Re: [PATCH v2 2/5] media: i2c: ov5645: Use runtime PM

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hello,

On Fri, Oct 14, 2022 at 07:18:11PM +0000, Sakari Ailus wrote:
> On Fri, Oct 14, 2022 at 07:34:56PM +0100, Prabhakar wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > 
> > Switch to using runtime PM for power management.
> > 
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > ---
> > v1->v2
> > * Moved pm_runtime_*_autosuspend() calls after registering the subdev.
> > ---
> >  drivers/media/i2c/Kconfig  |   2 +-
> >  drivers/media/i2c/ov5645.c | 137 +++++++++++++++++++------------------
> >  2 files changed, 70 insertions(+), 69 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> > index 7806d4b81716..c0edd1017fe8 100644
> > --- a/drivers/media/i2c/Kconfig
> > +++ b/drivers/media/i2c/Kconfig
> > @@ -459,7 +459,7 @@ config VIDEO_OV5640
> >  config VIDEO_OV5645
> >  	tristate "OmniVision OV5645 sensor support"
> >  	depends on OF
> > -	depends on I2C && VIDEO_DEV
> > +	depends on I2C && PM && VIDEO_DEV
> >  	select MEDIA_CONTROLLER
> >  	select VIDEO_V4L2_SUBDEV_API
> >  	select V4L2_FWNODE
> > diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> > index 81e4e87e1821..1551690a94e0 100644
> > --- a/drivers/media/i2c/ov5645.c
> > +++ b/drivers/media/i2c/ov5645.c
> > @@ -27,6 +27,7 @@
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_graph.h>
> > +#include <linux/pm_runtime.h>
> >  #include <linux/regulator/consumer.h>
> >  #include <linux/slab.h>
> >  #include <linux/types.h>
> > @@ -108,7 +109,6 @@ struct ov5645 {
> >  	u8 timing_tc_reg21;
> >  
> >  	struct mutex power_lock; /* lock to protect power state */
> > -	int power_count;
> >  
> >  	struct gpio_desc *enable_gpio;
> >  	struct gpio_desc *rst_gpio;
> > @@ -635,8 +635,24 @@ static int ov5645_set_register_array(struct ov5645 *ov5645,
> >  	return 0;
> >  }
> >  
> > -static int ov5645_set_power_on(struct ov5645 *ov5645)
> > +static int ov5645_set_power_off(struct device *dev)
> >  {
> > +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> > +	struct ov5645 *ov5645 = to_ov5645(sd);
> > +
> > +	ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x58);

I'm not sure this belongs here, but it can be addressed later.

