Re: [Patch v2 5/7] media: i2c: ov2659: Add powerdown/reset gpio handling

[Benoit Parrot]

Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> wrote on Fri [2019-Sep-20 13:17:06 +0300]:
> Hi Benoit,
> 
> Thanks for the update.
> 
> On Thu, Sep 19, 2019 at 03:39:53PM -0500, Benoit Parrot wrote:
> > On some board it is possible that the sensor 'powerdown' and or 'reset'
> > pin might be controlled by gpio instead of being tied.
> > 
> > To implement we add pm_runtime support which will handle the power
> > up/down sequence.
> > 
> > Now originally the driver assumed tat the sensor would always stay
> > powered and there keep its register setting. We cannot assume that this
> > anymore, so every time we "power up" we need to re-program the initial
> > registers configuration first. This was previously done only at probe
> > time.
> > 
> > Signed-off-by: Benoit Parrot <bparrot@xxxxxx>
> > ---
> >  drivers/media/i2c/Kconfig  |  2 +-
> >  drivers/media/i2c/ov2659.c | 88 +++++++++++++++++++++++++++++++++++++-
> >  2 files changed, 88 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> > index 7eee1812bba3..315c1d8bdb7b 100644
> > --- a/drivers/media/i2c/Kconfig
> > +++ b/drivers/media/i2c/Kconfig
> > @@ -634,7 +634,7 @@ config VIDEO_OV2640
> >  config VIDEO_OV2659
> >  	tristate "OmniVision OV2659 sensor support"
> >  	depends on VIDEO_V4L2 && I2C
> > -	depends on MEDIA_CAMERA_SUPPORT
> > +	depends on MEDIA_CAMERA_SUPPORT && GPIOLIB
> >  	select V4L2_FWNODE
> >  	help
> >  	  This is a Video4Linux2 sensor driver for the OmniVision
> > diff --git a/drivers/media/i2c/ov2659.c b/drivers/media/i2c/ov2659.c
> > index f77320e8a60d..170f80a1a51f 100644
> > --- a/drivers/media/i2c/ov2659.c
> > +++ b/drivers/media/i2c/ov2659.c
> > @@ -22,9 +22,11 @@
> >  
> >  #include <linux/clk.h>
> >  #include <linux/delay.h>
> > +#include <linux/gpio/consumer.h>
> >  #include <linux/i2c.h>
> >  #include <linux/module.h>
> >  #include <linux/of_graph.h>
> > +#include <linux/pm_runtime.h>
> >  
> >  #include <media/i2c/ov2659.h>
> >  #include <media/v4l2-ctrls.h>
> > @@ -218,6 +220,11 @@ struct ov2659 {
> >  	struct sensor_register *format_ctrl_regs;
> >  	struct ov2659_pll_ctrl pll;
> >  	int streaming;
> > +	/* used to control the sensor PWDN pin */
> > +	struct gpio_desc *pwdn_gpio;
> > +	/* used to control the sensor RESETB pin */
> > +	struct gpio_desc *resetb_gpio;
> > +	int on;
> >  };
> >  
> >  static const struct sensor_register ov2659_init_regs[] = {
> > @@ -1184,9 +1191,17 @@ static int ov2659_s_stream(struct v4l2_subdev *sd, int on)
> >  		/* Stop Streaming Sequence */
> >  		ov2659_set_streaming(ov2659, 0);
> >  		ov2659->streaming = on;
> > +		pm_runtime_put(&client->dev);
> >  		goto unlock;
> >  	}
> >  
> > +	ret = pm_runtime_get_sync(&client->dev);
> > +	if (ret < 0) {
> > +		pm_runtime_put_noidle(&client->dev);
> > +		goto unlock;
> > +	}
> > +
> > +	ov2659_init(sd, 0);
> >  	ov2659_set_pixel_clock(ov2659);
> >  	ov2659_set_frame_size(ov2659);
> >  	ov2659_set_format(ov2659);
> > @@ -1243,6 +1258,32 @@ static const char * const ov2659_test_pattern_menu[] = {
> >  	"Vertical Color Bars",
> >  };
> >  
> > +static int ov2659_set_power(struct ov2659 *ov2659, int on)
> > +{
> > +	struct i2c_client *client = ov2659->client;
> > +
> > +	dev_dbg(&client->dev, "%s: on: %d\n", __func__, on);
> > +
> > +	if (on) {
> > +		if (ov2659->pwdn_gpio)
> > +			gpiod_direction_output(ov2659->pwdn_gpio, 0);
> > +
> > +		if (ov2659->resetb_gpio) {
> > +			gpiod_set_value(ov2659->resetb_gpio, 1);
> > +			usleep_range(500, 1000);
> > +			gpiod_set_value(ov2659->resetb_gpio, 0);
> > +			usleep_range(3000, 5000);
> > +		}
> 
> Please move the code to the runtime PM callbacks.
> 
> > +	} else {
> > +		if (ov2659->pwdn_gpio)
> > +			gpiod_direction_output(ov2659->pwdn_gpio, 1);
> 
> Gpiod API works with NULL GPIOs, too, so no need to check here.

