[RFC: PATCH v5] i2c: exynos5: add High Speed I2C controller driver
From: Naveen Krishna Chatradhi
Date: Wed Mar 20 2013 - 12:27:32 EST
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>
---
Changes since v4:
1. Fixed ISR routine to handle interrupt and fifo status registers
2. Handle the error return
3. Split the exynos5_i2c_set_timing to report error
4. Added description for the static functions and modes of operation
5. implemented TX fifo and RX fifo usage
.../devicetree/bindings/i2c/i2c-exynos5.txt | 50 ++
drivers/i2c/busses/Kconfig | 7 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-exynos5.c | 871 ++++++++++++++++++++
4 files changed, 929 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..e8e6483
--- /dev/null
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -0,0 +1,871 @@
+/**
+ * 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>
+
+/*
+ * HSI2C controller from Samsung supports 2 modes of operation
+ * 1. Auto mode: Where in master automatically controls the whole transaction
+ * 2. Manual mode: Software controls the transaction by issuing commands
+ * START, READ, WRITE, STOP, RESTART in I2C_MANUAL_CMD register.
+ *
+ * Operation mode can be selected by setting AUTO_MODE bit in I2C_CONF register
+ *
+ * Special bits are available for both modes of operation to set commands
+ * and for checking transfer status
+ */
+
+/* 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 (0x30 << 16)
+#define HSI2C_RXFIFO_TRIGGER_LEVEL (0x30 << 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_INT_STAT Register bits */
+#define HSI2C_INT_TX_ALMOSTEMPTY (1u << 0)
+#define HSI2C_INT_RX_ALMOSTFULL (1u << 1)
+#define HSI2C_INT_TX_UNDERRUN (1u << 2)
+#define HSI2C_INT_TX_OVERRUN (1u << 3)
+#define HSI2C_INT_RX_UNDERRUN (1u << 4)
+#define HSI2C_INT_RX_OVERRUN (1u << 5)
+#define HSI2C_INT_TRAILING (1u << 6)
+#define HSI2C_INT_I2C (1u << 9)
+#define HSI2C_RX_INT (HSI2C_INT_RX_ALMOSTFULL | \
+ HSI2C_INT_RX_UNDERRUN | \
+ HSI2C_INT_RX_OVERRUN | \
+ HSI2C_INT_TRAILING)
+
+/* I2C_FIFO_STAT Register bits */
+#define HSI2C_RX_FIFO_EMPTY (1u << 24)
+#define HSI2C_RX_FIFO_FULL (1u << 23)
+#define HSI2C_RX_FIFO_LVL(x) ((x >> 16) & 0x7f)
+#define HSI2C_TX_FIFO_EMPTY (1u << 8)
+#define HSI2C_TX_FIFO_FULL (1u << 7)
+#define HSI2C_TX_FIFO_LVL(x) ((x >> 0) & 0x7f)
+#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_TIMEOUT_AUTO (1u << 4)
+#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 msg_len;
+
+ unsigned int irq;
+
+ void __iomem *regs;
+ struct clk *clk;
+ struct device *dev;
+ int state;
+
+ /* GPIO lines for SDA/SCL*/
+ int gpios[2];
+
+ /* Controller operating frequency */
+ unsigned int clock;
+ unsigned int clk_cycle;
+ unsigned int clk_div;
+
+ /* 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);
+}
+
+/* exynos5_i2c_clock_info: Calculates the clock divisor and
+ * the clock cycle length (SCLK High + SCLK Low)
+ *
+ * Returns 0 on success, -EINVAL if the cycle length cannot
+ * be calculated.
+ */
+static int exynos5_i2c_clock_info(struct exynos5_i2c *i2c)
+{
+ unsigned int op_clk = i2c->clock;
+ unsigned int clkin = clk_get_rate(i2c->clk);
+ unsigned int i, utemp0 = 0, utemp1 = 0, utemp2 = 0;
+ unsigned int t_ftl_cycle;
+
+ /* 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;
+ }
+ }
+
+ if (utemp2 <= 0)
+ return -EINVAL;
+
+ i2c->clk_cycle = utemp2;
+ i2c->clk_div = i;
+
+ return 0;
+}
+
+/* exynos5_i2c_set_timing: updates the registers with appropriate
+ * timing values calculated earlier (exynos5_i2c_clock_info)
+ *
+ * To handle the error case in calculates and to avoid the subsequent
+ * calculates the clk_div and clk_cycle are stored
+ */
+static void 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 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;
+
+ n_clkdiv = i2c->clk_div;
+ t_scl_l = i2c->clk_cycle / 2;
+ t_scl_h = i2c->clk_cycle / 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 = i2c->clk_cycle;
+
+ 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);
+}
+
+/* exynos5_i2c_init: configures the controller for I2C functionality
+ * Programs I2C controller for Master mode operation
+ *
+ * Note: Currently, supports AUTO mode of operation.
+ */
+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
+ *
+ * INT_STATUS registers gives the interrupt details. Further,
+ * FIFO_STATUS or TRANS_STATUS registers are to be check for detailed
+ * state of the bus.
