On Thu, Nov 13, 2014 at 03:32:21PM -0300, Ezequiel Garcia wrote:
> From: James Hogan <james.hogan@xxxxxxxxxx>
>
> Add support for the IMG I2C Serial Control Bus (SCB) found on the
> Pistachio and TZ1090 SoCs.
>
> Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
> [Ezequiel: code cleaning and rebasing]
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxx>
> ---
> drivers/i2c/busses/Kconfig | 10 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-img-scb.c | 1412 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 1423 insertions(+)
> create mode 100644 drivers/i2c/busses/i2c-img-scb.c
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 917c358..653f73e 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -523,6 +523,16 @@ config I2C_IBM_IIC
> This driver can also be built as a module. If so, the module
> will be called i2c-ibm_iic.
>
> +config I2C_IMG
> + tristate "Imagination Technologies I2C SCB Controller"
> + depends on SOC_TZ1090 || COMPILE_TEST
> + help
> + Say Y here if you want to use the IMG I2C SCB controller,
> + available on the TZ1090 SoC.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-img-scb.
> +
> config I2C_IMX
> tristate "IMX I2C interface"
> depends on ARCH_MXC
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 78d56c5..84861ea 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -50,6 +50,7 @@ obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o
> obj-$(CONFIG_I2C_HIGHLANDER) += i2c-highlander.o
> obj-$(CONFIG_I2C_HIX5HD2) += i2c-hix5hd2.o
> obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o
> +obj-$(CONFIG_I2C_IMG) += i2c-img-scb.o
> obj-$(CONFIG_I2C_IMX) += i2c-imx.o
> obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
> obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
> diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c
> new file mode 100644
> index 0000000..0fcc169
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-img-scb.c
> @@ -0,0 +1,1412 @@
> +/*
> + * I2C adapter for the IMG Serial Control Bus (SCB) IP block.
> + *
> + * Copyright (C) 2009, 2010, 2012, 2014 Imagination Technologies Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * There are three ways that this I2C controller can be driven:
> + *
> + * - Raw control of the SDA and SCK signals.
> + *
> + * This corresponds to MODE_RAW, which takes control of the signals
> + * directly for a certain number of clock cycles (the INT_TIMING
> + * interrupt can be used for timing).
> + *
> + * - Atomic commands. A low level I2C symbol (such as generate
> + * start/stop/ack/nack bit, generate byte, receive byte, and receive
> + * ACK) is given to the hardware, with detection of completion by bits
> + * in the LINESTAT register.
> + *
> + * This mode of operation is used by MODE_ATOMIC, which uses an I2C
> + * state machine in the interrupt handler to compose/react to I2C
> + * transactions using atomic mode commands, and also by MODE_SEQUENCE,
> + * which emits a simple fixed sequence of atomic mode commands.
> + *
> + * Due to software control, the use of atomic commands usually results
> + * in suboptimal use of the bus, with gaps between the I2C symbols while
> + * the driver decides what to do next.
> + *
> + * - Automatic mode. A bus address, and whether to read/write is
> + * specified, and the hardware takes care of the I2C state machine,
> + * using a FIFO to send/receive bytes of data to an I2C slave. The
> + * driver just has to keep the FIFO drained or filled in response to the
> + * appropriate FIFO interrupts.
> + *
> + * This corresponds to MODE_AUTOMATIC, which manages the FIFOs and deals
> + * with control of repeated start bits between I2C messages.
> + *
> + * Use of automatic mode and the FIFO can make much more efficient use
> + * of the bus compared to individual atomic commands, with potentially
> + * no wasted time between I2C symbols or I2C messages.
> + *
> + * In most cases MODE_AUTOMATIC is used, however if any of the messages in
> + * a transaction are zero byte writes (e.g. used by i2cdetect for probing
> + * the bus), MODE_ATOMIC must be used since automatic mode is normally
> + * started by the writing of data into the FIFO.
> + *
> + * The other modes are used in specific circumstances where MODE_ATOMIC and
> + * MODE_AUTOMATIC aren't appropriate. MODE_RAW is used to implement a bus
> + * recovery routine. MODE_SEQUENCE is used to reset the bus and make sure
> + * it is in a sane state.
> + *
> + * Notice that the driver implements a timer-based timeout mechanism.
> + * The reason for this mechanism is to reduce the number of interrupts
> + * received in automatic mode.
> + *
> + * The driver would get a slave event and transaction done interrupts for
> + * each atomic mode command that gets completed. However, these events are
> + * not needed in automatic mode, becase those atomic mode commands are
Thanks for rewording Ezequiel. It's now much clearer than my original
mega-sentence!
There's a minor typo on this line btw. s/becase/bacause/.
Cheers
James
> + * managed automatically by the hardware.
> + *
> + * In practice, normal I2C transactions will be complete well before you
> + * get the timer interrupt, as the timer is re-scheduled during FIFO
> + * maintenance and disabled after the transaction is complete.
> + *
> + * In this way normal automatic mode operation isn't impacted by
> + * unnecessary interrupts, but the exceptional abort condition can still be
> + * detected (with a slight delay).
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/completion.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/timer.h>
