On 12 March 2013 18:43, Simon Glass <sjg@xxxxxxxxxxxx> wrote: > [please excuse my mailer html confusion] > > Hi Naveen, > > On Mon, Mar 11, 2013 at 9:32 PM, Naveen Krishna Chatradhi > <ch.naveen@xxxxxxxxxxx> wrote: >> >> Adds support for High Speed I2C driver found in Exynos5 and later >> SoCs from Samsung. This driver currently supports Auto mode. >> >> Driver only supports Device Tree method. >> Note: Added debugfs support for registers view, not tested. >> >> Signed-off-by: Taekgyun Ko <taeggyun.ko@xxxxxxxxxxx> >> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx> >> Cc: R. Chandrasekar <rcsekar@xxxxxxxxxxx> >> --- >> Changes since v3: http://lkml.org/lkml/2012/12/28/46 >> 1. Added Documentation for DT bindings >> 2. Removed the bus_num, as Doug's pick id from DT is merged in i2c/for-next >> 3. Split the xfer function for better clarity. >> 4. Streamlined code flow in isr, handled trans_status register in xfer_msg call. >> >> .../devicetree/bindings/i2c/i2c-exynos5.txt | 50 ++ >> drivers/i2c/busses/Kconfig | 7 + >> drivers/i2c/busses/Makefile | 1 + >> drivers/i2c/busses/i2c-exynos5.c | 743 ++++++++++++++++++++ >> 4 files changed, 801 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-exynos5.txt >> create mode 100644 drivers/i2c/busses/i2c-exynos5.c >> >> diff --git a/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt >> new file mode 100644 >> index 0000000..0bc9347 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt >> @@ -0,0 +1,50 @@ >> +* Samsung's High Speed I2C controller >> + >> +The Samsung's High Speed I2C controller is used to interface with I2C devices >> +at various speeds ranging from 100khz to 3.4Mhz. >> + >> +Required properties: >> + - compatible: value should be. >> + (a) "samsung,exynos5-hsi2c", for i2c compatible with exynos5 hsi2c. >> + - reg: physical base address of the controller and length of memory mapped >> + region. >> + - interrupts: interrupt number to the cpu. >> + >> + - Samsung GPIO variant (deprecated): >> + - gpios: The order of the gpios should be the following: <SDA, SCL>. >> + The gpio specifier depends on the gpio controller. >> + - Pinctrl variant (preferred, if available): >> + - pinctrl-0: Pin control group to be used for this controller. >> + - pinctrl-names: Should contain only one value - "default". >> + >> +Optional properties: >> + - samsung,hs-mode: Mode of operation, High speed or Fast speed mode. If not >> + specified, default value is 0. >> + - samsung,hs-clock-freq: Desired operating frequency in Hz of the bus. >> + If not specified, the default value in Hz is 100000. >> + - samsung,fs-clock-freq: Desired operarting frequency in Hz of the bus. >> + If not specified, the default value in Hz is 100000. >> + >> +Example: >> + >> + hsi2c@12ca0000 { >> + compatible = "samsung,exynos5-hsi2c"; >> + reg = <0x12ca0000 0x100>; >> + interrupts = <56>; >> + samsung,fs-clock-freq = <100000>; >> + /* Samsung GPIO variant begins here */ >> + gpios = <&gpd1 2 0 /* SDA */ >> + &gpd1 3 0 /* SCL */>; >> + /* Samsung GPIO variant ends here */ >> + /* Pinctrl variant begins here */ >> + pinctrl-0 = <&i2c4_bus>; >> + pinctrl-names = "default"; >> + /* Pinctrl variant ends here */ >> + #address-cells = <1>; >> + #size-cells = <0>; >> + >> + s2mps11_pmic@66 { >> + compatible = "samsung,s2mps11-pmic"; >> + reg = <0x66>; >> + }; >> + }; >> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig >> index a3725de..78b4936 100644 >> --- a/drivers/i2c/busses/Kconfig >> +++ b/drivers/i2c/busses/Kconfig >> @@ -434,6 +434,13 @@ config I2C_EG20T >> ML7213/ML7223/ML7831 is companion chip for Intel Atom E6xx series. >> ML7213/ML7223/ML7831 