Re: [PATCH v4 2/5] media: i2c: imx355: Support devicetree and power management

[Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>]

On 12/11/25 03:48, Richard Acayan wrote:
> A device tree compatible makes it possible for this driver to be used on
> Open Firmware devices. Initialization of power-managed resources such as
> the reset GPIO and voltage regulators can be specified in the device
> tree and handled by the driver. Add support for this so the Pixel 3a can
> use the driver.
> 
> Signed-off-by: Richard Acayan <mailingradian@gmail.com>
> ---
>   drivers/media/i2c/imx355.c | 118 ++++++++++++++++++++++++++++++++++---
>   1 file changed, 110 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/media/i2c/imx355.c b/drivers/media/i2c/imx355.c
> index 776107efe386..c225bb8959bd 100644
> --- a/drivers/media/i2c/imx355.c
> +++ b/drivers/media/i2c/imx355.c
> @@ -3,9 +3,13 @@
>   
>   #include <linux/acpi.h>
>   #include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
>   #include <linux/i2c.h>
>   #include <linux/module.h>
> +#include <linux/of.h>
>   #include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
>   #include <linux/unaligned.h>
>   
>   #include <media/v4l2-ctrls.h>
> @@ -125,6 +129,15 @@ struct imx355 {
>   	 * Protect access to sensor v4l2 controls.
>   	 */
>   	struct mutex mutex;
> +
> +	struct gpio_desc *reset_gpio;
> +	struct regulator_bulk_data supplies[3];
> +};
> +
> +static const char * const imx355_supply_names[] = {
> +	"avdd",
> +	"dvdd",
> +	"dovdd",
>   };
>   
>   static const struct imx355_reg imx355_global_regs[] = {
> @@ -1515,6 +1528,54 @@ static const struct v4l2_subdev_internal_ops imx355_internal_ops = {
>   	.open = imx355_open,
>   };
>   
> +static int imx355_power_off(struct device *dev)
> +{
> +	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct imx355 *imx355 = to_imx355(sd);
> +
> +	gpiod_set_value_cansleep(imx355->reset_gpio, 0);

It's expected that the reset/shutdown GPIO is active low.

> +
> +	regulator_bulk_disable(ARRAY_SIZE(imx355->supplies), imx355->supplies);
> +	clk_disable_unprepare(imx355->clk);
> +
> +	return 0;
> +}
> +
> +static int imx355_power_on(struct device *dev)
> +{
> +	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct imx355 *imx355 = to_imx355(sd);
> +	int ret;
> +
> +	ret = clk_prepare_enable(imx355->clk);
> +	if (ret) {
> +		dev_err(dev, "failed to enable clocks: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(imx355->supplies),
> +				    imx355->supplies);
> +	if (ret) {
> +		dev_err(dev, "failed to enable regulators: %d\n", ret);
> +		goto error_disable_clocks;
> +	}
> +
> +	usleep_range(5000, 5100);
> +	gpiod_set_value_cansleep(imx355->reset_gpio, 1);
> +	usleep_range(8000, 8100);
> +
> +	return 0;
> +
> +error_disable_clocks:
> +	clk_disable_unprepare(imx355->clk);
> +	return ret;
> +}
> +
> +static DEFINE_RUNTIME_DEV_PM_OPS(imx355_pm_ops, imx355_power_off,
> +				 imx355_power_on, NULL);
> +
>   /* Initialize control handlers */
>   static int imx355_init_controls(struct imx355 *imx355)
>   {
> @@ -1668,6 +1729,7 @@ static int imx355_probe(struct i2c_client *client)
>   {
>   	struct imx355 *imx355;
>   	unsigned long freq;
> +	size_t i;
>   	int ret;
>   
>   	imx355 = devm_kzalloc(&client->dev, sizeof(*imx355), GFP_KERNEL);
> @@ -1678,7 +1740,7 @@ static int imx355_probe(struct i2c_client *client)
>   
>   	mutex_init(&imx355->mutex);
>   
> -	imx355->clk = devm_v4l2_sensor_clk_get(imx355->dev, NULL);
> +	imx355->clk = devm_v4l2_sensor_clk_get(imx355->dev, "mclk");

Please keep an unset clock name, NULL is fine here, and it removes
a risk of the regression.