Didn't realize that. I'll check.

> 
> Isn't the direction supposed to be already output, so set_value would be
> more appropriate here, and above.

Oh yeah the direction should already be set.

> 
> > +	}
> > +
> > +	ov2659->on = on;
> > +
> > +	return 0;
> > +}
> > +
> >  /* -----------------------------------------------------------------------------
> >   * V4L2 subdev internal operations
> >   */
> > @@ -1323,7 +1364,6 @@ static int ov2659_detect(struct v4l2_subdev *sd)
> >  			ret = -ENODEV;
> >  		} else {
> >  			dev_info(&client->dev, "Found OV%04X sensor\n", id);
> > -			ret = ov2659_init(sd, 0);
> >  		}
> >  	}
> >  
> > @@ -1400,6 +1440,18 @@ static int ov2659_probe(struct i2c_client *client)
> >  	    ov2659->xvclk_frequency > 27000000)
> >  		return -EINVAL;
> >  
> > +	/* Optional gpio don't fail if not present */
> > +	ov2659->pwdn_gpio = devm_gpiod_get_optional(&client->dev, "powerdown",
> > +						    GPIOD_OUT_LOW);
> > +	if (IS_ERR(ov2659->pwdn_gpio))
> > +		return PTR_ERR(ov2659->pwdn_gpio);
> > +
> > +	/* Optional gpio don't fail if not present */
> > +	ov2659->resetb_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> > +						      GPIOD_OUT_HIGH);
> > +	if (IS_ERR(ov2659->resetb_gpio))
> > +		return PTR_ERR(ov2659->resetb_gpio);
> > +
> >  	v4l2_ctrl_handler_init(&ov2659->ctrls, 2);
> >  	ov2659->link_frequency =
> >  			v4l2_ctrl_new_std(&ov2659->ctrls, &ov2659_ctrl_ops,
> > @@ -1445,6 +1497,9 @@ static int ov2659_probe(struct i2c_client *client)
> >  	ov2659->frame_size = &ov2659_framesizes[2];
> >  	ov2659->format_ctrl_regs = ov2659_formats[0].format_ctrl_regs;
> >  
> > +	pm_runtime_enable(&client->dev);
> > +	pm_runtime_get_sync(&client->dev);
> 
> This makes the driver depend on runtime PM.

Obviously.
Why? Is that bad?

> 
> See e.g. the smiapp driver for an example how to make it work without. It
> wasn't trivial. :I You won't need autosuspend.

I took a look at that driver, but I don't get your reference to being able
to work without runtime pm!
That driver looks pretty similar to ov7740.c which I used as a reference
for this.

> 
> > +
> >  	ret = ov2659_detect(sd);
> >  	if (ret < 0)
> >  		goto error;
> > @@ -1458,10 +1513,14 @@ static int ov2659_probe(struct i2c_client *client)
> >  
> >  	dev_info(&client->dev, "%s sensor driver registered !!\n", sd->name);
> >  
> > +	pm_runtime_put(&client->dev);
> > +
> >  	return 0;
> >  
> >  error:
> >  	v4l2_ctrl_handler_free(&ov2659->ctrls);
> > +	pm_runtime_put(&client->dev);
> > +	pm_runtime_disable(&client->dev);
> >  	media_entity_cleanup(&sd->entity);
> >  	mutex_destroy(&ov2659->lock);
> >  	return ret;
> > @@ -1477,9 +1536,35 @@ static int ov2659_remove(struct i2c_client *client)
> >  	media_entity_cleanup(&sd->entity);
> >  	mutex_destroy(&ov2659->lock);
> >  
> > +	pm_runtime_disable(&client->dev);
> > +
> >  	return 0;
> >  }
> >  
> > +static int ov2659_runtime_suspend(struct device *dev)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +	struct ov2659 *ov2659 = to_ov2659(sd);
> > +
> > +	ov2659_set_power(ov2659, 0);
> > +
> > +	return 0;
> > +}
> > +
> > +static int ov2659_runtime_resume(struct device *dev)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +	struct ov2659 *ov2659 = to_ov2659(sd);
> > +
> > +	return ov2659_set_power(ov2659, 1);
> > +}
> > +
> > +static const struct dev_pm_ops ov2659_pm_ops = {
> > +	SET_RUNTIME_PM_OPS(ov2659_runtime_suspend, ov2659_runtime_resume, NULL)
> > +};
> > +
> >  static const struct i2c_device_id ov2659_id[] = {
> >  	{ "ov2659", 0 },
> >  	{ /* sentinel */ },
> > @@ -1497,6 +1582,7 @@ MODULE_DEVICE_TABLE(of, ov2659_of_match);
> >  static struct i2c_driver ov2659_i2c_driver = {
> >  	.driver = {
> >  		.name	= DRIVER_NAME,
> > +		.pm	= &ov2659_pm_ops,
> >  		.of_match_table = of_match_ptr(ov2659_of_match),
> >  	},
> >  	.probe_new	= ov2659_probe,
> 
> -- 
> Kind regards,
> 
> Sakari Ailus
> sakari.ailus@xxxxxxxxxxxxxxx