Re: [PATCH 1/3] i2c: exynos5: add High Speed I2C controller driver

Naveen Krishna Ch
2012-11-28T04:23:20Z

Hello Felipe, Thomas,

Thanks for your time and valuable comments,
I will post the next version with you comments addressed.

On 27 November 2012 19:04, Thomas Abraham <thomas.abraham-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
>
> On 27 November 2012 18:30, Naveen Krishna Chatradhi
> <ch.naveen-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> 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.
> >
> > Signed-off-by: Taekgyun Ko <taeggyun.ko-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > Signed-off-by: Naveen Krishna Chatradhi <ch.naveen-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > ---
> > drivers/i2c/busses/Kconfig | 6 +
> > drivers/i2c/busses/Makefile | 1 +
> > drivers/i2c/busses/i2c-exynos5.c | 758
> > ++++++++++++++++++++++++++++++++++++++
> > drivers/i2c/busses/i2c-exynos5.h | 80 ++++
> > 4 files changed, 845 insertions(+)
> > create mode 100644 drivers/i2c/busses/i2c-exynos5.c
> > create mode 100644 drivers/i2c/busses/i2c-exynos5.h
> >
> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> > index 65dd599..88e8833 100644
> > --- a/drivers/i2c/busses/Kconfig
> > +++ b/drivers/i2c/busses/Kconfig
> > @@ -609,6 +609,12 @@ config I2C_S3C2410
> > Say Y here to include support for I2C controller in the
> > Samsung SoCs.
> >
> > +config I2C_EXYNOS5
> > + tristate "Exynos5 HS-I2C Driver"
> > + help
> > + Say Y here to include support for High Speed I2C controller in
> > the
> > + Exynos5 series SoCs from Samsung.
> > +
> > config I2C_S6000
> > tristate "S6000 I2C support"
> > depends on XTENSA_VARIANT_S6000
> > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> > index 2d33d62..426b4fd 100644
> > --- a/drivers/i2c/busses/Makefile
> > +++ b/drivers/i2c/busses/Makefile
> > @@ -60,6 +60,7 @@ obj-$(CONFIG_I2C_PUV3) += i2c-puv3.o
> > obj-$(CONFIG_I2C_PXA) += i2c-pxa.o
> > obj-$(CONFIG_I2C_PXA_PCI) += i2c-pxa-pci.o
> > obj-$(CONFIG_I2C_S3C2410) += i2c-s3c2410.o
> > +obj-$(CONFIG_I2C_EXYNOS5) += i2c-exynos5.o
> > obj-$(CONFIG_I2C_S6000) += i2c-s6000.o
> > obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o
> > obj-$(CONFIG_I2C_SH_MOBILE) += i2c-sh_mobile.o
> > diff --git a/drivers/i2c/busses/i2c-exynos5.c
> > b/drivers/i2c/busses/i2c-exynos5.c
> > new file mode 100644
> > index 0000000..5983aa9
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-exynos5.c
> > @@ -0,0 +1,758 @@
> > +/* linux/drivers/i2c/busses/i2c-exynos5.c
> > + *
> > + * Copyright (C) 2012 Samsung Electronics Co., Ltd.
