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Message-ID: <e95881dd-72ba-4a1e-b312-b1efeec0a074@windriver.com>
Date: Sun, 28 Dec 2025 14:27:41 +0800
From: xiaolei wang <xiaolei.wang@...driver.com>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: sakari.ailus@...ux.intel.com, dave.stevenson@...pberrypi.com,
jacopo@...ndi.org, mchehab@...nel.org,
prabhakar.mahadev-lad.rj@...renesas.com, hverkuil+cisco@...nel.org,
johannes.goede@....qualcomm.com, hverkuil-cisco@...all.nl,
jai.luthra@...asonboard.com, linux-media@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] media: i2c: ov5647: Switch to using the sub-device
state lock
Hi Laurent,
On 12/27/25 19:21, Laurent Pinchart wrote:
> CAUTION: This email comes from a non Wind River email account!
> Do not click links or open attachments unless you recognize the sender and know the content is safe.
>
> Hi Xiaolei,
>
> Thank you for the patch.
>
> On Fri, Dec 26, 2025 at 11:13:11AM +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().
> We try to convert image sensor drivers to the .enable_streams() and
> .disable_streams() operations at the same time as the conversion to
> v4l2_subdev_init_finalize(), to standardize on recent APIs. This hasn't
> been entirely successful so far (there are 40 drivers using
> v4l2_subdev_init_finalize() and only 22 of those use the new
> operations), but let's avoid making it worse :-)
>
> Could you please include a patch in v2 to move to the new
> .enable_streams() and .disable_streams() operations ?
Thank you very much for reviewing my patch and for the valuable feedback.
You're absolutely right about the importance of standardizing on the recent
APIs. I completely understand your concern about the inconsistency between
drivers using v4l2_subdev_init_finalize() and those using the new stream
operations, and I appreciate you pointing this out.
I apologize for not considering the .enable_streams() and .disable_streams()
operations in my initial patch. I will add a patch in version V2 to
enable the
new .enable_streams() and .disable_streams() operations.
Best regards,
Xiaolei
>
>> Signed-off-by: Xiaolei Wang <xiaolei.wang@...driver.com>
>> ---
>> drivers/media/i2c/ov5647.c | 40 +++++++++++++-------------------------
>> 1 file changed, 14 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
>> index 1f8e173417b8..2619971353fd 100644
>> --- a/drivers/media/i2c/ov5647.c
>> +++ b/drivers/media/i2c/ov5647.c
>> @@ -96,7 +96,6 @@ struct ov5647 {
>> struct v4l2_subdev sd;
>> struct regmap *regmap;
>> struct media_pad pad;
>> - struct mutex lock;
>> struct clk *xclk;
>> struct gpio_desc *pwdn;
>> bool clock_ncont;
>> @@ -657,7 +656,7 @@ static int ov5647_stream_on(struct v4l2_subdev *sd)
>> }
>>
>> /* Apply customized values from user when stream starts. */
>> - ret = __v4l2_ctrl_handler_setup(sd->ctrl_handler);
>> + ret = v4l2_ctrl_handler_setup(sd->ctrl_handler);
>> if (ret)
>> return ret;
>>
>> @@ -821,15 +820,12 @@ __ov5647_get_pad_crop(struct ov5647 *ov5647,
>> static int ov5647_s_stream(struct v4l2_subdev *sd, int enable)
>> {
>> struct i2c_client *client = v4l2_get_subdevdata(sd);
>> - struct ov5647 *sensor = to_sensor(sd);
>> int ret;
>>
>> - mutex_lock(&sensor->lock);
>> -
>> if (enable) {
>> ret = pm_runtime_resume_and_get(&client->dev);
>> if (ret < 0)
>> - goto error_unlock;
>> + return ret;
>>
>> ret = ov5647_stream_on(sd);
>> if (ret < 0) {
>> @@ -845,14 +841,10 @@ static int ov5647_s_stream(struct v4l2_subdev *sd, int enable)
>> pm_runtime_put(&client->dev);
>> }
>>
>> - mutex_unlock(&sensor->lock);
>> -
