This adds support for the ST Microelectronics DDC I2C bus
driver. This bus is used in the U300 architecture recently
added to RMK:s ARM tree.
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
Reviewed-by: Ben Dooks <ben-linux@xxxxxxxxx>
Reviewed-by: Jean Delvare <khali@xxxxxxxxxxxx>
---
drivers/i2c/busses/Kconfig | 12 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-stu300.c | 1022 +++++++++++++++++++++++++++++++++++++++
3 files changed, 1035 insertions(+), 0 deletions(-)
create mode 100644 drivers/i2c/busses/i2c-stu300.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index a48c8ae..8c5d568 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -513,6 +513,18 @@ config I2C_SIMTEC
This driver can also be built as a module. If so, the module
will be called i2c-simtec.
+config I2C_STU300
+ tristate "ST Microelectronics DDC I2C interface"
+ default y if MACH_U300
+ help
+ If you say yes to this option, support will be included for the
+ I2C interface from ST Microelectronics simply called "DDC I2C"
+ supporting both I2C and DDC, used in e.g. the U300 series
+ mobile platforms.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-stu300.
+
config I2C_VERSATILE
tristate "ARM Versatile/Realview I2C bus support"
depends on ARCH_VERSATILE || ARCH_REALVIEW
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 776acb6..edeabf0 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_I2C_S6000) += i2c-s6000.o
obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o
obj-$(CONFIG_I2C_SH_MOBILE) += i2c-sh_mobile.o
obj-$(CONFIG_I2C_SIMTEC) += i2c-simtec.o
+obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
# External I2C/SMBus adapter drivers
diff --git a/drivers/i2c/busses/i2c-stu300.c b/drivers/i2c/busses/i2c-stu300.c
new file mode 100644
index 0000000..2a2e569
--- /dev/null
+++ b/drivers/i2c/busses/i2c-stu300.c
@@ -0,0 +1,1022 @@
+/*
+ * Copyright (C) 2007-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * ST DDC I2C master mode driver, used in e.g. U300 series platforms.
+ * Author: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
+ * Author: Jonas Aaberg <jonas.aberg@xxxxxxxxxxxxxx>
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+/* the name of this kernel module */
+#define NAME "stu300"
+
+/* CR (Control Register) 8bit (R/W) */
+#define I2C_CR (0x00000000)
+#define I2C_CR_RESET_VALUE (0x00)
+#define I2C_CR_RESET_UMASK (0x00)
+#define I2C_CR_DDC1_ENABLE (0x80)
+#define I2C_CR_TRANS_ENABLE (0x40)
+#define I2C_CR_PERIPHERAL_ENABLE (0x20)
+#define I2C_CR_DDC2B_ENABLE (0x10)
+#define I2C_CR_START_ENABLE (0x08)
+#define I2C_CR_ACK_ENABLE (0x04)
+#define I2C_CR_STOP_ENABLE (0x02)
+#define I2C_CR_INTERRUPT_ENABLE (0x01)
+/* SR1 (Status Register 1) 8bit (R/-) */
+#define I2C_SR1 (0x00000004)
+#define I2C_SR1_RESET_VALUE (0x00)
+#define I2C_SR1_RESET_UMASK (0x00)
+#define I2C_SR1_EVF_IND (0x80)
+#define I2C_SR1_ADD10_IND (0x40)
+#define I2C_SR1_TRA_IND (0x20)
+#define I2C_SR1_BUSY_IND (0x10)
+#define I2C_SR1_BTF_IND (0x08)
+#define I2C_SR1_ADSL_IND (0x04)
+#define I2C_SR1_MSL_IND (0x02)
+#define I2C_SR1_SB_IND (0x01)
+/* SR2 (Status Register 2) 8bit (R/-) */
+#define I2C_SR2 (0x00000008)
+#define I2C_SR2_RESET_VALUE (0x00)
+#define I2C_SR2_RESET_UMASK (0x40)
+#define I2C_SR2_MASK (0xBF)
+#define I2C_SR2_SCLFAL_IND (0x80)
+#define I2C_SR2_ENDAD_IND (0x20)
+#define I2C_SR2_AF_IND (0x10)
+#define I2C_SR2_STOPF_IND (0x08)
+#define I2C_SR2_ARLO_IND (0x04)
+#define I2C_SR2_BERR_IND (0x02)
+#define I2C_SR2_DDC2BF_IND (0x01)
+/* CCR (Clock Control Register) 8bit (R/W) */
+#define I2C_CCR (0x0000000C)
+#define I2C_CCR_RESET_VALUE (0x00)
+#define I2C_CCR_RESET_UMASK (0x00)
+#define I2C_CCR_MASK (0xFF)
+#define I2C_CCR_FMSM (0x80)