> > + *
> > + * Exynos5 series High Speed I2C controller driver
> > + *
> > + * 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/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/clk.h>
> > +#include <linux/slab.h>
> > +#include <linux/io.h>
> > +#include <linux/of_i2c.h>
> > +#include <linux/of_gpio.h>
> > +
> > +#include <asm/irq.h>
> > +#include "i2c-exynos5.h"
> > +
> > +#define HSI2C_POLLING 0
> > +#define HSI2C_FAST_SPD 0
> > +#define HSI2C_HIGH_SPD 1
> > +
> > +/* Max time to wait for bus to become idle after a xfer */
> > +#define EXYNOS5_I2C_TIMEOUT (msecs_to_jiffies(1000))
> > +
> > +struct exynos5_i2c {
> > + unsigned int suspended:1;
> > +
> > + struct i2c_msg *msg;
> > + struct completion msg_complete;
> > + unsigned int msg_byte_ptr;
> > +
> > + unsigned int irq;
> > +
> > + void __iomem *regs;
> > + struct clk *clk;
> > + struct device *dev;
> > + struct resource *ioarea;
> > + struct i2c_adapter adap;
> > + unsigned int bus_number;
> > + unsigned int speed_mode;
> > + unsigned int fast_speed;
> > + unsigned int high_speed;
> > + int operation_mode;
> > + int gpios[2];
> > +};
> > +
> > +static struct platform_device_id exynos5_driver_ids[] = {
> > + {
> > + .name = "exynos5-hs-i2c",
> > + .driver_data = 0,
> > + }, { },
> > +};
> > +MODULE_DEVICE_TABLE(platform, exynos5_driver_ids);
> > +
> > +#ifdef CONFIG_OF
> > +static const struct of_device_id exynos5_i2c_match[] = {
> > + { .compatible = "samsung,exynos5-hs-i2c", .data = (void *)0 },
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(of, exynos5_i2c_match);
> > +#endif
> > +
> > +static inline void dump_i2c_register(struct exynos5_i2c *i2c)
> > +{
> > + dev_dbg(i2c->dev, "Register dump(%d) :\n %x\n %x\n %x\n %x\n"
> > + " %x\n %x\n %x\n %x\n %x\n"
> > + " %x\n %x\n %x\n %x\n %x\n"
> > + " %x\n %x\n %x\n %x\n %x\n"
> > + " %x\n %x\n %x\n %x\n %x\n"
> > + , i2c->suspended
> > + , readl(i2c->regs + HSI2C_CTL)
> > + , readl(i2c->regs + HSI2C_FIFO_CTL)
> > + , readl(i2c->regs + HSI2C_TRAILIG_CTL)
> > + , readl(i2c->regs + HSI2C_CLK_CTL)
> > + , readl(i2c->regs + HSI2C_CLK_SLOT)
> > + , readl(i2c->regs + HSI2C_INT_ENABLE)
> > + , readl(i2c->regs + HSI2C_INT_STATUS)
> > + , readl(i2c->regs + HSI2C_ERR_STATUS)
> > + , readl(i2c->regs + HSI2C_FIFO_STATUS)
> > + , readl(i2c->regs + HSI2C_TX_DATA)
> > + , readl(i2c->regs + HSI2C_RX_DATA)
> > + , readl(i2c->regs + HSI2C_CONF)
> > + , readl(i2c->regs + HSI2C_AUTO_CONFING)
> > + , readl(i2c->regs + HSI2C_TIMEOUT)
> > + , readl(i2c->regs + HSI2C_MANUAL_CMD)
> > + , readl(i2c->regs + HSI2C_TRANS_STATUS)
> > + , readl(i2c->regs + HSI2C_TIMING_HS1)
> > + , readl(i2c->regs + HSI2C_TIMING_HS2)
> > + , readl(i2c->regs + HSI2C_TIMING_HS3)
> > + , readl(i2c->regs + HSI2C_TIMING_FS1)
> > + , readl(i2c->regs + HSI2C_TIMING_FS2)
> > + , readl(i2c->regs + HSI2C_TIMING_FS3)
> > + , readl(i2c->regs + HSI2C_TIMING_SLA)
> > + , readl(i2c->regs + HSI2C_ADDR));