>   	if (IS_ERR(imx355->clk))
>   		return dev_err_probe(imx355->dev, PTR_ERR(imx355->clk),
>   				     "failed to get clock\n");
> @@ -1689,16 +1751,28 @@ static int imx355_probe(struct i2c_client *client)
>   				     "external clock %lu is not supported\n",
>   				     freq);
>   
> -	/* Initialize subdev */
> -	v4l2_i2c_subdev_init(&imx355->sd, client, &imx355_subdev_ops);
> +	for (i = 0; i < ARRAY_SIZE(imx355_supply_names); i++)
> +		imx355->supplies[i].supply = imx355_supply_names[i];
>   
> -	/* Check module identity */
> -	ret = imx355_identify_module(imx355);
> +	ret = devm_regulator_bulk_get(imx355->dev,
> +				      ARRAY_SIZE(imx355->supplies),
> +				      imx355->supplies);
>   	if (ret) {
> -		dev_err(imx355->dev, "failed to find sensor: %d", ret);
> +		dev_err_probe(imx355->dev, ret, "could not get regulators");
>   		goto error_probe;
>   	}
>   
> +	imx355->reset_gpio = devm_gpiod_get_optional(imx355->dev, "reset",
> +						     GPIOD_OUT_LOW);

While switching the logic to active low GPIO, it should be GPIOD_OUT_HIGH here.

> +	if (IS_ERR(imx355->reset_gpio)) {
> +		ret = dev_err_probe(imx355->dev, PTR_ERR(imx355->reset_gpio),
> +				    "failed to get gpios");
> +		goto error_probe;
> +	}
> +
> +	/* Initialize subdev */
> +	v4l2_i2c_subdev_init(&imx355->sd, client, &imx355_subdev_ops);
> +
>   	imx355->hwcfg = imx355_get_hwcfg(imx355->dev);
>   	if (!imx355->hwcfg) {
>   		dev_err(imx355->dev, "failed to get hwcfg");
> @@ -1706,13 +1780,26 @@ static int imx355_probe(struct i2c_client *client)
>   		goto error_probe;
>   	}
>   
> +	ret = imx355_power_on(imx355->dev);
> +	if (ret) {
> +		dev_err(imx355->dev, "failed to power on sensor: %d", ret);
> +		goto error_probe;
> +	}
> +
> +	/* Check module identity */
> +	ret = imx355_identify_module(imx355);
> +	if (ret) {
> +		dev_err(imx355->dev, "failed to find sensor: %d", ret);
> +		goto error_power_off;
> +	}
> +
>   	/* Set default mode to max resolution */
>   	imx355->cur_mode = &supported_modes[0];
>   
>   	ret = imx355_init_controls(imx355);
>   	if (ret) {
>   		dev_err(imx355->dev, "failed to init controls: %d", ret);
> -		goto error_probe;
> +		goto error_power_off;
>   	}
>   
>   	/* Initialize subdev */
> @@ -1752,6 +1839,9 @@ static int imx355_probe(struct i2c_client *client)
>   error_handler_free:
>   	v4l2_ctrl_handler_free(imx355->sd.ctrl_handler);
>   
> +error_power_off:
> +	imx355_power_off(imx355->dev);
> +
>   error_probe:
>   	mutex_destroy(&imx355->mutex);
>   
> @@ -1768,7 +1858,11 @@ static void imx355_remove(struct i2c_client *client)
>   	v4l2_ctrl_handler_free(sd->ctrl_handler);
>   
>   	pm_runtime_disable(imx355->dev);
> -	pm_runtime_set_suspended(imx355->dev);
> +
> +	if (!pm_runtime_status_suspended(imx355->dev)) {
> +		imx355_power_off(imx355->dev);
> +		pm_runtime_set_suspended(imx355->dev);
> +	}
>   
>   	mutex_destroy(&imx355->mutex);
>   }
> @@ -1779,10 +1873,18 @@ static const struct acpi_device_id imx355_acpi_ids[] __maybe_unused = {
>   };
>   MODULE_DEVICE_TABLE(acpi, imx355_acpi_ids);
>   
> +static const struct of_device_id imx355_match_table[] __maybe_unused = {
> +	{ .compatible = "sony,imx355", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, imx355_match_table);
> +
>   static struct i2c_driver imx355_i2c_driver = {
>   	.driver = {
>   		.name = "imx355",
>   		.acpi_match_table = ACPI_PTR(imx355_acpi_ids),
> +		.of_match_table = imx355_match_table,
> +		.pm = &imx355_pm_ops,
>   	},
>   	.probe = imx355_probe,
>   	.remove = imx355_remove,

-- 
Best wishes,
Vladimir