+#define I2C_CCR_CC_MASK (0x7F)
+/* OAR1 (Own Address Register 1) 8bit (R/W) */
+#define I2C_OAR1 (0x00000010)
+#define I2C_OAR1_RESET_VALUE (0x00)
+#define I2C_OAR1_RESET_UMASK (0x00)
+#define I2C_OAR1_ADD_MASK (0xFF)
+/* OAR2 (Own Address Register 2) 8bit (R/W) */
+#define I2C_OAR2 (0x00000014)
+#define I2C_OAR2_RESET_VALUE (0x40)
+#define I2C_OAR2_RESET_UMASK (0x19)
+#define I2C_OAR2_MASK (0xE6)
+#define I2C_OAR2_FR_25_10MHZ (0x00)
+#define I2C_OAR2_FR_10_1667MHZ (0x20)
+#define I2C_OAR2_FR_1667_2667MHZ (0x40)
+#define I2C_OAR2_FR_2667_40MHZ (0x60)
+#define I2C_OAR2_FR_40_5333MHZ (0x80)
+#define I2C_OAR2_FR_5333_66MHZ (0xA0)
+#define I2C_OAR2_FR_66_80MHZ (0xC0)
+#define I2C_OAR2_FR_80_100MHZ (0xE0)
+#define I2C_OAR2_FR_MASK (0xE0)
+#define I2C_OAR2_ADD_MASK (0x06)
+/* DR (Data Register) 8bit (R/W) */
+#define I2C_DR (0x00000018)
+#define I2C_DR_RESET_VALUE (0x00)
+#define I2C_DR_RESET_UMASK (0xFF)
+#define I2C_DR_D_MASK (0xFF)
+/* ECCR (Extended Clock Control Register) 8bit (R/W) */
+#define I2C_ECCR (0x0000001C)
+#define I2C_ECCR_RESET_VALUE (0x00)
+#define I2C_ECCR_RESET_UMASK (0xE0)
+#define I2C_ECCR_MASK (0x1F)
+#define I2C_ECCR_CC_MASK (0x1F)
+
+/*
+ * These events are more or less responses to commands
+ * sent into the hardware, presumably reflecting the state
+ * of an internal state machine.
+ */
+enum stu300_event {
+ STU300_EVENT_NONE = 0,
+ STU300_EVENT_1,
+ STU300_EVENT_2,
+ STU300_EVENT_3,
+ STU300_EVENT_4,
+ STU300_EVENT_5,
+ STU300_EVENT_6,
+ STU300_EVENT_7,
+ STU300_EVENT_8,
+ STU300_EVENT_9
+};
+
+enum stu300_error {
+ STU300_ERROR_NONE = 0,
+ STU300_ERROR_ACKNOWLEDGE_FAILURE,
+ STU300_ERROR_BUS_ERROR,
+ STU300_ERROR_ARBITRATION_LOST
+};
+
+/* timeout waiting for the controller to respond */
+#define STU300_TIMEOUT (msecs_to_jiffies(1000))
+
+/*
+ * The number of address send athemps tried before giving up.
+ * If the first one failes it seems like 5 to 8 attempts are required.
+ */
+#define NUM_ADDR_RESEND_ATTEMPTS 10
+
+/* I2C clock speed, in Hz 0-400kHz*/
+static unsigned int scl_frequency = 100000;
+module_param(scl_frequency, uint, 0644);
+
+struct stu300_dev {
+ /* Parent platform device */
+ struct platform_device *pdev;
+ /* Corresponding I2C adapter */
+ struct i2c_adapter adapter;
+ /* Location of I/O area in memory, and size */
+ u32 phybase;
+ u32 physize;
+ void __iomem *virtbase;
+ /* Hardware block clock */
+ struct clk *clk;
+ /* Assigned interrupt line */
+ int irq;
+ /* This locks the following cmd_ variables */
+ spinlock_t cmd_issue_lock;
+ /* Acknowledge completion for I2C command */
+ struct completion cmd_complete;
+ /* Event coming in as a response to a command */
+ enum stu300_event cmd_event;
+ /* Error code as response to a command */
+ enum stu300_error cmd_err;
+ /* Current bus speed, in Hz */
+ unsigned int speed;
+ /* Index and length of current message */
+ int msg_index;
+ int msg_len;
+};
+
+/* Local forward function declarations */
+static int stu300_init_hw(struct stu300_dev *dev);
+
+/*
+ * The block needs writes in both MSW and LSW in order
+ * for all data lines to reach their destination.
+ */
+static inline void stu300_wr8(u32 value, void __iomem *address)
+{
+ writel((value << 16) | value, address);
+}
+
+/*
+ * This merely masks off the duplicates which appear
+ * in bytes 1-3.
+ */
+static inline u32 stu300_r8(void __iomem *address)
+{
+ return readl(address) & 0x000000FFU;
+}
+
+/*
+ * Tells whether a certain event or events occurred in
+ * response to a command. The events represent states in
+ * the internal state machine of the hardware. The events
+ * are not very well described in the hardware
+ * documentation and can only be treated as abstract state
+ * machine states.