> > +}
> > +
> > +static inline void exynos5_i2c_stop(struct exynos5_i2c *i2c)
> > +{
> > + writel(0, i2c->regs + HSI2C_INT_ENABLE);
> > +
> > + complete(&i2c->msg_complete);
> > +}
> > +
> > +static inline void exynos5_disable_irq(struct exynos5_i2c *i2c)
> > +{
> > + unsigned long tmp = readl(i2c->regs + HSI2C_INT_STATUS);
> > +
> > + writel(tmp, i2c->regs + HSI2C_INT_STATUS);
> > +}
> > +
> > +static void exynos5_i2c_en_timeout(struct exynos5_i2c *i2c)
> > +{
> > + unsigned long i2c_timeout = readl(i2c->regs + HSI2C_TIMEOUT);
> > +
> > + /* Clear to enable Timeout */
> > + i2c_timeout &= ~HSI2C_TIMEOUT_EN;
> > + writel(i2c_timeout, i2c->regs + HSI2C_TIMEOUT);
> > +}
> > +
> > +static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
> > +{
> > + struct exynos5_i2c *i2c = dev_id;
> > + unsigned char byte;
> > +
> > + if (i2c->msg->flags & I2C_M_RD) {
> > + while ((readl(i2c->regs + HSI2C_FIFO_STATUS) &
> > + 0x1000000) == 0) {
> > + byte = (unsigned char)readl(i2c->regs +
> > HSI2C_RX_DATA);
> > + i2c->msg->buf[i2c->msg_byte_ptr++] = byte;
> > + }
> > +
> > + if (i2c->msg_byte_ptr >= i2c->msg->len)
> > + exynos5_i2c_stop(i2c);
> > + } else {
> > + byte = i2c->msg->buf[i2c->msg_byte_ptr++];
> > + writel(byte, i2c->regs + HSI2C_TX_DATA);
> > +
> > + if (i2c->msg_byte_ptr >= i2c->msg->len)
> > + exynos5_i2c_stop(i2c);
> > + }
> > +
> > + exynos5_disable_irq(i2c);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int exynos5_i2c_init(struct exynos5_i2c *i2c);
> > +
> > +static int exynos5_i2c_reset(struct exynos5_i2c *i2c)
> > +{
> > + unsigned long usi_ctl;
> > +
> > + usi_ctl = readl(i2c->regs + HSI2C_CTL);
> > + usi_ctl |= (1u << 31);
> > + writel(usi_ctl, i2c->regs + HSI2C_CTL);
> > + usi_ctl = readl(i2c->regs + HSI2C_CTL);
> > + usi_ctl &= ~(1u << 31);
>
> If the bit mask and bit position values are used more than once, it
> helps to define them as constants.
>
> > + writel(usi_ctl, i2c->regs + HSI2C_CTL);
> > + exynos5_i2c_init(i2c);
> > +
> > + return 0;
> > +}
> > +
> > +static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c,
> > + struct i2c_msg *msgs, int num, int stop)
> > +{
> > + unsigned long timeout;
> > + unsigned long trans_status;
> > + unsigned long usi_fifo_stat;
> > + unsigned long usi_ctl;
> > + unsigned long i2c_auto_conf;
> > + unsigned long i2c_addr;
> > + unsigned long usi_int_en;
> > + unsigned long usi_fifo_ctl;
> > + unsigned char byte;
> > + int ret = 0;
> > + int operation_mode = i2c->operation_mode;
> > +
> > + i2c->msg = msgs;
> > + i2c->msg_byte_ptr = 0;
> > +
> > + init_completion(&i2c->msg_complete);
> > +
> > + usi_ctl = readl(i2c->regs + HSI2C_CTL);
> > + i2c_auto_conf = readl(i2c->regs + HSI2C_AUTO_CONFING);
> > +
> > + exynos5_i2c_en_timeout(i2c);
> > +
> > + /* Set default trigger level for TXFIFO and RXFIFO */
> > + usi_fifo_ctl = HSI2C_TXFIFO_TRIGGER_LEVEL |
> > + HSI2C_RXFIFO_TRIGGER_LEVEL;
> > + /* Enable RXFIFO and TXFIFO */
