Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2e65676f authored by Grygorii Strashko's avatar Grygorii Strashko Committed by Wolfram Sang
Browse files

i2c: davinci: use bus recovery infrastructure 



This patch converts Davinci I2C driver to use I2C bus recovery
infrastructure, introduced by commit 5f9296ba ("i2c: Add
bus recovery infrastructure").

The i2c_bus_recovery_info is configured for Davinci I2C adapter
only in case scl_pin is provided in platform data.

As the controller must be held in reset while doing so, the
recovery routine must re-init the controller. Since this was already
being done after each call to i2c_recover_bus, move those calls into
the recovery_prepare/unprepare routines and as well.

Acked-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 2b2190a3

drivers/i2c/busses/i2c-davinci.c

+36 −41
Original line number Diff line number Diff line
@@ -129,43 +129,6 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg) 
	return readw_relaxed(i2c_dev->base + reg);

}



/* Generate a pulse on the i2c clock pin. */

static void davinci_i2c_clock_pulse(unsigned int scl_pin)

{

	u16 i;



	if (scl_pin) {

		/* Send high and low on the SCL line */

		for (i = 0; i < 9; i++) {

			gpio_set_value(scl_pin, 0);

			udelay(20);

			gpio_set_value(scl_pin, 1);

			udelay(20);

		}

	}

}



/* This routine does i2c bus recovery as specified in the

 * i2c protocol Rev. 03 section 3.16 titled "Bus clear"

 */

static void davinci_i2c_recover_bus(struct davinci_i2c_dev *dev)

{

	u32 flag = 0;

	struct davinci_i2c_platform_data *pdata = dev->pdata;



	dev_err(dev->dev, "initiating i2c bus recovery\n");

	/* Send NACK to the slave */

	flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);

	flag |=  DAVINCI_I2C_MDR_NACK;

	/* write the data into mode register */

	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);

	davinci_i2c_clock_pulse(pdata->scl_pin);

	/* Send STOP */

	flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);

	flag |= DAVINCI_I2C_MDR_STP;

	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);

}



static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,

								int val)

{
@@ -262,6 +225,34 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev) 
	return 0;

}



/*

 * This routine does i2c bus recovery by using i2c_generic_gpio_recovery

 * which is provided by I2C Bus recovery infrastructure.

 */

static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap)

{

	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);



	/* Disable interrupts */

	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0);



	/* put I2C into reset */

	davinci_i2c_reset_ctrl(dev, 0);

}



static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap)

{

	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);



	i2c_davinci_init(dev);

}



static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {

	.recover_bus = i2c_generic_gpio_recovery,

	.prepare_recovery = davinci_i2c_prepare_recovery,

	.unprepare_recovery = davinci_i2c_unprepare_recovery,

};



/*

 * Waiting for bus not busy

 */
@@ -282,8 +273,7 @@ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev, 
				return -ETIMEDOUT;

			} else {

				to_cnt = 0;

				davinci_i2c_recover_bus(dev);

				i2c_davinci_init(dev);

				i2c_recover_bus(&dev->adapter);

			}

		}

		if (allow_sleep)
@@ -372,8 +362,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) 
						dev->adapter.timeout);

	if (!time_left) {

		dev_err(dev->dev, "controller timed out\n");

		davinci_i2c_recover_bus(dev);

		i2c_davinci_init(dev);

		i2c_recover_bus(adap);

		dev->buf_len = 0;

		return -ETIMEDOUT;

	}
@@ -712,6 +701,12 @@ static int davinci_i2c_probe(struct platform_device *pdev) 
	adap->timeout = DAVINCI_I2C_TIMEOUT;

	adap->dev.of_node = pdev->dev.of_node;



	if (dev->pdata->scl_pin) {

		adap->bus_recovery_info = &davinci_i2c_gpio_recovery_info;

		adap->bus_recovery_info->scl_gpio = dev->pdata->scl_pin;

		adap->bus_recovery_info->sda_gpio = dev->pdata->sda_pin;

	}



	adap->nr = pdev->id;

	r = i2c_add_numbered_adapter(adap);

	if (r) {