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Date:   Mon, 27 Nov 2023 08:55:37 +0100
From:   Tommaso Merciai <tomm.merciai@gmail.com>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     linuxfancy@googlegroups.com,
        Steve Longerbeam <slongerbeam@gmail.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] media: ov5640: use subdev active state
Message-ID: <ZWRLeTTxNDB7YpBS@tom-HP-ZBook-Fury-15-G7-Mobile-Workstation>
References: <20231126103401.2617585-1-tomm.merciai@gmail.com>
 <20231126144828.GA12891@pendragon.ideasonboard.com>
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Hi Laurent,
Thanks for reviewing this.

On Sun, Nov 26, 2023 at 04:48:28PM +0200, Laurent Pinchart wrote:
> Hi Tommaso,
> 
> Thank you for the patch.
> 
> On Sun, Nov 26, 2023 at 11:34:01AM +0100, Tommaso Merciai wrote:
> > Port the ov5640 sensor driver to use the subdev active state.
> > 
> > After the ov5640 configurations steps call v4l2_subdev_init_finalize
> > that finalizes the initialization of the subdevice.
> > From now we use subdevice active state to simplify format handling and
> > locking
> > 
> > References:
> >  - https://patchwork.kernel.org/project/linux-media/patch/20230710155203.92366-6-jacopo.mondi@ideasonboard.com/
> >  - https://linuxtv.org/downloads/v4l-dvb-apis/driver-api/v4l2-subdev.html#c.v4l2_subdev_cleanup
> > 
> > Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
> > ---
> >  drivers/media/i2c/ov5640.c | 89 ++++++++++----------------------------
> >  1 file changed, 24 insertions(+), 65 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
> > index 3f79a3b77044..44a073d3df64 100644
> > --- a/drivers/media/i2c/ov5640.c
> > +++ b/drivers/media/i2c/ov5640.c
> > @@ -446,9 +446,6 @@ struct ov5640_dev {
> >  	struct gpio_desc *pwdn_gpio;
> >  	bool   upside_down;
> >  
> > -	/* lock to protect all members below */
> > -	struct mutex lock;
> > -
> >  	struct v4l2_mbus_framefmt fmt;
> 
> This field should go too. The point of using the subdev active state is
> to move state information from the device-specific structure to the
> subdev state.

Thanks for the clarification.

> 
> Ideally the pending_fmt_change, current_mode, last_mode, current_fr,
> frame_interval and pending_mode_change fields should go too. That's more
> work and it's probably OK if we keep some of those fields for the time
> being.
> 
> One low(er) hanging fruit is current_fr and frame_interval, which would
> be nice to address soon. Removing them completely will require the "[RFC
> PATCH v1 0/4] media: v4l2-subdev: Improve frame interval handling" patch
> series ([1]), for which I plan to send a v2 soon. You can submit a v2 of
> this patch, dropping the fmt field, without waiting for the improved
> frame interval handling. It should however be fairly to merge the
> current_fr and frame_interval fields (dropping the ov5640_frame_rate
> enum as a result), it would be nice to see that as a patch already.
> 
> [1] https://lore.kernel.org/linux-media/20231024005130.28026-1-laurent.pinchart@ideasonboard.com

No problem I can wait. And work on top of your work later.
Please let me know if you need some test, I have a working imx8mp-evk +
ov5640 env on my side on top of sailus/media_tree/master (Actually I'm
using this for alvium driver upstream)

Hope this can help :)