> > + usi_fifo_ctl = HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN;
> > +
> > + writel(usi_fifo_ctl, i2c->regs + HSI2C_FIFO_CTL);
> > +
> > + usi_int_en = 0;
> > + if (msgs->flags & I2C_M_RD) {
> > + usi_ctl &= ~HSI2C_TXCHON;
> > + usi_ctl |= HSI2C_RXCHON;
> > +
> > + i2c_auto_conf |= HSI2C_READ_WRITE;
> > +
> > + usi_int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN |
> > + HSI2C_INT_TRAILING_EN);
> > + } else {
> > + usi_ctl &= ~HSI2C_RXCHON;
> > + usi_ctl |= HSI2C_TXCHON;
> > +
> > + i2c_auto_conf &= ~HSI2C_READ_WRITE;
> > +
> > + usi_int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN;
> > + }
> > +
> > + if (stop == 1)
> > + i2c_auto_conf |= HSI2C_STOP_AFTER_TRANS;
> > + else
> > + i2c_auto_conf &= ~HSI2C_STOP_AFTER_TRANS;
> > +
> > +
> > + i2c_addr = readl(i2c->regs + HSI2C_ADDR);
> > +
> > + /* Clear Slave Address for I2C Master (Auto mode only) */
> > + i2c_addr &= ~(0x3ff << 10);
> > + /* Clear Slave Address for I2C Slave */
> > + i2c_addr &= ~(0x3ff << 0);
> > + /* Clear Master ID for I2C Master (Auto and HS mode only) */
> > + if (i2c->speed_mode == HSI2C_HIGH_SPD)
> > + i2c_addr &= ~(0xff << 24);
> > +
> > + i2c_addr |= ((msgs->addr & 0x7f) << 10);
> > + writel(i2c_addr, i2c->regs + HSI2C_ADDR);
> > +
> > + writel(usi_ctl, i2c->regs + HSI2C_CTL);
> > +
> > + /* Clear and set TRANS_LEN */
> > + i2c_auto_conf &= ~(0xffff);
> > + i2c_auto_conf |= i2c->msg->len;
> > + writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONFING);
> > +
> > + /* Start data transfer in Master mode */
> > + i2c_auto_conf = readl(i2c->regs + HSI2C_AUTO_CONFING);
> > + i2c_auto_conf |= HSI2C_MASTER_RUN;
> > + writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONFING);
> > +
> > + /* Enable appropriate interrupts */
> > + if (operation_mode != HSI2C_POLLING)
> > + writel(usi_int_en, i2c->regs + HSI2C_INT_ENABLE);
> > +
> > + ret = -EAGAIN;
> > + if (msgs->flags & I2C_M_RD) {
> > + if (operation_mode == HSI2C_POLLING) {
> > + timeout = jiffies + EXYNOS5_I2C_TIMEOUT;
> > + while (time_before(jiffies, timeout)) {
> > + if ((readl(i2c->regs +
> > HSI2C_FIFO_STATUS) &
> > + 0x1000000) == 0) {
> > + byte = (unsigned char)readl
> > + (i2c->regs +
> > HSI2C_RX_DATA);
> > +
> > i2c->msg->buf[i2c->msg_byte_ptr++]
> > + = byte;
> > + }
> > +
> > + if (i2c->msg_byte_ptr >= i2c->msg->len)
> > {
> > + ret = 0;
> > + break;
> > + }
> > + }
> > +
> > + if (ret == -EAGAIN) {
> > + exynos5_i2c_reset(i2c);
> > + dev_warn(i2c->dev, "rx timeout\n");
> > + return ret;
> > + }
> > + } else {
> > + timeout =
> > wait_for_completion_interruptible_timeout
> > + (&i2c->msg_complete,
> > EXYNOS5_I2C_TIMEOUT);
> > +
> > + if (timeout == 0) {
> > + exynos5_i2c_reset(i2c);
> > + dev_warn(i2c->dev, "rx timeout\n");
> > + return ret;
> > + }
> > +
> > + ret = 0;
> > + }
> > + } else {
> > + if (operation_mode == HSI2C_POLLING) {
> > + timeout = jiffies + EXYNOS5_I2C_TIMEOUT;
