Commit 55355341 authored by Virupax Sadashivpetimath's avatar Virupax Sadashivpetimath Committed by Ben Dooks
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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: default avatarVirupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
Reviewed-by: default avatarJonas Aberg <jonas.aberg@stericsson.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent ebd10e07

drivers/i2c/busses/i2c-nomadik.c

+26 −13
Original line number Diff line number Diff line
@@ -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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