+ *
+ * @ret 0 = event has not occurred, any other value means
+ * the event occurred.
+ */
+static int stu300_event_occurred(struct stu300_dev *dev,
+ enum stu300_event mr_event) {
+ u32 status1;
+ u32 status2;
+
+ /* What event happened? */
+ status1 = stu300_r8(dev->virtbase + I2C_SR1);
+ if (!(status1 & I2C_SR1_EVF_IND))
+ /* No event at all */
+ return 0;
+ status2 = stu300_r8(dev->virtbase + I2C_SR2);
+
+ switch (mr_event) {
+ case STU300_EVENT_1:
+ if (status1 & I2C_SR1_ADSL_IND)
+ return 1;
+ break;
+ case STU300_EVENT_2:
+ case STU300_EVENT_3:
+ case STU300_EVENT_7:
+ case STU300_EVENT_8:
+ if (status1 & I2C_SR1_BTF_IND) {
+ if (status2 & I2C_SR2_AF_IND)
+ dev->cmd_err = STU300_ERROR_ACKNOWLEDGE_FAILURE;
+ else if (status2 & I2C_SR2_BERR_IND)
+ dev->cmd_err = STU300_ERROR_BUS_ERROR;
+ return 1;
+ }
+ break;
+ case STU300_EVENT_4:
+ if (status2 & I2C_SR2_STOPF_IND)
+ return 1;
+ break;
+ case STU300_EVENT_5:
+ if (status1 & I2C_SR1_SB_IND)
+ /* Clear start bit */
+ return 1;
+ break;
+ case STU300_EVENT_6:
+ if (status2 & I2C_SR2_ENDAD_IND) {
+ /* First check for any errors */
+ if (status2 & I2C_SR2_AF_IND)
+ dev->cmd_err = STU300_ERROR_ACKNOWLEDGE_FAILURE;
+ return 1;
+ }
+ break;
+ case STU300_EVENT_9:
+ if (status1 & I2C_SR1_ADD10_IND)
+ return 1;
+ break;
+ default:
+ break;
+ }
+ if (status2 & I2C_SR2_ARLO_IND)
+ dev->cmd_err = STU300_ERROR_ARBITRATION_LOST;
+ return 0;
+}
+
+static irqreturn_t stu300_irh(int irq, void *data)
+{
+ struct stu300_dev *dev = data;
+ int res;
+
+ /* See if this was what we were waiting for */
+ spin_lock(&dev->cmd_issue_lock);
+ if (dev->cmd_event != STU300_EVENT_NONE) {
+ res = stu300_event_occurred(dev, dev->cmd_event);
+ if (res || dev->cmd_err != STU300_ERROR_NONE) {
+ u32 val;
+
+ complete(&dev->cmd_complete);
+ /* Block any multiple interrupts */
+ val = stu300_r8(dev->virtbase + I2C_CR);
+ val &= ~I2C_CR_INTERRUPT_ENABLE;
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+ }
+ }
+ spin_unlock(&dev->cmd_issue_lock);
+ return IRQ_HANDLED;
+}
+
+/*
+ * Sends a command and then waits for the bits masked by *flagmask*
+ * to go high or low by IRQ awaiting.
+ */
+static int stu300_start_and_await_event(struct stu300_dev *dev,
+ u8 cr_value,
+ enum stu300_event mr_event)
+{
+ int ret;
+
+ if (unlikely(irqs_disabled())) {
+ /* TODO: implement polling for this case if need be. */
+ dev_err(&dev->pdev->dev, "irqs are disabled on this "
+ "system!\n");
+ return -EIO;
+ }
+
+ /* Lock command issue, fill in an event we wait for */
+ spin_lock_irq(&dev->cmd_issue_lock);
+ init_completion(&dev->cmd_complete);
+ dev->cmd_err = STU300_ERROR_NONE;
+ dev->cmd_event = mr_event;
+ spin_unlock_irq(&dev->cmd_issue_lock);
+
+ /* Turn on interrupt, send command and wait. */
+ cr_value |= I2C_CR_INTERRUPT_ENABLE;
+ stu300_wr8(cr_value, dev->virtbase + I2C_CR);
+ ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
+ STU300_TIMEOUT);
+
+ if (ret < 0) {
+ dev_err(&dev->pdev->dev,
+ "wait_for_completion_interruptible_timeout() "
+ "returned %d waiting for event %04x\n", ret, mr_event);
+ return ret;
+ }
+
+ if (ret == 0) {
+ dev_err(&dev->pdev->dev, "controller timed out "
+ "waiting for event %d, reinit hardware\n", mr_event);
+ (void) stu300_init_hw(dev);
+ return -ETIMEDOUT;
+ }
+
+ if (dev->cmd_err != STU300_ERROR_NONE) {
+ dev_err(&dev->pdev->dev, "controller (start) "
+ "error %d waiting for event %d, reinit hardware\n",
+ dev->cmd_err, mr_event);
+ (void) stu300_init_hw(dev);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/*
+ * This waits for a flag to be set, if it is not set on entry, an interrupt is
+ * configured to wait for the flag using a completion.
