Hi Dragos,
On Tuesday 24 May 2016 12:13:22 Dragos Bogdan wrote:
> The part can be reset by a low pulse on the RESET pin (i.e. a hardware
> reset) with a minimum width of 5 ms. It is recommended to wait 5 ms after
> the low pulse before an I2C write is performed to the part. For safety
> reasons, the delays will be 10 ms.
> The RESET pin can be tied high, so the GPIO is optional.
>
> Signed-off-by: Dragos Bogdan <dragos.bog...@analog.com>
> ---
> drivers/media/i2c/adv7604.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
> index 41a1bfc..fac0ff1 100644
> --- a/drivers/media/i2c/adv7604.c
> +++ b/drivers/media/i2c/adv7604.c
> @@ -164,6 +164,7 @@ struct adv76xx_state {
> struct adv76xx_platform_data pdata;
>
> struct gpio_desc *hpd_gpio[4];
> + struct gpio_desc *reset_gpio;
>
> struct v4l2_subdev sd;
> struct media_pad pads[ADV76XX_PAD_MAX];
> @@ -2996,6 +2997,21 @@ static int configure_regmaps(struct adv76xx_state
> *state) return 0;
> }
>
> +static int adv76xx_reset(struct adv76xx_state *state)
> +{
> + if (state->reset_gpio) {
> + /* ADV76XX can be reset by a low reset pulse of minimum 5 ms. */
> + gpiod_set_value_cansleep(state->reset_gpio, 0);
> + mdelay(10);
A busy loop of 10ms is very long, please use usleep_range() instead. As the
minimum is 5ms and you're fine with 10ms, you can use usleep_range(5000,
10000).
> + gpiod_set_value_cansleep(state->reset_gpio, 1);
> + /* It is recommended to wait 5 ms after the low pulse before */
> + /* an I2C write is performed to the ADV76XX. */
> + mdelay(10);
Ditto.
> + }
> +
> + return 0;
> +}
> +
> static int adv76xx_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> @@ -3059,6 +3075,12 @@ static int adv76xx_probe(struct i2c_client *client,
> if (state->hpd_gpio[i])
> v4l_info(client, "Handling HPD %u GPIO\n", i);
> }
> + state->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(state->reset_gpio))
> + return PTR_ERR(state->reset_gpio);
> +
> + adv76xx_reset(state);
>
> state->timings = cea640x480;
> state->format = adv76xx_format_info(state, MEDIA_BUS_FMT_YUYV8_2X8);
--
Regards,
Laurent Pinchart
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