> > + while (time_before(jiffies, timeout) &&
> > + (i2c->msg_byte_ptr < i2c->msg->len)) {
> > + if ((readl(i2c->regs +
> > HSI2C_FIFO_STATUS)
> > + & 0x7f) < 64) {
> > + byte = i2c->msg->buf
> > + [i2c->msg_byte_ptr++];
> > + writel(byte,
> > + i2c->regs +
> > HSI2C_TX_DATA);
> > + }
> > + }
> > + } else {
> > + timeout =
> > wait_for_completion_interruptible_timeout
> > + (&i2c->msg_complete,
> > EXYNOS5_I2C_TIMEOUT);
> > +
> > + if (timeout == 0) {
> > + exynos5_i2c_reset(i2c);
> > + dev_warn(i2c->dev, "tx timeout\n");
> > + return ret;
> > + }
> > +
> > + timeout = jiffies + timeout;
> > + }
> > + while (time_before(jiffies, timeout)) {
> > + usi_fifo_stat = readl(i2c->regs +
> > HSI2C_FIFO_STATUS);
> > + trans_status = readl(i2c->regs +
> > HSI2C_TRANS_STATUS);
> > + if ((usi_fifo_stat == HSI2C_FIFO_EMPTY) &&
> > + ((trans_status == 0) ||
> > + ((stop == 0) &&
> > + (trans_status == 0x20000)))) {
> > + ret = 0;
> > + break;
> > + }
> > + }
> > + if (ret == -EAGAIN) {
> > + exynos5_i2c_reset(i2c);
> > + dev_warn(i2c->dev, "tx 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;
> > + int stop = 0;
> > + struct i2c_msg *msgs_ptr = msgs;
> > +
> > + if (i2c->suspended) {
> > + dev_err(i2c->dev, "HS-I2C is not initialzed.\n");
> > + return -EIO;
> > + }
> > +
> > + clk_prepare_enable(i2c->clk);
> > +
> > + for (retry = 0; retry < adap->retries; retry++) {
> > + for (i = 0; i < num; i++) {
> > + if (i == num - 1)
> > + stop = 1;
> > + ret = exynos5_i2c_xfer_msg(i2c, msgs_ptr, 1,
> > stop);
> > + msgs_ptr++;
> > +
> > + if (ret == -EAGAIN) {
> > + msgs_ptr = msgs;
> > + stop = 0;
> > + break;
> > + }
> > + }
> > + if (i == num) {
> > + clk_disable_unprepare(i2c->clk);
> > + return num;
> > + }
> > +
> > + dev_dbg(i2c->dev, "retrying transfer (%d)\n", retry);
> > +
> > + udelay(100);
> > + }
> > +
> > + clk_disable_unprepare(i2c->clk);
> > +
> > + return -EREMOTEIO;
> > +}
> > +
> > +static u32 exynos5_i2c_func(struct i2c_adapter *adap)
> > +{
> > + return I2C_FUNC_I2C;
> > +}
> > +
> > +static const struct i2c_algorithm exynos5_i2c_algorithm = {
> > + .master_xfer = exynos5_i2c_xfer,
> > + .functionality = exynos5_i2c_func,
> > +};
> > +
> > +static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c)
> > +{
> > + unsigned long i2c_timing_s1;
> > + unsigned long i2c_timing_s2;
> > + unsigned long i2c_timing_s3;
> > + unsigned long i2c_timing_sla;
> > + unsigned int op_clk;
> > + 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;
> > +
> > + if (i2c->speed_mode == HSI2C_HIGH_SPD)
> > + op_clk = i2c->high_speed;
> > + else
> > + op_clk = i2c->fast_speed;
> > +
> > + /* 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;
> > + }
> > + }
> > +
> > + 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;
> > +}
> > +
> > +#ifdef CONFIG_OF
>
> If this driver supports only device tree (as stated in the commit
> message), then this #ifdef can be avoided.
