i2c-nomadik: add code to retry on timeout failure

It is seen that i2c-nomadik controller randomly stops generating the
interrupts leading to a i2c timeout. As a workaround to this problem,
add retries to the on going transfer on failure.

Signed-off-by: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index 234e4a9..b49ff25 100644 (file)
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -255,8 +255,6 @@ static int init_hw(struct nmk_i2c_dev *dev)
 {
        int stat;
 
-       clk_enable(dev->clk);
-
        stat = flush_i2c_fifo(dev);
        if (stat)
                goto exit;
@@ -271,8 +269,6 @@ static int init_hw(struct nmk_i2c_dev *dev)
        dev->cli.operation = I2C_NO_OPERATION;
 
 exit:
-       /* TODO: Why disable clocks after init hw? */
-       clk_disable(dev->clk);
        /*
         * TODO: What is this delay for?
         * Must be pretty pointless since the hw block
@@ -572,6 +568,7 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
        u32 cause;
        struct nmk_i2c_dev *dev = i2c_get_adapdata(i2c_adap);
        u32 i2c_sr;
+       int j;
 
        dev->busy = true;
 
@@ -579,63 +576,67 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
                regulator_enable(dev->regulator);
        pm_runtime_get_sync(&dev->pdev->dev);
 
+       clk_enable(dev->clk);
+
        status = init_hw(dev);
        if (status)
-               goto out2;
+               goto out;
 
-       clk_enable(dev->clk);
-
-       /* setup the i2c controller */
-       setup_i2c_controller(dev);
+       for (j = 0; j < 3; j++) {
+               /* setup the i2c controller */
+               setup_i2c_controller(dev);
 
-       for (i = 0; i < num_msgs; i++) {
-               if (unlikely(msgs[i].flags & I2C_M_TEN)) {
-                       dev_err(&dev->pdev->dev, "10 bit addressing"
-                                       "not supported\n");
+               for (i = 0; i < num_msgs; i++) {
+                       if (unlikely(msgs[i].flags & I2C_M_TEN)) {
+                               dev_err(&dev->pdev->dev, "10 bit addressing"
+                                               "not supported\n");
 
-                       status = -EINVAL;
-                       goto out;
-               }
-               dev->cli.slave_adr      = msgs[i].addr;
-               dev->cli.buffer         = msgs[i].buf;
-               dev->cli.count          = msgs[i].len;
-               dev->stop = (i < (num_msgs - 1)) ? 0 : 1;
-               dev->result = 0;
-
-               if (msgs[i].flags & I2C_M_RD) {
-                       /* it is a read operation */
-                       dev->cli.operation = I2C_READ;
-                       status = read_i2c(dev);
-               } else {
-                       /* write operation */
-                       dev->cli.operation = I2C_WRITE;
-                       status = write_i2c(dev);
-               }
-               if (status || (dev->result)) {
-                       i2c_sr = readl(dev->virtbase + I2C_SR);
-                       /*
-                        * Check if the controller I2C operation status is set
-                        * to ABORT(11b).
-                        */
-                       if (((i2c_sr >> 2) & 0x3) == 0x3) {
-                               /* get the abort cause */
-                               cause = (i2c_sr >> 4)
-                                       & 0x7;
-                               dev_err(&dev->pdev->dev, "%s\n", cause >=
-                                               ARRAY_SIZE(abort_causes) ?
+                               status = -EINVAL;
+                               goto out;
+                       }
+                       dev->cli.slave_adr      = msgs[i].addr;
+                       dev->cli.buffer         = msgs[i].buf;
+                       dev->cli.count          = msgs[i].len;
+                       dev->stop = (i < (num_msgs - 1)) ? 0 : 1;
+                       dev->result = 0;
+
+                       if (msgs[i].flags & I2C_M_RD) {
+                               /* it is a read operation */
+                               dev->cli.operation = I2C_READ;
+                               status = read_i2c(dev);
+                       } else {
+                               /* write operation */
+                               dev->cli.operation = I2C_WRITE;
+                               status = write_i2c(dev);
+                       }
+                       if (status || (dev->result)) {
+                               i2c_sr = readl(dev->virtbase + I2C_SR);
+                               /*
+                                * Check if the controller I2C operation status
+                                * is set to ABORT(11b).
+                                */
+                               if (((i2c_sr >> 2) & 0x3) == 0x3) {
+                                       /* get the abort cause */
+                                       cause = (i2c_sr >> 4)
+                                               & 0x7;
+                                       dev_err(&dev->pdev->dev, "%s\n", cause
+                                               >= ARRAY_SIZE(abort_causes) ?
                                                "unknown reason" :
                                                abort_causes[cause]);
-                       }
+                               }
 
-                       status = status ? status : dev->result;
-                       goto out;
+                               status = status ? status : dev->result;
+
+                               break;
+                       }
+                       udelay(I2C_DELAY);
                }
-               udelay(I2C_DELAY);
+               if (status == 0)
+                       break;
        }
 
 out:
        clk_disable(dev->clk);
-out2:
        pm_runtime_put_sync(&dev->pdev->dev);
        if (dev->regulator)
                regulator_disable(dev->regulator);