> > +	gpiod_set_value_cansleep(ov5645->rst_gpio, 1);
> > +	gpiod_set_value_cansleep(ov5645->enable_gpio, 0);
> > +	clk_disable_unprepare(ov5645->xclk);
> > +	regulator_bulk_disable(OV5645_NUM_SUPPLIES, ov5645->supplies);
> > +
> > +	return 0;
> > +}
> > +
> > +static int ov5645_set_power_on(struct device *dev)
> > +{
> > +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> > +	struct ov5645 *ov5645 = to_ov5645(sd);
> >  	int ret;
> >  
> >  	ret = regulator_bulk_enable(OV5645_NUM_SUPPLIES, ov5645->supplies);
> > @@ -658,57 +674,19 @@ static int ov5645_set_power_on(struct ov5645 *ov5645)
> >  
> >  	msleep(20);
> >  
> > -	return 0;
> > -}
> > -
> > -static void ov5645_set_power_off(struct ov5645 *ov5645)
> > -{
> > -	gpiod_set_value_cansleep(ov5645->rst_gpio, 1);
> > -	gpiod_set_value_cansleep(ov5645->enable_gpio, 0);
> > -	clk_disable_unprepare(ov5645->xclk);
> > -	regulator_bulk_disable(OV5645_NUM_SUPPLIES, ov5645->supplies);
> > -}
> > -
> > -static int ov5645_s_power(struct v4l2_subdev *sd, int on)
> > -{
> > -	struct ov5645 *ov5645 = to_ov5645(sd);
> > -	int ret = 0;
> > -
> > -	mutex_lock(&ov5645->power_lock);
> > -
> > -	/* If the power count is modified from 0 to != 0 or from != 0 to 0,
> > -	 * update the power state.
> > -	 */
> > -	if (ov5645->power_count == !on) {
> > -		if (on) {
> > -			ret = ov5645_set_power_on(ov5645);
> > -			if (ret < 0)
> > -				goto exit;
> > -
> > -			ret = ov5645_set_register_array(ov5645,
> > -					ov5645_global_init_setting,
> > +	ret = ov5645_set_register_array(ov5645, ov5645_global_init_setting,
> >  					ARRAY_SIZE(ov5645_global_init_setting));
> > -			if (ret < 0) {
> > -				dev_err(ov5645->dev,
> > -					"could not set init registers\n");
> > -				ov5645_set_power_off(ov5645);
> > -				goto exit;
> > -			}
> > -
> > -			usleep_range(500, 1000);
> > -		} else {
> > -			ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x58);
> > -			ov5645_set_power_off(ov5645);
> > -		}
> > +	if (ret < 0) {
> > +		dev_err(ov5645->dev, "could not set init registers\n");
> > +		goto exit;
> >  	}
> >  
> > -	/* Update the power count. */
> > -	ov5645->power_count += on ? 1 : -1;
> > -	WARN_ON(ov5645->power_count < 0);
> > +	usleep_range(500, 1000);
> >  
> > -exit:
> > -	mutex_unlock(&ov5645->power_lock);
> > +	return 0;
> >  
> > +exit:
> > +	ov5645_set_power_off(dev);
> >  	return ret;
> >  }
> >  
> > @@ -795,7 +773,7 @@ static int ov5645_s_ctrl(struct v4l2_ctrl *ctrl)
> >  	int ret;
> >  
> >  	mutex_lock(&ov5645->power_lock);
> > -	if (!ov5645->power_count) {
> > +	if (!pm_runtime_get_if_in_use(ov5645->dev)) {
> >  		mutex_unlock(&ov5645->power_lock);
> >  		return 0;
> >  	}
> > @@ -827,6 +805,7 @@ static int ov5645_s_ctrl(struct v4l2_ctrl *ctrl)
> >  		break;
> >  	}
> >  
> > +	pm_runtime_put_autosuspend(ov5645->dev);
> 
> I think you'll need pm_runtime_mark_last_busy() before this. I missed this
> on the last round. Maybe in probe() too. Feel free to resend just this
> patch.
> 
> >  	mutex_unlock(&ov5645->power_lock);
> >  
> >  	return ret;
> > @@ -991,6 +970,10 @@ static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
> >  	int ret;
> >  
> >  	if (enable) {
> > +		ret = pm_runtime_resume_and_get(ov5645->dev);
> > +		if (ret < 0)
> > +			return ret;
> > +
> >  		ret = ov5645_set_register_array(ov5645,
> >  					ov5645->current_mode->data,
> >  					ov5645->current_mode->data_size);
> > @@ -998,22 +981,22 @@ static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
> >  			dev_err(ov5645->dev, "could not set mode %dx%d\n",
> >  				ov5645->current_mode->width,
> >  				ov5645->current_mode->height);
> > -			return ret;
> > +			goto err_rpm_put;
> >  		}
> >  		ret = v4l2_ctrl_handler_setup(&ov5645->ctrls);
> >  		if (ret < 0) {
> >  			dev_err(ov5645->dev, "could not sync v4l2 controls\n");
> > -			return ret;
> > +			goto err_rpm_put;
> >  		}
> >  
> >  		ret = ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x45);
> >  		if (ret < 0)
> > -			return ret;
> > +			goto err_rpm_put;
> >  
> >  		ret = ov5645_write_reg(ov5645, OV5645_SYSTEM_CTRL0,
> >  				       OV5645_SYSTEM_CTRL0_START);
> >  		if (ret < 0)
> > -			return ret;
> > +			goto err_rpm_put;
> >  	} else {
> >  		ret = ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x40);
> >  		if (ret < 0)
> > @@ -1023,14 +1006,15 @@ static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
> >  				       OV5645_SYSTEM_CTRL0_STOP);
> >  		if (ret < 0)
> >  			return ret;
> > +		pm_runtime_put(ov5645->dev);
> >  	}
> >  
> >  	return 0;
> > -}
> >  
> > -static const struct v4l2_subdev_core_ops ov5645_core_ops = {
> > -	.s_power = ov5645_s_power,
> > -};
> > +err_rpm_put:
> > +	pm_runtime_put(ov5645->dev);
> > +	return ret;
> > +}
> >  
> >  static const struct v4l2_subdev_video_ops ov5645_video_ops = {
> >  	.s_stream = ov5645_s_stream,
> > @@ -1046,7 +1030,6 @@ static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
> >  };
> >  
> >  static const struct v4l2_subdev_ops ov5645_subdev_ops = {
> > -	.core = &ov5645_core_ops,
> >  	.video = &ov5645_video_ops,
> >  	.pad = &ov5645_subdev_pad_ops,
> >  };
> > @@ -1188,11 +1171,9 @@ static int ov5645_probe(struct i2c_client *client)
> >  		goto free_ctrl;
> >  	}
> >  
> > -	ret = ov5645_s_power(&ov5645->sd, true);
> > -	if (ret < 0) {
> > -		dev_err(dev, "could not power up OV5645\n");
> > +	ret = ov5645_set_power_on(dev);
> > +	if (ret)
> >  		goto free_entity;
> > -	}
> >  
> >  	ret = ov5645_read_reg(ov5645, OV5645_CHIP_ID_HIGH, &chip_id_high);
> >  	if (ret < 0 || chip_id_high != OV5645_CHIP_ID_HIGH_BYTE) {
> > @@ -1209,12 +1190,16 @@ static int ov5645_probe(struct i2c_client *client)
> >  
> >  	dev_info(dev, "OV5645 detected at address 0x%02x\n", client->addr);
> >  
> > +	pm_runtime_set_active(dev);
> > +	pm_runtime_get_noresume(dev);
> > +	pm_runtime_enable(dev);
> > +
> >  	ret = ov5645_read_reg(ov5645, OV5645_AEC_PK_MANUAL,
> >  			      &ov5645->aec_pk_manual);