is completely compatible for Intel EG20T PCH. >> >> +config I2C_EXYNOS5 >> + tristate "Exynos5 high-speed I2C driver" >> + depends on ARCH_EXYNOS5 && OF >> + help >> + Say Y here to include support for High-speed I2C controller in the >> + Exynos5 based Samsung SoCs. >> + >> config I2C_GPIO >> tristate "GPIO-based bitbanging I2C" >> depends on GENERIC_GPIO >> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile >> index 8f4fc23..b19366c 100644 >> --- a/drivers/i2c/busses/Makefile >> +++ b/drivers/i2c/busses/Makefile >> @@ -42,6 +42,7 @@ i2c-designware-platform-objs := i2c-designware-platdrv.o >> obj-$(CONFIG_I2C_DESIGNWARE_PCI) += i2c-designware-pci.o >> i2c-designware-pci-objs := i2c-designware-pcidrv.o >> obj-$(CONFIG_I2C_EG20T) += i2c-eg20t.o >> +obj-$(CONFIG_I2C_EXYNOS5) += i2c-exynos5.o >> obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o >> obj-$(CONFIG_I2C_HIGHLANDER) += i2c-highlander.o >> obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o >> diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c >> new file mode 100644 >> index 0000000..fe30b0b >> --- /dev/null >> +++ b/drivers/i2c/busses/i2c-exynos5.c >> @@ -0,0 +1,743 @@ >> +/** >> + * i2c-exynos5.c - Samsung Exynos5 I2C Controller Driver >> + * >> + * Copyright (C) 2013 Samsung Electronics Co., 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. >> +*/ >> + >> +#include <linux/kernel.h> >> +#include <linux/module.h> >> +#include <linux/debugfs.h> >> + >> +#include <linux/i2c.h> >> +#include <linux/init.h> >> +#include <linux/time.h> >> +#include <linux/interrupt.h> >> +#include <linux/delay.h> >> +#include <linux/errno.h> >> +#include <linux/err.h> >> +#include <linux/platform_device.h> >> +#include <linux/pm_runtime.h> >> +#include <linux/clk.h> >> +#include <linux/slab.h> >> +#include <linux/io.h> >> +#include <linux/of_address.h> >> +#include <linux/of_gpio.h> >> +#include <linux/of_irq.h> >> +#include <linux/of_i2c.h> >> + >> +/* Register Map */ >> +#define HSI2C_CTL 0x00 >> +#define HSI2C_FIFO_CTL 0x04 >> +#define HSI2C_TRAILIG_CTL 0x08 >> +#define HSI2C_CLK_CTL 0x0C >> +#define HSI2C_CLK_SLOT 0x10 >> +#define HSI2C_INT_ENABLE 0x20 >> +#define HSI2C_INT_STATUS 0x24 >> +#define HSI2C_ERR_STATUS 0x2C >> +#define HSI2C_FIFO_STATUS 0x30 >> +#define HSI2C_TX_DATA 0x34 >> +#define HSI2C_RX_DATA 0x38 >> +#define HSI2C_CONF 0x40 >> +#define HSI2C_AUTO_CONF 0x44 >> +#define HSI2C_TIMEOUT 0x48 >> +#define HSI2C_MANUAL_CMD 0x4C >> +#define HSI2C_TRANS_STATUS 0x50 >> +#define HSI2C_TIMING_HS1 0x54 >> +#define HSI2C_TIMING_HS2 0x58 >> +#define HSI2C_TIMING_HS3 0x5C >> +#define HSI2C_TIMING_FS1 0x60 >> +#define HSI2C_TIMING_FS2 0x64 >> +#define HSI2C_TIMING_FS3 0x68 >> +#define HSI2C_TIMING_SLA 0x6C >> +#define HSI2C_ADDR 0x70 >> + >> +/* I2C_CTL Register bits */ >> +#define HSI2C_FUNC_MODE_I2C (1u << 0) >> +#define HSI2C_MASTER (1u << 3) >> +#define HSI2C_RXCHON (1u << 6) >> +#define HSI2C_TXCHON (1u << 7) >> +#define HSI2C_SW_RST (1u << 31) >> + >> +/* I2C_FIFO_CTL Register bits */ >> +#define HSI2C_RXFIFO_EN (1u << 0) >> +#define HSI2C_TXFIFO_EN (1u << 1) >> +#define HSI2C_TXFIFO_TRIGGER_LEVEL (0x20 << 16) >> +#define HSI2C_RXFIFO_TRIGGER_LEVEL (0x20 << 4) >> + >> +/* I2C_TRAILING_CTL Register bits */ >> +#define HSI2C_TRAILING_COUNT (0xf) >> + >> +/* I2C_INT_EN Register bits */ >> +#define HSI2C_INT_TX_ALMOSTEMPTY_EN (1u << 0) >> +#define HSI2C_INT_RX_ALMOSTFULL_EN (1u << 1) >> +#define HSI2C_INT_TRAILING_EN (1u << 6) >> +#define HSI2C_INT_I2C_EN (1u << 9) >> + >> +/* I2C_FIFO_STAT Register bits */ >> +#define HSI2C_RX_FIFO_EMPTY (1u << 24) >> +#define HSI2C_RX_FIFO_FULL (1u << 