> +
> +/* Register offsets */
> +
> +#define SCB_STATUS_REG 0x00
> +#define SCB_OVERRIDE_REG 0x04
> +#define SCB_READ_ADDR_REG 0x08
> +#define SCB_READ_COUNT_REG 0x0c
> +#define SCB_WRITE_ADDR_REG 0x10
> +#define SCB_READ_DATA_REG 0x14
> +#define SCB_WRITE_DATA_REG 0x18
> +#define SCB_FIFO_STATUS_REG 0x1c
> +#define SCB_CONTROL_SOFT_RESET 0x1f
> +#define SCB_CLK_SET_REG 0x3c
> +#define SCB_INT_STATUS_REG 0x40
> +#define SCB_INT_CLEAR_REG 0x44
> +#define SCB_INT_MASK_REG 0x48
> +#define SCB_CONTROL_REG 0x4c
> +#define SCB_TIME_TPL_REG 0x50
> +#define SCB_TIME_TPH_REG 0x54
> +#define SCB_TIME_TP2S_REG 0x58
> +#define SCB_TIME_TBI_REG 0x60
> +#define SCB_TIME_TSL_REG 0x64
> +#define SCB_TIME_TDL_REG 0x68
> +#define SCB_TIME_TSDL_REG 0x6c
> +#define SCB_TIME_TSDH_REG 0x70
> +#define SCB_READ_XADDR_REG 0x74
> +#define SCB_WRITE_XADDR_REG 0x78
> +#define SCB_WRITE_COUNT_REG 0x7c
> +#define SCB_CORE_REV_REG 0x80
> +#define SCB_TIME_TCKH_REG 0x84
> +#define SCB_TIME_TCKL_REG 0x88
> +#define SCB_FIFO_FLUSH_REG 0x8c
> +#define SCB_READ_FIFO_REG 0x94
> +#define SCB_CLEAR_REG 0x98
> +
> +/* SCB_CONTROL_REG bits */
> +
> +#define SCB_CONTROL_CLK_ENABLE 0x1e0
> +#define SCB_CONTROL_TRANSACTION_HALT 0x200
> +
> +#define FIFO_READ_FULL BIT(0)
> +#define FIFO_READ_EMPTY BIT(1)
> +#define FIFO_WRITE_FULL BIT(2)
> +#define FIFO_WRITE_EMPTY BIT(3)
> +
> +/* SCB_CLK_SET_REG bits */
> +#define SCB_FILT_DISABLE BIT(31)
> +#define SCB_FILT_BYPASS BIT(30)
> +#define SCB_FILT_INC_MASK 0x7f
> +#define SCB_FILT_INC_SHIFT 16
> +#define SCB_INC_MASK 0x7f
> +#define SCB_INC_SHIFT 8
> +
> +/* SCB_INT_*_REG bits */
> +
> +#define INT_BUS_INACTIVE BIT(0)
> +#define INT_UNEXPECTED_START BIT(1)
> +#define INT_SCLK_LOW_TIMEOUT BIT(2)
> +#define INT_SDAT_LOW_TIMEOUT BIT(3)
> +#define INT_WRITE_ACK_ERR BIT(4)
> +#define INT_ADDR_ACK_ERR BIT(5)
> +#define INT_FIFO_FULL BIT(9)
> +#define INT_FIFO_FILLING BIT(10)
> +#define INT_FIFO_EMPTY BIT(11)
> +#define INT_FIFO_EMPTYING BIT(12)
> +#define INT_TRANSACTION_DONE BIT(15)
> +#define INT_SLAVE_EVENT BIT(16)
> +#define INT_TIMING BIT(18)
> +
> +#define INT_FIFO_FULL_FILLING (INT_FIFO_FULL | INT_FIFO_FILLING)
> +#define INT_FIFO_EMPTY_EMPTYING (INT_FIFO_EMPTY | INT_FIFO_EMPTYING)
> +
> +/* Level interrupts need clearing after handling instead of before */
> +#define INT_LEVEL 0x01e00
> +
> +/* Don't allow any interrupts while the clock may be off */
> +#define INT_ENABLE_MASK_INACTIVE 0x00000
> +
> +/* Interrupt masks for the different driver modes */
> +
> +#define INT_ENABLE_MASK_RAW INT_TIMING
> +
> +#define INT_ENABLE_MASK_ATOMIC (INT_TRANSACTION_DONE | \
> + INT_SLAVE_EVENT | \
> + INT_ADDR_ACK_ERR | \
> + INT_WRITE_ACK_ERR)
> +
> +#define INT_ENABLE_MASK_AUTOMATIC (INT_SCLK_LOW_TIMEOUT | \
> + INT_ADDR_ACK_ERR | \
> + INT_WRITE_ACK_ERR | \
> + INT_FIFO_FULL | \
> + INT_FIFO_FILLING | \
> + INT_FIFO_EMPTY | \
> + INT_FIFO_EMPTYING)
> +
> +#define INT_ENABLE_MASK_WAITSTOP (INT_SLAVE_EVENT | \
> + INT_ADDR_ACK_ERR | \
> + INT_WRITE_ACK_ERR)
> +
> +/* SCB_STATUS_REG fields */
> +
> +#define LINESTAT_SCLK_LINE_STATUS BIT(0)
> +#define LINESTAT_SCLK_EN BIT(1)
> +#define LINESTAT_SDAT_LINE_STATUS BIT(2)
> +#define LINESTAT_SDAT_EN BIT(3)
> +#define LINESTAT_DET_START_STATUS BIT(4)
> +#define LINESTAT_DET_STOP_STATUS BIT(5)
> +#define LINESTAT_DET_ACK_STATUS BIT(6)
> +#define LINESTAT_DET_NACK_STATUS BIT(7)
> +#define LINESTAT_BUS_IDLE BIT(8)
> +#define LINESTAT_T_DONE_STATUS BIT(9)
> +#define LINESTAT_SCLK_OUT_STATUS BIT(10)
> +#define LINESTAT_SDAT_OUT_STATUS BIT(11)
> +#define LINESTAT_GEN_LINE_MASK_STATUS BIT(12)
> +#define LINESTAT_START_BIT_DET BIT(13)
> +#define LINESTAT_STOP_BIT_DET BIT(14)
> +#define LINESTAT_ACK_DET BIT(15)
> +#define LINESTAT_NACK_DET BIT(16)
> +#define LINESTAT_INPUT_HELD_V BIT(17)
> +#define LINESTAT_ABORT_DET BIT(18)
> +#define LINESTAT_ACK_OR_NACK_DET (LINESTAT_ACK_DET | LINESTAT_NACK_DET)
> +#define LINESTAT_INPUT_DATA 0xff000000
> +#define LINESTAT_INPUT_DATA_SHIFT 24
> +
> +#define LINESTAT_CLEAR_SHIFT 13
> +#define LINESTAT_LATCHED (0x3f << LINESTAT_CLEAR_SHIFT)
> +
> +/* SCB_OVERRIDE_REG fields */
> +
> +#define OVERRIDE_SCLK_OVR BIT(0)
> +#define OVERRIDE_SCLKEN_OVR BIT(1)
> +#define OVERRIDE_SDAT_OVR BIT(2)
> +#define OVERRIDE_SDATEN_OVR BIT(3)
> +#define OVERRIDE_MASTER BIT(9)
> +#define OVERRIDE_LINE_OVR_EN BIT(10)
> +#define OVERRIDE_DIRECT BIT(11)
> +#define OVERRIDE_CMD_SHIFT 4
> +#define OVERRIDE_CMD_MASK 0x1f
> +#define OVERRIDE_DATA_SHIFT 24
> +
> +#define OVERRIDE_SCLK_DOWN (OVERRIDE_LINE_OVR_EN | \
> + OVERRIDE_SCLKEN_OVR)
> +#define OVERRIDE_SCLK_UP (OVERRIDE_LINE_OVR_EN | \
> + OVERRIDE_SCLKEN_OVR | \
> + OVERRIDE_SCLK_OVR)
> +#define OVERRIDE_SDAT_DOWN (OVERRIDE_LINE_OVR_EN | \
> + OVERRIDE_SDATEN_OVR)
> +#define OVERRIDE_SDAT_UP (OVERRIDE_LINE_OVR_EN | \
> + OVERRIDE_SDATEN_OVR | \
> + OVERRIDE_SDAT_OVR)
> +
> +/* OVERRIDE_CMD values */
> +
> +#define CMD_PAUSE 0x00
> +#define CMD_GEN_DATA 0x01
> +#define CMD_GEN_START 0x02
> +#define CMD_GEN_STOP 0x03
> +#define CMD_GEN_ACK 0x04
> +#define CMD_GEN_NACK 0x05
> +#define CMD_RET_DATA 0x08
> +#define CMD_RET_ACK 0x09
> +
> +/* Fixed timing values */
> +
> +#define TIMEOUT_TBI 0x0
> +#define TIMEOUT_TSL 0xffff
> +#define TIMEOUT_TDL 0x0
> +
> +/* Transaction timeout */
> +
> +#define IMG_I2C_TIMEOUT (msecs_to_jiffies(1000))
> +
> +/*
> + * Worst incs are 1 (innacurate) and 16*256 (irregular).
> + * So a sensible inc is the logarithmic mean: 64 (2^6), which is
> + * in the middle of the valid range (0-127).
