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i2c: davinci: use bus recovery infrastructure 

This patch converts Davinci I2C driver to use I2C bus recovery
infrastructure, introduced by commit 5f9296ba21 ("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: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Grygorii Strashko 2015-04-06 15:38:40 +03:00 committed by Wolfram Sang
parent 2b2190a375
commit 2e65676f71
1 changed files with 36 additions and 41 deletions
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77
drivers/i2c/busses/i2c-davinci.c
View File

@ -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) {