0 - t0_time0);
+	} while (timeElapsedSince < minimum_delay);
+
+	// return elapsed time
+	return (u32)(timeElapsedSince / EXT_CLOCK_FREQUENCY_MHZ);
+}
+
+
+
+static inline void NPCM7XX_smb_write_byte(struct NPCM7XX_i2c *bus, u8 data)
+{
+	I2C_DEBUG2("\t\tSDA master bus%d wr 0x%x\n", bus->num, data);
+
+	iowrite8(data, NPCM7XX_SMBSDA(bus));
+	NPCM7XX_smb_calc_PEC(bus, data);
+}
+
+static inline bool NPCM7XX_smb_read_byte(struct NPCM7XX_i2c *bus, u8 *data)
+{
+	*data = ioread8(NPCM7XX_SMBSDA(bus));
+	I2C_DEBUG2("\t\tSDA master bus%d rd 0x%x\n", bus->num, *data);
+	NPCM7XX_smb_calc_PEC(bus, *data);
+	return true;
+}
+
+static inline void NPCM7XX_smb_select_bank(struct NPCM7XX_i2c *bus,
+						enum smb_bank  bank)
+{
+	if (bus->fifo_use == true)
+		iowrite8((ioread8(NPCM7XX_SMBCTL3(bus)) & ~SMBCTL3_BNK_SEL) |
+		FIELD_PREP(SMBCTL3_BNK_SEL, bank), NPCM7XX_SMBCTL3(bus));
+}
+
+
+static inline u16 NPCM7XX_smb_get_index(struct NPCM7XX_i2c *bus)
+{
+	u16 index = 0;
+
+	if (bus->operation == SMB_READ_OPER)
+		index = bus->rd_ind;
+	else if (bus->operation == SMB_WRITE_OPER)
+		index = bus->wr_ind;
+
+	return index;
+}
+
+
+
+static inline void NPCM7XX_smb_master_start(struct NPCM7XX_i2c *bus)
+{
+	NPCM7XX_I2C_EVENT_LOG(NPCM7XX_I2C_EVENT_START);
+
+	iowrite8(ioread8(NPCM7XX_SMBCTL1(bus)) | NPCM7XX_SMBCTL1_START,
+		 NPCM7XX_SMBCTL1(bus));
+
+}
+
+static inline void NPCM7XX_smb_master_stop(struct NPCM7XX_i2c *bus)
+{
+	NPCM7XX_I2C_EVENT_LOG(NPCM7XX_I2C_EVENT_STOP);
+
+#ifdef SMB_SW_BYPASS_HW_ISSUE_SMB_STOP
+	// override HW issue: SMBus may fail to supply stop condition in Master
+	// Write operation.
+	// Need to delay at least 5 us from the last int, before issueing a stop
+	_npcm7xx_delay_relative(5, bus->int_time_stamp[0],
+					bus->int_time_stamp[1]);
+
+#endif //   SMB_SW_BYPASS_HW_ISSUE_SMB_STOP
+
+	iowrite8(ioread8(NPCM7XX_SMBCTL1(bus)) | NPCM7XX_SMBCTL1_STOP,
+		 NPCM7XX_SMBCTL1(bus));
+
+
+	if (bus->fifo_use) {
+		NPCM7XX_smb_select_bank(bus, SMB_BANK_1);
+
+		NPCM7XX_smb_clear_rx_fifo(bus);
+
+		iowrite8(ioread8(NPCM7XX_SMBFIF_CTS(bus)) |
+				 NPCM7XX_SMBFIF_CTS_SLVRSTR |
+				 NPCM7XX_SMBFIF_CTS_RXF_TXE,
+				 NPCM7XX_SMBFIF_CTS(bus));
+
+		iowrite8(0, NPCM7XX_SMBTXF_CTL(bus));
+	}
+
+
+}
+
+static inline void NPCM7XX_smb_abort_data(struct NPCM7XX_i2c *bus)
+{
+	unsigned int timeout = ABORT_TIMEOUT;
+
+	NPCM7XX_I2C_EVENT_LOG(NPCM7XX_I2C_EVENT_ABORT);
+
+	// Generate a STOP condition
+	NPCM7XX_smb_master_stop(bus);
+
+	// Clear NEGACK, STASTR and BER bits
+	iowrite8(NPCM7XX_SMBST_STASTR | NPCM7XX_SMBST_NEGACK |
+		NPCM7XX_SMBST_BER, NPCM7XX_SMBST(bus));
+
+	// Wait till STOP condition is generated
+	while (FIELD_GET(NPCM7XX_SMBCTL1_STOP, ioread8(NPCM7XX_SMBCTL1(bus)))) {
+		timeout--;
+		if (!FIELD_GET(NPCM7XX_SMBCTL1_STOP,
+				ioread8(NPCM7XX_SMBCTL1(bus))))
+			break;
+		if (timeout <= 1) {
+			dev_err(bus->dev, "%s, abort timeout!\n", __func__);
+			break;
+		}
+	}
+}
+
+
+static inline void NPCM7XX_smb_stall_after_start(struct NPCM7XX_i2c *bus,
+			bool stall)
+{
+	I2C_DEBUG2("\t\tSDA stall bus%d\n", bus->num);
+	iowrite8((ioread8(NPCM7XX_SMBCTL1(bus))
+		& ~NPCM7XX_SMBCTL1_STASTRE)
+		| FIELD_PREP(NPCM7XX_SMBCTL1_STASTRE, stall),
+		NPCM7XX_SMBCTL1(bus));
+}
+
+static inline void NPCM7XX_smb_nack(struct NPCM7XX_i2c *bus)
+{
+	if (bus->rd_ind < (bus->rd_size - 1))
+		dev_info(bus->dev,
+			"\tNACK err bus%d, SA=0x%x, rd(%d\%d), op=%d st=%d\n",
+			bus->num, bus->dest_addr, bus->rd_ind, bus->rd_size,
+			bus->operation, bus->state);
+	iowrite8(ioread8(NPCM7XX_SMBCTL1(bus)) | NPCM7XX_SMBCTL1_ACK,
+		 NPCM7XX_SMBCTL1(bus));
+}
+
+
+static void NPCM7XX_smb_disable(struct NPCM7XX_i2c *bus)
+{
+	int i;
+
+	// select bank 0 for SMB addresses
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_0);
+
+	// Slave Addresses Removal
+	for (i = SMB_SLAVE_ADDR1; i < SMB_NUM_OF_ADDR; i++)
+		iowrite8(0, NPCM7XX_SMBADDR(bus, i));
+
+	// select bank 0 for SMB addresses
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_1);
+
+
+	// Disable module.
+	iowrite8((ioread8(NPCM7XX_SMBCTL2(bus))	& ~SMBCTL2_ENABLE),
+			NPCM7XX_SMBCTL2(bus));
+
+	// Set module disable
+	bus->state = SMB_DISABLE;
+}
+
+static void NPCM7XX_smb_enable(struct NPCM7XX_i2c *bus)
+{
+	iowrite8((ioread8(NPCM7XX_SMBCTL2(bus)) | SMBCTL2_ENABLE),
+			NPCM7XX_SMBCTL2(bus));
+}
+
+static bool NPCM7XX_smb_init_module(struct NPCM7XX_i2c *bus, enum smb_mode mode,
+				    u16 bus_freq)
+{
+	// Check whether module already enabled or frequency is out of bounds
+	if (((bus->state != SMB_DISABLE) &&
+		(bus->state != SMB_IDLE)) ||
+		(bus_freq < SMBUS_FREQ_MIN) || (bus_freq > SMBUS_FREQ_MAX))
+		return false;
+
+
+	// Configure FIFO disabled mode so slave will not use fifo
+	// (maste will set it on if supported)
+	bus->threshold_fifo = SMBUS_FIFO_SIZE;
+	iowrite8(ioread8(NPCM7XX_SMBFIF_CTL(bus)) & ~NPCM7XX_SMBFIF_CTL_FIFO_EN,
+		 NPCM7XX_SMBFIF_CTL(bus));
+
+	bus->fifo_use = false;
+
+	// Configure SMB module clock frequency
+	if (!NPCM7XX_smb_init_clk(bus, mode, bus_freq)) {
+		pr_err("NPCM7XX_smb_init_clk failed\n");
+		return false;
+	}
+
+	NPCM7XX_smb_disable(bus);
+
+	// Enable module (before configuring CTL1)
+	NPCM7XX_smb_enable(bus);
+
+	bus->state = SMB_IDLE;
+
+	// Enable SMB int and New Address Match int source
+	iowrite8((ioread8(NPCM7XX_SMBCTL1(bus)) | NPCM7XX_SMBCTL1_NMINTE),
+				NPCM7XX_SMBCTL1(bus));
+
+	NPCM7XX_smb_int_enable(bus, true);
+
+	return true;
+}
+
+static bool NPCM7XX_smb_master_start_xmit(struct NPCM7XX_i2c *bus,
+					  u8 slave_addr, u16 nwrite, u16 nread,
+					  u8 *write_data, u8 *read_data,
+					  bool use_PEC)
+{
+	//
+	// Allow only if bus is not busy
+	//
+	if ((bus->state != SMB_IDLE)
+	    ||
+	    ((nwrite >= 32*1024)
+	    && (nwrite != SMB_QUICK_PROT)) ||
+	    ((nread >= 32*1024) && (nread != SMB_BLOCK_PROT)
+	    && (nread != SMB_QUICK_PROT))
+
+	    )	{
+		dev_info(bus->dev, "\tbus%d->state != SMB_IDLE\n", bus->num);
+		return false;
+	}
+
+	// Configure FIFO mode :
+	if (FIELD_GET(SMB_VER_FIFO_EN, ioread8(SMB_VER(bus)))) {
+		bus->fifo_use = true;
+		iowrite8(ioread8(NPCM7XX_SMBFIF_CTL(bus)) |
+			NPCM7XX_SMBFIF_CTL_FIFO_EN, NPCM7XX_SMBFIF_CTL(bus));
+	} else
+		bus->fifo_use = false;
+
+	// Update driver state
+	bus->master_or_slave = SMB_MASTER;
+	bus->state = SMB_MASTER_START;
+	if (nwrite > 0)
+		bus->operation = SMB_WRITE_OPER;
+	else
+		bus->operation = SMB_READ_OPER;
+
+
+	if ((nwrite == 0) && (nread == 0))
+		nwrite = nread = SMB_QUICK_PROT;
+
+	bus->dest_addr = (u8)(slave_addr << 1);// Translate 7bit to 8bit format
+	bus->wr_data_buf = write_data;
+	bus->wr_size = nwrite;
+	bus->wr_ind = 0;
+	bus->rd_data_buf = read_data;
+	bus->rd_size = nread;
+	bus->rd_ind = 0;
+	bus->PEC_use = use_PEC;
+	bus->read_block_use = false;
+	bus->retry_count = SMB_RETRY_MAX_COUNT;
+
+	// Check if transaction uses Block read protocol
+	if ((bus->rd_size == SMB_BLOCK_PROT) ||
+	    (bus->rd_size == SMB_EXCLUDE_BLOCK_SIZE_FROM_BUF)) {
+		bus->read_block_use = true;
+
+		// Change nread in order to configure receive threshold to 1
+		nread = 1;
+	}
+
+	// clear BER just in case it is set due to a previous transaction
+	iowrite8(NPCM7XX_SMBST_BER, NPCM7XX_SMBST(bus));
+
+
+	// Initiate SMBus master transaction
+	// Generate a Start condition on the SMBus
+	if (bus->fifo_use == true) {
+		// select bank 1 for FIFO regs
+		NPCM7XX_smb_select_bank(bus, SMB_BANK_1);
+
+		// clear FIFO and relevant status bits.