> + */
> +#define SCB_OPT_INC 64
> +
> +/* Setup the clock enable filtering for 25 ns */
> +#define SCB_FILT_GLITCH 25
> +
> +/*
> + * Bits to return from interrupt handler functions for different modes.
> + * This delays completion until we've finished with the registers, so that the
> + * function waiting for completion can safely disable the clock to save power.
> + */
> +#define ISR_COMPLETE_M BIT(31)
> +#define ISR_FATAL_M BIT(30)
> +#define ISR_WAITSTOP BIT(29)
> +#define ISR_STATUS_M 0x0000ffff /* contains +ve errno */
> +#define ISR_COMPLETE(err) (ISR_COMPLETE_M | (ISR_STATUS_M & (err)))
> +#define ISR_FATAL(err) (ISR_COMPLETE(err) | ISR_FATAL_M)
> +
> +#define REL_SOC_IP_SCB_2_2_1 0x00020201
> +
> +enum img_i2c_mode {
> + MODE_INACTIVE,
> + MODE_RAW,
> + MODE_ATOMIC,
> + MODE_AUTOMATIC,
> + MODE_SEQUENCE,
> + MODE_FATAL,
> + MODE_WAITSTOP,
> + MODE_SUSPEND,
> +};
> +
> +/* Timing parameters for i2c modes (in ns) */
> +struct img_i2c_timings {
> + const char *name;
> + unsigned int max_bitrate;
> + unsigned int tckh, tckl, tsdh, tsdl;
> + unsigned int tp2s, tpl, tph;
> +};
> +
> +/* The timings array must be ordered from slower to faster */
> +static struct img_i2c_timings timings[] = {
> + /* Standard mode */
> + {
> + .name = "standard",
> + .max_bitrate = 100000,
> + .tckh = 4000,
> + .tckl = 4700,
> + .tsdh = 4700,
> + .tsdl = 8700,
> + .tp2s = 4700,
> + .tpl = 4700,
> + .tph = 4000,
> + },
> + /* Fast mode */
> + {
> + .name = "fast",
> + .max_bitrate = 400000,
> + .tckh = 600,
> + .tckl = 1300,
> + .tsdh = 600,
> + .tsdl = 1200,
> + .tp2s = 1300,
> + .tpl = 600,
> + .tph = 600,
> + },
> +};
> +
> +/* Reset dance */
> +static u8 img_i2c_reset_seq[] = { CMD_GEN_START,
> + CMD_GEN_DATA, 0xff,
> + CMD_RET_ACK,
> + CMD_GEN_START,
> + CMD_GEN_STOP,
> + 0 };
> +/* Just issue a stop (after an abort condition) */
> +static u8 img_i2c_stop_seq[] = { CMD_GEN_STOP,
> + 0 };
> +
> +/* We're interested in different interrupts depending on the mode */
> +static unsigned int img_i2c_int_enable_by_mode[] = {
> + [MODE_INACTIVE] = INT_ENABLE_MASK_INACTIVE,
> + [MODE_RAW] = INT_ENABLE_MASK_RAW,
> + [MODE_ATOMIC] = INT_ENABLE_MASK_ATOMIC,
> + [MODE_AUTOMATIC] = INT_ENABLE_MASK_AUTOMATIC,
> + [MODE_SEQUENCE] = INT_ENABLE_MASK_ATOMIC,
> + [MODE_FATAL] = 0,
> + [MODE_WAITSTOP] = INT_ENABLE_MASK_WAITSTOP,
> + [MODE_SUSPEND] = 0,
> +};
> +
> +/* Atomic command names */
> +static const char * const img_i2c_atomic_cmd_names[] = {
> + [CMD_PAUSE] = "PAUSE",
> + [CMD_GEN_DATA] = "GEN_DATA",
> + [CMD_GEN_START] = "GEN_START",
> + [CMD_GEN_STOP] = "GEN_STOP",
> + [CMD_GEN_ACK] = "GEN_ACK",
> + [CMD_GEN_NACK] = "GEN_NACK",
> + [CMD_RET_DATA] = "RET_DATA",
> + [CMD_RET_ACK] = "RET_ACK",
> +};
> +
> +struct img_i2c {
> + struct i2c_adapter adap;
> +
> + void __iomem *base;
> +
> + /*
> + * The scb core clock is used to get the input frequency, and to disable
> + * it after every set of transactions to save some power.
> + */
> + struct clk *scb_clk, *sys_clk;
> + unsigned int bitrate;
> + bool need_wr_rd_fence;
> +
> + /* state */
> + struct completion msg_complete;
> + spinlock_t lock; /* lock before doing anything with the state */
> + struct i2c_msg msg;
> +
> + /* After the last transaction, wait for a stop bit */
> + bool last_msg;
> + int msg_status;
> +
> + enum img_i2c_mode mode;
> + u32 int_enable; /* depends on mode */
> + u32 line_status; /* line status over command */
> +
> + /*
> + * To avoid slave event interrupts in automatic mode, use a timer to
> + * poll the abort condition if we don't get an interrupt for too long.
> + */
> + struct timer_list check_timer;
> + bool t_halt;
> +
> + /* atomic mode state */
> + bool at_t_done;
> + bool at_slave_event;
> + int at_cur_cmd;
> + u8 at_cur_data;
> +
> + /* Sequence: either reset or stop. See img_i2c_sequence. */
> + u8 *seq;
> +
> + /* raw mode */
> + unsigned int raw_timeout;
> +};
> +
> +static void img_i2c_writel(struct img_i2c *i2c, u32 offset, u32 value)
> +{
> + writel(value, i2c->base + offset);
> +}
> +
> +static u32 img_i2c_readl(struct img_i2c *i2c, u32 offset)
> +{
> + return readl(i2c->base + offset);
> +}
> +
> +/*
> + * The code to read from the master read fifo, and write to the master
> + * write fifo, checks a bit in an SCB register before every byte to
> + * ensure that the fifo is not full (write fifo) or empty (read fifo).
> + * Due to clock domain crossing inside the SCB block the updated value
> + * of this bit is only visible after 2 cycles.
> + *
> + * The scb_wr_rd_fence() function does 2 dummy writes (to the read-only
> + * revision register), and it's called after reading from or writing to the
> + * fifos to ensure that subsequent reads of the fifo status bits do not read
> + * stale values.