Totally unrelated to this patch, can we drop all these register reads ?
The registers are written through he ov5645_global_init_setting array,
we know what the values are.

> >  	if (ret < 0) {
> >  		dev_err(dev, "could not read AEC/AGC mode\n");
> >  		ret = -ENODEV;
> > -		goto power_down;
> > +		goto err_pm_runtime;
> >  	}
> >  
> >  	ret = ov5645_read_reg(ov5645, OV5645_TIMING_TC_REG20,
> > @@ -1222,7 +1207,7 @@ static int ov5645_probe(struct i2c_client *client)
> >  	if (ret < 0) {
> >  		dev_err(dev, "could not read vflip value\n");
> >  		ret = -ENODEV;
> > -		goto power_down;
> > +		goto err_pm_runtime;
> >  	}
> >  
> >  	ret = ov5645_read_reg(ov5645, OV5645_TIMING_TC_REG21,
> > @@ -1230,23 +1215,30 @@ static int ov5645_probe(struct i2c_client *client)
> >  	if (ret < 0) {
> >  		dev_err(dev, "could not read hflip value\n");
> >  		ret = -ENODEV;
> > -		goto power_down;
> > +		goto err_pm_runtime;
> >  	}
> >  
> > -	ov5645_s_power(&ov5645->sd, false);
> > -
> >  	ret = v4l2_async_register_subdev(&ov5645->sd);
> >  	if (ret < 0) {
> >  		dev_err(dev, "could not register v4l2 device\n");
> > +		pm_runtime_disable(dev);
> > +		pm_runtime_set_suspended(dev);
> >  		goto free_entity;

This looks weird, why do we need special handling of runtime PM here,
instead of just jumping to err_pm_runtime ?

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> >  	}
> >  
> > +	pm_runtime_set_autosuspend_delay(dev, 1000);
> > +	pm_runtime_use_autosuspend(dev);
> > +	pm_runtime_put_autosuspend(dev);
> > +
> >  	ov5645_entity_init_cfg(&ov5645->sd, NULL);
> >  
> >  	return 0;
> >  
> > +err_pm_runtime:
> > +	pm_runtime_disable(dev);
> > +	pm_runtime_put_noidle(dev);
> >  power_down:
> > -	ov5645_s_power(&ov5645->sd, false);
> > +	ov5645_set_power_off(dev);
> >  free_entity:
> >  	media_entity_cleanup(&ov5645->sd.entity);
> >  free_ctrl:
> > @@ -1264,6 +1256,10 @@ static void ov5645_remove(struct i2c_client *client)
> >  	v4l2_async_unregister_subdev(&ov5645->sd);
> >  	media_entity_cleanup(&ov5645->sd.entity);
> >  	v4l2_ctrl_handler_free(&ov5645->ctrls);
> > +	pm_runtime_disable(ov5645->dev);
> > +	if (!pm_runtime_status_suspended(ov5645->dev))
> > +		ov5645_set_power_off(ov5645->dev);
> > +	pm_runtime_set_suspended(ov5645->dev);
> >  	mutex_destroy(&ov5645->power_lock);
> >  }
> >  
> > @@ -1279,10 +1275,15 @@ static const struct of_device_id ov5645_of_match[] = {
> >  };
> >  MODULE_DEVICE_TABLE(of, ov5645_of_match);
> >  
> > +static const struct dev_pm_ops ov5645_pm_ops = {
> > +	SET_RUNTIME_PM_OPS(ov5645_set_power_off, ov5645_set_power_on, NULL)
> > +};
> > +
> >  static struct i2c_driver ov5645_i2c_driver = {
> >  	.driver = {
> >  		.of_match_table = ov5645_of_match,
> >  		.name  = "ov5645",
> > +		.pm = &ov5645_pm_ops,
> >  	},
> >  	.probe_new = ov5645_probe,
> >  	.remove = ov5645_remove,

-- 
Regards,

Laurent Pinchart