Re: [PATCH v2 2/3] media: i2c: ov9282: Switch to using the sub-device state lock

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Xiaolei,

Thanks for the update. A few comments below...

On Sun, Mar 01, 2026 at 06:48:08PM +0800, Xiaolei Wang wrote:
> Switch to using the sub-device state lock and properly call
> v4l2_subdev_init_finalize() / v4l2_subdev_cleanup() on probe() /
> remove().
> 
> Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
> Reviewed-by: Tarang Raval <tarang.raval@siliconsignals.io>
> ---
>  drivers/media/i2c/ov9282.c | 50 +++++++++++++++-----------------------
>  1 file changed, 19 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c
> index 8bfaa3ae4be5..8acbd43838d5 100644
> --- a/drivers/media/i2c/ov9282.c
> +++ b/drivers/media/i2c/ov9282.c
> @@ -221,7 +221,6 @@ struct ov9282 {
>  	bool noncontinuous_clock;
>  	const struct ov9282_mode *cur_mode;
>  	u32 code;
> -	struct mutex mutex;
>  };
>  
>  static const s64 link_freq[] = {
> @@ -795,8 +794,6 @@ static int ov9282_get_pad_format(struct v4l2_subdev *sd,
>  {
>  	struct ov9282 *ov9282 = to_ov9282(sd);
>  
> -	mutex_lock(&ov9282->mutex);
> -
>  	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
>  		struct v4l2_mbus_framefmt *framefmt;
>  
> @@ -807,8 +804,6 @@ static int ov9282_get_pad_format(struct v4l2_subdev *sd,
>  				       fmt);
>  	}
>  
> -	mutex_unlock(&ov9282->mutex);
> -
>  	return 0;
>  }
>  
> @@ -829,8 +824,6 @@ static int ov9282_set_pad_format(struct v4l2_subdev *sd,
>  	u32 code;
>  	int ret = 0;
>  
> -	mutex_lock(&ov9282->mutex);
> -
>  	mode = v4l2_find_nearest_size(supported_modes,
>  				      ARRAY_SIZE(supported_modes),
>  				      width, height,
> @@ -856,8 +849,6 @@ static int ov9282_set_pad_format(struct v4l2_subdev *sd,
>  		}
>  	}
>  
> -	mutex_unlock(&ov9282->mutex);
> -
>  	return ret;
>  }
>  
> @@ -904,10 +895,8 @@ static int ov9282_get_selection(struct v4l2_subdev *sd,
>  	case V4L2_SEL_TGT_CROP: {
>  		struct ov9282 *ov9282 = to_ov9282(sd);
>  
> -		mutex_lock(&ov9282->mutex);
>  		sel->r = *__ov9282_get_pad_crop(ov9282, sd_state, sel->pad,
>  						sel->which);
> -		mutex_unlock(&ov9282->mutex);
>  
>  		return 0;
>  	}
> @@ -1019,9 +1008,10 @@ static int ov9282_stop_streaming(struct ov9282 *ov9282)
>  static int ov9282_set_stream(struct v4l2_subdev *sd, int enable)
>  {
>  	struct ov9282 *ov9282 = to_ov9282(sd);
> +	struct v4l2_subdev_state *state;
>  	int ret;
>  
> -	mutex_lock(&ov9282->mutex);
> +	state = v4l2_subdev_lock_and_get_active_state(sd);
>  
>  	if (enable) {
>  		ret = pm_runtime_resume_and_get(ov9282->dev);
> @@ -1036,14 +1026,14 @@ static int ov9282_set_stream(struct v4l2_subdev *sd, int enable)
>  		pm_runtime_put(ov9282->dev);
>  	}
>  
> -	mutex_unlock(&ov9282->mutex);
> +	v4l2_subdev_unlock_state(state);
>  
>  	return 0;
>  
>  error_power_off:
>  	pm_runtime_put(ov9282->dev);
>  error_unlock:
> -	mutex_unlock(&ov9282->mutex);
> +	v4l2_subdev_unlock_state(state);
>  
>  	return ret;
>  }
> @@ -1285,9 +1275,6 @@ static int ov9282_init_controls(struct ov9282 *ov9282)
>  	if (ret)
>  		return ret;
>  
> -	/* Serialize controls with sensor device */
> -	ctrl_hdlr->lock = &ov9282->mutex;
> -
>  	/* Initialize exposure and gain */
>  	lpfr = mode->vblank + mode->height;
>  	ov9282->exp_ctrl = v4l2_ctrl_new_std(ctrl_hdlr,
> @@ -1409,13 +1396,10 @@ static int ov9282_probe(struct i2c_client *client)
>  		return dev_err_probe(ov9282->dev, PTR_ERR(ov9282->regmap),
>  				     "Failed to init CCI\n");
>  
> -	mutex_init(&ov9282->mutex);
> -
>  	ret = ov9282_power_on(ov9282->dev);
> -	if (ret) {
> -		dev_err(ov9282->dev, "failed to power-on the sensor");
> -		goto error_mutex_destroy;
> -	}
> +	if (ret)
> +		return dev_err_probe(ov9282->dev, ret,
> +				     "failed to power-on the sensor");
>  
>  	/* Check module identity */
>  	ret = ov9282_detect(ov9282);
> @@ -1448,10 +1432,10 @@ static int ov9282_probe(struct i2c_client *client)
>  		goto error_handler_free;
>  	}
>  
> -	ret = v4l2_async_register_subdev_sensor(&ov9282->sd);
> +	ov9282->sd.state_lock = ov9282->ctrl_handler.lock;
> +	ret = v4l2_subdev_init_finalize(&ov9282->sd);
>  	if (ret < 0) {
> -		dev_err(ov9282->dev,
> -			"failed to register async subdev: %d", ret);
> +		ret = dev_err_probe(ov9282->dev, ret, "failed to init subdev\n");

