Re: [PATCH] media: adv7604: improve usage of gpiod API

[Hans Verkuil <hverkuil@xs4all.nl>]

Hi Uwe,

On 03/02/2015 08:00 AM, Uwe Kleine-König wrote:
> Since 39b2bbe3d715 (gpio: add flags argument to gpiod_get*() functions)
> which appeared in v3.17-rc1, the gpiod_get* functions take an additional
> parameter that allows to specify direction and initial value for output.
> Simplify accordingly.
> 
> Moreover use devm_gpiod_get_index_optional instead of
> devm_gpiod_get_index with ignoring all errors.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
> BTW, sparse fails to check this file with many errors like:
> 
> 	drivers/media/i2c/adv7604.c:311:11: error: unknown field name in initializer
> 
> Didn't look into that.

That's a sparse bug that's been fixed in the sparse repo, but not in the 0.5.0
release (they really should make a new sparse release IMHO).

Some comments below:

> ---
>  drivers/media/i2c/adv7604.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
> index 5a7c9389a605..ddeeb6695a4b 100644
> --- a/drivers/media/i2c/adv7604.c
> +++ b/drivers/media/i2c/adv7604.c
> @@ -537,12 +537,8 @@ static void adv7604_set_hpd(struct adv7604_state *state, unsigned int hpd)
>  {
>  	unsigned int i;
>  
> -	for (i = 0; i < state->info->num_dv_ports; ++i) {
> -		if (IS_ERR(state->hpd_gpio[i]))
> -			continue;

Why this change? See also below:

> -
> +	for (i = 0; i < state->info->num_dv_ports; ++i)
>  		gpiod_set_value_cansleep(state->hpd_gpio[i], hpd & BIT(i));
> -	}
>  
>  	v4l2_subdev_notify(&state->sd, ADV7604_HOTPLUG, &hpd);
>  }
> @@ -2720,13 +2716,13 @@ static int adv7604_probe(struct i2c_client *client,
>  	/* Request GPIOs. */
>  	for (i = 0; i < state->info->num_dv_ports; ++i) {
>  		state->hpd_gpio[i] =
> -			devm_gpiod_get_index(&client->dev, "hpd", i);
> +			devm_gpiod_get_index_optional(&client->dev, "hpd", i,
> +						      GPIOD_OUT_LOW);
>  		if (IS_ERR(state->hpd_gpio[i]))
> -			continue;
> -
> -		gpiod_direction_output(state->hpd_gpio[i], 0);
> +			return PTR_ERR(state->hpd_gpio[i]);

This isn't correct. The use of gpio is optional, on some boards a different
mechanism is used to control the hpd, and there devm_gpiod_get_index will just
return an error. That's OK, we just continue in that case.

Regards,

	Hans

>  
> -		v4l_info(client, "Handling HPD %u GPIO\n", i);
> +		if (state->hpd_gpio[i])
> +			v4l_info(client, "Handling HPD %u GPIO\n", i);
>  	}
>  
>  	state->timings = cea640x480;
>