>> return 0;
>>
>> error_pm:
>> pm_runtime_put(&client->dev);
>> -error_unlock:
>> - mutex_unlock(&sensor->lock);
>>
>> return ret;
>> }
>> @@ -900,7 +892,6 @@ static int ov5647_get_pad_fmt(struct v4l2_subdev *sd,
>> const struct v4l2_mbus_framefmt *sensor_format;
>> struct ov5647 *sensor = to_sensor(sd);
>>
>> - mutex_lock(&sensor->lock);
>> switch (format->which) {
>> case V4L2_SUBDEV_FORMAT_TRY:
>> sensor_format = v4l2_subdev_state_get_format(sd_state,
>> @@ -912,7 +903,6 @@ static int ov5647_get_pad_fmt(struct v4l2_subdev *sd,
>> }
>>
>> *fmt = *sensor_format;
>> - mutex_unlock(&sensor->lock);
>>
>> return 0;
>> }
>> @@ -930,7 +920,6 @@ static int ov5647_set_pad_fmt(struct v4l2_subdev *sd,
>> fmt->width, fmt->height);
>>
>> /* Update the sensor mode and apply at it at streamon time. */
>> - mutex_lock(&sensor->lock);
>> if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
>> *v4l2_subdev_state_get_format(sd_state, format->pad) = mode->format;
>> } else {
>> @@ -959,7 +948,6 @@ static int ov5647_set_pad_fmt(struct v4l2_subdev *sd,
>> exposure_def);
>> }
>> *fmt = mode->format;
>> - mutex_unlock(&sensor->lock);
>>
>> return 0;
>> }
>> @@ -972,10 +960,8 @@ static int ov5647_get_selection(struct v4l2_subdev *sd,
>> case V4L2_SEL_TGT_CROP: {
>> struct ov5647 *sensor = to_sensor(sd);
>>
>> - mutex_lock(&sensor->lock);
>> sel->r = *__ov5647_get_pad_crop(sensor, sd_state, sel->pad,
>> sel->which);
>> - mutex_unlock(&sensor->lock);
>>
>> return 0;
>> }
>> @@ -1149,9 +1135,6 @@ static int ov5647_s_ctrl(struct v4l2_ctrl *ctrl)
>> struct i2c_client *client = v4l2_get_subdevdata(sd);
>> int ret = 0;
>>
>> -
>> - /* v4l2_ctrl_lock() locks our own mutex */
>> -
>> if (ctrl->id == V4L2_CID_VBLANK) {
>> int exposure_max, exposure_def;
>>
>> @@ -1351,13 +1334,11 @@ static int ov5647_probe(struct i2c_client *client)
>> return -EINVAL;
>> }
>>
>> - mutex_init(&sensor->lock);
>> -
>> sensor->mode = OV5647_DEFAULT_MODE;
>>
>> ret = ov5647_init_controls(sensor);
>> if (ret)
>> - goto mutex_destroy;
>> + return ret;
>>
>> sd = &sensor->sd;
>> v4l2_i2c_subdev_init(sd, client, &ov5647_subdev_ops);
>> @@ -1385,9 +1366,16 @@ static int ov5647_probe(struct i2c_client *client)
>> if (ret < 0)
>> goto power_off;
>>
>> + sd->state_lock = sensor->ctrls.lock;
>> + ret = v4l2_subdev_init_finalize(sd);
>> + if (ret < 0) {
>> + dev_err(&client->dev, "failed to init subdev: %d", ret);
>> + goto power_off;
>> + }
>> +
>> ret = v4l2_async_register_subdev(sd);
>> if (ret < 0)
>> - goto power_off;
>> + goto v4l2_subdev_cleanup;
>>
>> /* Enable runtime PM and turn off the device */
>> pm_runtime_set_active(dev);
>> @@ -1398,14 +1386,14 @@ static int ov5647_probe(struct i2c_client *client)
>>
>> return 0;
>>
>> +v4l2_subdev_cleanup:
>> + v4l2_subdev_cleanup(sd);
>> power_off:
>> ov5647_power_off(dev);
>> entity_cleanup:
>> media_entity_cleanup(&sd->entity);
>> ctrl_handler_free:
>> v4l2_ctrl_handler_free(&sensor->ctrls);
>> -mutex_destroy:
>> - mutex_destroy(&sensor->lock);
>>
>> return ret;
>> }
>> @@ -1416,11 +1404,11 @@ static void ov5647_remove(struct i2c_client *client)
>> struct ov5647 *sensor = to_sensor(sd);
>>
>> v4l2_async_unregister_subdev(&sensor->sd);
>> + v4l2_subdev_cleanup(sd);
>> media_entity_cleanup(&sensor->sd.entity);
>> v4l2_ctrl_handler_free(&sensor->ctrls);
>> v4l2_device_unregister_subdev(sd);
>> pm_runtime_disable(&client->dev);
>> - mutex_destroy(&sensor->lock);
>> }
>>
>> static const struct dev_pm_ops ov5647_pm_ops = {
> --
> Regards,
>
> Laurent Pinchart
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