+		iowrite8(ioread8(NPCM7XX_SMBFIF_CTS(bus))
+			 | NPCM7XX_SMBFIF_CTS_SLVRSTR
+			 | NPCM7XX_SMBFIF_CTS_CLR_FIFO
+			 | NPCM7XX_SMBFIF_CTS_RXF_TXE, NPCM7XX_SMBFIF_CTS(bus));
+
+		if (bus->operation == SMB_READ_OPER) {
+			//This is a read only operation. Configure the FIFO
+			//threshold according to the needed # of bytes to read.
+
+			NPCM7XX_smb_set_fifo(bus, nread, -1);
+
+		} else if (bus->operation == SMB_WRITE_OPER) {
+			NPCM7XX_smb_set_fifo(bus, -1, nwrite);
+		}
+	}
+
+	bus->int_cnt = 100;
+	bus->event_log = 0;
+
+	NPCM7XX_smb_master_start(bus);
+
+	return true;
+}
+
+
+// enable\disable end of busy (EOB) interrupt
+static inline void NPCM7XX_smb_eob_int(struct NPCM7XX_i2c *bus, bool enable)
+{
+	if (enable == true)
+		iowrite8(ioread8(NPCM7XX_SMBCTL1(bus)) |
+			NPCM7XX_SMBCTL1_EOBINTE, NPCM7XX_SMBCTL1(bus));
+	else {
+		iowrite8(ioread8(NPCM7XX_SMBCTL1(bus)) &
+			(~NPCM7XX_SMBCTL1_EOBINTE), NPCM7XX_SMBCTL1(bus));
+
+		// Clear EO_BUSY pending bit:
+		iowrite8(ioread8(NPCM7XX_SMBCST3(bus)) |
+			NPCM7XX_SMBCST3_EO_BUSY, NPCM7XX_SMBCST3(bus));
+	}
+}
+
+
+static inline bool NPCM7XX_smb_tx_fifo_full(struct NPCM7XX_i2c *bus)
+{
+	// check if TX FIFO full:
+	return (bool)FIELD_GET(NPCM7XX_SMBTXF_STS_TX_THST,
+			ioread8(NPCM7XX_SMBTXF_STS(bus)));
+}
+
+
+static inline bool NPCM7XX_smb_rx_fifo_full(struct NPCM7XX_i2c *bus)
+{
+	// check if RX FIFO full:
+	return (bool)FIELD_GET(NPCM7XX_SMBRXF_STS_RX_THST,
+			ioread8(NPCM7XX_SMBRXF_STS(bus)));
+}
+
+static inline void NPCM7XX_smb_clear_tx_fifo(struct NPCM7XX_i2c *bus)
+{
+	// clear TX FIFO:
+	iowrite8(ioread8(NPCM7XX_SMBTXF_STS(bus)) |
+		 NPCM7XX_SMBTXF_STS_TX_THST,
+		 NPCM7XX_SMBTXF_STS(bus));
+}
+
+
+static inline void NPCM7XX_smb_clear_rx_fifo(struct NPCM7XX_i2c *bus)
+{
+	// clear RX FIFO:
+	iowrite8(ioread8(NPCM7XX_SMBRXF_STS(bus)) |
+			 NPCM7XX_SMBRXF_STS_RX_THST,
+			 NPCM7XX_SMBRXF_STS(bus));
+}
+
+
+
+// configure the FIFO before using it. If nread is -1 RX FIFO will not be
+// configured. same for	nwrite
+static void NPCM7XX_smb_set_fifo(struct NPCM7XX_i2c *bus, int nread,
+			int nwrite)
+{
+	if (bus->fifo_use == false)
+		return;
+
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_1);
+
+	NPCM7XX_smb_clear_tx_fifo(bus);
+	NPCM7XX_smb_clear_rx_fifo(bus);
+
+	// configure RX FIFO
+	if (nread > 0) {
+		// clear LAST bit:
+		iowrite8(ioread8(NPCM7XX_SMBRXF_CTL(bus)) &
+					(~NPCM7XX_SMBRXF_CTL_LAST_PEC),
+					NPCM7XX_SMBRXF_CTL(bus));
+
+
+		if (nread > SMBUS_FIFO_SIZE && (nread != SMB_QUICK_PROT))
+			iowrite8((ioread8(NPCM7XX_SMBRXF_CTL(bus)) &
+				~NPCM7XX_SMBRXF_CTL_RX_THR)
+				| FIELD_PREP(NPCM7XX_SMBRXF_CTL_RX_THR,
+				SMBUS_FIFO_SIZE), NPCM7XX_SMBRXF_CTL(bus));
+		else {
+			iowrite8((ioread8(NPCM7XX_SMBRXF_CTL(bus)) &
+				~NPCM7XX_SMBRXF_CTL_RX_THR)
+				| FIELD_PREP(NPCM7XX_SMBRXF_CTL_RX_THR,
+				(u8)(nread)), NPCM7XX_SMBRXF_CTL(bus));
+		}
+		if ((nread <= SMBUS_FIFO_SIZE)	 &&
+		    (bus->rd_size != SMB_BLOCK_PROT) &&
+		    (bus->rd_size != SMB_EXCLUDE_BLOCK_SIZE_FROM_BUF))
+			iowrite8(ioread8(NPCM7XX_SMBRXF_CTL(bus)) |
+				NPCM7XX_SMBRXF_CTL_LAST_PEC,
+				NPCM7XX_SMBRXF_CTL(bus));
+
+	}
+
+
+
+	// configure TX FIFO
+	if (nwrite > 0) {
+
+		if (nwrite > SMBUS_FIFO_SIZE)
+			// data to send is more then FIFO size.
+			// Configure the FIFO int to be mid of FIFO.
+			iowrite8(NPCM7XX_SMBTXF_CTL_THR_TXIE |
+				(SMBUS_FIFO_SIZE / 2),
+				NPCM7XX_SMBTXF_CTL(bus));
+		else if ((nwrite > SMBUS_FIFO_SIZE / 2) &&
+					(bus->wr_ind != 0))
+			// wr_ind != 0 means that this is not the first
+			// write. since int is in the mid of FIFO, only
+			// half of the fifo is empty.
+			// Continue to configure the FIFO int to be mid
+			// of FIFO.
+			iowrite8(NPCM7XX_SMBTXF_CTL_THR_TXIE |
+					(SMBUS_FIFO_SIZE / 2),
+					NPCM7XX_SMBTXF_CTL(bus));
+		else {
+
+			// This is the either first write (wr_ind = 0)
+			// and data to send is less or equal to FIFO
+			// size.
+			// Or this is the last write and data to send
+			// is less or equal half FIFO size.
+			// In both cases disable the FIFO threshold int.
+			// The next int will happen after the FIFO will
+			// get empty.
+			iowrite8((u8)0, NPCM7XX_SMBTXF_CTL(bus));
+		}
+
+		NPCM7XX_smb_clear_tx_fifo(bus);
+	}
+
+}
+
+static
+void NPCM7XX_smb_read_from_fifo(struct NPCM7XX_i2c *bus, u8 bytes_in_fifo)
+{
+	while (bytes_in_fifo--) {
+		// Keep read data
+		u8 data = ioread8(NPCM7XX_SMBSDA(bus));
+
+		NPCM7XX_smb_calc_PEC(bus, data);
+		if (bus->rd_ind < bus->rd_size) {
+			bus->rd_data_buf[bus->rd_ind++] = data;
+			if ((bus->rd_ind == 1) &&
+			    (bus->rd_size == SMB_BLOCK_PROT))
+				// First byte indicates length in block protocol
+				bus->rd_size = data;
+		}
+	}
+}
+
+static void NPCM7XX_smb_master_fifo_read(struct NPCM7XX_i2c *bus)
+{
+	u16 rcount;
+	u8 fifo_bytes;
+	enum smb_state_ind ind = SMB_MASTER_DONE_IND;
+
+	rcount = bus->rd_size - bus->rd_ind;
+
+
+	// In order not to change the RX_TRH during transaction (we found that
+	// this might be problematic if it takes too much time to read the FIFO)
+	//  we read the data in the following way. If the number of bytes to
+	// read == FIFO Size + C (where C < FIFO Size)then first read C bytes
+	// and in the next int we read rest of the data.
+	if ((rcount < (2 * SMBUS_FIFO_SIZE)) && (rcount > SMBUS_FIFO_SIZE))
+		fifo_bytes = (u8)(rcount - SMBUS_FIFO_SIZE);
+	else
+		fifo_bytes = FIELD_GET(NPCM7XX_SMBRXF_STS_RX_BYTES, ioread8(
+		NPCM7XX_SMBRXF_STS(bus)));
+
+	if (rcount - fifo_bytes == 0) {
+		// last byte is about to be read - end of transaction.