+ */
+static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
+{
+ struct exynos5_i2c *i2c = dev_id;
+ u32 fifo_level, int_status, fifo_status, trans_status;
+ unsigned char byte;
+ int len = 0;
+
+ i2c->state = -EINVAL;
+
+ int_status = readl(i2c->regs + HSI2C_INT_STATUS);
+ fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS);
+
+ if (int_status & HSI2C_INT_I2C) {
+ trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS);
+ if (trans_status & HSI2C_NO_DEV_ACK) {
+ dev_dbg(i2c->dev, "No ACK from device\n");
+ i2c->state = -ENXIO;
+ } else if (trans_status & HSI2C_NO_DEV) {
+ dev_dbg(i2c->dev, "No device\n");
+ i2c->state = -ENXIO;
+ } else if (trans_status & HSI2C_TRANS_ABORT) {
+ dev_dbg(i2c->dev, "Deal with arbitration lose\n");
+ i2c->state = -EAGAIN;
+ } else if (trans_status & HSI2C_TIMEOUT_AUTO) {
+ dev_dbg(i2c->dev, "Accessing device timed out\n");
+ i2c->state = -EAGAIN;
+ }
+ }
+ /* TX_ALMOSTEMPTY can happen along with HSI2C_INT_I2C */
+ else if (int_status &
+ (HSI2C_INT_TX_UNDERRUN | HSI2C_INT_TX_ALMOSTEMPTY)) {
+ fifo_level = HSI2C_TX_FIFO_LVL(fifo_status);
+
+ /* To support probing the devices for detection */
+ if (i2c->msg->len == 0) {
+ i2c->state = -ENXIO;
+ goto stop;
+ }
+
+ /* 0x30 is the default trigger level for TX FIFO */
+ len = 48 - fifo_level;
+
+ if (len > i2c->msg->len)
+ len = i2c->msg->len;
+
+ i2c->msg_len += len;
+ while (len > 0) {
+ byte = i2c->msg->buf[i2c->msg_ptr++];
+ writel(byte, i2c->regs + HSI2C_TX_DATA);
+ len--;
+ }
+ i2c->state = 0;
+ goto stop;
+ }
+ /* If TX FIFO is full (give chance to clear) */
+ else if (int_status & HSI2C_INT_TX_OVERRUN)
+ i2c->state = 0;
+
+ if (int_status & (HSI2C_INT_RX_OVERRUN | HSI2C_INT_TRAILING |
+ HSI2C_INT_RX_UNDERRUN | HSI2C_INT_RX_ALMOSTFULL)) {
+ fifo_level = HSI2C_RX_FIFO_LVL(fifo_status);
+
+ if (fifo_level >= i2c->msg->len)
+ len = i2c->msg->len;
+ else
+ len = fifo_level;
+
+ i2c->msg_len += len;
+ while (len > 0) {
+ byte = (unsigned char)
+ readl(i2c->regs + HSI2C_RX_DATA);
+ i2c->msg->buf[i2c->msg_ptr++] = byte;
+ len--;
+ }
+ i2c->state = 0;
+ }
+
+
+ stop:
+ if ((i2c->msg_len == i2c->msg->len) || (i2c->state < 0))
+ 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;
+}
+
+/*
+ * exynos5_i2c_message_start: Configures the bus and starts the xfer
+ * i2c: struct exynos5_i2c pointer for the current bus
+ * stop: Enables stop after transfer if set. Set for last transfer of
+ * in the list of messages.
+ *
+ * Configures the bus for read/write function
+ * Sets chip address to talk to, message length to be sent.
+ * Enables appropriate interrupts and sends start xfer command.
+ */
+static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
+{
+ u32 i2c_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);
+
+ i2c_ctl = readl(i2c->regs + HSI2C_CTL);
+ i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON);
+
+ if (i2c->msg->flags & I2C_M_RD) {
+ 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_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;
+ int ret;
+
+ i2c->msg = msgs;
+ i2c->msg_ptr = 0;
+ i2c->msg_len = 0;
+
+ exynos5_i2c_message_start(i2c, stop);
+
+ ret = wait_for_completion_interruptible_timeout
+ (&i2c->msg_complete, EXYNOS5_I2C_TIMEOUT);
+ if (ret >= 0)
+ timeout = ret;
+ else
+ return ret;
+
+ ret = i2c->state;
+
+ if (timeout == 0) {
+ exynos5_i2c_reset(i2c);
+ dev_warn(i2c->dev, "%s timeout\n",
+ (msgs->flags & I2C_M_RD) ? "rx" : "tx");
+ return ret;
+ }
+
+ if (ret == -EAGAIN) {
+ exynos5_i2c_reset(i2c);
+ 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;
+ struct i2c_msg *msgs_ptr = msgs;
+ int retry, i = 0;
+ int ret, ret_pm;
+ int stop = 0;
+
+ 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++) {
+ stop = (i == num - 1);
+
+ ret = exynos5_i2c_xfer_msg(i2c, msgs_ptr, stop);
+ msgs_ptr++;
+
+ if (ret == -EAGAIN) {
+ msgs_ptr = msgs;
+ break;
+ } else if (ret < 0) {
+ goto out;
+ }
+ }
+
+ if ((i == num) && (ret != -EAGAIN))
+ break;
+
+ dev_dbg(i2c->dev, "retrying transfer (%d)\n", retry);
+
+ udelay(100);
+ }
+
+ check:
+ if (i == num) {
+ /* only one message, return number of bytes transfered */
+ if (num == 1)
+ ret = i2c->msg_len;
+ else
+ ret = num;
+ } else {
+ /* Only one message, cannot access the device */
+ if (i == 1)
+ ret = -EREMOTEIO;
+ else
+ ret = i;
+
+ dev_warn(i2c->dev, "xfer message failed\n");
+ }
+
+ 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;
+
+ ret = exynos5_i2c_clock_info(i2c);
+ if (ret)
+ goto err_pm;
+
+ 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@xxxxxxxxxxx>");
+MODULE_AUTHOR("Taekgyun Ko, <taeggyun.ko@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
1.7.9.5
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