* [PATCH v2] [media] adv7604: Add support for hardware reset
@ 2016-05-24 14:33 Dragos Bogdan
2016-06-15 16:09 ` Laurent Pinchart
0 siblings, 1 reply; 2+ messages in thread
From: Dragos Bogdan @ 2016-05-24 14:33 UTC (permalink / raw)
To: Hans Verkuil, Mauro Carvalho Chehab
Cc: Lars-Peter Clausen, linux-media, 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>
---
Changes since v1:
- Replace mdelay() with usleep_range();
- Limit the comments to 75 characters per line.
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..73c79bb 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);
+ 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);
+ }
+
+ 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);
--
2.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] [media] adv7604: Add support for hardware reset
2016-05-24 14:33 [PATCH v2] [media] adv7604: Add support for hardware reset Dragos Bogdan
@ 2016-06-15 16:09 ` Laurent Pinchart
0 siblings, 0 replies; 2+ messages in thread
From: Laurent Pinchart @ 2016-06-15 16:09 UTC (permalink / raw)
To: Dragos Bogdan
Cc: Hans Verkuil, Mauro Carvalho Chehab, Lars-Peter Clausen, linux-media
Hi Dragos,
Thank you for the patch.
On Tuesday 24 May 2016 17:33:27 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 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>
> ---
> Changes since v1:
> - Replace mdelay() with usleep_range();
> - Limit the comments to 75 characters per line.
>
> 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..73c79bb 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)
Given that the function always returns 0 and that the return value is never
checked I'd turn it into a void function.
> +{
> + if (state->reset_gpio) {
Nitpicking, if you write this as
if (!state->reset_gpio)
return;
then you can lower the indendation of the following code block. That's a
matter of style and preferences though, so I'll let you decide what you
prefer.
Apart from that,
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> + /* 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);
> + }
> +
> + 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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2016-06-15 16:09 ` Laurent Pinchart
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