Assigning ret here won't do anything, will it?

>  		goto error_media_entity;
>  	}
>  
> @@ -1459,16 +1443,22 @@ static int ov9282_probe(struct i2c_client *client)
>  	pm_runtime_enable(ov9282->dev);
>  	pm_runtime_idle(ov9282->dev);

The sensor may be powered down here...

>  
> +	ret = v4l2_async_register_subdev_sensor(&ov9282->sd);
> +	if (ret < 0)
> +		goto v4l2_subdev_cleanup;
> +
>  	return 0;
>  
> +v4l2_subdev_cleanup:
> +	v4l2_subdev_cleanup(&ov9282->sd);
> +	pm_runtime_disable(ov9282->dev);
> +	pm_runtime_set_suspended(ov9282->dev);
>  error_media_entity:
>  	media_entity_cleanup(&ov9282->sd.entity);
>  error_handler_free:
>  	v4l2_ctrl_handler_free(ov9282->sd.ctrl_handler);
>  error_power_off:
>  	ov9282_power_off(ov9282->dev);

and again here.

I'd suggest to call pm_runtime_idle() after registering the async
sub-device to avoid doing this twice.

> -error_mutex_destroy:
> -	mutex_destroy(&ov9282->mutex);
>  
>  	return ret;
>  }
> @@ -1482,9 +1472,9 @@ static int ov9282_probe(struct i2c_client *client)
>  static void ov9282_remove(struct i2c_client *client)
>  {
>  	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> -	struct ov9282 *ov9282 = to_ov9282(sd);
>  
>  	v4l2_async_unregister_subdev(sd);
> +	v4l2_subdev_cleanup(sd);
>  	media_entity_cleanup(&sd->entity);
>  	v4l2_ctrl_handler_free(sd->ctrl_handler);
>  
> @@ -1492,8 +1482,6 @@ static void ov9282_remove(struct i2c_client *client)
>  	if (!pm_runtime_status_suspended(&client->dev))
>  		ov9282_power_off(&client->dev);
>  	pm_runtime_set_suspended(&client->dev);
> -
> -	mutex_destroy(&ov9282->mutex);
>  }
>  
>  static const struct dev_pm_ops ov9282_pm_ops = {

-- 
Kind regards,

Sakari Ailus