+ */
+static int stu300_await_event(struct stu300_dev *dev,
+ enum stu300_event mr_event)
+{
+ int ret;
+ u32 val;
+
+ if (unlikely(irqs_disabled())) {
+ /* TODO: implement polling for this case if need be. */
+ dev_err(&dev->pdev->dev, "irqs are disabled on this "
+ "system!\n");
+ return -EIO;
+ }
+
+ /* Is it already here? */
+ spin_lock_irq(&dev->cmd_issue_lock);
+ dev->cmd_err = STU300_ERROR_NONE;
+ if (stu300_event_occurred(dev, mr_event)) {
+ spin_unlock_irq(&dev->cmd_issue_lock);
+ goto exit_await_check_err;
+ }
+ init_completion(&dev->cmd_complete);
+ dev->cmd_err = STU300_ERROR_NONE;
+ dev->cmd_event = mr_event;
+
+ /* Turn on the I2C interrupt for current operation */
+ val = stu300_r8(dev->virtbase + I2C_CR);
+ val |= I2C_CR_INTERRUPT_ENABLE;
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+
+ /* Twice paranoia (possible HW glitch) */
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+
+ /* Check again: is it already here? */
+ if (unlikely(stu300_event_occurred(dev, mr_event))) {
+ /* Disable IRQ again. */
+ val &= ~I2C_CR_INTERRUPT_ENABLE;
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+ spin_unlock_irq(&dev->cmd_issue_lock);
+ goto exit_await_check_err;
+ }
+
+ /* Unlock the command block and wait for the event to occur */
+ spin_unlock_irq(&dev->cmd_issue_lock);
+ ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
+ STU300_TIMEOUT);
+
+ if (ret < 0) {
+ dev_err(&dev->pdev->dev,
+ "wait_for_completion_interruptible_timeout()"
+ "returned %d waiting for event %04x\n", ret, mr_event);
+ return ret;
+ }
+
+ if (ret == 0) {
+ if (mr_event != STU300_EVENT_6) {
+ dev_err(&dev->pdev->dev, "controller "
+ "timed out waiting for event %d, reinit "
+ "hardware\n", mr_event);
+ (void) stu300_init_hw(dev);
+ }
+ return -ETIMEDOUT;
+ }
+
+ exit_await_check_err:
+ if (dev->cmd_err != STU300_ERROR_NONE) {
+ if (mr_event != STU300_EVENT_6) {
+ dev_err(&dev->pdev->dev, "controller "
+ "error (await_event) %d waiting for event %d, "
+ "reinit hardware\n", dev->cmd_err, mr_event);
+ (void) stu300_init_hw(dev);
+ }
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/*
+ * Waits for the busy bit to go low by repeated polling.
+ */
+#define BUSY_RELEASE_ATTEMPTS 10
+static int stu300_wait_while_busy(struct stu300_dev *dev)
+{
+ unsigned long timeout;
+ int i;
+
+ for (i = 0; i < BUSY_RELEASE_ATTEMPTS; i++) {
+ timeout = jiffies + STU300_TIMEOUT;
+
+ while (!time_after(jiffies, timeout)) {
+ /* Is not busy? */
+ if ((stu300_r8(dev->virtbase + I2C_SR1) &
+ I2C_SR1_BUSY_IND) == 0)
+ return 0;
+ msleep(1);
+ }
+
+ dev_err(&dev->pdev->dev, "transaction timed out "
+ "waiting for device to be free (not busy). "
+ "Attempt: %d\n", i+1);
+
+ dev_err(&dev->pdev->dev, "base address = "
+ "0x%08x, reinit hardware\n", (u32) dev->virtbase);
+
+ (void) stu300_init_hw(dev);
+ }
+
+ dev_err(&dev->pdev->dev, "giving up after %d attempts "
+ "to reset the bus.\n", BUSY_RELEASE_ATTEMPTS);
+
+ return -ETIMEDOUT;
+}
+
+struct stu300_clkset {
+ unsigned long rate;
+ u32 setting;
+};
+
+static const struct stu300_clkset stu300_clktable[] = {
+ { 0, 0xFFU },
+ { 2500000, I2C_OAR2_FR_25_10MHZ },
+ { 10000000, I2C_OAR2_FR_10_1667MHZ },
+ { 16670000, I2C_OAR2_FR_1667_2667MHZ },
+ { 26670000, I2C_OAR2_FR_2667_40MHZ },
+ { 40000000, I2C_OAR2_FR_40_5333MHZ },
+ { 53330000, I2C_OAR2_FR_5333_66MHZ },
+ { 66000000, I2C_OAR2_FR_66_80MHZ },
+ { 80000000, I2C_OAR2_FR_80_100MHZ },
+ { 100000000, 0xFFU },
+};
+
+static int stu300_set_clk(struct stu300_dev *dev, unsigned long clkrate)
+{
+
+ u32 val;
+ int i = 0;
+
+ /* Locate the apropriate clock setting */