+		// Stop should be set before reading last byte.
+		NPCM7XX_smb_eob_int(bus, true);
+
+		NPCM7XX_smb_master_stop(bus);
+
+		NPCM7XX_smb_read_from_fifo(bus, fifo_bytes);
+
+		if (NPCM7XX_smb_get_PEC(bus) != 0)
+			ind = SMB_MASTER_PEC_ERR_IND;
+		bus->state = SMB_STOP_PENDING;
+		bus->stop_ind = ind;
+
+	} else {
+		NPCM7XX_smb_read_from_fifo(bus, fifo_bytes);
+		rcount = bus->rd_size - bus->rd_ind;
+
+		NPCM7XX_smb_set_fifo(bus, rcount, -1);
+	}
+
+}
+
+
+static void NPCM7XX_smb_write_to_fifo(struct NPCM7XX_i2c *bus,
+				      u16 max_bytes_to_send)
+{
+	dev_dbg(bus->dev, "SDA master bus%d fifo wr %d bytes\n", bus->num,
+		   max_bytes_to_send);
+
+	// Fill the FIFO, while the FIFO is not full and there are more bytes to
+	// write
+	while ((max_bytes_to_send--) && (SMBUS_FIFO_SIZE -
+		FIELD_GET(NPCM7XX_SMBTXF_STS_TX_BYTES,
+		ioread8(NPCM7XX_SMBTXF_STS(bus))))) {
+		// write the data
+		if (bus->wr_ind < bus->wr_size) {
+			if ((bus->PEC_use == true) &&
+			    ((bus->wr_ind + 1) == bus->wr_size) &&
+			    ((bus->rd_size == 0) ||
+			    (bus->master_or_slave == SMB_SLAVE))) {
+				// Master send PEC in write protocol, Slave send
+				// PEC in read protocol.
+				NPCM7XX_smb_write_PEC(bus);
+				bus->wr_ind++;
+			} else
+				NPCM7XX_smb_write_byte(bus,
+					bus->wr_data_buf[bus->wr_ind++]);
+		} else {
+
+#ifdef SMB_WRAP_AROUND_BUFFER
+			// We're out of bytes. Ask the higher level for
+			// more bytes. Let it know that driver
+			// used all its' bytes
+
+			NPCM7XX_smb_clear_tx_fifo(bus);
+
+			// Reset state for the remaining bytes transaction
+			bus->state = SMB_SLAVE_MATCH;
+
+			// Notify upper layer of transaction completion
+			NPCM7XX_smb_callback(bus,
+					SMB_SLAVE_XMIT_MISSING_DATA_IND,
+					bus->wr_ind);
+
+			iowrite8(NPCM7XX_SMBST_SDAST, NPCM7XX_SMBST(bus));
+#else
+			NPCM7XX_smb_write_byte(bus, 0xFF);
+#endif
+		}
+	}
+}
+
+
+static bool NPCM7XX_smb_init_clk(struct NPCM7XX_i2c *bus, enum smb_mode mode,
+				 u16 bus_freq)
+{
+	u16  k1 = 0;
+	u16  k2 = 0;
+	u8   dbnct = 0;
+	u16  sclfrq = 0;
+	u8   hldt = 7;
+	bool fastMode = false;
+	u32  source_clock_freq;
+
+	source_clock_freq = bus->apb_clk;
+
+
+	// Frequency is less or equal to 100 KHz
+	if (bus_freq <= SMBUS_FREQ_100KHz) {
+		// Set frequency (in khz):
+		// SCLFRQ = T(SCL)/4/T(CLK) =
+		// FREQ(CLK)/4/FREQ(SCL) = FREQ(CLK) / ( FREQ(SCL)*4 )
+		sclfrq = (u16)((source_clock_freq /
+				((u32)bus_freq * _1KHz_ * 4)));
+
+		// Check whether requested freq can be achieved in current CLK
+		if ((sclfrq < SCLFRQ_MIN) || (sclfrq > SCLFRQ_MAX))
+			return false;
+
+		if (source_clock_freq >= 40000000)
+			hldt = 17;
+		else if (source_clock_freq >= 12500000)
+			hldt = 15;
+		else
+			hldt = 7;
+	}
+
+	// Frequency equal to 400 KHz
+	else if (bus_freq == SMBUS_FREQ_400KHz) {
+		sclfrq = 0;
+		fastMode = true;
+
+		if ((mode == SMB_MASTER && source_clock_freq < 7500000) ||
+		   (mode == SMB_SLAVE && source_clock_freq < 10000000))
+		  // 400KHz cannot be supported for master core clock < 7.5 MHz
+		  // or slave core clock < 10 MHz
+			return false;
+
+		// Master or Slave with frequency > 25 MHz
+		if (mode == SMB_MASTER || source_clock_freq > 25000000) {
+			// Set HLDT:
+			// SDA hold time:  (HLDT-7) * T(CLK) >= 300
+			// HLDT = 300/T(CLK) + 7 = 300 * FREQ(CLK) + 7
+			hldt = (u8)DIV_CEILING((300 *
+				(source_clock_freq / _1KHz_)), (_1MHz_)) + 7;
+
+			if (mode == SMB_MASTER) {
+				// Set k1:
+				// clk low time: k1 * T(CLK) - T(SMBFO) >= 1300
+				// T(SMBRO) = T(SMBFO) = 300
+				// k1 = (1300 + T(SMBFO)) / T(CLK) =
+				//			1600 * FREQ(CLK)
+				k1 = ROUND_UP(((u16)DIV_CEILING((1600 *
+					(source_clock_freq / _1KHz_)),
+					(_1MHz_))), 2);
+
+				// Set k2:
+				// setup: (k2 - 1) * T(CLK) - T(SMBFO) >= 600
+				// T(SMBRO) = T(SMBFO) = 300
+				// k2 = (600 + T(SMBFO)) / T(CLK) + 1 = 900 *
+				// FREQ(CLK) + 1
+				k2 = ROUND_UP(((u16)DIV_CEILING(
+					(900 *  (source_clock_freq / _1KHz_)),
+					(_1MHz_)) + 1), 2);
+
+				// Check whether requested frequency can be
+				// achieved in current CLK
+				if ((k1 < SCLFRQ_MIN) || (k1 > SCLFRQ_MAX) ||
+				    (k2 < SCLFRQ_MIN) || (k2 > SCLFRQ_MAX))
+					return false;
+			}
+		} else { // Slave with frequency 10-25 MHz
+			hldt = 7;
+			dbnct = 2;
+		}
+	}
+
+	// Frequency equal to 1 MHz
+	else if (bus_freq == SMBUS_FREQ_1MHz) {
+		sclfrq = 0;
+		fastMode = true;
+
+		if ((mode == SMB_MASTER && source_clock_freq < 15000000) ||
+		    (mode == SMB_SLAVE	&& source_clock_freq < 24000000))
+		// 1MHz cannot be supported for master core clock < 15 MHz
+		// or slave core clock < 24 MHz
+			return false;
+
+		// Master or Slave with frequency > 40 MHz
+		if (mode == SMB_MASTER || source_clock_freq > 40000000) {
+
+			// Set HLDT:
+			// SDA hold time:  (HLDT-7) * T(CLK) >= 120
+			// HLDT = 120/T(CLK) + 7 = 120 * FREQ(CLK) + 7
+			hldt = (u8)DIV_CEILING((120 *
+				(source_clock_freq / _1KHz_)),
+				((u32)_1MHz_)) + 7;
+
+			if (mode == SMB_MASTER) {
+
+				// Set k1:
+				// clk low time: k1 * T(CLK) - T(SMBFO) >= 500
+				// T(SMBRO) = T(SMBFO) = 120
+				// k1 = (500 + T(SMBFO)) / T(CLK) = 620 * FREQ
+				k1 = ROUND_UP(((u16)DIV_CEILING((620 *
+					(source_clock_freq / _1KHz_)),
+					((u32)_1MHz_))), 2);
+
+
+				// Set k2:
+				// START setup: (k2 - 1) * T - T(SMBFO) >= 260
+				// T(SMBRO) = T(SMBFO) = 120
+				// k2 = (260 + T(SMBFO)) / T + 1 = 380 *
+				// FREQ(CLK) + 1
+				k2 = ROUND_UP(((u16)DIV_CEILING((380
+					* (source_clock_freq / _1KHz_)),
+					((u32)_1MHz_))
+					+ 1), 2);
+
+
+				// Check whether requested frequency can be
+				// achieved in current CLK
+				if ((k1 < SCLFRQ_MIN) || (k1 > SCLFRQ_MAX) ||
+				    (k2 < SCLFRQ_MIN) || (k2 > SCLFRQ_MAX)) {
+					return false;
+				}
+			}
+		// Slave with frequency 24-40 MHz
+		} else {
+			hldt = 7;
+			dbnct = 2;
+		}
+	}
+
+	// Frequency larger than 1 MHz
+	else
+		return false;
+
+
+
+	// After clock parameters calculation update the reg
+	iowrite8((ioread8(NPCM7XX_SMBCTL2(bus))
+		& ~SMBCTL2_SCLFRQ6_0) | FIELD_PREP(SMBCTL2_SCLFRQ6_0,
+		sclfrq & 0x7F), NPCM7XX_SMBCTL2(bus));
+
+	iowrite8((ioread8(NPCM7XX_SMBCTL3(bus)) & ~SMBCTL3_SCLFRQ8_7) |
+		 FIELD_PREP(SMBCTL3_SCLFRQ8_7,
+		 (sclfrq >> 7) & 0x3), NPCM7XX_SMBCTL3(bus));
+
+	iowrite8((ioread8(NPCM7XX_SMBCTL3(bus))
+		& ~SMBCTL3_400K_MODE) | FIELD_PREP(SMBCTL3_400K_MODE,
+		fastMode), NPCM7XX_SMBCTL3(bus));
+
+	iowrite8((ioread8(NPCM7XX_SMBCTL3(bus)) & ~SMBCTL3_400K_MODE) |
+		 FIELD_PREP(SMBCTL3_400K_MODE, fastMode), NPCM7XX_SMBCTL3(bus));
+
+
+	// Select Bank 0 to access NPCM7XX_SMBCTL4/NPCM7XX_SMBCTL5