> + */
> +static void img_i2c_wr_rd_fence(struct img_i2c *i2c)
> +{
> + if (i2c->need_wr_rd_fence) {
> + img_i2c_writel(i2c, SCB_CORE_REV_REG, 0);
> + img_i2c_writel(i2c, SCB_CORE_REV_REG, 0);
> + }
> +}
> +
> +static void img_i2c_switch_mode(struct img_i2c *i2c, enum img_i2c_mode mode)
> +{
> + i2c->mode = mode;
> + i2c->int_enable = img_i2c_int_enable_by_mode[mode];
> + i2c->line_status = 0;
> +}
> +
> +static void img_i2c_raw_op(struct img_i2c *i2c)
> +{
> + i2c->raw_timeout = 0;
> + img_i2c_writel(i2c, SCB_OVERRIDE_REG,
> + OVERRIDE_SCLKEN_OVR |
> + OVERRIDE_SDATEN_OVR |
> + OVERRIDE_MASTER |
> + OVERRIDE_LINE_OVR_EN |
> + OVERRIDE_DIRECT |
> + ((i2c->at_cur_cmd & OVERRIDE_CMD_MASK) << OVERRIDE_CMD_SHIFT) |
> + (i2c->at_cur_data << OVERRIDE_DATA_SHIFT));
> +}
> +
> +static const char *img_i2c_atomic_op_name(unsigned int cmd)
> +{
> + if (unlikely(cmd >= ARRAY_SIZE(img_i2c_atomic_cmd_names)))
> + return "UNKNOWN";
> + return img_i2c_atomic_cmd_names[cmd];
> +}
> +
> +/* Send a single atomic mode command to the hardware */
> +static void img_i2c_atomic_op(struct img_i2c *i2c, int cmd, u8 data)
> +{
> + i2c->at_cur_cmd = cmd;
> + i2c->at_cur_data = data;
> +
> + /* work around lack of data setup time when generating data */
> + if (cmd == CMD_GEN_DATA && i2c->mode == MODE_ATOMIC) {
> + u32 line_status = img_i2c_readl(i2c, SCB_STATUS_REG);
> +
> + if (line_status & LINESTAT_SDAT_LINE_STATUS && !(data & 0x80)) {
> + /* hold the data line down for a moment */
> + img_i2c_switch_mode(i2c, MODE_RAW);
> + img_i2c_raw_op(i2c);
> + return;
> + }
> + }
> +
> + dev_dbg(i2c->adap.dev.parent,
> + "atomic cmd=%s (%d) data=%#x\n",
> + img_i2c_atomic_op_name(cmd), cmd, data);
> + i2c->at_t_done = (cmd == CMD_RET_DATA || cmd == CMD_RET_ACK);
> + i2c->at_slave_event = false;
> + i2c->line_status = 0;
> +
> + img_i2c_writel(i2c, SCB_OVERRIDE_REG,
> + ((cmd & OVERRIDE_CMD_MASK) << OVERRIDE_CMD_SHIFT) |
> + OVERRIDE_MASTER |
> + OVERRIDE_DIRECT |
> + (data << OVERRIDE_DATA_SHIFT));
> +}
> +
> +/* Start a transaction in atomic mode */
> +static void img_i2c_atomic_start(struct img_i2c *i2c)
> +{
> + img_i2c_switch_mode(i2c, MODE_ATOMIC);
> + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
> + img_i2c_atomic_op(i2c, CMD_GEN_START, 0x00);
> +}
> +
> +static void img_i2c_soft_reset(struct img_i2c *i2c)
> +{
> + i2c->t_halt = false;
> + img_i2c_writel(i2c, SCB_CONTROL_REG, 0);
> + img_i2c_writel(i2c, SCB_CONTROL_REG,
> + SCB_CONTROL_CLK_ENABLE | SCB_CONTROL_SOFT_RESET);
> +}
> +
> +/* enable or release transaction halt for control of repeated starts */
> +static void img_i2c_transaction_halt(struct img_i2c *i2c, bool t_halt)
> +{
> + u32 val;
> +
> + if (i2c->t_halt == t_halt)
> + return;
> + i2c->t_halt = t_halt;
> + val = img_i2c_readl(i2c, SCB_CONTROL_REG);
> + if (t_halt)
> + val |= SCB_CONTROL_TRANSACTION_HALT;
> + else
> + val &= ~SCB_CONTROL_TRANSACTION_HALT;
> + img_i2c_writel(i2c, SCB_CONTROL_REG, val);
> +}
> +
> +/* Drain data from the FIFO into the buffer (automatic mode) */
> +static void img_i2c_read_fifo(struct img_i2c *i2c)
> +{
> + while (i2c->msg.len) {
> + u32 fifo_status;
> + u8 data;
> +
> + fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG);
> + if (fifo_status & FIFO_READ_EMPTY)
> + break;
> +
> + data = img_i2c_readl(i2c, SCB_READ_DATA_REG);
> + *i2c->msg.buf = data;
> +
> + img_i2c_writel(i2c, SCB_READ_FIFO_REG, 0xff);
> + img_i2c_wr_rd_fence(i2c);
> + i2c->msg.len--;
> + i2c->msg.buf++;
> + }
> +}
> +
> +/* Fill the FIFO with data from the buffer (automatic mode) */
> +static void img_i2c_write_fifo(struct img_i2c *i2c)
> +{
> + while (i2c->msg.len) {
> + u32 fifo_status;
> +
> + fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG);
> + if (fifo_status & FIFO_WRITE_FULL)
> + break;
> +
> + img_i2c_writel(i2c, SCB_WRITE_DATA_REG, *i2c->msg.buf);
> + img_i2c_wr_rd_fence(i2c);
> + i2c->msg.len--;
> + i2c->msg.buf++;
> + }
> +
> + /* Disable fifo emptying interrupt if nothing more to write */
> + if (!i2c->msg.len)
> + i2c->int_enable &= ~INT_FIFO_EMPTYING;
> +}
> +
> +/* Start a read transaction in automatic mode */
> +static void img_i2c_read(struct img_i2c *i2c)
> +{
> + img_i2c_switch_mode(i2c, MODE_AUTOMATIC);
> + if (!i2c->last_msg)
> + i2c->int_enable |= INT_SLAVE_EVENT;
> +
> + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
> + img_i2c_writel(i2c, SCB_READ_ADDR_REG, i2c->msg.addr);
> + img_i2c_writel(i2c, SCB_READ_COUNT_REG, i2c->msg.len);
> +
> + img_i2c_transaction_halt(i2c, false);
> + mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
> +}
> +
> +/* Start a write transaction in automatic mode */
> +static void img_i2c_write(struct img_i2c *i2c)
> +{
> + img_i2c_switch_mode(i2c, MODE_AUTOMATIC);
> + if (!i2c->last_msg)
> + i2c->int_enable |= INT_SLAVE_EVENT;
> +
> + img_i2c_writel(i2c, SCB_WRITE_ADDR_REG, i2c->msg.addr);
> + img_i2c_writel(i2c, SCB_WRITE_COUNT_REG, i2c->msg.len);
> +
> + img_i2c_transaction_halt(i2c, false);
> + mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
> + img_i2c_write_fifo(i2c);
> +
> + /* img_i2c_write_fifo() may modify int_enable */
> + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
> +}
> +
> +/*
> + * Indicate that the transaction is complete. This is called from the
> + * ISR to wake up the waiting thread, after which the ISR must not
> + * access any more SCB registers.
