[PATCH v3] [media] adv7604: Add support for hardware reset

[PATCH v3] [media] adv7604: Add support for hardware reset

[Dragos Bogdan]

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 between 5 and 10 ms.

The RESET pin can be tied high, so the GPIO is optional.

Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
Changes since v2:
 - adv76xx_reset() is now a void function (it always returned 0).

Changes since v1:
 - Replace mdelay() with usleep_range();
 - Limit the comments to 75 characters per line.

 drivers/media/i2c/adv7604.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
index 41a1bfc..ab4f933 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 +2997,19 @@ static int configure_regmaps(struct adv76xx_state *state)
 	return 0;
 }
 
+static void 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);
+		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. */
+		usleep_range(5000, 10000);
+	}
+}
+
 static int adv76xx_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -3059,6 +3073,12 @@ 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);
-- 
2.1.4

Re: [PATCH v3] [media] adv7604: Add support for hardware reset

[Jean-Michel Hautbois]

Hi,

2016-06-22 13:30 GMT+02:00 Dragos Bogdan <dragos.bogdan@analog.com>:
> 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 between 5 and 10 ms.
>
> The RESET pin can be tied high, so the GPIO is optional.
>
> Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
> Changes since v2:
>  - adv76xx_reset() is now a void function (it always returned 0).
>
> Changes since v1:
>  - Replace mdelay() with usleep_range();
>  - Limit the comments to 75 characters per line.
>
>  drivers/media/i2c/adv7604.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
> index 41a1bfc..ab4f933 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 +2997,19 @@ static int configure_regmaps(struct adv76xx_state *state)
>         return 0;
>  }
>
> +static void 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);
> +               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. */
> +               usleep_range(5000, 10000);
> +       }
> +}
> +
>  static int adv76xx_probe(struct i2c_client *client,
>                          const struct i2c_device_id *id)
>  {
> @@ -3059,6 +3073,12 @@ 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);
> --
> 2.1.4
>
> --
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I now have this patch in my tree and I can get into a point where
status is V4L2_IN_ST_NO_SYNC and stays there...
If I set a resolution (say, 1920x1080@60), and then use another one
without unplugging the cable, I can get into this state.
If I don't have the reset call, there is not such problem.

Any idea why ?
I tried (without a high conviction) to add i call to adv76xx_reset
inside g_input_status when there is no sync, it is better, but not
perfect (I still can get a status = 0x10003 for example).

Thanks,
JM