linux-kernel - Re: [PATCH v3 24/25] drivers: media: i2c: imx258: Add support for reset gpio

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Date: Wed, 3 Apr 2024 19:03:37 +0200
From: Ondřej Jirman <megous@...ous.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: git@...gi311.com, linux-media@...r.kernel.org, 
	dave.stevenson@...pberrypi.com, jacopo.mondi@...asonboard.com, mchehab@...nel.org, 
	robh@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org, 
	shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de, 
	festevam@...il.com, devicetree@...r.kernel.org, imx@...ts.linux.dev, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, pavel@....cz, 
	phone-devel@...r.kernel.org
Subject: Re: [PATCH v3 24/25] drivers: media: i2c: imx258: Add support for
 reset gpio

Hi,

On Wed, Apr 03, 2024 at 04:28:59PM GMT, Sakari Ailus wrote:
> Hi Luis,
> 
> Could you unify the subject prefix for the driver patches, please? E.g.
> "media: imx258: " would be fine.
> 
> On Wed, Apr 03, 2024 at 09:03:53AM -0600, git@...gi311.com wrote:
> > From: Luis Garcia <git@...gi311.com>
> > 
> > It was documented in DT, but not implemented.
> > 
> > Signed-off-by: Ondrej Jirman <megous@...ous.com>
> > Signed-off-by: Luis Garcia <git@...gi311.com>
> > ---
> >  drivers/media/i2c/imx258.c | 14 +++++++++++++-
> >  1 file changed, 13 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c
> > index 163f04f6f954..4c117c4829f1 100644
> > --- a/drivers/media/i2c/imx258.c
> > +++ b/drivers/media/i2c/imx258.c
> > @@ -680,6 +680,7 @@ struct imx258 {
> >  	unsigned int csi2_flags;
> >  
> >  	struct gpio_desc *powerdown_gpio;
> > +	struct gpio_desc *reset_gpio;
> >  
> >  	/*
> >  	 * Mutex for serialized access:
> > @@ -1232,7 +1233,11 @@ static int imx258_power_on(struct device *dev)
> >  		regulator_bulk_disable(IMX258_NUM_SUPPLIES, imx258->supplies);
> >  	}
> >  
> > -	return ret;
> > +	gpiod_set_value_cansleep(imx258->reset_gpio, 0);
> > +
> > +	usleep_range(400, 500);
> 
> You could mention this at least in the commit message.

This is T6 in the datasheet: https://megous.com/dl/tmp/92c9223ce877216e.png


> > +
> > +	return 0;
> >  }
> >  
> >  static int imx258_power_off(struct device *dev)
> > @@ -1243,6 +1248,7 @@ static int imx258_power_off(struct device *dev)
> >  	clk_disable_unprepare(imx258->clk);
> >  	regulator_bulk_disable(IMX258_NUM_SUPPLIES, imx258->supplies);
> >  
> > +	gpiod_set_value_cansleep(imx258->reset_gpio, 1);
> 
> Same question than on the other GPIO: does this belong here?

No, this should be before the regulator_bulk_disable.

See: https://megous.com/dl/tmp/c96180b23d7ce63a.png

kind regards,
	o.

> >  	gpiod_set_value_cansleep(imx258->powerdown_gpio, 1);
> >  
> >  	return 0;
> > @@ -1554,6 +1560,12 @@ static int imx258_probe(struct i2c_client *client)
> >  	if (IS_ERR(imx258->powerdown_gpio))
> >  		return PTR_ERR(imx258->powerdown_gpio);
> >  
> > +	/* request optional reset pin */
> > +	imx258->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> > +						    GPIOD_OUT_HIGH);
> > +	if (IS_ERR(imx258->reset_gpio))
> > +		return PTR_ERR(imx258->reset_gpio);
> > +
> >  	/* Initialize subdev */
> >  	v4l2_i2c_subdev_init(&imx258->sd, client, &imx258_subdev_ops);
> >  
> 
> -- 
> Regards,
> 
> Sakari Ailus