> + */
> +static void img_i2c_complete_transaction(struct img_i2c *i2c, int status)
> +{
> + img_i2c_switch_mode(i2c, MODE_INACTIVE);
> + if (status) {
> + i2c->msg_status = status;
> + img_i2c_transaction_halt(i2c, false);
> + }
> + complete(&i2c->msg_complete);
> +}
> +
> +static unsigned int img_i2c_raw_atomic_delay_handler(struct img_i2c *i2c,
> + u32 int_status, u32 line_status)
> +{
> + /* Stay in raw mode for this, so we don't just loop infinitely */
> + img_i2c_atomic_op(i2c, i2c->at_cur_cmd, i2c->at_cur_data);
> + img_i2c_switch_mode(i2c, MODE_ATOMIC);
> + return 0;
> +}
> +
> +static unsigned int img_i2c_raw(struct img_i2c *i2c, u32 int_status,
> + u32 line_status)
> +{
> + if (int_status & INT_TIMING) {
> + if (i2c->raw_timeout == 0)
> + return img_i2c_raw_atomic_delay_handler(i2c,
> + int_status, line_status);
> + --i2c->raw_timeout;
> + }
> + return 0;
> +}
> +
> +static unsigned int img_i2c_sequence(struct img_i2c *i2c, u32 int_status)
> +{
> + static const unsigned int continue_bits[] = {
> + [CMD_GEN_START] = LINESTAT_START_BIT_DET,
> + [CMD_GEN_DATA] = LINESTAT_INPUT_HELD_V,
> + [CMD_RET_ACK] = LINESTAT_ACK_DET | LINESTAT_NACK_DET,
> + [CMD_RET_DATA] = LINESTAT_INPUT_HELD_V,
> + [CMD_GEN_STOP] = LINESTAT_STOP_BIT_DET,
> + };
> + int next_cmd = -1;
> + u8 next_data = 0x00;
> +
> + if (int_status & INT_SLAVE_EVENT)
> + i2c->at_slave_event = true;
> + if (int_status & INT_TRANSACTION_DONE)
> + i2c->at_t_done = true;
> +
> + if (!i2c->at_slave_event || !i2c->at_t_done)
> + return 0;
> +
> + /* wait if no continue bits are set */
> + if (i2c->at_cur_cmd >= 0 &&
> + i2c->at_cur_cmd < ARRAY_SIZE(continue_bits)) {
> + unsigned int cont_bits = continue_bits[i2c->at_cur_cmd];
> +
> + if (cont_bits) {
> + cont_bits |= LINESTAT_ABORT_DET;
> + if (!(i2c->line_status & cont_bits))
> + return 0;
> + }
> + }
> +
> + /* follow the sequence of commands in i2c->seq */
> + next_cmd = *i2c->seq;
> + /* stop on a nil */
> + if (!next_cmd) {
> + img_i2c_writel(i2c, SCB_OVERRIDE_REG, 0);
> + return ISR_COMPLETE(0);
> + }
> + /* when generating data, the next byte is the data */
> + if (next_cmd == CMD_GEN_DATA) {
> + ++i2c->seq;
> + next_data = *i2c->seq;
> + }
> + ++i2c->seq;
> + img_i2c_atomic_op(i2c, next_cmd, next_data);
> +
> + return 0;
> +}
> +
> +static void img_i2c_reset_start(struct img_i2c *i2c)
> +{
> + /* Initiate the magic dance */
> + img_i2c_switch_mode(i2c, MODE_SEQUENCE);
> + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
> + i2c->seq = img_i2c_reset_seq;
> + i2c->at_slave_event = true;
> + i2c->at_t_done = true;
> + i2c->at_cur_cmd = -1;
> +
> + /* img_i2c_reset_seq isn't empty so the following won't fail */
> + img_i2c_sequence(i2c, 0);
> +}
> +
> +static void img_i2c_stop_start(struct img_i2c *i2c)
> +{
> + /* Initiate a stop bit sequence */
> + img_i2c_switch_mode(i2c, MODE_SEQUENCE);
> + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
> + i2c->seq = img_i2c_stop_seq;
> + i2c->at_slave_event = true;
> + i2c->at_t_done = true;
> + i2c->at_cur_cmd = -1;
> +
> + /* img_i2c_stop_seq isn't empty so the following won't fail */
> + img_i2c_sequence(i2c, 0);
> +}
> +
> +static unsigned int img_i2c_atomic(struct img_i2c *i2c,
> + u32 int_status,
> + u32 line_status)
> +{
> + int next_cmd = -1;
> + u8 next_data = 0x00;
> +
> + if (int_status & INT_SLAVE_EVENT)
> + i2c->at_slave_event = true;
> + if (int_status & INT_TRANSACTION_DONE)
> + i2c->at_t_done = true;
> +
> + if (!i2c->at_slave_event || !i2c->at_t_done)
> + goto next_atomic_cmd;
> + if (i2c->line_status & LINESTAT_ABORT_DET) {
> + dev_dbg(i2c->adap.dev.parent, "abort condition detected\n");
> + next_cmd = CMD_GEN_STOP;
> + i2c->msg_status = -EIO;
> + goto next_atomic_cmd;
> + }
> +
> + /* i2c->at_cur_cmd may have completed */
> + switch (i2c->at_cur_cmd) {
> + case CMD_GEN_START:
> + next_cmd = CMD_GEN_DATA;
> + next_data = (i2c->msg.addr << 1);
> + if (i2c->msg.flags & I2C_M_RD)
> + next_data |= 0x1;
> + break;
> + case CMD_GEN_DATA:
> + if (i2c->line_status & LINESTAT_INPUT_HELD_V)
> + next_cmd = CMD_RET_ACK;
> + break;
> + case CMD_RET_ACK:
> + if (i2c->line_status & LINESTAT_ACK_DET) {
> + if (i2c->msg.len == 0) {
> + next_cmd = CMD_GEN_STOP;
> + } else if (i2c->msg.flags & I2C_M_RD) {
> + next_cmd = CMD_RET_DATA;
> + } else {
> + next_cmd = CMD_GEN_DATA;
> + next_data = *i2c->msg.buf;
> + --i2c->msg.len;
> + ++i2c->msg.buf;
> + }
> + } else if (i2c->line_status & LINESTAT_NACK_DET) {
> + i2c->msg_status = -EIO;
> + next_cmd = CMD_GEN_STOP;
> + }
> + break;
> + case CMD_RET_DATA:
> + if (i2c->line_status & LINESTAT_INPUT_HELD_V) {
> + *i2c->msg.buf = (i2c->line_status &
> + LINESTAT_INPUT_DATA)
> + >> LINESTAT_INPUT_DATA_SHIFT;
> + --i2c->msg.len;
> + ++i2c->msg.buf;
> + if (i2c->msg.len)
> + next_cmd = CMD_GEN_ACK;
> + else
> + next_cmd = CMD_GEN_NACK;
> + }
> + break;
> + case CMD_GEN_ACK:
> + if (i2c->line_status & LINESTAT_ACK_DET) {
> + next_cmd = CMD_RET_DATA;
> + } else {
> + i2c->msg_status = -EIO;
> + next_cmd = CMD_GEN_STOP;
> + }
> + break;
> + case CMD_GEN_NACK:
> + next_cmd = CMD_GEN_STOP;
> + break;
> + case CMD_GEN_STOP:
> + img_i2c_writel(i2c, SCB_OVERRIDE_REG, 0);
> + return ISR_COMPLETE(0);
> + default:
> + dev_err(i2c->adap.dev.parent, "bad atomic command %d\n",
> + i2c->at_cur_cmd);
> + i2c->msg_status = -EIO;
> + next_cmd = CMD_GEN_STOP;
> + break;
> + }
> +
> +next_atomic_cmd:
> + if (next_cmd != -1) {
> + /* don't actually stop unless we're the last transaction */
> + if (next_cmd == CMD_GEN_STOP && !i2c->msg_status &&
> + !i2c->last_msg)
> + return ISR_COMPLETE(0);
> + img_i2c_atomic_op(i2c, next_cmd, next_data);
> + }
> + return 0;
> +}
> +
> +/*
> + * Timer function to check if something has gone wrong in automatic mode (so we
> + * don't have to handle so many interrupts just to catch an exception).