+ while (i < ARRAY_SIZE(stu300_clktable) &&
+ stu300_clktable[i].rate < clkrate)
+ i++;
+
+ if (stu300_clktable[i].setting == 0xFFU) {
+ dev_err(&dev->pdev->dev, "too %s clock rate requested "
+ "(%lu Hz).\n", i ? "high" : "low", clkrate);
+ return -EINVAL;
+ }
+
+ stu300_wr8(stu300_clktable[i].setting,
+ dev->virtbase + I2C_OAR2);
+
+ dev_dbg(&dev->pdev->dev, "Clock rate %lu Hz, I2C bus speed %d Hz "
+ "virtbase %p\n", clkrate, dev->speed, dev->virtbase);
+
+ if (dev->speed > 100000)
+ /* Fast Mode I2C */
+ val = ((clkrate/dev->speed)-9)/3;
+ else
+ /* Standard Mode I2C */
+ val = ((clkrate/dev->speed)-7)/2;
+
+ /* According to spec the divider must be > 2 */
+ if (val < 0x002) {
+ dev_err(&dev->pdev->dev, "too low clock rate (%lu Hz).\n",
+ clkrate);
+ return -EINVAL;
+ }
+
+ /* We have 12 bits clock divider only! */
+ if (val & 0xFFFFF000U) {
+ dev_err(&dev->pdev->dev, "too high clock rate (%lu Hz).\n",
+ clkrate);
+ return -EINVAL;
+ }
+
+ if (dev->speed > 100000) {
+ /* CC6..CC0 */
+ stu300_wr8((val & I2C_CCR_CC_MASK) | I2C_CCR_FMSM,
+ dev->virtbase + I2C_CCR);
+ dev_dbg(&dev->pdev->dev, "set clock divider to 0x%08x, "
+ "Fast Mode I2C\n", val);
+ } else {
+ /* CC6..CC0 */
+ stu300_wr8((val & I2C_CCR_CC_MASK),
+ dev->virtbase + I2C_CCR);
+ dev_dbg(&dev->pdev->dev, "set clock divider to "
+ "0x%08x, Standard Mode I2C\n", val);
+ }
+
+ /* CC11..CC7 */
+ stu300_wr8(((val >> 7) & 0x1F),
+ dev->virtbase + I2C_ECCR);
+
+ return 0;
+}
+
+
+static int stu300_init_hw(struct stu300_dev *dev)
+{
+ u32 dummy;
+ unsigned long clkrate;
+ int ret;
+
+ /* Disable controller */
+ stu300_wr8(0x00, dev->virtbase + I2C_CR);
+ /*
+ * Set own address to some default value (0x00).
+ * We do not support slave mode anyway.
+ */
+ stu300_wr8(0x00, dev->virtbase + I2C_OAR1);
+ /*
+ * The I2C controller only operates properly in 26 MHz but we
+ * program this driver as if we didn't know. This will also set the two
+ * high bits of the own address to zero as well.
+ * There is no known hardware issue with running in 13 MHz
+ * However, speeds over 200 kHz are not used.
+ */
+ clkrate = clk_get_rate(dev->clk);
+ ret = stu300_set_clk(dev, clkrate);
+ if (ret)
+ return ret;
+ /*
+ * Enable block, do it TWICE (hardware glitch)
+ * Setting bit 7 can enable DDC mode. (Not used currently.)
+ */
+ stu300_wr8(I2C_CR_PERIPHERAL_ENABLE,
+ dev->virtbase + I2C_CR);
+ stu300_wr8(I2C_CR_PERIPHERAL_ENABLE,
+ dev->virtbase + I2C_CR);
+ /* Make a dummy read of the status register SR1 & SR2 */
+ dummy = stu300_r8(dev->virtbase + I2C_SR2);
+ dummy = stu300_r8(dev->virtbase + I2C_SR1);
+
+ return 0;
+}
+
+
+
+/* Send slave address. */
+static int stu300_send_address(struct stu300_dev *dev,
+ struct i2c_msg *msg, int resend)
+{
+ u32 val;
+ int ret;
+
+ if (msg->flags & I2C_M_TEN)
+ /* This is probably how 10 bit addresses look */
+ val = (0xf0 | (((u32) msg->addr & 0x300) >> 7)) &
+ I2C_DR_D_MASK;
+ else
+ val = ((msg->addr << 1) & I2C_DR_D_MASK);
+
+ if (msg->flags & I2C_M_RD) {
+ /* This is the direction bit */
+ val |= 0x01;
+ if (resend)
+ dev_dbg(&dev->pdev->dev, "read resend\n");
+ } else if (resend)
+ dev_dbg(&dev->pdev->dev, "write resend\n");
+ stu300_wr8(val, dev->virtbase + I2C_DR);
+
+ /* For 10bit addressing, await 10bit request (EVENT 9) */
+ if (msg->flags & I2C_M_TEN) {
+ ret = stu300_await_event(dev, STU300_EVENT_9);
+ /*
+ * The slave device wants a 10bit address, send the rest
+ * of the bits (the LSBits)
+ */
+ val = msg->addr & I2C_DR_D_MASK;
+ /* This clears "event 9" */
+ stu300_wr8(val, dev->virtbase + I2C_DR);
+ if (ret != 0)
+ return ret;
+ }
+ /* FIXME: Why no else here? two events for 10bit?
