Re: [PATCH v3 23/25] drivers: media: i2c: imx258: Add support for powerdown gpio

From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: git@luigi311.com
Cc: linux-media@vger.kernel.org, dave.stevenson@raspberrypi.com,
	jacopo.mondi@ideasonboard.com, mchehab@kernel.org,
	robh@kernel.org, krzysztof.kozlowski+dt@linaro.org,
	conor+dt@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de,
	kernel@pengutronix.de, festevam@gmail.com,
	devicetree@vger.kernel.org, imx@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, pavel@ucw.cz,
	phone-devel@vger.kernel.org, Ondrej Jirman <megi@xff.cz>
Subject: Re: [PATCH v3 23/25] drivers: media: i2c: imx258: Add support for powerdown gpio
Date: Wed, 3 Apr 2024 16:25:41 +0000	[thread overview]
Message-ID: <Zg2DBasC501hMQSS@kekkonen.localdomain> (raw)
In-Reply-To: <20240403150355.189229-24-git@luigi311.com>

Hi Luis, Ondrej,

On Wed, Apr 03, 2024 at 09:03:52AM -0600, git@luigi311.com wrote:
> From: Luis Garcia <git@luigi311.com>
> 
> On some boards powerdown signal needs to be deasserted for this
> sensor to be enabled.
> 
> Signed-off-by: Ondrej Jirman <megi@xff.cz>
> Signed-off-by: Luis Garcia <git@luigi311.com>
> ---
>  drivers/media/i2c/imx258.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c
> index 30352c33f63c..163f04f6f954 100644
> --- a/drivers/media/i2c/imx258.c
> +++ b/drivers/media/i2c/imx258.c
> @@ -679,6 +679,8 @@ struct imx258 {
>  	unsigned int lane_mode_idx;
>  	unsigned int csi2_flags;
>  
> +	struct gpio_desc *powerdown_gpio;
> +
>  	/*
>  	 * Mutex for serialized access:
>  	 * Protect sensor module set pad format and start/stop streaming safely.
> @@ -1213,6 +1215,8 @@ static int imx258_power_on(struct device *dev)
>  	struct imx258 *imx258 = to_imx258(sd);
>  	int ret;
>  
> +	gpiod_set_value_cansleep(imx258->powerdown_gpio, 0);

What does the spec say? Should this really happen before switching on the
supplies below?

> +
>  	ret = regulator_bulk_enable(IMX258_NUM_SUPPLIES,
>  				    imx258->supplies);
>  	if (ret) {
> @@ -1224,6 +1228,7 @@ static int imx258_power_on(struct device *dev)
>  	ret = clk_prepare_enable(imx258->clk);
>  	if (ret) {
>  		dev_err(dev, "failed to enable clock\n");
> +		gpiod_set_value_cansleep(imx258->powerdown_gpio, 1);
>  		regulator_bulk_disable(IMX258_NUM_SUPPLIES, imx258->supplies);
>  	}
>  
> @@ -1238,6 +1243,8 @@ 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->powerdown_gpio, 1);
> +
>  	return 0;
>  }
>  
> @@ -1541,6 +1548,12 @@ static int imx258_probe(struct i2c_client *client)
>  	if (!imx258->variant_cfg)
>  		imx258->variant_cfg = &imx258_cfg;
>  
> +	/* request optional power down pin */
> +	imx258->powerdown_gpio = devm_gpiod_get_optional(&client->dev, "powerdown",
> +						    GPIOD_OUT_HIGH);
> +	if (IS_ERR(imx258->powerdown_gpio))
> +		return PTR_ERR(imx258->powerdown_gpio);
> +
>  	/* Initialize subdev */
>  	v4l2_i2c_subdev_init(&imx258->sd, client, &imx258_subdev_ops);
>  

-- 
Regards,

Sakari Ailus

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