> + */
> +static void img_i2c_check_timer(unsigned long arg)
> +{
> + struct img_i2c *i2c = (struct img_i2c *)arg;
> + unsigned long flags;
> + unsigned int line_status;
> +
> + spin_lock_irqsave(&i2c->lock, flags);
> + line_status = img_i2c_readl(i2c, SCB_STATUS_REG);
> +
> + /* check for an abort condition */
> + if (line_status & LINESTAT_ABORT_DET) {
> + dev_dbg(i2c->adap.dev.parent,
> + "abort condition detected by check timer\n");
> + /* enable slave event interrupt mask to trigger irq */
> + img_i2c_writel(i2c, SCB_INT_MASK_REG,
> + i2c->int_enable | INT_SLAVE_EVENT);
> + }
> +
> + spin_unlock_irqrestore(&i2c->lock, flags);
> +}
> +
> +static unsigned int img_i2c_auto(struct img_i2c *i2c,
> + unsigned int int_status,
> + unsigned int line_status)
> +{
> + if (int_status & (INT_WRITE_ACK_ERR | INT_ADDR_ACK_ERR))
> + return ISR_COMPLETE(EIO);
> +
> + if (line_status & LINESTAT_ABORT_DET) {
> + dev_dbg(i2c->adap.dev.parent, "abort condition detected\n");
> + /* empty the read fifo */
> + if ((i2c->msg.flags & I2C_M_RD) &&
> + (int_status & INT_FIFO_FULL_FILLING))
> + img_i2c_read_fifo(i2c);
> + /* use atomic mode and try to force a stop bit */
> + i2c->msg_status = -EIO;
> + img_i2c_stop_start(i2c);
> + return 0;
> + }
> +
> + /* Enable transaction halt on start bit */
> + if (!i2c->last_msg && i2c->line_status & LINESTAT_START_BIT_DET) {
> + img_i2c_transaction_halt(i2c, true);
> + /* we're no longer interested in the slave event */
> + i2c->int_enable &= ~INT_SLAVE_EVENT;
> + }
> +
> + mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
> +
> + if (i2c->msg.flags & I2C_M_RD) {
> + if (int_status & INT_FIFO_FULL_FILLING) {
> + img_i2c_read_fifo(i2c);
> + if (i2c->msg.len == 0)
> + return ISR_WAITSTOP;
> + }
> + } else {
> + if (int_status & INT_FIFO_EMPTY_EMPTYING) {
> + /*
> + * The write fifo empty indicates that we're in the
> + * last byte so it's safe to start a new write
> + * transaction without losing any bytes from the
> + * previous one.
> + * see 2.3.7 Repeated Start Transactions.
> + */
> + if ((int_status & INT_FIFO_EMPTY) &&
> + i2c->msg.len == 0)
> + return ISR_WAITSTOP;
> + img_i2c_write_fifo(i2c);
> + }
> + }
> +
> + return 0;
> +}
> +
> +static irqreturn_t img_i2c_isr(int irq, void *dev_id)
> +{
> + struct img_i2c *i2c = (struct img_i2c *)dev_id;
> + u32 int_status, line_status;
> + /* We handle transaction completion AFTER accessing registers */
> + unsigned int hret;
> +
> + /* Read interrupt status register. */
> + int_status = img_i2c_readl(i2c, SCB_INT_STATUS_REG);
> + /* Clear detected interrupts. */
> + img_i2c_writel(i2c, SCB_INT_CLEAR_REG, int_status);
> +
> + /*
> + * Read line status and clear it until it actually is clear. We have
> + * to be careful not to lose any line status bits that get latched.
> + */
> + line_status = img_i2c_readl(i2c, SCB_STATUS_REG);
> + if (line_status & LINESTAT_LATCHED) {
> + img_i2c_writel(i2c, SCB_CLEAR_REG,
> + (line_status & LINESTAT_LATCHED)
> + >> LINESTAT_CLEAR_SHIFT);
> + img_i2c_wr_rd_fence(i2c);
> + }
> +
> + spin_lock(&i2c->lock);
> +
> + /* Keep track of line status bits received */
> + i2c->line_status &= ~LINESTAT_INPUT_DATA;
> + i2c->line_status |= line_status;
> +
> + /*
> + * Certain interrupts indicate that sclk low timeout is not
> + * a problem. If any of these are set, just continue.
> + */
> + if ((int_status & INT_SCLK_LOW_TIMEOUT) &&
> + !(int_status & (INT_SLAVE_EVENT |
> + INT_FIFO_EMPTY |
> + INT_FIFO_FULL))) {
> + dev_crit(i2c->adap.dev.parent,
> + "fatal: clock low timeout occurred %s addr 0x%02x\n",
> + (i2c->msg.flags & I2C_M_RD) ? "reading" : "writing",
> + i2c->msg.addr);
> + hret = ISR_FATAL(EIO);
> + goto out;
> + }
> +
> + if (i2c->mode == MODE_ATOMIC)
> + hret = img_i2c_atomic(i2c, int_status, line_status);
> + else if (i2c->mode == MODE_AUTOMATIC)
> + hret = img_i2c_auto(i2c, int_status, line_status);
> + else if (i2c->mode == MODE_SEQUENCE)
> + hret = img_i2c_sequence(i2c, int_status);
> + else if (i2c->mode == MODE_WAITSTOP && (int_status & INT_SLAVE_EVENT) &&
> + (line_status & LINESTAT_STOP_BIT_DET))
> + hret = ISR_COMPLETE(0);
> + else if (i2c->mode == MODE_RAW)
> + hret = img_i2c_raw(i2c, int_status, line_status);
> + else
> + hret = 0;
> +
> + /* Clear detected level interrupts. */
> + img_i2c_writel(i2c, SCB_INT_CLEAR_REG, int_status & INT_LEVEL);
> +
> +out:
> + if (hret & ISR_WAITSTOP) {
> + /*
> + * Only wait for stop on last message.
> + * Also we may already have detected the stop bit.
> + */
> + if (!i2c->last_msg || i2c->line_status & LINESTAT_STOP_BIT_DET)
> + hret = ISR_COMPLETE(0);
> + else
> + img_i2c_switch_mode(i2c, MODE_WAITSTOP);
> + }
> +
> + /* now we've finished using regs, handle transaction completion */
> + if (hret & ISR_COMPLETE_M) {
> + int status = -(hret & ISR_STATUS_M);
> +
> + img_i2c_complete_transaction(i2c, status);
> + if (hret & ISR_FATAL_M)
> + img_i2c_switch_mode(i2c, MODE_FATAL);
> + }
> +
> + /* Enable interrupts (int_enable may be altered by changing mode) */
> + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
> +
> + spin_unlock(&i2c->lock);
> +
> + return IRQ_HANDLED;
> +}
> +
> +/* Force a bus reset sequence and wait for it to complete */
> +static int img_i2c_reset_bus(struct img_i2c *i2c)
> +{
> + unsigned long flags;
> + int ret;
> +
> + spin_lock_irqsave(&i2c->lock, flags);
> + reinit_completion(&i2c->msg_complete);
> + img_i2c_reset_start(i2c);
> + spin_unlock_irqrestore(&i2c->lock, flags);
> +
> + ret = wait_for_completion_timeout(&i2c->msg_complete, IMG_I2C_TIMEOUT);
> + if (ret == 0)
> + return -ETIMEDOUT;
> + return 0;
> +}
> +
> +static int img_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
> + int num)
> +{
> + struct img_i2c *i2c = i2c_get_adapdata(adap);
> + bool atomic = false;
> + int i, ret;
> +
> + if (i2c->mode == MODE_SUSPEND) {
> + WARN(1, "refusing to service transaction in suspended state\n");
> + return -EIO;
> + }
> +
> + if (i2c->mode == MODE_FATAL)
> + return -EIO;
> +
> + for (i = 0; i < num; i++) {
> + if (likely(msgs[i].len))
> + continue;
> + /*
> + * 0 byte reads are not possible because the slave could try
> + * and pull the data line low, preventing a stop bit.