Regards,
Tommaso

> 
> >  	bool pending_fmt_change;
> >  
> > @@ -2784,30 +2781,6 @@ static int ov5640_try_frame_interval(struct ov5640_dev *sensor,
> >  	return mode ? rate : -EINVAL;
> >  }
> >  
> > -static int ov5640_get_fmt(struct v4l2_subdev *sd,
> > -			  struct v4l2_subdev_state *sd_state,
> > -			  struct v4l2_subdev_format *format)
> > -{
> > -	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> > -	struct v4l2_mbus_framefmt *fmt;
> > -
> > -	if (format->pad != 0)
> > -		return -EINVAL;
> > -
> > -	mutex_lock(&sensor->lock);
> > -
> > -	if (format->which == V4L2_SUBDEV_FORMAT_TRY)
> > -		fmt = v4l2_subdev_state_get_format(sd_state, format->pad);
> > -	else
> > -		fmt = &sensor->fmt;
> > -
> > -	format->format = *fmt;
> > -
> > -	mutex_unlock(&sensor->lock);
> > -
> > -	return 0;
> > -}
> > -
> >  static int ov5640_try_fmt_internal(struct v4l2_subdev *sd,
> >  				   struct v4l2_mbus_framefmt *fmt,
> >  				   const struct ov5640_mode_info **new_mode)
> > @@ -2958,21 +2931,14 @@ static int ov5640_set_fmt(struct v4l2_subdev *sd,
> >  	if (format->pad != 0)
> >  		return -EINVAL;
> >  
> > -	mutex_lock(&sensor->lock);
> > -
> > -	if (sensor->streaming) {
> > -		ret = -EBUSY;
> > -		goto out;
> > -	}
> > +	if (sensor->streaming)
> > +		return -EBUSY;
> >  
> >  	ret = ov5640_try_fmt_internal(sd, mbus_fmt, &new_mode);
> >  	if (ret)
> > -		goto out;
> > +		return ret;
> >  
> > -	if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
> > -		*v4l2_subdev_state_get_format(sd_state, 0) = *mbus_fmt;
> > -		goto out;
> > -	}
> > +	*v4l2_subdev_state_get_format(sd_state, 0) = *mbus_fmt;
> >  
> >  	if (new_mode != sensor->current_mode) {
> >  		sensor->current_fr = new_mode->def_fps;
> > @@ -2987,26 +2953,16 @@ static int ov5640_set_fmt(struct v4l2_subdev *sd,
> >  
> >  	ov5640_update_pixel_rate(sensor);
> >  
> > -out:
> > -	mutex_unlock(&sensor->lock);
> > -	return ret;
> > +	return 0;
> >  }
> >  
> >  static int ov5640_get_selection(struct v4l2_subdev *sd,
> >  				struct v4l2_subdev_state *sd_state,
> >  				struct v4l2_subdev_selection *sel)
> >  {
> > -	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> > -	const struct ov5640_mode_info *mode = sensor->current_mode;
> > -	const struct ov5640_timings *timings;
> > -
> >  	switch (sel->target) {
> >  	case V4L2_SEL_TGT_CROP: {
> > -		mutex_lock(&sensor->lock);
> > -		timings = ov5640_timings(sensor, mode);
> > -		sel->r = timings->analog_crop;
> > -		mutex_unlock(&sensor->lock);
> > -
> > +		sel->r = *v4l2_subdev_state_get_crop(sd_state, 0);
> >  		return 0;
> >  	}
> >  
> > @@ -3441,9 +3397,6 @@ static int ov5640_init_controls(struct ov5640_dev *sensor)
> >  
> >  	v4l2_ctrl_handler_init(hdl, 32);
> >  
> > -	/* we can use our own mutex for the ctrl lock */
> > -	hdl->lock = &sensor->lock;
> > -
> >  	/* Clock related controls */
> >  	ctrls->pixel_rate = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_PIXEL_RATE,
> >  			      ov5640_pixel_rates[OV5640_NUM_PIXEL_RATES - 1],
> > @@ -3609,9 +3562,7 @@ static int ov5640_g_frame_interval(struct v4l2_subdev *sd,
> >  {
> >  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> >  
> > -	mutex_lock(&sensor->lock);
> >  	fi->interval = sensor->frame_interval;
> > -	mutex_unlock(&sensor->lock);
> >  
> >  	return 0;
> >  }
> > @@ -3620,13 +3571,14 @@ static int ov5640_s_frame_interval(struct v4l2_subdev *sd,
> >  				   struct v4l2_subdev_frame_interval *fi)
> >  {
> >  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> > +	struct v4l2_subdev_state *state;
> >  	const struct ov5640_mode_info *mode;
