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authorVirupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>2011-05-13 12:30:34 +0200
committerBen Dooks <ben-linux@fluff.org>2011-05-25 00:20:47 +0100
commit553553413a6abdda220a697ef439ba2f4b1d4a7c (patch)
tree7f3ea5e0f05c9cd00cb845e458f13ea1c5e968fd /drivers/i2c
parentebd10e0783d9fb92a147e60902e22c2d3f3ad69d (diff)
downloadop-kernel-dev-553553413a6abdda220a697ef439ba2f4b1d4a7c.zip
op-kernel-dev-553553413a6abdda220a697ef439ba2f4b1d4a7c.tar.gz
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>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-nomadik.c39
1 files changed, 26 insertions, 13 deletions
diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index b49ff25..e3cd62e 100644
--- 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
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