23) >> +#define HSI2C_TX_FIFO_EMPTY (1u << 8) >> +#define HSI2C_TX_FIFO_FULL (1u << 7) >> + >> +#define HSI2C_RX_FIFO_EMPTY (1u << 24) >> +#define HSI2C_FIFO_EMPTY (HSI2C_RX_FIFO_EMPTY | \ >> + HSI2C_TX_FIFO_EMPTY) >> + >> +/* I2C_CONF Register bits */ >> +#define HSI2C_AUTO_MODE (1u << 31) >> +#define HSI2C_10BIT_ADDR_MODE (1u << 30) >> +#define HSI2C_HS_MODE (1u << 29) >> + >> +/* I2C_AUTO_CONF Register bits */ >> +#define HSI2C_READ_WRITE (1u << 16) >> +#define HSI2C_STOP_AFTER_TRANS (1u << 17) >> +#define HSI2C_MASTER_RUN (1u << 31) >> + >> +/* I2C_TIMEOUT Register bits */ >> +#define HSI2C_TIMEOUT_EN (1u << 31) >> + >> +/* I2C_TRANS_STATUS register bits */ >> +#define HSI2C_MASTER_BUSY (1u << 17) >> +#define HSI2C_SLAVE_BUSY (1u << 16) >> +#define HSI2C_NO_DEV (1u << 3) >> +#define HSI2C_NO_DEV_ACK (1u << 2) >> +#define HSI2C_TRANS_ABORT (1u << 1) >> +#define HSI2C_TRANS_DONE (1u << 0) >> + >> +/* I2C_ADDR register bits */ >> +#define HSI2C_SLV_ADDR_SLV(x) ((x & 0x3ff) << 0) >> +#define HSI2C_SLV_ADDR_MAS(x) ((x & 0x3ff) << 10) >> +#define HSI2C_MASTER_ID(x) ((x & 0xff) << 24) >> + >> +/* Controller operating frequency, timing values for operation >> + * are calculated against this frequency >> + */ >> +#define HSI2C_HS_TX_CLOCK 1000000 >> +#define HSI2C_FS_TX_CLOCK 1000000 >> +#define HSI2C_HIGH_SPD 1 >> +#define HSI2C_FAST_SPD 0 >> + >> +#define EXYNOS5_I2C_TIMEOUT (msecs_to_jiffies(1000)) >> + >> +/* timeout for pm runtime autosuspend */ >> +#define EXYNOS5_I2C_PM_TIMEOUT 1000 /* ms */ >> + >> +struct exynos5_i2c { >> + struct i2c_adapter adap; >> + unsigned int suspended:1; >> + >> + struct i2c_msg *msg; >> + struct completion msg_complete; >> + unsigned int msg_ptr; >> + >> + unsigned int irq; >> + >> + void __iomem *regs; >> + struct clk *clk; >> + struct device *dev; >> + >> + /* GPIO lines for SDA/SCL*/ >> + int gpios[2]; >> + >> + /* Controller operating frequency */ >> + unsigned int clock; >> + >> + /* HSI2C Controller can operate in >> + * 1. High speed upto 3.4Mbps >> + * 2. Fast speed upto 1Mbps >> + */ >> + int speed_mode; >> +}; >> + >> +static const struct of_device_id exynos5_i2c_match[] = { >> + { .compatible = "samsung,exynos5-hsi2c" }, >> + {}, >> +}; >> +MODULE_DEVICE_TABLE(of, exynos5_i2c_match); >> + >> +static inline void exynos5_i2c_stop(struct exynos5_i2c *i2c) >> +{ >> + writel(0, i2c->regs + HSI2C_INT_ENABLE); >> + >> + complete(&i2c->msg_complete); >> +} >> + >> +static void exynos5_i2c_en_timeout(struct exynos5_i2c *i2c) >> +{ >> + u32 i2c_timeout = readl(i2c->regs + HSI2C_TIMEOUT); >> + >> + /* Clear to enable Timeout */ >> + i2c_timeout &= ~HSI2C_TIMEOUT_EN; >> + writel(i2c_timeout, i2c->regs + HSI2C_TIMEOUT); >> +} >> + >> +static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c) >> +{ >> + u32 i2c_timing_s1; >> + u32 i2c_timing_s2; >> + u32 i2c_timing_s3; >> + u32 i2c_timing_sla; >> + unsigned int op_clk = i2c->clock; >> + unsigned int clkin = clk_get_rate(i2c->clk); >> + unsigned int n_clkdiv; >> + unsigned int t_start_su, t_start_hd; >> + unsigned int t_stop_su; >> + unsigned int t_data_su, t_data_hd; >> + unsigned int t_scl_l, t_scl_h; >> + unsigned int t_sr_release; >> + unsigned int t_ftl_cycle; >> + unsigned int i = 0, utemp0 = 0, utemp1 = 0, utemp2 = 0; > > > Can you think of a better name for utemp0 and utemp2? Is utemp2 a clock divisor? Nope, utemp2 is not a clock divisor. "i" in the next loop is. There is no real logic to name them. except for the formula described below. Any suggestions please? > >> >> + >> + /* FPCLK / FI2C = >> + * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE >> + * uTemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) >> + * uTemp1 = (TSCLK_L + TSCLK_H + 2) >> + * uTemp2 = TSCLK_L + TSCLK_H >> + */ >> + t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7; >> + utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle; >> + >> + /* CLK_DIV max is 256 */ >> + for (i = 0; i < 256; i++) { >> + utemp1 = utemp0 / (i + 1); >> + /* SCLK_L/H max is 256 / 2 */ >> + if (utemp1 < 128) { >> + utemp2 = utemp1 - 2; >> + break; >> + } > > > I suppose this loop can't exit until i is at least utemp / 128, so > perhaps could start the loop at that value? This code seems to be on > the noirq resume path, so should be fast if possible. For me this works for i = 0 itself so never really took any time. But, yes this can happen. i will split the function > > What happens if i gets to 256? Is that an error, since in that case > utemp2 is not set? Right utemp2 <=0 is an error. I'm not sure keeping the reset values of the registers intact in such case would be a good idea, Should i just return in probe. > > Also could consider moving this loop into a function. Sure > >> >> + } >> >> + >> + n_clkdiv = i; >> + t_scl_l = utemp2 / 2; >> + t_scl_h = utemp2 / 2; >> + t_start_su = t_scl_l; >> + t_start_hd = t_scl_l; >> + t_stop_su = t_scl_l; >> + t_data_su = t_scl_l / 2; >> + t_data_hd = t_scl_l / 2; >> + t_sr_release = utemp2; >> + >> + i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8; >> + i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0; >> + i2c_timing_s3 = n_clkdiv << 16 | t_sr_release << 0; >> + i2c_timing_sla = t_data_hd << 0; >> + >> + dev_dbg(i2c->dev, "tSTART_SU: %X, tSTART_HD: %X, tSTOP_SU: %X\n", >> + t_start_su, t_start_hd, t_stop_su); >> + dev_dbg(i2c->dev, "tDATA_SU: %X, tSCL_L: %X, tSCL_H: %X\n", >> + t_data_su, t_scl_l, t_scl_h); >> + dev_dbg(i2c->dev, "nClkDiv: %X, tSR_RELEASE: %X\n", >> + n_clkdiv, t_sr_release); >> + dev_dbg(i2c->dev, "tDATA_HD: %X\n", t_data_hd); >> + >> + if (i2c->speed_mode == HSI2C_HIGH_SPD) { >> + writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_HS1); >> + writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_HS2); >> + writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3); >> + } else { >> + writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_FS1); >> + writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_FS2); >> + writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_FS3); >> + } >> + writel(i2c_timing_sla, i2c->regs + HSI2C_TIMING_SLA); >> + >> + return 0; >> +} >> + >> +static void exynos5_i2c_init(struct exynos5_i2c *i2c) >> +{ >> + u32 i2c_conf = readl(i2c->regs + HSI2C_CONF); >> + >> + writel((HSI2C_FUNC_MODE_I2C | HSI2C_MASTER), >> + i2c->regs + HSI2C_CTL); >> + writel(HSI2C_TRAILING_COUNT, i2c->regs + HSI2C_TRAILIG_CTL); >> + >> + exynos5_i2c_set_timing(i2c); >> + >> + if (i2c->speed_mode == HSI2C_HIGH_SPD) >> + i2c_conf |= HSI2C_HS_MODE; >> + >> + writel(i2c_conf | HSI2C_AUTO_MODE, i2c->regs + HSI2C_CONF); >> +} >> + >> +static void exynos5_i2c_reset(struct exynos5_i2c *i2c) >> +{ >> + u32 i2c_ctl; >> + >> + /* Set and clear the bit for reset */ >> + i2c_ctl = readl(i2c->regs + HSI2C_CTL); >> + i2c_ctl |= HSI2C_SW_RST; >> + writel(i2c_ctl, i2c->regs + HSI2C_CTL); >> + >> + i2c_ctl = readl(i2c->regs + HSI2C_CTL); >> + i2c_ctl &= ~HSI2C_SW_RST; >> + writel(i2c_ctl, i2c->regs + HSI2C_CTL); >> + >> + /* Initialize the configure registers */ >> + exynos5_i2c_init(i2c); >> +} >> + >> +static void exynos5_i2c_master_run(struct exynos5_i2c *i2c) >> +{ >> + /* Start data transfer in Master mode */ >> + u32 i2c_auto_conf = readl(i2c->regs + HSI2C_AUTO_CONF); >> + i2c_auto_conf |= HSI2C_MASTER_RUN; >> + writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONF); >> +} >> + >> +/** >> + * exynos5_i2c_irq: top level IRQ servicing routine >> +*/ >> +static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id) >> +{ >> + struct exynos5_i2c *i2c = dev_id; >> + unsigned char byte; >> + > > > Can other sorts of irqs happen? Errors? TX_ALMOSTEMPTY, RX_ALMOSTFULL, TX_UNDERRUN, TX_OVERRUN,, RX_UNDERRUN, RX_OVERRUN, TRAILING, I2C_INT are the possible interrupts. > >> >> + if (i2c->msg->flags & I2C_M_RD) { >> + while (!