+ * Await event 6 (normal) or event 9 (10bit)
+ */
+
+ if (resend)
+ dev_dbg(&dev->pdev->dev, "await event 6\n");
+ ret = stu300_await_event(dev, STU300_EVENT_6);
+
+ /*
+ * Clear any pending EVENT 6 no matter what happend during
+ * await_event.
+ */
+ val = stu300_r8(dev->virtbase + I2C_CR);
+ val |= I2C_CR_PERIPHERAL_ENABLE;
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+
+ return ret;
+}
+
+static int stu300_xfer_msg(struct i2c_adapter *adap,
+ struct i2c_msg *msg, int stop)
+{
+ u32 cr;
+ u32 val;
+ u32 i;
+ int ret;
+ int attempts = 0;
+ struct stu300_dev *dev = i2c_get_adapdata(adap);
+
+
+ clk_enable(dev->clk);
+
+ /* Remove this if (0) to trace each and every message. */
+ if (0) {
+ dev_dbg(&dev->pdev->dev, "I2C message to: 0x%04x, len: %d, "
+ "flags: 0x%04x, stop: %d\n",
+ msg->addr, msg->len, msg->flags, stop);
+ }
+
+ /* Zero-length messages are not supported by this hardware */
+ if (msg->len == 0) {
+ ret = -EINVAL;
+ goto exit_disable;
+ }
+
+ /*
+ * For some reason, sending the address sometimes fails when running
+ * on the 13 MHz clock. No interrupt arrives. This is a work around,
+ * which tries to restart and send the address up to 10 times before
+ * really giving up. Usually 5 to 8 attempts are enough.
+ */
+ do {
+ if (attempts)
+ dev_dbg(&dev->pdev->dev, "wait while busy\n");
+ /* Check that the bus is free, or wait until some timeout */
+ ret = stu300_wait_while_busy(dev);
+ if (ret != 0)
+ goto exit_disable;
+
+ if (attempts)
+ dev_dbg(&dev->pdev->dev, "re-int hw\n");
+ /*
+ * According to ST, there is no problem if the clock is
+ * changed between 13 and 26 MHz during a transfer.
+ */
+ ret = stu300_init_hw(dev);
+ if (ret)
+ goto exit_disable;
+
+ /* Send a start condition */
+ cr = I2C_CR_PERIPHERAL_ENABLE;
+ /* Setting the START bit puts the block in master mode */
+ if (!(msg->flags & I2C_M_NOSTART))
+ cr |= I2C_CR_START_ENABLE;
+ if ((msg->flags & I2C_M_RD) && (msg->len > 1))
+ /* On read more than 1 byte, we need ack. */
+ cr |= I2C_CR_ACK_ENABLE;
+ /* Check that it gets through */
+ if (!(msg->flags & I2C_M_NOSTART)) {
+ if (attempts)
+ dev_dbg(&dev->pdev->dev, "send start event\n");
+ ret = stu300_start_and_await_event(dev, cr,
+ STU300_EVENT_5);
+ }
+
+ if (attempts)
+ dev_dbg(&dev->pdev->dev, "send address\n");
+
+ if (ret == 0)
+ /* Send address */
+ ret = stu300_send_address(dev, msg, attempts != 0);
+
+ if (ret != 0) {
+ attempts++;
+ dev_dbg(&dev->pdev->dev, "failed sending address, "
+ "retrying. Attempt: %d msg_index: %d/%d\n",
+ attempts, dev->msg_index, dev->msg_len);
+ }
+
+ } while (ret != 0 && attempts < NUM_ADDR_RESEND_ATTEMPTS);
+
+ if (attempts < NUM_ADDR_RESEND_ATTEMPTS && attempts > 0) {
+ dev_dbg(&dev->pdev->dev, "managed to get address "
+ "through after %d attempts\n", attempts);
+ } else if (attempts == NUM_ADDR_RESEND_ATTEMPTS) {
+ dev_dbg(&dev->pdev->dev, "I give up, tried %d times "
+ "to resend address.\n",
+ NUM_ADDR_RESEND_ATTEMPTS);
+ goto exit_disable;
+ }
+
+ if (msg->flags & I2C_M_RD) {
+ /* READ: we read the actual bytes one at a time */
+ for (i = 0; i < msg->len; i++) {
+ if (i == msg->len-1) {
+ /*
+ * Disable ACK and set STOP condition before
+ * reading last byte
+ */
+ val = I2C_CR_PERIPHERAL_ENABLE;
+
+ if (stop)
+ val |= I2C_CR_STOP_ENABLE;
+
+ stu300_wr8(val,
+ dev->virtbase + I2C_CR);
+ }
+ /* Wait for this byte... */
+ ret = stu300_await_event(dev, STU300_EVENT_7);