> + */
> + if (unlikely(msgs[i].flags & I2C_M_RD))
> + return -EIO;
> + /*
> + * 0 byte writes are possible and used for probing, but we
> + * cannot do them in automatic mode, so use atomic mode
> + * instead.
> + */
> + atomic = true;
> + }
> +
> + ret = clk_prepare_enable(i2c->scb_clk);
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < num; i++) {
> + struct i2c_msg *msg = &msgs[i];
> + unsigned long flags;
> +
> + spin_lock_irqsave(&i2c->lock, flags);
> +
> + /*
> + * Make a copy of the message struct. We mustn't modify the
> + * original or we'll confuse drivers and i2c-dev.
> + */
> + i2c->msg = *msg;
> + i2c->msg_status = 0;
> +
> + /*
> + * After the last message we must have waited for a stop bit.
> + * Not waiting can cause problems when the clock is disabled
> + * before the stop bit is sent, and the linux I2C interface
> + * requires separate transfers not to joined with repeated
> + * start.
> + */
> + i2c->last_msg = (i == num - 1);
> + reinit_completion(&i2c->msg_complete);
> +
> + if (atomic)
> + img_i2c_atomic_start(i2c);
> + else if (msg->flags & I2C_M_RD)
> + img_i2c_read(i2c);
> + else
> + img_i2c_write(i2c);
> + spin_unlock_irqrestore(&i2c->lock, flags);
> +
> + ret = wait_for_completion_timeout(&i2c->msg_complete,
> + IMG_I2C_TIMEOUT);
> + del_timer_sync(&i2c->check_timer);
> +
> + if (ret == 0) {
> + dev_err(adap->dev.parent, "i2c transfer timed out\n");
> + i2c->msg_status = -ETIMEDOUT;
> + break;
> + }
> +
> + if (i2c->msg_status)
> + break;
> + }
> +
> + clk_disable_unprepare(i2c->scb_clk);
> +
> + return i2c->msg_status ? i2c->msg_status : num;
> +}
> +
> +static u32 img_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static const struct i2c_algorithm img_i2c_algo = {
> + .master_xfer = img_i2c_xfer,
> + .functionality = img_i2c_func,
> +};
> +
> +static int img_i2c_init(struct img_i2c *i2c)
> +{
> + unsigned int clk_khz, bitrate_khz, clk_period, tckh, tckl, tsdh;
> + unsigned int i, ret, data, prescale, inc, int_bitrate, filt;
> + struct img_i2c_timings timing;
> + u32 rev;
> +
> + ret = clk_prepare_enable(i2c->scb_clk);
> + if (ret)
> + return ret;
> +
> + rev = img_i2c_readl(i2c, SCB_CORE_REV_REG);
> + if ((rev & 0x00ffffff) < 0x00020200) {
> + dev_info(i2c->adap.dev.parent,
> + "Unknown hardware revision (%d.%d.%d.%d)\n",
> + (rev >> 24) & 0xff, (rev >> 16) & 0xff,
> + (rev >> 8) & 0xff, rev & 0xff);
> + clk_disable_unprepare(i2c->scb_clk);
> + return -EINVAL;
> + }
> +
> + if (rev == REL_SOC_IP_SCB_2_2_1) {
> + i2c->need_wr_rd_fence = true;
> + dev_info(i2c->adap.dev.parent, "fence quirk enabled");
> + }
> +
> + bitrate_khz = i2c->bitrate / 1000;
> + clk_khz = clk_get_rate(i2c->scb_clk) / 1000;
> +
> + /* Determine what mode we're in from the bitrate */
> + timing = timings[0];
> + for (i = 0; i < ARRAY_SIZE(timings); i++) {
> + if (i2c->bitrate <= timings[i].max_bitrate) {
> + timing = timings[i];
> + break;
> + }
> + }
> +
> + /* Find the prescale that would give us that inc (approx delay = 0) */
> + prescale = SCB_OPT_INC * clk_khz / (256 * 16 * bitrate_khz);
> + prescale = clamp_t(unsigned int, prescale, 1, 8);
> + clk_khz /= prescale;
> +
> + /* Setup the clock increment value */
> + inc = (256 * 16 * bitrate_khz) / clk_khz;
> +
> + /*
> + * The clock generation logic allows to filter glitches on the bus.
> + * This filter is able to remove bus glitches shorter than 50ns.
> + * If the clock enable rate is greater than 20 MHz, no filtering
> + * is required, so we need to disable it.
> + * If it's between the 20-40 MHz range, there's no need to divide
> + * the clock to get a filter.
