Message-id: <1363062732-27869-1-git-send-email-ch.naveen@samsung.com>
Date:	Tue, 12 Mar 2013 10:02:12 +0530
From:	Naveen Krishna Chatradhi <ch.naveen@...sung.com>
To:	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-samsung-soc@...r.kernel.org
Cc:	w.sang@...gutronix.de, khali@...ux-fr.org, ben-linux@...ff.org,
	grant.likely@...retlab.ca, devicetree-discuss@...ts.ozlabs.org,
	sjg@...omium.org, grundler@...omium.org, naveen@...omium.org,
	broonie@...nsource.wolfsonmicro.com
Subject: [PATCH] i2c: exynos5: add High Speed I2C controller driver

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@...sung.com>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@...sung.com>
Cc: R. Chandrasekar <rcsekar@...sung.com>
---
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@...a0000 {
+		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;
+
+	/* 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;
+}
+
+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;
+
+	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);
+
+	}
+
+	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;
+}
+
+static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
+{
+	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);
+
+	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)
+		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;
+		}
+
+		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);
+				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;
+			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;
+		}
+		if (i == num) {
+			ret = num;
+			goto out;
+		}
+
+		dev_dbg(i2c->dev, "retrying transfer (%d)\n", retry);
+
+		udelay(100);
+	}
+
+	ret = -EREMOTEIO;
+ 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)
+{
+	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@...sung.com>");
+MODULE_AUTHOR("Taekgyun Ko, <taeggyun.ko@...sung.com>");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5

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