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_0);
+
+	if (bus_freq >= SMBUS_FREQ_400KHz) {
+
+		// k1 and k2 are relevant for master mode only
+		if (mode == SMB_MASTER) {
+
+			// Set SCL Low/High Time:
+			// k1 = 2 * SCLLT7-0 -> Low Time  = k1 / 2
+			// k2 = 2 * SCLLT7-0 -> High Time = k2 / 2
+			iowrite8((u8)k1 / 2, NPCM7XX_SMBSCLLT(bus));
+			iowrite8((u8)k2 / 2, NPCM7XX_SMBSCLHT(bus));
+		} else // DBNCT is relevant for slave mode only
+			iowrite8((ioread8(NPCM7XX_SMBCTL5(bus)) &
+			   ~SMBCTL5_DBNCT) | FIELD_PREP(SMBCTL5_DBNCT, dbnct),
+			NPCM7XX_SMBCTL5(bus));
+	}
+
+	iowrite8((ioread8(NPCM7XX_SMBCTL4(bus)) & ~SMBCTL4_HLDT)
+		 | FIELD_PREP(SMBCTL4_HLDT,
+		 hldt), NPCM7XX_SMBCTL4(bus));
+
+	// Return to Bank 1
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_1);
+
+	return true;
+}
+
+
+#if defined(SMB_CAPABILITY_TIMEOUT_SUPPORT)
+static void NPCM7XX_smb_enable_timeout(struct NPCM7XX_i2c *bus, bool enable)
+{
+	u8 toCkDiv;
+	u8 smbEnabled;
+	u8 smbctl1 = 0;
+
+	dev_info(bus->dev, "SDA master bus%d enable TO %d\n", bus->num, enable);
+
+	if (enable) {
+
+		// TO_CKDIV may be changed only when the SMB is disabled
+		smbEnabled = FIELD_GET(SMBCTL2_ENABLE,
+				ioread8(NPCM7XX_SMBCTL2(bus)));
+
+		// If SMB is enabled - disable the SMB module
+		if (smbEnabled) {
+
+			// Save NPCM7XX_SMBCTL1 relevant bits. It is being
+			// cleared when the module is disabled
+			smbctl1 = ioread8(NPCM7XX_SMBCTL1(bus)) &
+				(NPCM7XX_SMBCTL1_GCMEN
+				NPCM7XX_SMBCTL1_INTEN
+				| NPCM7XX_SMBCTL1_NMINTE);
+
+			// Disable the SMB module
+			iowrite8(ioread8(NPCM7XX_SMBCTL2(bus) &
+				~SMBCTL2_ENABLE), NPCM7XX_SMBCTL2(bus));
+		}
+
+		// Clear EO_BUSY pending bit
+		iowrite8(ioread8(NPCM7XX_SMBT_OUT(bus))|
+			NPCM7XX_SMBT_OUT_T_OUTST,
+			 NPCM7XX_SMBT_OUT(bus));
+
+		// Configure the division of the SMB Module Basic clock (BCLK)
+		// to generate the 1 KHz clock of the timeout detector.
+		// The timeout detector has an “n+1” divider, controlled
+		// by TO_CKDIV and a fixed divider by 1000.
+		// Together they generate the 1 ms clock cycle
+		toCkDiv = (u8)(((bus->apb_clk / _1KHz_) / 1000) - 1);
+
+		// Set the bus timeout clock divisor
+		iowrite8((ioread8(NPCM7XX_SMBT_OUT(bus)) &
+			~NPCM7XX_SMBT_OUT_TO_CKDIV)
+			| FIELD_PREP(NPCM7XX_SMBT_OUT_TO_CKDIV,
+			toCkDiv), NPCM7XX_SMBT_OUT(bus));
+
+		// If SMB was enabled - re-enable the SMB module
+		if (smbEnabled) {
+
+			// Enable the SMB module
+			NPCM7XX_smb_enable(bus);
+
+			// Restore NPCM7XX_SMBCTL1 status
+			iowrite8(smbctl1, NPCM7XX_SMBCTL1(bus));
+		}
+	}
+
+
+	// Enable/Disable the bus timeout int
+	iowrite8((ioread8(NPCM7XX_SMBT_OUT(bus)) & ~NPCM7XX_SMBT_OUT_T_OUTIE)
+		 | FIELD_PREP(NPCM7XX_SMBT_OUT_T_OUTIE,
+		 enable), NPCM7XX_SMBT_OUT(bus));
+}
+#endif
+
+static void NPCM7XX_smb_int_master_handler(struct NPCM7XX_i2c *bus)
+{
+
+	// A negative acknowledge has occurred
+	if (FIELD_GET(NPCM7XX_SMBST_NEGACK, ioread8(NPCM7XX_SMBST(bus)))) {
+		dev_dbg(bus->dev, "NACK bus = %d\n", bus->num);
+		NPCM7XX_I2C_EVENT_LOG(NPCM7XX_I2C_EVENT_NACK);
+		if (bus->fifo_use) {
+			// if there are still untransmitted bytes in TX FIFO
+			// reduce them from wr_ind
+			bus->wr_ind -= FIELD_GET(NPCM7XX_SMBTXF_STS_TX_BYTES,
+					 ioread8(NPCM7XX_SMBTXF_STS(bus)));
+
+			dev_dbg(bus->dev, "NACK bus%d fifo, wr_ind = %d\n",
+					bus->num, bus->wr_ind);
+
+			// clear the FIFO
+			iowrite8(NPCM7XX_SMBFIF_CTS_CLR_FIFO,
+					NPCM7XX_SMBFIF_CTS(bus));
+		}
+
+		// In master write operation, NACK is a problem
+
+		// number of bytes sent to master less than required
+		// notify upper layer.
+		NPCM7XX_smb_master_abort(bus);
+
+		// iowrite8(NPCM7XX_SMBST_NEGACK, NPCM7XX_SMBST(bus));
+		bus->state = SMB_IDLE;
+
+		// In Master mode, NEGACK should be cleared only after
+		// generating STOP.
+		// In such case, the bus is released from stall only after the
+		// software clears NEGACK bit.
+		// Then a Stop condition is sent.
+		iowrite8(NPCM7XX_SMBST_NEGACK, NPCM7XX_SMBST(bus));
+
+		NPCM7XX_smb_callback(bus, SMB_NACK_IND, bus->wr_ind);
+
+		return;
+	}
+
+
+	// Master mode: a Bus Error has been identified
+	if (FIELD_GET(NPCM7XX_SMBST_BER, ioread8(NPCM7XX_SMBST(bus)))) {
+		// Check whether bus arbitration or Start or Stop during data
+		// xfer bus arbitration problem should not result in recovery
+		if (FIELD_GET(NPCM7XX_SMBST_MASTER,
+				ioread8(NPCM7XX_SMBST(bus))))
+			// Only current master is allowed to issue stop
+			NPCM7XX_smb_master_abort(bus);
+		else {
+
+			// Bus arbitration loss
+			if (bus->retry_count-- > 0) {
+				dev_info(bus->dev, "\tretry bus%d\n", bus->num);
+				// Perform a retry (generate a start condition
+				// as soon as the SMBus is free)
+				iowrite8(NPCM7XX_SMBST_BER, NPCM7XX_SMBST(bus));
+				NPCM7XX_smb_master_start(bus);
+				return;
+			}
+		}
+		iowrite8(NPCM7XX_SMBST_BER, NPCM7XX_SMBST(bus));
+		bus->state = SMB_IDLE;
+		NPCM7XX_smb_callback(bus, SMB_BUS_ERR_IND,
+						NPCM7XX_smb_get_index(bus));
+		return;
+	}
+
+#if defined(SMB_CAPABILITY_TIMEOUT_SUPPORT)
+	// A Bus Timeout has been identified
+	if ((FIELD_GET(NPCM7XX_SMBT_OUT_T_OUTIE,
+	     ioread8(NPCM7XX_SMBT_OUT(bus))) == 1)
+	     &&  // bus timeout int is on
+	     (FIELD_GET(NPCM7XX_SMBT_OUT_T_OUTST,
+	     // and bus timeout status is set
+	     ioread8(NPCM7XX_SMBT_OUT(bus))))) {
+		NPCM7XX_smb_master_abort(bus);
+		NPCM7XX_I2C_EVENT_LOG(NPCM7XX_I2C_EVENT_TO);
+		iowrite8(ioread8(NPCM7XX_SMBT_OUT(bus)) |
+			NPCM7XX_SMBT_OUT_T_OUTST,
+			NPCM7XX_SMBT_OUT(bus));// Clear EO_BUSY pending bit
+		bus->state = SMB_IDLE;
+		NPCM7XX_smb_callback(bus, SMB_BUS_ERR_IND,
+			NPCM7XX_smb_get_index(bus));
+		return;
+	}
+#endif
+
+
+	// A Master End of Busy (meaning Stop Condition happened)
+		// End of Busy int is on and End of Busy is set
+	if ((FIELD_GET(NPCM7XX_SMBCTL1_EOBINTE,
+			ioread8(NPCM7XX_SMBCTL1(bus))) == 1) &&
+	    (FIELD_GET(NPCM7XX_SMBCST3_EO_BUSY,
+			ioread8(NPCM7XX_SMBCST3(bus))))) {
+		dev_dbg(bus->dev, "End of busy bus = %d\n", bus->num);
+
+		NPCM7XX_I2C_EVENT_LOG(NPCM7XX_I2C_EVENT_EOB);
+
+		NPCM7XX_smb_eob_int(bus, false);
+
+		bus->state = SMB_IDLE;
+
+		if ((bus->wr_size == SMB_QUICK_PROT) ||
+		    (bus->rd_size == SMB_QUICK_PROT) ||
+		    (bus->rd_size == 0)) {
+			NPCM7XX_smb_callback(bus, bus->stop_ind, 0);
+		} else {
+			NPCM7XX_smb_callback(bus, bus->stop_ind, bus->rd_ind);
+		}
+		return;
+	}
+
+
+
+	// Address sent and requested stall occurred (Master mode)
+	if (FIELD_GET(NPCM7XX_SMBST_STASTR, ioread8(NPCM7XX_SMBST(bus)))) {
+		dev_dbg(bus->dev, "master stall bus = %d\n", bus->num);
+
+		ASSERT(FIELD_GET(NPCM7XX_SMBST_MASTER,
+			ioread8(NPCM7XX_SMBST(bus))));
