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@xxxxxxxxxx>
Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
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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