>
> > +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);
> > + goto free_gpio;
> > + }
> > + i2c->gpios[idx] = gpio;
> > +
> > + ret = gpio_request(gpio, "hsi2c-bus");
>
> Using devm_gpio_request here can simplify the error handling path.
>
> > + if (ret) {
> > + dev_err(i2c->dev, "gpio [%d] request failed\n",
> > gpio);
> > + goto free_gpio;
> > + }
> > + }
> > + return 0;
> > +
> > +free_gpio:
> > + while (--idx >= 0)
> > + gpio_free(i2c->gpios[idx]);
> > + return -EINVAL;
> > +}
> > +
> > +static void exynos5_i2c_dt_gpio_free(struct exynos5_i2c *i2c)
> > +{
> > + unsigned int idx;
> > +
> > + for (idx = 0; idx < 2; idx++)
> > + gpio_free(i2c->gpios[idx]);
> > +}
> > +#else
> > +static int exynos5_i2c_parse_dt_gpio(struct exynos5_i2c *i2c)
> > +{
> > + return 0;
> > +}
> > +
> > +static void exynos5_i2c_dt_gpio_free(struct exynos5_i2c *i2c)
> > +{
> > +}
> > +#endif
> > +
> > +static int exynos5_i2c_init(struct exynos5_i2c *i2c)
> > +{
> > + unsigned long usi_ctl = HSI2C_FUNC_MODE_I2C | HSI2C_MASTER;
> > + unsigned long usi_trailing_ctl = HSI2C_TRAILING_COUNT;
> > + unsigned long i2c_conf = readl(i2c->regs + HSI2C_CONF);
> > +
> > + if (exynos5_i2c_parse_dt_gpio(i2c))
> > + return -EINVAL;
> > +
> > + writel(usi_ctl, i2c->regs + HSI2C_CTL);
> > +
> > + writel(usi_trailing_ctl, 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, i2c->regs + HSI2C_CONF);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int exynos5_i2c_probe(struct platform_device *pdev)
> > +{
> > + struct exynos5_i2c *i2c;
> > + struct resource *res;
> > + int ret;
> > +
> > + i2c = devm_kzalloc(&pdev->dev, sizeof(struct exynos5_i2c),
> > GFP_KERNEL);
> > + if (!i2c) {
> > + dev_err(&pdev->dev, "no memory for state\n");
> > + return -ENOMEM;
> > + }
> > +
> > + if (pdev->dev.of_node) {
> > + /* i2c bus number is dynamically assigned */
> > + i2c->bus_number = -1;
> > +
> > + if (of_property_read_u32(pdev->dev.of_node,
> > + "samsung,hsi2c-speed-mode",
> > &i2c->speed_mode))
> > + i2c->speed_mode = 1;
> > + if (!of_property_read_u32(pdev->dev.of_node,
> > + "samsung,hsi2c-hs-clk",
> > &i2c->high_speed))
> > + i2c->high_speed = 2500000;
> > + if (!of_property_read_u32(pdev->dev.of_node,
> > + "samsung,hsi2c-fs-clk",
> > &i2c->fast_speed))
> > + i2c->fast_speed = 400000;
> > + } else {
> > + dev_err(&pdev->dev, "no device node\n");
> > + return -ENOENT;
> > + }
> > +
> > + strlcpy(i2c->adap.name, "exynos5250-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 = clk_get(&pdev->dev, "hsi2c");
> > + if (IS_ERR(i2c->clk)) {
> > + dev_err(&pdev->dev, "cannot get clock\n");
> > + ret = -ENOENT;
> > + goto err_noclk;
> > + }
> > +
> > + clk_prepare_enable(i2c->clk);
> > +
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + if (res == NULL) {
> > + dev_err(&pdev->dev, "cannot find HS-I2C IO resource\n");
> > + ret = -ENOENT;
> > + goto err_clk;
> > + }
> > +
> > + i2c->ioarea = request_mem_region(res->start, resource_size(res),
> > + pdev->name);
>
> Since this is dt-only driver, use of_iomap here.