+
+		// Check for Quick Command SMBus protocol (block protocol)
+		if ((bus->wr_size == SMB_QUICK_PROT)
+		    ||
+		    (bus->rd_size == SMB_QUICK_PROT)) {
+
+			// No need to write any data bytes -
+			//  reached here only in Quick Command
+			NPCM7XX_smb_eob_int(bus, true);
+
+			NPCM7XX_smb_master_stop(bus);
+
+			// Update status
+			bus->state = SMB_STOP_PENDING;
+			bus->stop_ind = SMB_MASTER_DONE_IND;
+
+		} else if (bus->rd_size == 1)
+
+			// Receiving one byte only - set NACK after ensuring
+			// slave ACKed the address byte
+			NPCM7XX_smb_nack(bus);
+
+		// Reset stall-after-address-byte
+		NPCM7XX_smb_stall_after_start(bus, false);
+
+		// Clear stall only after setting STOP
+		iowrite8(NPCM7XX_SMBST_STASTR, NPCM7XX_SMBST(bus));
+		return;
+	}
+
+
+	// SDA status is set - transmit or receive, master
+	if (FIELD_GET(NPCM7XX_SMBST_SDAST, ioread8(NPCM7XX_SMBST(bus))) ||
+			(bus->fifo_use &&
+			(NPCM7XX_smb_tx_fifo_full(bus) ||
+			NPCM7XX_smb_rx_fifo_full(bus)))) {
+
+		// Status Bit is cleared by writing to or reading from SDA
+		// (depending on current direction)
+		dev_dbg(bus->dev, "SDA set bus%d addr 0x%x state=%d op=%d\n",
+			  bus->num, bus->dest_addr, bus->state, bus->operation);
+
+		switch (bus->state) {
+
+		// Handle unsuccessful bus mastership
+		case SMB_IDLE:
+			NPCM7XX_smb_master_abort(bus);
+			return;
+
+		case SMB_MASTER_START:
+			if (FIELD_GET(NPCM7XX_SMBST_MASTER,
+				ioread8(NPCM7XX_SMBST(bus)))) {
+				u8 addr_byte = bus->dest_addr;
+
+				dev_dbg(bus->dev, "SDA master bus%d start\n",
+						bus->num);
+
+
+				bus->crc_data = 0;
+				// Check for Quick Command SMBus protocol
+				if ((bus->wr_size == SMB_QUICK_PROT)
+					|| (bus->rd_size == SMB_QUICK_PROT))
+				// Need to stall after successful completion
+				// of sending address byte
+					NPCM7XX_smb_stall_after_start(bus,
+									true);
+				// Prepare address byte
+				if (bus->wr_size == 0) {
+					if (bus->rd_size == 1)
+	// Receiving one byte only - stall after successful completion of
+	// sending address byte. If we NACK here, and slave doesn't ACK the
+	// address, we might unintentionally NACK the next multi-byte read
+						NPCM7XX_smb_stall_after_start(
+							bus, true);
+
+					// Set direction to Read
+					addr_byte |= (u8)0x1;
+					bus->operation = SMB_READ_OPER;
+				} else
+					bus->operation = SMB_WRITE_OPER;
+				// Write the address to the bus
+				bus->state = SMB_OPER_STARTED;
+				NPCM7XX_smb_write_byte(bus, addr_byte);
+			} else
+				dev_err(bus->dev,
+				   "SDA, bus%d is not master, wr %d 0x%x...\n",
+				   bus->num, bus->wr_size, bus->wr_data_buf[0]);
+			break;
+
+		// SDA status is set - transmit or receive: Handle master mode
+		case SMB_OPER_STARTED:
+			if (bus->operation == SMB_WRITE_OPER)
+				NPCM7XX_smb_int_master_handler_write(bus);
+
+			else if (bus->operation == SMB_READ_OPER)
+				NPCM7XX_smb_int_master_handler_read(bus);
+
+
+			else
+				pr_err("I2C%d: unknown operation state.\n",
+					bus->num);
+
+			break;
+		default:
+			dev_err(bus->dev, "master sda err on state machine\n");
+		}
+		// End of master operation: SDA status is set - tx or rx.
+	} //SDAST
+}
+
+
+static void NPCM7XX_smb_int_master_handler_write(struct NPCM7XX_i2c *bus)
+{
+	u16 wcount;
+
+	dev_dbg(bus->dev, "SDA master bus%d addr=0x%x oper wr\n", bus->num,
+			bus->dest_addr);
+	NPCM7XX_I2C_EVENT_LOG(NPCM7XX_I2C_EVENT_WRITE);
+
+	if (bus->fifo_use == true)
+		NPCM7XX_smb_clear_tx_fifo(bus);
+
+	// Master write operation - last byte handling
+	if (bus->wr_ind == bus->wr_size) {
+		dev_dbg(bus->dev, "SDA master bus%d addr 0x%x last byte\n",
+			   bus->num, bus->dest_addr);
+		if ((bus->fifo_use == true) &&
+			(FIELD_GET(NPCM7XX_SMBTXF_STS_TX_BYTES,
+			ioread8(NPCM7XX_SMBTXF_STS(bus))) > 0))
+	// No more bytes to send (to add to the FIFO), however the FIFO is not
+	// empty yet. It is still in the middle of tx. Currently there's nothing
+	// to do except for waiting to the end of the tx.
+	// We will get an int when the FIFO will get empty.
+			return;
+
+		if (bus->rd_size == 0) {
+			// all bytes have been written, in a pure wr operation
+			NPCM7XX_smb_eob_int(bus, true);
+
+			// Issue a STOP condition on the bus
+			NPCM7XX_smb_master_stop(bus);
+			// Clear SDA Status bit (by writing dummy byte)
+			NPCM7XX_smb_write_byte(bus, 0xFF);
+
+			bus->state = SMB_STOP_PENDING;
+			bus->stop_ind = SMB_MASTER_DONE_IND;
+		} else {
+			// last write-byte written on previous int - need to
+			// restart & send slave address
+			if ((bus->PEC_use == true) &&
+			    (bus->rd_size < SMB_EXCLUDE_BLOCK_SIZE_FROM_BUF))
+			    // PEC is used but the protocol is not block read
+			    // then we add extra bytes for PEC support
+				bus->rd_size += 1; // move this to xmit !!!
+
+			if (bus->fifo_use == true) {
+				if (((bus->rd_size == 1) ||
+					bus->rd_size ==
+					   SMB_EXCLUDE_BLOCK_SIZE_FROM_BUF ||
+					bus->rd_size == SMB_BLOCK_PROT)) {
+					// SMBus Block read transaction.
+
+					iowrite8(0, NPCM7XX_SMBTXF_CTL(bus));
+					iowrite8(1, NPCM7XX_SMBRXF_CTL(bus));
+
+
+				}
+			}
+
+			NPCM7XX_smb_set_fifo(bus, bus->rd_size, -1);
+
+			// Generate (Repeated) Start upon next write to SDA
+			NPCM7XX_smb_master_start(bus);
+
+			if (bus->rd_size == 1)
+
+	// Receiving one byte only - stall after successful completion of send
+	// address byte. If we NACK here, and slave doesn't ACK the address, we
+	// might unintentionally NACK the next multi-byte read
+
+				NPCM7XX_smb_stall_after_start(bus, true);
+
+			// send the slave address in read direction
+			NPCM7XX_smb_write_byte(bus, bus->dest_addr | 0x1);
+
+			// Next int will occur on read
+			bus->operation = SMB_READ_OPER;
+		}
+	} else {
+		if ((bus->PEC_use == true) && (bus->wr_ind == 0)
+		    && (bus->rd_size == 0))// extra bytes for PEC support
+			bus->wr_size += 1;
+
+		// write next byte not last byte and not slave address
+		if ((bus->fifo_use == false) || (bus->wr_size == 1)) {
+			if ((bus->PEC_use == true) && (bus->rd_size == 0) &&
+			    (bus->wr_ind + 1 == bus->wr_size)) {
+				// Master write protocol to send PEC byte.
+				NPCM7XX_smb_write_PEC(bus);
+				bus->wr_ind++;
+			} else
+				NPCM7XX_smb_write_byte(bus,
+					bus->wr_data_buf[bus->wr_ind++]);
+		} else { // FIFO is used
+			wcount = bus->wr_size - bus->wr_ind;
+			NPCM7XX_smb_set_fifo(bus, -1, wcount);
+
+			NPCM7XX_smb_write_to_fifo(bus, wcount);
+
+		}
+	}
+
+
+}
+
+static void NPCM7XX_smb_int_master_handler_read(struct NPCM7XX_i2c *bus)
+{
+	u16 block_zero_bytes;
+	// Master read operation (pure read or following a write operation).
