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Message-ID: <20251227112129.GG4094@pendragon.ideasonboard.com>
Date: Sat, 27 Dec 2025 13:21:29 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Xiaolei Wang <xiaolei.wang@...driver.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 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 ?
> 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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