>
> > +
> > + if (i2c->ioarea == NULL) {
> > + dev_err(&pdev->dev, "cannot request HS-I2C IO\n");
> > + ret = -ENXIO;
> > + goto err_clk;
> > + }
> > +
> > + i2c->regs = ioremap(res->start, resource_size(res));
> > +
> > + if (i2c->regs == NULL) {
> > + dev_err(&pdev->dev, "cannot map HS-I2C IO\n");
> > + ret = -ENXIO;
> > + goto err_ioarea;
> > + }
> > +
> > + dev_dbg(&pdev->dev, "registers %p (%p, %p)\n",
> > + i2c->regs, i2c->ioarea, res);
> > +
> > + i2c->adap.algo_data = i2c;
> > + i2c->adap.dev.parent = &pdev->dev;
> > +
> > + ret = exynos5_i2c_init(i2c);
> > + if (ret != 0)
> > + goto err_iomap;
> > +
> > + i2c->irq = ret = platform_get_irq(pdev, 0);
>
> irq_of_parse_and_map() here.
>
> > + if (ret <= 0) {
> > + dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
> > + goto err_iomap;
> > + }
> > +
> > + ret = request_irq(i2c->irq, exynos5_i2c_irq, IRQF_DISABLED,
> > + dev_name(&pdev->dev), i2c);
> > +
> > + if (ret != 0) {
> > + dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n",
> > i2c->irq);
> > + goto err_iomap;
> > + }
> > +
> > + i2c->adap.nr = i2c->bus_number;
> > + i2c->adap.dev.of_node = pdev->dev.of_node;
> > +
> > + ret = i2c_add_numbered_adapter(&i2c->adap);
> > + if (ret < 0) {
> > + dev_err(&pdev->dev, "failed to add bus to i2c core\n");
> > + goto err_irq;
> > + }
> > +
> > + of_i2c_register_devices(&i2c->adap);
> > + platform_set_drvdata(pdev, i2c);
> > +
> > + dev_info(&pdev->dev, "%s: Exynos5 HS-I2C adapter\n",
> > + dev_name(&i2c->adap.dev));
> > + clk_disable_unprepare(i2c->clk);
> > + return 0;
> > +
> > + err_irq:
> > + free_irq(i2c->irq, i2c);
> > +
> > + err_iomap:
> > + iounmap(i2c->regs);
> > +
> > + err_ioarea:
> > + release_resource(i2c->ioarea);
> > + kfree(i2c->ioarea);
> > +
> > + err_clk:
> > + clk_disable_unprepare(i2c->clk);
> > + clk_put(i2c->clk);
> > +
> > + err_noclk:
> > + return ret;
> > +}
> > +
> > +static int exynos5_i2c_remove(struct platform_device *pdev)
> > +{
> > + struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
> > +
> > + i2c_del_adapter(&i2c->adap);
> > + free_irq(i2c->irq, i2c);
> > +
> > + clk_disable_unprepare(i2c->clk);
> > + clk_put(i2c->clk);
> > +
> > + iounmap(i2c->regs);
> > +
> > + release_resource(i2c->ioarea);
> > + exynos5_i2c_dt_gpio_free(i2c);
> > + kfree(i2c->ioarea);
> > +
> > + return 0;
> > +}
> > +
> > +#ifdef CONFIG_PM
> > +static int exynos5_i2c_suspend_noirq(struct device *dev)
> > +{
> > + struct platform_device *pdev = to_platform_device(dev);
> > + struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
> > +
> > + i2c_lock_adapter(&i2c->adap);
> > + i2c->suspended = 1;
> > + i2c_unlock_adapter(&i2c->adap);
> > +
> > + return 0;
> > +}
> > +
> > +static int exynos5_i2c_resume(struct device *dev)
> > +{
