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

[xiaolei wang <xiaolei.wang@windriver.com>]

Hi Sakari,

Thanks for the review!

On 3/2/26 20:49, Sakari Ailus wrote:
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>
> 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?
You're right. I'll remove the assignment and just call dev_err_probe() 
directly.
>
>>                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.
Thanks for catching this. I'll move pm_runtime_idle() after
v4l2_async_register_subdev_sensor() to avoid the potential double
power-off in the error path.

I'll send v2 with these fixes.

Best regards,
Xiaolei

>
>> -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