i2c-nomadik: change the TX and RX threshold

1) Increase RX FIFO threshold so that there is a reduction in
the number of interrupts handled to complete a transaction.

2) Fill TX FIFO in the write function.

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 b49ff25a2688d9c04354fdc620fa16c68940eb75..e3cd62e40df580e5bb8cdb151bd41a308da4cd55 100644 (file)
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -447,6 +447,24 @@ static int read_i2c(struct nmk_i2c_dev *dev)
        return status;
 }
 
+static void fill_tx_fifo(struct nmk_i2c_dev *dev, int no_bytes)
+{
+       int count;
+
+       for (count = (no_bytes - 2);
+                       (count > 0) &&
+                       (dev->cli.count != 0);
+                       count--) {
+               /* write to the Tx FIFO */
+               writeb(*dev->cli.buffer,
+                       dev->virtbase + I2C_TFR);
+               dev->cli.buffer++;
+               dev->cli.count--;
+               dev->cli.xfer_bytes++;
+       }
+
+}
+
 /**
  * write_i2c() - Write data to I2C client.
  * @dev: private data of I2C Driver
@@ -474,8 +492,13 @@ static int write_i2c(struct nmk_i2c_dev *dev)
        init_completion(&dev->xfer_complete);
 
        /* enable interrupts by settings the masks */
-       irq_mask = (I2C_IT_TXFNE | I2C_IT_TXFOVR |
-                       I2C_IT_MAL | I2C_IT_BERR);
+       irq_mask = (I2C_IT_TXFOVR | I2C_IT_MAL | I2C_IT_BERR);
+
+       /* Fill the TX FIFO with transmit data */
+       fill_tx_fifo(dev, MAX_I2C_FIFO_THRESHOLD);
+
+       if (dev->cli.count != 0)
+               irq_mask |= I2C_IT_TXFNE;
 
        /*
         * check if we want to transfer a single or multiple bytes, if so
@@ -702,17 +725,7 @@ static irqreturn_t i2c_irq_handler(int irq, void *arg)
                         */
                        disable_interrupts(dev, I2C_IT_TXFNE);
                } else {
-                       for (count = (MAX_I2C_FIFO_THRESHOLD - tft - 2);
-                                       (count > 0) &&
-                                       (dev->cli.count != 0);
-                                       count--) {
-                               /* write to the Tx FIFO */
-                               writeb(*dev->cli.buffer,
-                                       dev->virtbase + I2C_TFR);
-                               dev->cli.buffer++;
-                               dev->cli.count--;
-                               dev->cli.xfer_bytes++;
-                       }
+                       fill_tx_fifo(dev, (MAX_I2C_FIFO_THRESHOLD - tft));
                        /*
                         * if done, close the transfer by disabling the
                         * corresponding TXFNE interrupt