+	NPCM7XX_I2C_EVENT_LOG(NPCM7XX_I2C_EVENT_READ);
+
+	if (bus->rd_ind > bus->rd_size)
+		dev_dbg(bus->dev, "SDA master bus%d addr=0x%x rd %d / %d\n",
+			bus->num, bus->dest_addr, bus->rd_ind, bus->rd_size);
+
+	// Initialize number of bytes to include only the first byte (presents
+	// a case where number of bytes to read is zero); add PEC if applicable
+	block_zero_bytes = 1;
+	if (bus->PEC_use == true)
+		block_zero_bytes++;
+
+	// Perform master read, distinguishing between last byte and the rest of
+	// the bytes. The last byte should be read when the clock is stopped
+	if ((bus->rd_ind < (bus->rd_size - 1)) ||  bus->fifo_use == true) {
+		u8 data;
+
+		dev_dbg(bus->dev, "SDA bus%d addr=0x%x oper rd last fifo\n",
+			   bus->num, bus->dest_addr);
+		// byte to be read is not the last one
+		// Check if byte-before-last is about to be read
+		if ((bus->rd_ind == (bus->rd_size - 2)) &&
+		    bus->fifo_use == false){
+
+			// Set nack before reading byte-before-last, so that
+			// nack will be generated after receive of last byte
+			NPCM7XX_smb_nack(bus);
+
+			if (!FIELD_GET(NPCM7XX_SMBST_SDAST,
+					ioread8(NPCM7XX_SMBST(bus)))) {
+				// No data available - reset state for new xfer
+				bus->state = SMB_IDLE;
+
+				// Notify upper layer of rx completion
+				NPCM7XX_smb_callback(bus, SMB_NO_DATA_IND,
+							bus->rd_ind);
+			}
+		} else if (bus->rd_ind == 0) { //first byte handling:
+			// in block protocol first byte is the size
+			if (bus->rd_size == SMB_EXCLUDE_BLOCK_SIZE_FROM_BUF ||
+			    bus->rd_size == SMB_BLOCK_PROT) {
+				(void)NPCM7XX_smb_read_byte(bus, &data);
+
+				// First byte indicates length in block protocol
+				if (bus->rd_size ==
+						SMB_EXCLUDE_BLOCK_SIZE_FROM_BUF)
+					bus->rd_size = data;
+				else {
+					bus->rd_data_buf[bus->rd_ind++] = data;
+					bus->rd_size = data + 1;
+				}
+
+				if (bus->PEC_use == true) {
+					bus->rd_size += 1;
+					data += 1;
+				}
+
+				if (bus->fifo_use == true) {
+					iowrite8(
+					  ioread8(NPCM7XX_SMBFIF_CTS(bus))
+					  | NPCM7XX_SMBFIF_CTS_RXF_TXE,
+					  NPCM7XX_SMBFIF_CTS(bus));
+
+					// first byte in block protocol
+					// is zero -> not supported. read at
+					// least one byte
+					if (data == 0)
+						data = 1;
+				}
+				NPCM7XX_smb_set_fifo(bus, bus->rd_size, -1);
+			} else {
+				if (bus->fifo_use == false) {
+					(void)NPCM7XX_smb_read_byte(bus, &data);
+					bus->rd_data_buf[bus->rd_ind++] = data;
+				} else {
+					NPCM7XX_smb_clear_tx_fifo(bus);
+					NPCM7XX_smb_master_fifo_read(bus);
+				}
+			}
+
+		} else {
+			if (bus->fifo_use == true) {   // FIFO in used.
+				if ((bus->rd_size == block_zero_bytes) &&
+				    (bus->read_block_use == true)) {
+					NPCM7XX_smb_eob_int(bus, true);
+					NPCM7XX_smb_master_stop(bus);
+					NPCM7XX_smb_read_from_fifo(bus,
+					   FIELD_GET(NPCM7XX_SMBRXF_CTL_RX_THR,
+					   ioread8(NPCM7XX_SMBRXF_CTL(bus))));
+
+					bus->state = SMB_STOP_PENDING;
+					bus->stop_ind = SMB_BLOCK_BYTES_ERR_IND;
+
+				} else
+					NPCM7XX_smb_master_fifo_read(bus);
+			} else {
+				(void)NPCM7XX_smb_read_byte(bus, &data);
+				bus->rd_data_buf[bus->rd_ind++] = data;
+			}
+		}
+	} else {
+		// last byte is about to be read - end of transaction.
+		// Stop should be set before reading last byte.
+		u8 data;
+		enum smb_state_ind ind = SMB_MASTER_DONE_IND;
+
+		dev_dbg(bus->dev, "SDA master bus%d addr=0x%x oper rd last\n",
+			   bus->num, bus->dest_addr);
+		NPCM7XX_smb_eob_int(bus, true);
+
+		NPCM7XX_smb_master_stop(bus);
+
+		(void)NPCM7XX_smb_read_byte(bus, &data);
+
+		if ((bus->rd_size == block_zero_bytes)
+		    && (bus->read_block_use == true))
+			ind = SMB_BLOCK_BYTES_ERR_IND;
+		else {
+			bus->rd_data_buf[bus->rd_ind++] = data;
+			if (NPCM7XX_smb_get_PEC(bus) != 0)
+				ind = SMB_MASTER_PEC_ERR_IND;
+		}
+
+		bus->state = SMB_STOP_PENDING;
+		bus->stop_ind = ind;
+
+	} // last read byte
+} // read operation
+
+
+
+static void NPCM7XX_smb_reset(struct NPCM7XX_i2c *bus)
+{
+	// Save NPCM7XX_SMBCTL1 relevant bits. It is being cleared when the
+	// module is disabled
+	u8 smbctl1 = ioread8(NPCM7XX_SMBCTL1(bus)) & (NPCM7XX_SMBCTL1_GCMEN
+						      | NPCM7XX_SMBCTL1_INTEN
+						      | NPCM7XX_SMBCTL1_NMINTE);
+
+	// Disable the SMB module
+	iowrite8((ioread8(NPCM7XX_SMBCTL2(bus))	& ~SMBCTL2_ENABLE),
+			NPCM7XX_SMBCTL2(bus));
+
+	// Enable the SMB module
+	NPCM7XX_smb_enable(bus);
+
+	// Restore NPCM7XX_SMBCTL1 status
+	iowrite8(smbctl1, NPCM7XX_SMBCTL1(bus));
+
+	// Reset driver status
+	bus->state = SMB_IDLE;
+	//
+	// Configure FIFO disabled mode so slave will not use fifo
+	//  (master will set it on if supported)
+	iowrite8(ioread8(NPCM7XX_SMBFIF_CTL(bus)) & ~NPCM7XX_SMBFIF_CTL_FIFO_EN,
+		 NPCM7XX_SMBFIF_CTL(bus));
+	bus->fifo_use = false;
+}
+
+
+static int NPCM7XX_smb_master_abort(struct NPCM7XX_i2c *bus)
+{
+	int ret = -(EIO);
+
+	dev_dbg(bus->dev, "bus%d addr=0x%x\n", bus->num, bus->dest_addr);
+
+	// Only current master is allowed to issue Stop Condition
+	if (FIELD_GET(NPCM7XX_SMBST_MASTER, ioread8(NPCM7XX_SMBST(bus)))) {
+		NPCM7XX_smb_abort_data(bus);
+		ret = 0;
+
+	}
+
+	NPCM7XX_smb_reset(bus);
+
+	return ret;
+}
+
+
+static int NPCM7XX_smb_recovery(struct i2c_adapter *_adap)
+{
+	u8   iter = 27;	  // Allow one byte to be sent by the Slave
+	u16  timeout;
+	bool done = false;
+	struct NPCM7XX_i2c *bus = container_of(_adap, struct NPCM7XX_i2c, adap);
+
+	dev_info(bus->dev, "recovery bus%d\n",  bus->num);
+
+	might_sleep();
+
+	// Disable int
+	NPCM7XX_smb_int_enable(bus, false);
+
+	// Check If the SDA line is active (low)
+	if (FIELD_GET(NPCM7XX_SMBCST_TSDA, ioread8(NPCM7XX_SMBCST(bus))) == 0) {
+		// Repeat the following sequence until SDA is released
+		do {
+			// Issue a single SCL cycle
+			iowrite8(NPCM7XX_SMBCST_TGSCL, NPCM7XX_SMBCST(bus));
+			timeout = ABORT_TIMEOUT;
+			while (
+			    (FIELD_GET(NPCM7XX_SMBCST_TGSCL,
+			    ioread8(NPCM7XX_SMBCST(bus))) == 0) &&
+			    (timeout != 0))
+				timeout--;
+
+			// If SDA line is inactive (high), stop
+			if (
+					FIELD_GET(NPCM7XX_SMBCST_TSDA,
+					ioread8(NPCM7XX_SMBCST(bus))) == 1)
+				done = true;
+		} while ((done == false) && (--iter != 0));
+
+		// If SDA line is released (high)
+		if (done) {
+			// Clear BB (BUS BUSY) bit
+			iowrite8(NPCM7XX_SMBCST_BB, NPCM7XX_SMBCST(bus));
+
+			// Generate a START, to synchronize Master and Slave
+			NPCM7XX_smb_master_start(bus);
+
+			// Wait until START condition is sent, or timeout
+			timeout = ABORT_TIMEOUT;
+			while ((!FIELD_GET(NPCM7XX_SMBST_MASTER,
+			     ioread8(NPCM7XX_SMBST(bus))) == 0) &&
+			     (timeout != 0))
+				timeout--;
+
+			// If START condition was sent
+			if (timeout > 0) {
+				// Send an address byte
+				NPCM7XX_smb_write_byte(bus, bus->dest_addr);
+
+				// Generate a STOP condition
+				NPCM7XX_smb_master_stop(bus);
+			}
+			return 0;
+		}
+	}
+
+
+	// check if success:
+	if ((NPCM7XX_smb_get_SCL(_adap) == 1) &&
+	    (NPCM7XX_smb_get_SDA(_adap) == 1))
+		goto NPCM7XX_smb_recovery_done;
+
+	// hold clock low for 35ms: 25 and some spair:
+	NPCM7XX_smb_set_SCL(_adap, 0);
+	msleep(35);
+	NPCM7XX_smb_set_SCL(_adap, 1);
+	udelay(1000);
+
+	// check if success:
+	if ((NPCM7XX_smb_get_SCL(_adap) == 1) &&
+			(NPCM7XX_smb_get_SDA(_adap) == 1))
+		goto NPCM7XX_smb_recovery_done;
+
+	return 0;
+
+NPCM7XX_smb_recovery_done:
+
+	// Enable int
+	NPCM7XX_smb_int_enable(bus, true);
+
+	return -(ENOTRECOVERABLE);
+}
+
+
+static void NPCM7XX_smb_int_enable(struct NPCM7XX_i2c *bus, bool enable)
+{
+	iowrite8((ioread8(NPCM7XX_SMBCTL1(bus)) & ~NPCM7XX_SMBCTL1_INTEN) |
+		 FIELD_PREP(NPCM7XX_SMBCTL1_INTEN,
+		 enable), NPCM7XX_SMBCTL1(bus));
+}
+
+static const u8 crc8_table[256] = {
+	0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
+	0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
+	0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
+	0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
+	0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
+	0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
+	0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
+	0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
+	0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
+	0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
+	0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
+	0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
+	0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
+	0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
+	0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
+	0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
+	0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
+	0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
+	0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
+	0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
+	0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
+	0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
+	0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
+	0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
+	0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
+	0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
+	0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
+	0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
+	0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
+	0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
+	0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
+	0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3
+};
+
+static u8 NPCM7XX_smb_calc_crc8(u8 crc_data, u8 data)
+{
+	u8 tmp = crc_data ^ data;
+
+	crc_data = crc8_table[tmp];
+
+	return crc_data;
+}
+
+static void NPCM7XX_smb_calc_PEC(struct NPCM7XX_i2c *bus, u8 data)
+{
+	if (bus->PEC_use)
+		bus->crc_data = NPCM7XX_smb_calc_crc8(bus->crc_data, data);
+}
+
+static inline u8 NPCM7XX_smb_get_PEC(struct NPCM7XX_i2c *bus)
+{
+	if (bus->PEC_use)
+		return bus->crc_data;
+	else
+		return 0;
+}
+
+static inline void NPCM7XX_smb_write_PEC(struct NPCM7XX_i2c *bus)
+{
+	if (bus->PEC_use) {
+		// get PAC value and write to the bus:
+		NPCM7XX_smb_write_byte(bus, NPCM7XX_smb_get_PEC(bus));
+	}
+}
+
+
+//
+//  NPCM7XX SMB module allows writing to SCL and SDA pins directly
+//  without the need to change muxing of pins.