(readl(i2c->regs + HSI2C_FIFO_STATUS) & >> + HSI2C_RX_FIFO_EMPTY)) { >> + byte = (unsigned char)readl(i2c->regs + HSI2C_RX_DATA); >> + i2c->msg->buf[i2c->msg_ptr++] = byte; >> + } >> + } else { >> + byte = i2c->msg->buf[i2c->msg_ptr++]; >> + writel(byte, i2c->regs + HSI2C_TX_DATA); >> + > > > Extra blank line. Here you only write one byte - is there a tx FIFO > also, so we can avoid doing one interrupt per transmit byte? Sure, will implement in next version. > >> >> + } >> + >> + if (i2c->msg_ptr >= i2c->msg->len) >> + exynos5_i2c_stop(i2c); >> + >> + /* Set these bits to clear them */ >> + writel(readl(i2c->regs + HSI2C_INT_STATUS), >> + i2c->regs + HSI2C_INT_STATUS); >> + >> + return IRQ_HANDLED; > > > Are there any other interrupt types that can happen, like errors for example? TX_ALMOSTEMPTY, RX_ALMOSTFULL, TX_UNDERRUN, TX_OVERRUN,, RX_UNDERRUN, RX_OVERRUN, TRAILING, I2C_INT are the possible interrupts. No error cases > >> >> +} >> + >> +static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop) > > > Function comment would be useful - what is stop for? Sure > >> >> +{ >> + u32 i2c_ctl = readl(i2c->regs + HSI2C_CTL); >> + u32 int_en = HSI2C_INT_I2C_EN; >> + u32 i2c_auto_conf; >> + u32 fifo_ctl; >> + >> + exynos5_i2c_en_timeout(i2c); >> + >> + fifo_ctl = HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN | >> + HSI2C_TXFIFO_TRIGGER_LEVEL | HSI2C_RXFIFO_TRIGGER_LEVEL; >> + writel(fifo_ctl, i2c->regs + HSI2C_FIFO_CTL); >> + > > > You could > > i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON) > > here to simply code below. Thanks for the tip > >> >> + if (i2c->msg->flags & I2C_M_RD) { >> + i2c_ctl &= ~HSI2C_TXCHON; >> + i2c_ctl |= HSI2C_RXCHON; >> + >> + i2c_auto_conf |= HSI2C_READ_WRITE; >> + >> + int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN | >> + HSI2C_INT_TRAILING_EN); >> + } else { >> + i2c_ctl &= ~HSI2C_RXCHON; >> + i2c_ctl |= HSI2C_TXCHON; >> + >> + int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN; >> + } >> + >> + if (stop == 1) >> + i2c_auto_conf |= HSI2C_STOP_AFTER_TRANS; >> + >> + writel(HSI2C_SLV_ADDR_MAS(i2c->msg->addr), i2c->regs + HSI2C_ADDR); >> + >> + writel(i2c_ctl, i2c->regs + HSI2C_CTL); >> + >> + /* In auto mode the length of xfer cannot be 0 */ >> >> + if (i2c->msg->len <= 0) > > > What is auto mode? Perhaps a little comment at the top of the file > about the two modes? What does it mean when msg->len < 0? Will define. Sorry, i don't think i2c core will ever give msg->len as 0 (unles msg_send or msg_recv passes). > >> >> + i2c_auto_conf |= 0x1; >> + else >> + i2c_auto_conf |= i2c->msg->len; >> + >> + writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONF); >> + >> + exynos5_i2c_master_run(i2c); >> + >> + writel(int_en, i2c->regs + HSI2C_INT_ENABLE); >> +} >> + >> +static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c, >> + struct i2c_msg *msgs, int stop) >> +{ >> + unsigned long timeout; >> + u32 trans_status; >> + u32 fifo_stat; >> + int ret = -EAGAIN, val; >> + >> + i2c->msg = msgs; >> + i2c->msg_ptr = 0; >> + >> + exynos5_i2c_message_start(i2c, stop); >> + >> + val = wait_for_completion_interruptible_timeout >> + (&i2c->msg_complete, EXYNOS5_I2C_TIMEOUT); >> + if (val >= 0) >> + timeout = val; >> + >> + if (msgs->flags & I2C_M_RD) { >> + if (timeout == 0) { >> + exynos5_i2c_reset(i2c); >> + dev_warn(i2c->dev, "rx timeout\n"); >> + return ret; >> + } >> + >> + ret = 0; >> + } else { >> + if (timeout == 0) { >> + exynos5_i2c_reset(i2c); >> + dev_warn(i2c->dev, "tx timeout\n"); >> + return ret; >> + } > > > Could perhaps make the timeout check common (put above the if (msgs->flags)). Sure > >> >> + >> + timeout = jiffies + timeout; >> + >> + while (time_before(jiffies, timeout)) { >> + fifo_stat = readl(i2c->regs + HSI2C_FIFO_STATUS); >> + trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS); >> + if ((trans_status & HSI2C_NO_DEV) || >> + (trans_status & HSI2C_NO_DEV_ACK && >> + !(i2c->msg->flags & I2C_M_IGNORE_NAK))) { >> + exynos5_i2c_reset(i2c); > > > I think these continuation lines should be indented a little more. Sure > >> >> + return -ENXIO; >> + } >> + if ((fifo_stat == HSI2C_FIFO_EMPTY) && >> + ((trans_status == 0) || >> + ((stop == 0) && >> + (trans_status == HSI2C_MASTER_BUSY)))) { >> + ret = 0; >> + break; >> + } >> + } >> >> + if (ret == -EAGAIN) { >> + exynos5_i2c_reset(i2c); >> + dev_warn(i2c->dev, "xfer timeout\n"); >> + return ret; >> + } >> + } >> + >> + return ret; >> +} >> + >> +static int exynos5_i2c_xfer(struct i2c_adapter *adap, >> + struct i2c_msg *msgs, int num) >> +{ >> + struct exynos5_i2c *i2c = (struct exynos5_i2c *)adap->algo_data; >> + int retry, i; >> + int ret, ret_pm; >> + int stop = 0; >> + struct i2c_msg *msgs_ptr = msgs; >> + >> + if (i2c->suspended) { >> + dev_err(i2c->dev, "HS-I2C is not initialzed.\n"); >> + return -EIO; >> + } >> + >> + ret_pm = pm_runtime_get_sync(i2c->dev); >> + if (IS_ERR_VALUE(ret_pm)) { >> + ret = -EIO; >> + goto out; >> + } >> + >> + clk_prepare_enable(i2c->clk); >> + >> + for (retry = 0; retry < adap->retries; retry++) { >> + for (i = 0; i < num; i++) { >> + if (i == num - 1) >> + stop = 1; > > > Perhaps: > > stop = (i == num - 1); > > so you can avoid the other assignments to stop Thanks for the tip > >> >> + ret = exynos5_i2c_xfer_msg(i2c, msgs_ptr, stop); >> + msgs_ptr++; >> + >> + if (ret == -EAGAIN) { >> + msgs_ptr = msgs; >> + stop = 0; >> + break; >> + } else if (ret == -ENXIO) >> + goto out; > > > {} around else part also I think I thought, single line doesn't require a brace. > >> >> + } >> + if (i == num) { >> + ret = num; >> + goto out; >> + } >> + >> + dev_dbg(i2c->dev, "retrying transfer (%d)\n", retry); >> + >> + udelay(100); >> + } >> + >> + ret = -EREMOTEIO; > > > Perhaps a dev_warn() here? Sure > >> >> + out: >> + clk_disable_unprepare(i2c->clk); >> + pm_runtime_mark_last_busy(i2c->dev); >> + pm_runtime_put_autosuspend(i2c->dev); >> + return ret; >> +} >> + >> +static u32 exynos5_i2c_func(struct i2c_adapter *adap) >> +{ >> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; >> +} >> + >> +static const struct i2c_algorithm exynos5_i2c_algorithm = { >> + .master_xfer = exynos5_i2c_xfer, >> + .functionality = exynos5_i2c_func, >> +}; >> + >> +/** >> + * Parse a list of GPIOs from a node property and request each one >> + * >> + * @param i2c i2c driver data >> + * @return 0 on success, -EINVAL on error, in which case no GPIOs requested >> +*/ >> +static int exynos5_i2c_parse_dt_gpio(struct exynos5_i2c *i2c) >> +{ >> + int idx, gpio, ret; >> + >> + for (idx = 0; idx < 2; idx++) { >> + gpio = of_get_gpio(i2c->dev->of_node, idx); >> + if (!gpio_is_valid(gpio)) { >> + dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio); >> + return -EINVAL; >> + } >> + i2c->gpios[idx] = gpio; >> + >> + ret = devm_gpio_request(i2c->dev, gpio, "i2c-bus"); >> + if (ret) { >> + dev_err(i2c->dev, "gpio [%d] request failed\n", gpio); >> + return -EINVAL; >> + } >> + } >> + return 0; >> +} >> + >> +#define HSI2C_REG(regname) {.name = #regname, .offset = regname} >> +static struct debugfs_reg32 exynos5_hsi2c_regs[] = { >> + HSI2C_REG(HSI2C_CTL), HSI2C_REG(HSI2C_FIFO_CTL), >> + HSI2C_REG(HSI2C_TRAILIG_CTL), HSI2C_REG(HSI2C_CLK_CTL), >> + HSI2C_REG(HSI2C_CLK_SLOT), HSI2C_REG(HSI2C_INT_ENABLE), >> + HSI2C_REG(HSI2C_INT_STATUS), HSI2C_REG(HSI2C_ERR_STATUS), >> + HSI2C_REG(HSI2C_FIFO_STATUS), HSI2C_REG(HSI2C_TX_DATA), >> + HSI2C_REG(HSI2C_RX_DATA), HSI2C_REG(HSI2C_CONF), >> + HSI2C_REG(HSI2C_AUTO_CONF), HSI2C_REG(HSI2C_TIMEOUT), >> + HSI2C_REG(HSI2C_MANUAL_CMD), HSI2C_REG(HSI2C_TRANS_STATUS), >> + HSI2C_REG(HSI2C_TIMING_HS1), HSI2C_REG(HSI2C_TIMING_HS2), >> + HSI2C_REG(HSI2C_TIMING_HS3), HSI2C_REG(HSI2C_TIMING_FS1), >> + HSI2C_REG(HSI2C_TIMING_FS2), HSI2C_REG(HSI2C_TIMING_FS3), >> + HSI2C_REG(HSI2C_TIMING_SLA), HSI2C_REG(HSI2C_ADDR), >> +}; >> + >> +static struct debugfs_regset32 exynos5_hsi2c_regset = { >> + .regs = exynos5_hsi2c_regs, >> + .nregs = ARRAY_SIZE(exynos5_hsi2c_regs), >> +}; >> + >> +static struct dentry *exynos5_hsi2c_reg_debugfs; >> + >> +static int exynos5_i2c_probe(struct platform_device *pdev) >> +{ >> + struct device_node *np = pdev->dev.of_node; >> + struct exynos5_i2c *i2c; >> + int ret; >> + >> + if (!np) { >> + dev_err(&pdev->dev, "no device node\n"); >> + return -ENOENT; >> + } >> + >> + i2c = devm_kzalloc(&pdev->dev, sizeof(struct exynos5_i2c), GFP_KERNEL); >> + if (!i2c) { >> + dev_err(&pdev->dev, "no memory for state\n"); >> + return -ENOMEM; >> + } >> + >> + /* Mode of operation High/Fast Speed mode */ >> + if (of_get_property(np, "samsung,hs-mode", NULL)) { >> + i2c->speed_mode = 1; >> + if (of_property_read_u32(np, "samsung,hs-clock", &i2c->clock)) >> + i2c->clock = HSI2C_HS_TX_CLOCK; >> + } else { >> + i2c->speed_mode = 0; >> + if (of_property_read_u32(np, "samsung,fs-clock", &i2c->clock)) >> + i2c->clock = HSI2C_FS_TX_CLOCK; >> + } >> + >> + strlcpy(i2c->adap.name, "exynos5-i2c", sizeof(i2c->adap.name)); >> + i2c->adap.owner = THIS_MODULE; >> + i2c->adap.algo = &exynos5_i2c_algorithm; >> + i2c->adap.retries = 2; >> + i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD; >> + >> + i2c->dev = &pdev->dev; >> + i2c->clk = devm_clk_get(&pdev->dev, "hsi2c"); >> + if (IS_ERR(i2c->clk)) { >> + dev_err(&pdev->dev, "cannot get clock\n"); >> + return -ENOENT; >> + } >> + >> + clk_prepare_enable(i2c->clk); >> + >> + i2c->regs = of_iomap(np, 0); >> + if (!i2c->regs) { >> + dev_err(&pdev->dev, "cannot map HS-I2C IO\n"); >> + ret = -EADDRNOTAVAIL; >> + goto err_clk; >> + } >> + >> + i2c->adap.algo_data = i2c; >> + i2c->adap.dev.parent = &pdev->dev; >> + >> + /* parse device tree and inititalise the gpio */ >> + if (exynos5_i2c_parse_dt_gpio(i2c)) >> + return -EINVAL; >> + >> + init_completion(&i2c->msg_complete); >> + >> + i2c->irq = ret = irq_of_parse_and_map(np, 0); >> + if (ret <= 0) { >> + dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n"); >> + goto err_iomap; >> + } >> + >> + ret = devm_request_irq(&pdev->dev, i2c->irq, exynos5_i2c_irq, >> + 0, dev_name(&pdev->dev), i2c); >> + >> + if (ret != 0) { >> + dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", i2c->irq); >> + goto err_iomap; >> + } >> + >> + /* >> + * TODO: Use private lock to avoid race conditions as >> + * mentioned in pm_runtime.txt >> + */ >> + pm_runtime_enable(i2c->dev); >> + pm_runtime_set_autosuspend_delay(i2c->dev, EXYNOS5_I2C_PM_TIMEOUT); >> + pm_runtime_use_autosuspend(i2c->dev); >> + >> + ret = pm_runtime_get_sync(i2c->dev); >> + if (IS_ERR_VALUE(ret)) >> + goto err_iomap; >> + >> + exynos5_i2c_init(i2c); >> + i2c->adap.nr = -1; >> + i2c->adap.dev.of_node = np; >> + >> + ret = i2c_add_numbered_adapter(&i2c->adap); >> + if (ret < 0) { >> + dev_err(&pdev->dev, "failed to add bus to i2c core\n"); >> + goto err_pm; >> + } >> + >> + of_i2c_register_devices(&i2c->adap); >> + platform_set_drvdata(pdev, i2c); >> + >> + exynos5_hsi2c_reg_debugfs = debugfs_create_regset32("exynos5-hsi2c", >> + S_IFREG | S_IRUGO, >> + NULL, &exynos5_hsi2c_regset); >> + clk_disable_unprepare(i2c->clk); >> + pm_runtime_mark_last_busy(i2c->dev); >> + pm_runtime_put_autosuspend(i2c->dev); >> + >> + return 0; >> + >> + err_pm: >> + pm_runtime_put(i2c->dev); >> + pm_runtime_disable(&pdev->dev); >> + err_iomap: >> + iounmap(i2c->regs); >> + err_clk: >> + clk_disable_unprepare(i2c->clk); >> + return ret; >> +} >> + >> +static int exynos5_i2c_remove(struct platform_device *pdev) >> +{ >> + struct exynos5_i2c *i2c = platform_get_drvdata(pdev); >> + int ret; >> + >> + ret = pm_runtime_get_sync(&pdev->dev); >> + if (IS_ERR_VALUE(ret)) >> + return ret; >> + >> + clk_disable_unprepare(i2c->clk); >> + pm_runtime_put(&pdev->dev); >> + pm_runtime_disable(&pdev->dev); >> + >> + i2c_del_adapter(&i2c->adap); >> + >> + iounmap(i2c->regs); >> + >> + return 0; >> +} >> + >> +#ifdef CONFIG_PM >> +static int exynos5_i2c_suspend_noirq(struct device *dev) > > > Have you selected the noirq methods for a reason? I am just interested > in how you decided to use suspend_noirq() instead of suspend(). I've taken the reference from s3c24xx driver. My understanding is suspend late and resume faster. Kindly, help. > >> >> +{ >> + struct platform_device *pdev = to_platform_device(dev); >> + struct exynos5_i2c *i2c = platform_get_drvdata(pdev); >> + >> + i2c->suspended = 1; >> + >> + return 0; >> +} >> + >> +static int exynos5_i2c_resume_noirq(struct device *dev) >> +{ >> + struct platform_device *pdev = to_platform_device(dev); >> + struct exynos5_i2c *i2c = platform_get_drvdata(pdev); >> + >> + clk_prepare_enable(i2c->clk); >> + exynos5_i2c_init(i2c); >> + clk_disable_unprepare(i2c->clk); >> + i2c->suspended = 0; >> + >> + return 0; >> +} >> + >> +static const struct dev_pm_ops exynos5_i2c_dev_pm_ops = { >> + .suspend_noirq = exynos5_i2c_suspend_noirq, >> + .resume_noirq = exynos5_i2c_resume_noirq, >> +}; >> + >> +#define EXYNOS5_DEV_PM_OPS (&exynos5_i2c_dev_pm_ops) >> +#else >> +#define EXYNOS5_DEV_PM_OPS NULL >> +#endif >> + >> +static struct platform_driver exynos5_i2c_driver = { >> + .probe = exynos5_i2c_probe, >> + .remove = exynos5_i2c_remove, >> + .driver = { >> + .owner = THIS_MODULE, >> + .name = "exynos5-hsi2c", >> + .pm = EXYNOS5_DEV_PM_OPS, >> + .of_match_table = of_match_ptr(exynos5_i2c_match), >> + }, >> +}; >> + >> +static int __init i2c_adap_exynos5_init(void) >> +{ >> + return platform_driver_register(&exynos5_i2c_driver); >> +} >> +subsys_initcall(i2c_adap_exynos5_init); >> + >> +static void __exit i2c_adap_exynos5_exit(void) >> +{ >> + platform_driver_unregister(&exynos5_i2c_driver); >> +} >> +module_exit(i2c_adap_exynos5_exit); >> + >> +MODULE_DESCRIPTION("Exynos5 HS-I2C Bus driver"); >> +MODULE_AUTHOR("Naveen Krishna Chatradhi, <ch.naveen@xxxxxxxxxxx>"); >> +MODULE_AUTHOR("Taekgyun Ko, <taeggyun.ko@xxxxxxxxxxx>"); >> +MODULE_LICENSE("GPL"); >> -- >> 1.7.9.5 >> > > Regards, > Simon > -- > To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Shine bright, (: Nav :) -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
