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>

1 files changed, 49 insertions, 48 deletions

diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index 234e4a9070b8..b49ff25a2688 100644
--- 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);