+//  This feature will be used for recovery sequences i.e.
+//
+static void NPCM7XX_smb_set_SCL(struct i2c_adapter *_adap, int level)
+{
+	unsigned long flags;
+	struct NPCM7XX_i2c *bus = container_of(_adap, struct NPCM7XX_i2c, adap);
+
+	// Select Bank 0 to access NPCM7XX_SMBCTL4
+	spin_lock_irqsave(&bus->lock, flags);
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_0);
+#ifdef SMB_CAPABILITY_FORCE_SCL_SDA
+	// Set SCL_LVL, SDA_LVL bits as Read/Write (R/W)
+	iowrite8(ioread8(NPCM7XX_SMBCTL4(bus)) | SMBCTL4_LVL_WE,
+		 NPCM7XX_SMBCTL4(bus));
+
+	// Set level
+	iowrite8((ioread8(NPCM7XX_SMBCTL3(bus))
+		& ~SMBCTL3_SCL_LVL) | FIELD_PREP(SMBCTL3_SCL_LVL,
+		level), NPCM7XX_SMBCTL3(bus));
+
+	// Set SCL_LVL, SDA_LVL bits as Read Only (RO)
+	iowrite8(ioread8(NPCM7XX_SMBCTL4(bus))
+		 & ~SMBCTL4_LVL_WE, NPCM7XX_SMBCTL4(bus));
+#endif
+	// Return to Bank 1
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_1);
+	spin_unlock_irqrestore(&bus->lock, flags);
+}
+
+
+static int NPCM7XX_smb_get_SCL(struct i2c_adapter *_adap)
+{
+	unsigned long flags;
+	unsigned int ret = 0;
+	struct NPCM7XX_i2c *bus = container_of(_adap, struct NPCM7XX_i2c, adap);
+
+
+	// Select Bank 0 to access NPCM7XX_SMBCTL4
+	spin_lock_irqsave(&bus->lock, flags);
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_0);
+
+	// Get SCL level
+	ret = FIELD_GET(SMBCTL3_SCL_LVL,  ioread8(NPCM7XX_SMBCTL3(bus)));
+
+	// Return to Bank 1
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_1);
+	spin_unlock_irqrestore(&bus->lock, flags);
+	return ret;
+}
+
+
+
+static int NPCM7XX_smb_get_SDA(struct i2c_adapter *_adap)
+{
+	unsigned long flags;
+	unsigned int ret = 0;
+	struct NPCM7XX_i2c *bus = container_of(_adap, struct NPCM7XX_i2c, adap);
+
+	// Select Bank 0 to access NPCM7XX_SMBCTL4
+	spin_lock_irqsave(&bus->lock, flags);
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_0);
+
+	// Get SDA level
+	ret = FIELD_GET(SMBCTL3_SDA_LVL,  ioread8(NPCM7XX_SMBCTL3(bus)));
+
+	// Return to Bank 1
+	NPCM7XX_smb_select_bank(bus, SMB_BANK_1);
+	spin_unlock_irqrestore(&bus->lock, flags);
+	return ret;
+
+}
+
+
+
+static void NPCM7XX_smb_callback(struct NPCM7XX_i2c *bus,
+				enum smb_state_ind op_status, u16 info)
+{
+	struct i2c_msg *msgs = bus->msgs;
+	int msgs_num = bus->msgs_num;
+
+	if (op_status != 6)
+		dev_dbg(bus->dev, "CB bus%d status %d info %d\n", bus->num,
+			op_status, info);
+	switch (op_status) {
+	case SMB_MASTER_DONE_IND:
+	// Master transaction finished and all transmit bytes were sent
+	// info: number of bytes actually received after the Master
+	//	receive operation (if Master didn't issue receive it
+	//	should be 0)
+	// Notify that not all data was received on Master or Slave
+	// info:
+	//	on receive: number of actual bytes received
+	//	when PEC is used even if 'info' is the expected number
+	//	of bytes, it means that PEC error occurred.
+	{
+		if (msgs[0].flags & I2C_M_RD)
+			msgs[0].len = info;
+		else if (msgs_num == 2 && msgs[1].flags & I2C_M_RD)
+			msgs[1].len = info;
+
+		bus->cmd_err = 0;
+		complete(&bus->cmd_complete);
+	}
+	break;
+
+	case SMB_NO_DATA_IND:
+	// Notify that not all data was received on Master or Slave
+	// info:
+	//on receive: number of actual bytes received
+	//	when PEC is used even if 'info' is the expected number
+	//	of bytes,it means that PEC error occurred.
+	{
+		if (msgs[0].flags & I2C_M_RD)
+			msgs[0].len = info;
+		else if (msgs_num == 2 && msgs[1].flags & I2C_M_RD)
+			msgs[1].len = info;
+
+		bus->cmd_err = -EFAULT;
+		dev_info(bus->dev, "I2C%d no data: SA=0x%x wr=%d / %d, rd=%d / %d, ",
+			bus->num, bus->dest_addr, bus->wr_ind, bus->wr_size,
+			bus->rd_ind, bus->rd_size);
+
+		dev_info(bus->dev, "state %d, op=%d, ind=%d, int_cnt=%d, log=0x%x\n",
+			bus->state, bus->operation, bus->stop_ind,
+			bus->int_cnt, bus->event_log);
+		complete(&bus->cmd_complete);
+	}
+	break;
+	case SMB_NACK_IND:
+		// MASTER transmit got a NAK before transmitting all bytes
+		// info: number of transmitted bytes
+		bus->cmd_err = -EAGAIN;
+		complete(&bus->cmd_complete);
+
+		break;
+	case SMB_BUS_ERR_IND:
+		// Bus error
+		// info: has no meaning
+		bus->cmd_err = -EIO;
+		dev_info(bus->dev, "I2C%d BER: SA=0x%x wr=%d / %d, rd=%d / %d, ",
+			bus->num, bus->dest_addr, bus->wr_ind, bus->wr_size,
+			bus->rd_ind, bus->rd_size);
+
+		dev_info(bus->dev, "state %d, op=%d, ind=%d, int_cnt=%d, log=0x%x\n",
+			bus->state, bus->operation, bus->stop_ind,
+			bus->int_cnt, bus->event_log);
+
+		complete(&bus->cmd_complete);
+		break;
+	case SMB_WAKE_UP_IND:
+		// SMBus wake up
+		// info: has no meaning
+		break;
+	default:
+		break;
+	}
+}
+
+
+static int __NPCM7XX_i2c_init(struct NPCM7XX_i2c *bus,
+struct platform_device *pdev)
+{
+	u32 clk_freq;
+	int ret;
+
+	// Initialize the internal data structures
+	bus->state = SMB_DISABLE;
+	bus->master_or_slave = SMB_SLAVE;
+
+
+	ret = of_property_read_u32(pdev->dev.of_node,
+				   "bus-frequency", &clk_freq);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"Could not read bus-frequency property\n");
+		clk_freq = 100000;
+	}
+	dev_dbg(bus->dev, "clk_freq = %d\n", clk_freq);
+	ret = NPCM7XX_smb_init_module(bus, SMB_MASTER, clk_freq / 1000);
+	if (ret == false) {
+		dev_err(&pdev->dev,
+			"NPCM7XX_smb_init_module() failed\n");
+		return -1;
+	}
+#if defined(SMB_CAPABILITY_TIMEOUT_SUPPORT)
+	NPCM7XX_smb_enable_timeout(bus, true);
+#endif //SMB_CAPABILITY_TIMEOUT_SUPPORT
+
+	return 0;
+}
+
+
+static irqreturn_t NPCM7XX_i2c_bus_irq(int irq, void *dev_id)
+{
+	struct NPCM7XX_i2c *bus = dev_id;
+
+	bus->int_cnt++;
+
+	_npcm7xx_get_time_stamp(&bus->int_time_stamp[0],
+				&bus->int_time_stamp[1]);
+	if (bus->master_or_slave == SMB_MASTER)	{
+		NPCM7XX_smb_int_master_handler(bus);
+		return IRQ_HANDLED;
+	}
+
+	dev_err(bus->dev, "int unknown on bus%d\n", bus->num);
+
+	return IRQ_NONE;
+}
+
+
+static int  NPCM7XX_i2c_master_xfer(struct i2c_adapter *adap,
+					struct i2c_msg *msgs, int num)
+{
+	struct NPCM7XX_i2c *bus = adap->algo_data;
+	struct i2c_msg *msg0, *msg1;
+	unsigned long time_left, flags;
+	u16 nwrite, nread;
+	u8 *write_data, *read_data;
+	u8 slave_addr;
+	int ret = 0;
+
+	spin_lock_irqsave(&bus->lock, flags);
+	bus->cmd_err = -EPERM; // restart error to unused value by this driver.