+ if (ret != 0)
+ goto exit_disable;
+ /* This clears event 7 */
+ msg->buf[i] = (u8) stu300_r8(dev->virtbase + I2C_DR);
+ }
+ } else {
+ /* WRITE: we send the actual bytes one at a time */
+ for (i = 0; i < msg->len; i++) {
+ /* Write the byte */
+ stu300_wr8(msg->buf[i],
+ dev->virtbase + I2C_DR);
+ /* Check status */
+ ret = stu300_await_event(dev, STU300_EVENT_8);
+ /* Next write to DR will clear event 8 */
+ if (ret != 0) {
+ dev_err(&dev->pdev->dev, "error awaiting "
+ "event 8 (%d)\n", ret);
+ goto exit_disable;
+ }
+ }
+ /* Check NAK */
+ if (!(msg->flags & I2C_M_IGNORE_NAK)) {
+ if (stu300_r8(dev->virtbase + I2C_SR2) &
+ I2C_SR2_AF_IND) {
+ dev_err(&dev->pdev->dev, "I2C payload "
+ "send returned NAK!\n");
+ ret = -EIO;
+ goto exit_disable;
+ }
+ }
+ if (stop) {
+ /* Send stop condition */
+ val = I2C_CR_PERIPHERAL_ENABLE;
+ val |= I2C_CR_STOP_ENABLE;
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+ }
+ }
+
+ /* Check that the bus is free, or wait until some timeout occurs */
+ ret = stu300_wait_while_busy(dev);
+ if (ret != 0) {
+ dev_err(&dev->pdev->dev, "timout waiting for transfer "
+ "to commence.\n");
+ goto exit_disable;
+ }
+
+ /* Dummy read status registers */
+ val = stu300_r8(dev->virtbase + I2C_SR2);
+ val = stu300_r8(dev->virtbase + I2C_SR1);
+ ret = 0;
+
+ exit_disable:
+ /* Disable controller */
+ stu300_wr8(0x00, dev->virtbase + I2C_CR);
+ clk_disable(dev->clk);
+ return ret;
+}
+
+static int stu300_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ int ret = -1;
+ int i;
+ struct stu300_dev *dev = i2c_get_adapdata(adap);
+ dev->msg_len = num;
+ for (i = 0; i < num; i++) {
+ /*
+ * Another driver appears to send stop for each message,
+ * here we only do that for the last message. Possibly some
+ * peripherals require this behaviour, then their drivers
+ * have to send single messages in order to get "stop" for
+ * each message.
+ */
+ dev->msg_index = i;
+
+ ret = stu300_xfer_msg(adap, &msgs[i], (i == (num - 1)));
+ if (ret != 0) {
+ num = ret;
+ break;
+ }
+ }
+
+ return num;
+}
+
+static u32 stu300_func(struct i2c_adapter *adap)
+{
+ /* This is the simplest thing you can think of... */
+ return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR;
+}
+
+static const struct i2c_algorithm stu300_algo = {
+ .master_xfer = stu300_xfer,
+ .functionality = stu300_func,
+};
+
+static int __init
+stu300_probe(struct platform_device *pdev)
+{
+ struct stu300_dev *dev;
+ struct i2c_adapter *adap;
+ struct resource *res;
+ int bus_nr;
+ int ret = 0;
+
+ dev = kzalloc(sizeof(struct stu300_dev), GFP_KERNEL);
+ if (!dev) {
+ ret = -ENOMEM;
+ goto err_no_devmem;
+ }
+
+ bus_nr = pdev->id;
+ dev->clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(dev->clk)) {
+ ret = PTR_ERR(dev->clk);
+ dev_err(&pdev->dev, "could not retrieve i2c bus clock\n");
+ goto err_no_clk;
+ }
+
+ dev->pdev = pdev;
+ platform_set_drvdata(pdev, dev);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ ret = -ENOENT;
+ goto err_no_resource;
+ }
+
+ dev->phybase = res->start;
+ dev->physize = resource_size(res);
+
+ if (request_mem_region(dev->phybase, dev->physize,
+ NAME " I/O Area") == NULL) {
+ ret = -EBUSY;
+ goto err_no_ioregion;
+ }
+
+ dev->virtbase = ioremap(dev->phybase, dev->physize);
+ dev_dbg(&pdev->dev, "initialize bus device I2C%d on virtual "
+ "base 0x%08x\n", bus_nr, (u32) dev->virtbase);
+ if (!dev->virtbase) {
+ ret = -ENOMEM;
+ goto err_no_ioremap;
