i2c-stu300: I2C STU300 stability updates
- blk clk is enabled when an irq arrives. The clk should be enabled,
but just to make sure.
- All error bits are handled no matter state machine state
- All irq's will run complete() except for irq's that wasn't an event.
- No more looking into status registers just in case an interrupt
has happend and the irq handle wasn't executed.
- irq_disable/enable are now separete functions.
- clk settings calculation changed to round upwards instead of
downwards.
- Number of address send attempts before giving up is increased to 12
from 10 since it most times take 8 tries before getting through.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
diff --git a/drivers/i2c/busses/i2c-stu300.c b/drivers/i2c/busses/i2c-stu300.c
index 182e711..d2728a2 100644
--- a/drivers/i2c/busses/i2c-stu300.c
+++ b/drivers/i2c/busses/i2c-stu300.c
@@ -117,7 +117,8 @@
STU300_ERROR_NONE = 0,
STU300_ERROR_ACKNOWLEDGE_FAILURE,
STU300_ERROR_BUS_ERROR,
- STU300_ERROR_ARBITRATION_LOST
+ STU300_ERROR_ARBITRATION_LOST,
+ STU300_ERROR_UNKNOWN
};
/* timeout waiting for the controller to respond */
@@ -127,7 +128,7 @@
* 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
+#define NUM_ADDR_RESEND_ATTEMPTS 12
/* I2C clock speed, in Hz 0-400kHz*/
static unsigned int scl_frequency = 100000;
@@ -149,6 +150,7 @@
* @msg_index: index of current message
* @msg_len: length of current message
*/
+
struct stu300_dev {
struct platform_device *pdev;
struct i2c_adapter adapter;
@@ -188,6 +190,27 @@
return readl(address) & 0x000000FFU;
}
+static void stu300_irq_enable(struct stu300_dev *dev)
+{
+ u32 val;
+ val = stu300_r8(dev->virtbase + I2C_CR);
+ val |= I2C_CR_INTERRUPT_ENABLE;
+ /* Twice paranoia (possible HW glitch) */
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+}
+
+static void stu300_irq_disable(struct stu300_dev *dev)
+{
+ u32 val;
+ val = stu300_r8(dev->virtbase + I2C_CR);
+ val &= ~I2C_CR_INTERRUPT_ENABLE;
+ /* Twice paranoia (possible HW glitch) */
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+ stu300_wr8(val, dev->virtbase + I2C_CR);
+}
+
+
/*
* Tells whether a certain event or events occurred in
* response to a command. The events represent states in
@@ -196,9 +219,10 @@
* documentation and can only be treated as abstract state
* machine states.
*
- * @ret 0 = event has not occurred, any other value means
- * the event occurred.
+ * @ret 0 = event has not occurred or unknown error, any
+ * other value means the correct event occurred or an error.
*/
+
static int stu300_event_occurred(struct stu300_dev *dev,
enum stu300_event mr_event) {
u32 status1;
@@ -206,11 +230,28 @@
/* 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);
+ /* Block any multiple interrupts */
+ stu300_irq_disable(dev);
+
+ /* Check for errors first */
+ if (status2 & I2C_SR2_AF_IND) {
+ dev->cmd_err = STU300_ERROR_ACKNOWLEDGE_FAILURE;
+ return 1;
+ } else if (status2 & I2C_SR2_BERR_IND) {
+ dev->cmd_err = STU300_ERROR_BUS_ERROR;
+ return 1;
+ } else if (status2 & I2C_SR2_ARLO_IND) {
+ dev->cmd_err = STU300_ERROR_ARBITRATION_LOST;
+ return 1;
+ }
+
switch (mr_event) {
case STU300_EVENT_1:
if (status1 & I2C_SR1_ADSL_IND)
@@ -221,10 +262,6 @@
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;
@@ -240,8 +277,6 @@
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;
@@ -252,8 +287,15 @@
default:
break;
}
- if (status2 & I2C_SR2_ARLO_IND)
- dev->cmd_err = STU300_ERROR_ARBITRATION_LOST;
+ /* If we get here, we're on thin ice.
+ * Here we are in a status where we have
+ * gotten a response that does not match
+ * what we requested.
+ */
+ dev->cmd_err = STU300_ERROR_UNKNOWN;
+ dev_err(&dev->pdev->dev,
+ "Unhandled interrupt! %d sr1: 0x%x sr2: 0x%x\n",
+ mr_event, status1, status2);
return 0;
}
@@ -262,21 +304,20 @@
struct stu300_dev *dev = data;
int res;
+ /* Just make sure that the block is clocked */
+ clk_enable(dev->clk);
+
/* 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);
- }
- }
+ res = stu300_event_occurred(dev, dev->cmd_event);
+ if (res || dev->cmd_err != STU300_ERROR_NONE)
+ complete(&dev->cmd_complete);
+
spin_unlock(&dev->cmd_issue_lock);
+
+ clk_disable(dev->clk);
+
return IRQ_HANDLED;
}
@@ -308,7 +349,6 @@
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() "
@@ -342,7 +382,6 @@
enum stu300_event mr_event)
{
int ret;
- u32 val;
if (unlikely(irqs_disabled())) {
/* TODO: implement polling for this case if need be. */
@@ -354,36 +393,18 @@
/* 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;
+ init_completion(&dev->cmd_complete);
+
/* 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;
- }
+ stu300_irq_enable(dev);
/* 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()"
@@ -401,7 +422,6 @@
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 "
@@ -457,18 +477,19 @@
};
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 },
+ { 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)
{
@@ -494,10 +515,10 @@
if (dev->speed > 100000)
/* Fast Mode I2C */
- val = ((clkrate/dev->speed)-9)/3;
+ val = ((clkrate/dev->speed) - 9)/3 + 1;
else
/* Standard Mode I2C */
- val = ((clkrate/dev->speed)-7)/2;
+ val = ((clkrate/dev->speed) - 7)/2 + 1;
/* According to spec the divider must be > 2 */
if (val < 0x002) {
@@ -557,6 +578,7 @@
*/
clkrate = clk_get_rate(dev->clk);
ret = stu300_set_clk(dev, clkrate);
+
if (ret)
return ret;
/*
@@ -641,7 +663,6 @@
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. */
@@ -715,14 +736,15 @@
if (attempts < NUM_ADDR_RESEND_ATTEMPTS && attempts > 0) {
dev_dbg(&dev->pdev->dev, "managed to get address "
- "through after %d attempts\n", attempts);
+ "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);
+ "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++) {
@@ -804,8 +826,10 @@
{
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,
@@ -817,6 +841,7 @@
dev->msg_index = i;
ret = stu300_xfer_msg(adap, &msgs[i], (i == (num - 1)));
+
if (ret != 0) {
num = ret;
break;
@@ -845,6 +870,7 @@
struct resource *res;
int bus_nr;
int ret = 0;
+ char clk_name[] = "I2C0";
dev = kzalloc(sizeof(struct stu300_dev), GFP_KERNEL);
if (!dev) {
@@ -854,7 +880,8 @@
}
bus_nr = pdev->id;
- dev->clk = clk_get(&pdev->dev, NULL);
+ clk_name[3] += (char)bus_nr;
+ dev->clk = clk_get(&pdev->dev, clk_name);
if (IS_ERR(dev->clk)) {
ret = PTR_ERR(dev->clk);
dev_err(&pdev->dev, "could not retrieve i2c bus clock\n");