Re: [PATCH 3/8] media: i2c: ov08d10: add support for reset and power management

[Philipp Zabel]

On Do, 2026-02-26 at 09:56 +0100, Matthias Fend wrote:
> Add support for the required power supplies as well as the control of an
> optional sensor reset.
> 
> Signed-off-by: Matthias Fend <matthias.fend@xxxxxxxxx>
> ---
>  drivers/media/i2c/ov08d10.c | 104 +++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 97 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov08d10.c b/drivers/media/i2c/ov08d10.c
> index cfe18dcde174ddc1f198cb2aaa6b4a3b34045508..4dba264488b3e1950016deb3fa34732871cc34fc 100644
> --- a/drivers/media/i2c/ov08d10.c
> +++ b/drivers/media/i2c/ov08d10.c
[...]
> @@ -1379,6 +1442,7 @@ static int ov08d10_probe(struct i2c_client *client)
>  {
>  	struct ov08d10 *ov08d10;
>  	unsigned long freq;
> +	unsigned int i;
>  	int ret;
>  
>  	ov08d10 = devm_kzalloc(&client->dev, sizeof(*ov08d10), GFP_KERNEL);
> @@ -1404,12 +1468,32 @@ static int ov08d10_probe(struct i2c_client *client)
>  		return ret;
>  	}
>  
> +	ov08d10->reset = devm_reset_control_get_optional(ov08d10->dev, NULL);

Please use devm_reset_control_get_optional_exclusive() directly.

> +	if (IS_ERR(ov08d10->reset))
> +		return dev_err_probe(ov08d10->dev, PTR_ERR(ov08d10->reset),
> +				     "failed to get reset\n");
> +	reset_control_assert(ov08d10->reset);
> +
> +	for (i = 0; i < ARRAY_SIZE(ov08d10_supply_names); i++)
> +		ov08d10->supplies[i].supply = ov08d10_supply_names[i];
> +
> +	ret = devm_regulator_bulk_get(ov08d10->dev,
> +				      ARRAY_SIZE(ov08d10->supplies),
> +				      ov08d10->supplies);
> +	if (ret)
> +		return dev_err_probe(ov08d10->dev, ret,
> +				     "failed to get regulators\n");
> +
>  	v4l2_i2c_subdev_init(&ov08d10->sd, client, &ov08d10_subdev_ops);
>  
> +	ret = ov08d10_power_on(ov08d10->dev);
> +	if (ret)
> +		return dev_err_probe(ov08d10->dev, ret, "failed to power on\n");
> +
>  	ret = ov08d10_identify_module(ov08d10);
>  	if (ret) {
>  		dev_err(ov08d10->dev, "failed to find sensor: %d", ret);
> -		return ret;
> +		goto probe_error_power_off;
>  	}
>  
>  	mutex_init(&ov08d10->mutex);
> @@ -1430,6 +1514,9 @@ static int ov08d10_probe(struct i2c_client *client)
>  		goto probe_error_v4l2_ctrl_handler_free;
>  	}
>  
> +	pm_runtime_set_active(ov08d10->dev);
> +	pm_runtime_enable(ov08d10->dev);
> +
>  	ret = v4l2_async_register_subdev_sensor(&ov08d10->sd);
>  	if (ret < 0) {
>  		dev_err(ov08d10->dev, "failed to register V4L2 subdev: %d",
> @@ -1437,26 +1524,28 @@ static int ov08d10_probe(struct i2c_client *client)
>  		goto probe_error_media_entity_cleanup;
>  	}
>  
> -	/*
> -	 * Device is already turned on by i2c-core with ACPI domain PM.
> -	 * Enable runtime PM and turn off the device.
> -	 */

The commit message does not explain why this comment is dropped.

> -	pm_runtime_set_active(ov08d10->dev);
> -	pm_runtime_enable(ov08d10->dev);
>  	pm_runtime_idle(ov08d10->dev);
>  
>  	return 0;
>  
>  probe_error_media_entity_cleanup:
> +	pm_runtime_disable(ov08d10->dev);
> +	pm_runtime_set_suspended(ov08d10->dev);

Does this do the correct thing if v4l2_async_register_subdev_sensor()
returns -EPROBE_DEFER (for example via privacy led) and then it probes
a second time? It looks like the assumption pm_runtime_set_active()
doesn't hold then.

>  	media_entity_cleanup(&ov08d10->sd.entity);
>  
>  probe_error_v4l2_ctrl_handler_free:
>  	v4l2_ctrl_handler_free(ov08d10->sd.ctrl_handler);
>  	mutex_destroy(&ov08d10->mutex);
>  
> +probe_error_power_off:
> +	ov08d10_power_off(ov08d10->dev);
> +
>  	return ret;
>  }

regards
Philipp