[PATCH 3/4] i2c: Add option to send start condition after deblocking

[Heiko Schocher]

Hello Marek,

Am 07.02.2020 um 16:57 schrieb Marek Vasut:
> Add option to send start condition after deblocking SDA.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
>   drivers/i2c/i2c-uclass.c | 23 ++++++++++++++++++++---
>   include/i2c.h            |  4 +++-
>   2 files changed, 23 insertions(+), 4 deletions(-)

Reviewed-by: Heiko Schocher <hs at denx.de>

> diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
> index 86f529241f..e9ec388576 100644
> --- a/drivers/i2c/i2c-uclass.c
> +++ b/drivers/i2c/i2c-uclass.c
> @@ -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) {
> diff --git a/include/i2c.h b/include/i2c.h
> index 7c92042c58..059200115a 100644
> --- a/include/i2c.h
> +++ b/include/i2c.h
> @@ -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

Is there a tab missing? If so I can add it, when applying this patch.

>    * @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
> 

bye,
Heiko
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-52   Fax: +49-8142-66989-80   Email: hs at denx.de