+ }
+
+ dev->irq = platform_get_irq(pdev, 0);
+ if (request_irq(dev->irq, stu300_irh, IRQF_DISABLED,
+ NAME, dev)) {
+ ret = -EIO;
+ goto err_no_irq;
+ }
+
+ dev->speed = scl_frequency;
+
+ clk_enable(dev->clk);
+ ret = stu300_init_hw(dev);
+ clk_disable(dev->clk);
+
+ if (ret != 0) {
+ dev_err(&dev->pdev->dev, "error initializing hardware.\n");
+ goto err_init_hw;
+ }
+
+ /* IRQ event handling initialization */
+ spin_lock_init(&dev->cmd_issue_lock);
+ dev->cmd_event = STU300_EVENT_NONE;
+ dev->cmd_err = STU300_ERROR_NONE;
+
+ adap = &dev->adapter;
+ adap->owner = THIS_MODULE;
+ /* DDC class but actually often used for more generic I2C */
+ adap->class = I2C_CLASS_DDC;
+ strncpy(adap->name, "ST Microelectronics DDC I2C adapter",
+ sizeof(adap->name));
+ adap->nr = bus_nr;
+ adap->algo = &stu300_algo;
+ adap->dev.parent = &pdev->dev;
+ i2c_set_adapdata(adap, dev);
+
+ /* i2c device drivers may be active on return from add_adapter() */
+ ret = i2c_add_numbered_adapter(adap);
+ if (ret) {
+ dev_err(&dev->pdev->dev, "failure adding ST Micro DDC "
+ "I2C adapter\n");
+ goto err_add_adapter;
+ }
+ return 0;
+
+ err_add_adapter:
+ err_init_hw:
+ free_irq(dev->irq, dev);
+ err_no_irq:
+ iounmap(dev->virtbase);
+ err_no_ioremap:
+ release_mem_region(dev->phybase, dev->physize);
+ err_no_ioregion:
+ platform_set_drvdata(pdev, NULL);
+ err_no_resource:
+ clk_put(dev->clk);
+ err_no_clk:
+ kfree(dev);
+ err_no_devmem:
+ dev_err(&pdev->dev, "failed to add " NAME " adapter: %d\n",
+ pdev->id);
+ return ret;
+}
+
+#ifdef CONFIG_PM
+static int stu300_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct stu300_dev *dev = platform_get_drvdata(pdev);
+
+ /* Turn off everything */
+ stu300_wr8(0x00, dev->virtbase + I2C_CR);
+ return 0;
+}
+
+static int stu300_resume(struct platform_device *pdev)
+{
+ int ret = 0;
+ struct stu300_dev *dev = platform_get_drvdata(pdev);
+
+ clk_enable(dev->clk);
+ ret = stu300_init_hw(dev);
+ clk_disable(dev->clk);
+
+ if (ret != 0)
+ dev_err(&pdev->dev, "error re-initializing hardware.\n");
+ return ret;
+}
+#else
+#define stu300_suspend NULL
+#define stu300_resume NULL
+#endif
+
+static int __exit
+stu300_remove(struct platform_device *pdev)
+{
+ struct stu300_dev *dev = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&dev->adapter);
+ /* Turn off everything */
+ stu300_wr8(0x00, dev->virtbase + I2C_CR);
+ free_irq(dev->irq, dev);
+ iounmap(dev->virtbase);
+ release_mem_region(dev->phybase, dev->physize);
+ clk_put(dev->clk);
+ platform_set_drvdata(pdev, NULL);
+ kfree(dev);
+ return 0;
+}
+
+static struct platform_driver stu300_i2c_driver = {
+ .driver = {
+ .name = NAME,
+ .owner = THIS_MODULE,
+ },
+ .remove = __exit_p(stu300_remove),
+ .suspend = stu300_suspend,
+ .resume = stu300_resume,
+
+};
+
+static int __init stu300_init(void)
+{
+ return platform_driver_probe(&stu300_i2c_driver, stu300_probe);
+}
+
+static void __exit stu300_exit(void)
+{
+ platform_driver_unregister(&stu300_i2c_driver);
+}
+
+/*
+ * The systems using this bus often have very basic devices such
+ * as regulators on the I2C bus, so this needs to be loaded early.
+ * Therefore it is registered in the subsys_initcall().
+ */
+subsys_initcall(stu300_init);
+module_exit(stu300_exit);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("ST Micro DDC I2C adapter (stu300)");
+MODULE_LICENSE("GPL");
--
1.6.2.1
--
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