> >  	int frame_rate, ret = 0;
> >  
> >  	if (fi->pad != 0)
> >  		return -EINVAL;
> >  
> > -	mutex_lock(&sensor->lock);
> > +	state = v4l2_subdev_lock_and_get_active_state(sd);
> >  
> >  	if (sensor->streaming) {
> >  		ret = -EBUSY;
> > @@ -3663,7 +3615,7 @@ static int ov5640_s_frame_interval(struct v4l2_subdev *sd,
> >  		ov5640_update_pixel_rate(sensor);
> >  	}
> >  out:
> > -	mutex_unlock(&sensor->lock);
> > +	v4l2_subdev_unlock_state(state);
> >  	return ret;
> >  }
> >  
> > @@ -3694,6 +3646,7 @@ static int ov5640_enum_mbus_code(struct v4l2_subdev *sd,
> >  static int ov5640_s_stream(struct v4l2_subdev *sd, int enable)
> >  {
> >  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> > +	struct v4l2_subdev_state *state;
> >  	int ret = 0;
> >  
> >  	if (enable) {
> > @@ -3708,7 +3661,7 @@ static int ov5640_s_stream(struct v4l2_subdev *sd, int enable)
> >  		}
> >  	}
> >  
> > -	mutex_lock(&sensor->lock);
> > +	state = v4l2_subdev_lock_and_get_active_state(sd);
> >  
> >  	if (sensor->streaming == !enable) {
> >  		if (enable && sensor->pending_mode_change) {
> > @@ -3734,7 +3687,7 @@ static int ov5640_s_stream(struct v4l2_subdev *sd, int enable)
> >  	}
> >  
> >  out:
> > -	mutex_unlock(&sensor->lock);
> > +	v4l2_subdev_unlock_state(state);
> >  
> >  	if (!enable || ret) {
> >  		pm_runtime_mark_last_busy(&sensor->i2c_client->dev);
> > @@ -3778,7 +3731,7 @@ static const struct v4l2_subdev_video_ops ov5640_video_ops = {
> >  static const struct v4l2_subdev_pad_ops ov5640_pad_ops = {
> >  	.init_cfg = ov5640_init_cfg,
> >  	.enum_mbus_code = ov5640_enum_mbus_code,
> > -	.get_fmt = ov5640_get_fmt,
> > +	.get_fmt = v4l2_subdev_get_fmt,
> >  	.set_fmt = ov5640_set_fmt,
> >  	.get_selection = ov5640_get_selection,
> >  	.enum_frame_size = ov5640_enum_frame_size,
> > @@ -3918,8 +3871,6 @@ static int ov5640_probe(struct i2c_client *client)
> >  	if (ret)
> >  		goto entity_cleanup;
> >  
> > -	mutex_init(&sensor->lock);
> > -
> >  	ret = ov5640_init_controls(sensor);
> >  	if (ret)
> >  		goto entity_cleanup;
> > @@ -3938,9 +3889,16 @@ static int ov5640_probe(struct i2c_client *client)
> >  	if (ret)
> >  		goto err_pm_runtime;
> >  
> > +	sensor->sd.state_lock = sensor->ctrls.handler.lock;
> > +	ret = v4l2_subdev_init_finalize(&sensor->sd);
> > +	if (ret < 0) {
> > +		dev_err(dev, "subdev init error: %d\n", ret);
> > +		goto err_pm_runtime;
> > +	}
> > +
> >  	ret = v4l2_async_register_subdev_sensor(&sensor->sd);
> >  	if (ret)
> > -		goto err_pm_runtime;
> > +		goto subdev_cleanup;
> >  
> >  	pm_runtime_set_autosuspend_delay(dev, 1000);
> >  	pm_runtime_use_autosuspend(dev);
> > @@ -3949,6 +3907,8 @@ static int ov5640_probe(struct i2c_client *client)
> >  
> >  	return 0;
> >  
> > +subdev_cleanup:
> > +	v4l2_subdev_cleanup(&sensor->sd);
> >  err_pm_runtime:
> >  	pm_runtime_put_noidle(dev);
> >  	pm_runtime_disable(dev);
> > @@ -3957,7 +3917,6 @@ static int ov5640_probe(struct i2c_client *client)
> >  	v4l2_ctrl_handler_free(&sensor->ctrls.handler);
> >  entity_cleanup:
> >  	media_entity_cleanup(&sensor->sd.entity);
> > -	mutex_destroy(&sensor->lock);
> >  	return ret;
> >  }
> >  
> > @@ -3973,9 +3932,9 @@ static void ov5640_remove(struct i2c_client *client)
> >  	pm_runtime_set_suspended(dev);
> >  
> >  	v4l2_async_unregister_subdev(&sensor->sd);
> > +	v4l2_subdev_cleanup(sd);
> >  	media_entity_cleanup(&sensor->sd.entity);
> >  	v4l2_ctrl_handler_free(&sensor->ctrls.handler);
> > -	mutex_destroy(&sensor->lock);
> >  }
> >  
> >  static const struct dev_pm_ops ov5640_pm_ops = {
> 
> -- 
> Regards,
> 
> Laurent Pinchart