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i2c: Add option to send start condition after deblocking

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Add option to send start condition after deblocking SDA.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Heiko Schocher <hs@denx.de>
This commit is contained in:
Marek Vasut 2020-02-07 16:57:51 +01:00 committed by Heiko Schocher
parent 7231522a5e
commit a191728633
2 changed files with 23 additions and 4 deletions
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23
drivers/i2c/i2c-uclass.c
View File

@ -504,9 +504,10 @@ static int i2c_gpio_get_pin(struct gpio_desc *pin)
int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin,
struct gpio_desc *scl_pin,
unsigned int scl_count,
unsigned int start_count,
unsigned int delay)
{
int ret = 0;
int i, ret = -EREMOTEIO;
i2c_gpio_set_pin(sda_pin, 1);
i2c_gpio_set_pin(scl_pin, 1);
@ -518,8 +519,24 @@ int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin,
udelay(delay);
i2c_gpio_set_pin(scl_pin, 0);
udelay(delay);
if (i2c_gpio_get_pin(sda_pin))
if (i2c_gpio_get_pin(sda_pin)) {
ret = 0;
break;
}
}
if (!ret && start_count) {
for (i = 0; i < start_count; i++) {
/* Send start condition */
udelay(delay);
i2c_gpio_set_pin(sda_pin, 1);
udelay(delay);
i2c_gpio_set_pin(scl_pin, 1);
udelay(delay);
i2c_gpio_set_pin(sda_pin, 0);
udelay(delay);
i2c_gpio_set_pin(scl_pin, 0);
}
}
/* Then, send I2C stop */
@ -562,7 +579,7 @@ static int i2c_deblock_gpio(struct udevice *bus)
goto out_no_pinctrl;
}
ret0 = i2c_deblock_gpio_loop(&gpios[PIN_SDA], &gpios[PIN_SCL], 9, 5);
ret0 = i2c_deblock_gpio_loop(&gpios[PIN_SDA], &gpios[PIN_SCL], 9, 0, 5);
ret = pinctrl_select_state(bus, "default");
if (ret) {

4
include/i2c.h
View File

@ -339,12 +339,14 @@ int i2c_deblock(struct udevice *bus);
* @sda_pin: SDA GPIO
* @scl_pin: SCL GPIO
* @scl_count: Number of SCL clock cycles generated to deblock SDA
* @start_count:Number of I2C start conditions sent after deblocking SDA
* @delay: Delay between SCL clock line changes
* @return 0 if OK, -ve on error
*/
struct gpio_desc;
int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, struct gpio_desc *scl_pin,
unsigned int scl_count, unsigned int delay);
unsigned int scl_count, unsigned int start_count,
unsigned int delay);
/**
* struct dm_i2c_ops - driver operations for I2C uclass