> + */
> + if (clk_khz < 20000) {
> + filt = SCB_FILT_DISABLE;
> + } else if (clk_khz < 40000) {
> + filt = SCB_FILT_BYPASS;
> + } else {
> + /* Calculate filter clock */
> + filt = (64000 / ((clk_khz / 1000) * SCB_FILT_GLITCH));
> +
> + /* Scale up if needed */
> + if (64000 % ((clk_khz / 1000) * SCB_FILT_GLITCH))
> + inc++;
> +
> + if (filt > SCB_FILT_INC_MASK)
> + filt = SCB_FILT_INC_MASK;
> +
> + filt = (filt & SCB_FILT_INC_MASK) << SCB_FILT_INC_SHIFT;
> + }
> + data = filt | ((inc & SCB_INC_MASK) << SCB_INC_SHIFT) | (prescale - 1);
> + img_i2c_writel(i2c, SCB_CLK_SET_REG, data);
> +
> + /* Obtain the clock period of the fx16 clock in ns */
> + clk_period = (256 * 1000000) / (clk_khz * inc);
> +
> + /* Calculate the bitrate in terms of internal clock pulses */
> + int_bitrate = 1000000 / (bitrate_khz * clk_period);
> + if ((1000000 % (bitrate_khz * clk_period)) >=
> + ((bitrate_khz * clk_period) / 2))
> + int_bitrate++;
> +
> + /* Setup TCKH value */
> + tckh = timing.tckh / clk_period;
> + if (timing.tckh % clk_period)
> + tckh++;
> +
> + if (tckh > 0)
> + data = tckh - 1;
> + else
> + data = 0;
> +
> + img_i2c_writel(i2c, SCB_TIME_TCKH_REG, data);
> +
> + /* Setup TCKL value */
> + tckl = int_bitrate - tckh;
> +
> + if (tckl > 0)
> + data = tckl - 1;
> + else
> + data = 0;
> +
> + img_i2c_writel(i2c, SCB_TIME_TCKL_REG, data);
> +
> + /* Setup TSDH value */
> + tsdh = timing.tsdh / clk_period;
> + if (timing.tsdh % clk_period)
> + tsdh++;
> +
> + if (tsdh > 1)
> + data = tsdh - 1;
> + else
> + data = 0x01;
> + img_i2c_writel(i2c, SCB_TIME_TSDH_REG, data);
> +
> + /* This value is used later */
> + tsdh = data;
> +
> + /* Setup TPL value */
> + data = timing.tpl / clk_period;
> + if (data > 0)
> + --data;
> + img_i2c_writel(i2c, SCB_TIME_TPL_REG, data);
> +
> + /* Setup TPH value */
> + data = timing.tph / clk_period;
> + if (data > 0)
> + --data;
> + img_i2c_writel(i2c, SCB_TIME_TPH_REG, data);
> +
> + /* Setup TSDL value to TPL + TSDH + 2 */
> + img_i2c_writel(i2c, SCB_TIME_TSDL_REG, data + tsdh + 2);
> +
> + /* Setup TP2S value */
> + data = timing.tp2s / clk_period;
> + if (data > 0)
> + --data;
> + img_i2c_writel(i2c, SCB_TIME_TP2S_REG, data);
> +
> + img_i2c_writel(i2c, SCB_TIME_TBI_REG, TIMEOUT_TBI);
> + img_i2c_writel(i2c, SCB_TIME_TSL_REG, TIMEOUT_TSL);
> + img_i2c_writel(i2c, SCB_TIME_TDL_REG, TIMEOUT_TDL);
> +
> + /* Take module out of soft reset and enable clocks */
> + img_i2c_soft_reset(i2c);
> +
> + /* Disable all interrupts */
> + img_i2c_writel(i2c, SCB_INT_MASK_REG, 0);
> +
> + /* Clear all interrupts */
> + img_i2c_writel(i2c, SCB_INT_CLEAR_REG, ~0);
> +
> + /* Clear the scb_line_status events */
> + img_i2c_writel(i2c, SCB_CLEAR_REG, ~0);
> +
> + /* Enable interrupts */
> + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
> +
> + /* Perform a synchronous sequence to reset the bus */
> + ret = img_i2c_reset_bus(i2c);
> +
> + clk_disable_unprepare(i2c->scb_clk);
> +
> + return ret;
> +}
> +
> +static int img_i2c_probe(struct platform_device *pdev)
> +{
> + struct device_node *node = pdev->dev.of_node;
> + struct img_i2c *i2c;
> + struct resource *res;
> + int irq, ret;
> + u32 val;
> +
> + i2c = devm_kzalloc(&pdev->dev, sizeof(struct img_i2c), GFP_KERNEL);
> + if (!i2c)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + i2c->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(i2c->base))
> + return PTR_ERR(i2c->base);
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(&pdev->dev, "can't get irq number\n");
> + return irq;
> + }
> +
> + i2c->sys_clk = devm_clk_get(&pdev->dev, "sys");
> + if (IS_ERR(i2c->sys_clk)) {
> + dev_err(&pdev->dev, "can't get system clock\n");
> + return PTR_ERR(i2c->sys_clk);
> + }
> +
> + i2c->scb_clk = devm_clk_get(&pdev->dev, "scb");
> + if (IS_ERR(i2c->scb_clk)) {
> + dev_err(&pdev->dev, "can't get core clock\n");
> + return PTR_ERR(i2c->scb_clk);
> + }
> +
> + ret = devm_request_irq(&pdev->dev, irq, img_i2c_isr, 0,
> + pdev->name, i2c);
> + if (ret) {
> + dev_err(&pdev->dev, "can't request irq %d\n", irq);
> + return ret;
> + }
> +
> + /* Set up the exception check timer */
> + init_timer(&i2c->check_timer);
> + i2c->check_timer.function = img_i2c_check_timer;
> + i2c->check_timer.data = (unsigned long)i2c;
> +
> + i2c->bitrate = timings[0].max_bitrate;
> + if (!of_property_read_u32(node, "clock-frequency", &val))
> + i2c->bitrate = val;
> +
> + i2c_set_adapdata(&i2c->adap, i2c);
> + i2c->adap.dev.parent = &pdev->dev;
> + i2c->adap.dev.of_node = node;
> + i2c->adap.owner = THIS_MODULE;
> + i2c->adap.algo = &img_i2c_algo;
> + i2c->adap.retries = 5;
> + i2c->adap.nr = pdev->id;
> + snprintf(i2c->adap.name, sizeof(i2c->adap.name), "IMG SCB I2C");
> +
> + img_i2c_switch_mode(i2c, MODE_INACTIVE);
> + spin_lock_init(&i2c->lock);
> + init_completion(&i2c->msg_complete);
> +
> + platform_set_drvdata(pdev, i2c);
> +
> + ret = clk_prepare_enable(i2c->sys_clk);
> + if (ret)
> + return ret;
> +
> + ret = img_i2c_init(i2c);
> + if (ret)
> + goto disable_clk;
> +
> + ret = i2c_add_numbered_adapter(&i2c->adap);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to add adapter\n");
> + goto disable_clk;
> + }
> +
> + return 0;
> +
> +disable_clk:
> + clk_disable_unprepare(i2c->sys_clk);
> + return ret;
> +}
> +
> +static int img_i2c_remove(struct platform_device *dev)
> +{
> + struct img_i2c *i2c = platform_get_drvdata(dev);
> +
> + i2c_del_adapter(&i2c->adap);
> + clk_disable_unprepare(i2c->sys_clk);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int img_i2c_suspend(struct device *dev)
> +{
> + struct img_i2c *i2c = dev_get_drvdata(dev);
> +
> + img_i2c_switch_mode(i2c, MODE_SUSPEND);
> +
> + clk_disable_unprepare(i2c->sys_clk);
> +
> + return 0;
> +}
> +
> +static int img_i2c_resume(struct device *dev)
> +{
> + struct img_i2c *i2c = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = clk_prepare_enable(i2c->sys_clk);
> + if (ret)
> + return ret;
> +
> + img_i2c_init(i2c);
> +
> + return 0;
> +}
> +#endif /* CONFIG_PM_SLEEP */
> +
> +static SIMPLE_DEV_PM_OPS(img_i2c_pm, img_i2c_suspend, img_i2c_resume);
> +
> +static const struct of_device_id img_scb_i2c_match[] = {
> + { .compatible = "img,scb-i2c" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, img_scb_i2c_match);
> +
> +static struct platform_driver img_scb_i2c_driver = {
> + .driver = {
> + .name = "img-i2c-scb",
> + .of_match_table = img_scb_i2c_match,
> + .pm = &img_i2c_pm,
> + },
> + .probe = img_i2c_probe,
> + .remove = img_i2c_remove,
> +};
> +module_platform_driver(img_scb_i2c_driver);
> +
> +MODULE_AUTHOR("James Hogan <james.hogan@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("IMG host I2C driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.1.0
>
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