> > + struct platform_device *pdev = to_platform_device(dev);
> > + struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
> > +
> > + i2c_lock_adapter(&i2c->adap);
> > + clk_prepare_enable(i2c->clk);
> > + exynos5_i2c_init(i2c);
> > + clk_disable_unprepare(i2c->clk);
> > + i2c->suspended = 0;
> > + i2c_unlock_adapter(&i2c->adap);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct dev_pm_ops exynos5_i2c_dev_pm_ops = {
> > + .suspend_noirq = exynos5_i2c_suspend_noirq,
> > + .resume_noirq = exynos5_i2c_resume,
> > +};
> > +
> > +#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,
> > + .id_table = exynos5_driver_ids,
> > + .driver = {
> > + .owner = THIS_MODULE,
> > + .name = "exynos5-i2c",
> > + .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("Taekgyun Ko, <taeggyun.ko-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/i2c/busses/i2c-exynos5.h
> > b/drivers/i2c/busses/i2c-exynos5.h
> > new file mode 100644
> > index 0000000..063051e
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-exynos5.h
> > @@ -0,0 +1,80 @@
> > +/*
> > + * Copyright (C) 2012 Samsung Electronics Co., Ltd.
> > + *
> > + * Exynos5 series HS-I2C Controller
> > + *
> > + * 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.
> > +*/
> > +
> > +#ifndef __ASM_ARCH_REGS_HS_IIC_H
> > +#define __ASM_ARCH_REGS_HS_IIC_H __FILE__
> > +
> > +/*
> > + * 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_CONFING 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 */
> > +#define HSI2C_FUNC_MODE_I2C (1u << 0)
> > +#define HSI2C_MASTER (1u << 3)
> > +#define HSI2C_RXCHON (1u << 6)
> > +#define HSI2C_TXCHON (1u << 7)
> > +
> > +/* I2C_FIFO_CTL Register */
> > +#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 */
> > +#define HSI2C_TRAILING_COUNT (0xf)
> > +
> > +/* I2C_INT_EN Register */
> > +#define HSI2C_INT_TX_ALMOSTEMPTY_EN (1u << 0) /* For TX FIFO
> > */
> > +#define HSI2C_INT_RX_ALMOSTFULL_EN (1u << 1) /* For RX FIFO
> > */
> > +#define HSI2C_INT_TRAILING_EN (1u << 6)
> > +
> > +/* I2C_CONF Register */
> > +#define HSI2C_AUTO_MODE (1u << 31)
> > +#define HSI2C_10BIT_ADDR_MODE (1u << 30)
> > +#define HSI2C_HS_MODE (1u << 29)
> > +
> > +/* I2C_AUTO_CONF Register */
> > +#define HSI2C_READ_WRITE (1u << 16)
> > +#define HSI2C_STOP_AFTER_TRANS (1u << 17)
> > +#define HSI2C_MASTER_RUN (1u << 31)
> > +
> > +/* I2C_TIMEOUT Register */
> > +#define HSI2C_TIMEOUT_EN (1u << 31)
> > +
> > +#define HSI2C_FIFO_EMPTY (0x1000100)
> > +
> > +#define HSI2C_FS_BPS 400000
> > +#define HSI2C_HS_BPS 2500000
> > +
> > +#endif /* __ASM_ARCH_REGS_HS_IIC_H */
>
> Since these constants are only use in i2c-exynos5.c file, it is better
> to move these definitions into i2c-exynos5.c file.
>
> Thanks,
> Thomas.

--
Shine bright,
(: Nav :)