+	bus->int_cnt = 0;
+
+	iowrite8(0xFF, NPCM7XX_SMBST(bus));
+
+	if (num > 2 || num < 1) {
+		pr_err("I2C command not supported, num of msgs = %d\n", num);
+		spin_unlock_irqrestore(&bus->lock, flags);
+		return -EINVAL;
+	}
+
+	msg0 = &msgs[0];
+	slave_addr = msg0->addr;
+	if (msg0->flags & I2C_M_RD) { // read
+		if (num == 2) {
+			pr_err(" num = 2 but first msg is rd instead of wr\n");
+			spin_unlock_irqrestore(&bus->lock, flags);
+			return -EINVAL;
+		}
+		nwrite = 0;
+		write_data = NULL;
+		if (msg0->flags & I2C_M_RECV_LEN)
+			nread = SMB_BLOCK_PROT;
+		else
+			nread = msg0->len;
+
+		read_data = msg0->buf;
+
+	} else { // write
+		nwrite = msg0->len;
+		write_data = msg0->buf;
+		nread = 0;
+		read_data = NULL;
+		if (num == 2) {
+			msg1 = &msgs[1];
+			if (slave_addr != msg1->addr) {
+				pr_err(" SA==%02x but msg1->addr == %02x\n",
+					slave_addr, msg1->addr);
+				spin_unlock_irqrestore(&bus->lock, flags);
+				return -EINVAL;
+			}
+			if ((msg1->flags & I2C_M_RD) == 0) {
+				pr_err(" num = 2 but both msg are write.\n");
+				spin_unlock_irqrestore(&bus->lock, flags);
+				return -EINVAL;
+			}
+			if (msg1->flags & I2C_M_RECV_LEN)
+				nread = SMB_BLOCK_PROT;
+			else
+				nread = msg1->len;
+
+			read_data = msg1->buf;
+		}
+	}
+
+	bus->msgs = msgs;
+	bus->msgs_num = num;
+
+
+	reinit_completion(&bus->cmd_complete);
+
+	if (NPCM7XX_smb_master_start_xmit(bus, slave_addr, nwrite, nread,
+		write_data, read_data, 0) == false)
+		ret = -(EBUSY);
+
+	if (ret != -(EBUSY)) {
+		time_left = wait_for_completion_timeout(&bus->cmd_complete,
+							bus->adap.timeout);
+
+		if (time_left == 0 && bus->cmd_err == -EPERM) {
+
+#if defined(CONFIG_I2C_DEBUG_BUS)
+			dev_dbg(bus->dev, "I2C%d TO! SA=0x%x err %d, nwrite=%d, nread=%d",
+					bus->num, slave_addr,
+					bus->cmd_err,
+					nwrite, nread);
+			dev_dbg(bus->dev, "st%d, op%d, ind%d, int%d, ret%d, log0x%x\n",
+					bus->state, bus->operation,
+					bus->stop_ind, bus->int_cnt, ret,
+					bus->event_log);
+#endif
+			NPCM7XX_smb_master_abort(bus);
+			ret = -ETIMEDOUT;
+		} else
+			ret = bus->cmd_err;
+	} else {
+#if defined(CONFIG_I2C_DEBUG_BUS)
+		dev_dbg(bus->dev, "I2C%d busy! SA=0x%x error %d, nwrite=%d, nread=%d",
+				bus->num, slave_addr,
+				bus->cmd_err,
+				nwrite, nread);
+		dev_dbg(bus->dev, "st %d, op=%d, ind=%d, int_cnt=%d, ret=%d, log=0x%x\n",
+				bus->state, bus->operation,
+				bus->stop_ind, bus->int_cnt, ret,
+				bus->event_log);
+#endif
+	}
+
+	bus->msgs = NULL;
+	bus->msgs_num = 0;
+	spin_unlock_irqrestore(&bus->lock, flags);
+
+	// If nothing went wrong, return number of messages xferred.
+	if (ret >= 0)
+		return num;
+	else
+		return ret;
+}
+
+static u32 NPCM7XX_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+
+static const struct i2c_algorithm NPCM7XX_i2c_algo = {
+	.master_xfer = NPCM7XX_i2c_master_xfer,
+	.functionality = NPCM7XX_i2c_functionality,
+};
+
+
+static struct i2c_bus_recovery_info NPCM7XX_i2c_recovery = {
+	.recover_bus = NPCM7XX_smb_recovery,
+	.get_scl = NPCM7XX_smb_get_SCL,
+	.set_scl = NPCM7XX_smb_set_SCL,
+	.get_sda = NPCM7XX_smb_get_SDA,
+};
+
+
+static int  NPCM7XX_i2c_probe_bus(struct platform_device *pdev)
+{
+	struct NPCM7XX_i2c *bus;
+	struct resource *res;
+	struct clk *i2c_clk;
+	int ret;
+	int num;
+
+	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
+	if (!bus)
+		return -ENOMEM;
+
+#ifdef CONFIG_OF
+	num = of_alias_get_id(pdev->dev.of_node, "i2c");
+	bus->num = num;
+
+
+
+	i2c_clk = devm_clk_get(&pdev->dev, NULL);
+
+	if (IS_ERR(i2c_clk)) {
+		pr_err(" I2C probe failed: can't read clk.\n");
+		return	-EPROBE_DEFER;
+	}
+
+	bus->apb_clk = clk_get_rate(i2c_clk);
+	dev_dbg(bus->dev, "I2C APB clock is %d\n", bus->apb_clk);
+#endif //  CONFIG_OF
+
+
+	if (gcr_regmap == NULL) {
+		gcr_regmap = syscon_regmap_lookup_by_compatible(
+							"nuvoton,npcm750-gcr");
+		if (IS_ERR(gcr_regmap)) {
+			pr_err("%s: failed to find nuvoton,npcm750-gcr\n",
+			__func__);
+			return IS_ERR(gcr_regmap);
+		}
+		regmap_write(gcr_regmap, I2CSEGCTL_OFFSET, I2CSEGCTL_VAL);
+		pr_info("I2C%d: gcr mapped\n", bus->num);
+	}
+
+	if (clk_regmap == NULL) {
+		clk_regmap = syscon_regmap_lookup_by_compatible(
+			"nuvoton,npcm750-clk");
+		if (IS_ERR(clk_regmap)) {
+			pr_err("%s: failed to find nuvoton,npcm750-clk\n",
+						__func__);
+			return IS_ERR(clk_regmap);
+		}
+		pr_info("I2C%d: clk mapped\n", bus->num);
+	}
+
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dev_dbg(bus->dev, "resource: %pR\n", res);
+	bus->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(bus->base))
+		return PTR_ERR(bus->base);
+	dev_dbg(bus->dev, "base = %p\n", bus->base);
+
+	// Initialize the I2C adapter
+	spin_lock_init(&bus->lock);
+	init_completion(&bus->cmd_complete);
+	bus->adap.owner = THIS_MODULE;
+	bus->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+	bus->adap.retries = 0;
+	bus->adap.timeout = 500 * HZ / 1000;
+	bus->adap.algo = &NPCM7XX_i2c_algo;
+	bus->adap.algo_data = bus;
+	bus->adap.dev.parent = &pdev->dev;
+	bus->adap.dev.of_node = pdev->dev.of_node;
+	bus->adap.bus_recovery_info = &NPCM7XX_i2c_recovery;
+
+	snprintf(bus->adap.name, sizeof(bus->adap.name), "Nuvoton i2c");
+
+	bus->dev = &pdev->dev;
+
+	ret = __NPCM7XX_i2c_init(bus, pdev);
+	if (ret < 0)
+		return ret;
+
+	bus->irq = platform_get_irq(pdev, 0);
+	if (bus->irq < 0) {
+		pr_err("I2C platform_get_irq error.");
+		return -ENODEV;
+	}
+	dev_dbg(bus->dev, "irq = %d\n", bus->irq);
+
+	ret = request_irq(bus->irq, NPCM7XX_i2c_bus_irq, 0,
+			  dev_name(&pdev->dev), (void *)bus);
+	if (ret) {
+		dev_err(&pdev->dev, "I2C%d: request_irq fail\n", bus->num);
+		return ret;
+	}
+
+	ret = i2c_add_adapter(&bus->adap);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "I2C%d: i2c_add_adapter fail\n", bus->num);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, bus);
+
+	pr_info("i2c bus %d registered, irq %d\n",
+		  bus->adap.nr, bus->irq);
+
+	return 0;
+}
+
+static int  NPCM7XX_i2c_remove_bus(struct platform_device *pdev)
+{
+	struct NPCM7XX_i2c *bus = platform_get_drvdata(pdev);
+	unsigned long lock_flags;
+
+	spin_lock_irqsave(&bus->lock, lock_flags);
+
+	// Disable everything.
+	NPCM7XX_smb_disable(bus);
+
+	spin_unlock_irqrestore(&bus->lock, lock_flags);
+
+	i2c_del_adapter(&bus->adap);
+
+	return 0;
+}
+
+static const struct of_device_id NPCM7XX_i2c_bus_of_table[] = {
+	{ .compatible = "nuvoton,npcm750-i2c-bus", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, NPCM7XX_i2c_bus_of_table);
+
+static struct platform_driver NPCM7XX_i2c_bus_driver = {
+	.probe = NPCM7XX_i2c_probe_bus,
+	.remove = NPCM7XX_i2c_remove_bus,
+	.driver = {
+		.name = "nuvoton-i2c-bus",
+		.of_match_table = NPCM7XX_i2c_bus_of_table,
+	},
+};
+module_platform_driver(NPCM7XX_i2c_bus_driver);
+
+MODULE_AUTHOR("Avi Fishman <avi.fishman@xxxxxxxxx>");
+MODULE_AUTHOR("Tali Perry <tali.perry@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Nuvoton I2C Bus Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION(I2C_VERSION);
-- 
2.14.1

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