Re: [PATCH v3 2/4] media: i2c: imx355: Support devicetree and power management

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Richard,

On Fri, Sep 05, 2025 at 05:55:19PM -0400, 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 | 135 +++++++++++++++++++++++++++++++++----
>  1 file changed, 122 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/media/i2c/imx355.c b/drivers/media/i2c/imx355.c
> index b2dce67c0b6b..f7c51e50113e 100644
> --- a/drivers/media/i2c/imx355.c
> +++ b/drivers/media/i2c/imx355.c
> @@ -3,9 +3,14 @@
>  
>  #include <linux/unaligned.h>
>  #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 <media/v4l2-ctrls.h>
>  #include <media/v4l2-device.h>
>  #include <media/v4l2-event.h>
> @@ -121,6 +126,16 @@ struct imx355 {
>  	 * Protect access to sensor v4l2 controls.
>  	 */
>  	struct mutex mutex;
> +
> +	struct clk *mclk;
> +	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[] = {
> @@ -1516,6 +1531,57 @@ 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);
> +
> +	if (imx355->reset_gpio)
> +		gpiod_set_value_cansleep(imx355->reset_gpio, 0);

The gpiod framework can work with NULL descriptor so I don't think you need
to check for non-NULL before the calls. Same elsewhere.

> +
> +	regulator_bulk_disable(ARRAY_SIZE(imx355->supplies), imx355->supplies);
> +	clk_disable_unprepare(imx355->mclk);
> +
> +	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->mclk);
> +	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;
> +	}
> +
> +	if (imx355->reset_gpio) {
> +		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->mclk);
> +	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)
>  {
> @@ -1623,7 +1689,7 @@ static int imx355_init_controls(struct imx355 *imx355)
>  	return ret;
>  }
>  
> -static struct imx355_hwcfg *imx355_get_hwcfg(struct device *dev)
> +static struct imx355_hwcfg *imx355_get_hwcfg(struct device *dev, struct imx355 *imx355)
>  {
>  	struct imx355_hwcfg *cfg;
>  	struct v4l2_fwnode_endpoint bus_cfg = {
> @@ -1648,12 +1714,7 @@ static struct imx355_hwcfg *imx355_get_hwcfg(struct device *dev)
>  	if (!cfg)
>  		goto out_err;
>  
> -	ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency",
> -				       &cfg->ext_clk);
> -	if (ret) {
> -		dev_err(dev, "can't get clock frequency");
> -		goto out_err;
> -	}
> +	cfg->ext_clk = clk_get_rate(imx355->mclk);
>  
>  	dev_dbg(dev, "ext clk: %d", cfg->ext_clk);
>  	if (cfg->ext_clk != IMX355_EXT_CLK) {
> @@ -1683,6 +1744,7 @@ static struct imx355_hwcfg *imx355_get_hwcfg(struct device *dev)
>  static int imx355_probe(struct i2c_client *client)
>  {
>  	struct imx355 *imx355;
> +	size_t i;
>  	int ret;
>  
>  	imx355 = devm_kzalloc(&client->dev, sizeof(*imx355), GFP_KERNEL);
> @@ -1694,27 +1756,59 @@ static int imx355_probe(struct i2c_client *client)
>  	/* Initialize subdev */
>  	v4l2_i2c_subdev_init(&imx355->sd, client, &imx355_subdev_ops);
>  
> -	/* Check module identity */
> -	ret = imx355_identify_module(imx355);
> +	for (i = 0; i < ARRAY_SIZE(imx355_supply_names); i++)
> +		imx355->supplies[i].supply = imx355_supply_names[i];
> +
> +	ret = devm_regulator_bulk_get(&client->dev,
> +				      ARRAY_SIZE(imx355->supplies),
> +				      imx355->supplies);
>  	if (ret) {
> -		dev_err(&client->dev, "failed to find sensor: %d", ret);
> +		dev_err_probe(&client->dev, ret, "could not get regulators");
> +		goto error_probe;
> +	}
> +
> +	imx355->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
> +						     GPIOD_OUT_LOW);
> +	if (IS_ERR(imx355->reset_gpio)) {
> +		ret = dev_err_probe(&client->dev, PTR_ERR(imx355->reset_gpio),
> +				    "failed to get gpios");
> +		goto error_probe;
> +	}
> +
> +	imx355->mclk = devm_v4l2_sensor_clk_get(&client->dev, "mclk");
> +	if (IS_ERR(imx355->mclk)) {
> +		ret = dev_err_probe(&client->dev, PTR_ERR(imx355->mclk),
> +				    "failed to get mclk");
>  		goto error_probe;
>  	}
>  
> -	imx355->hwcfg = imx355_get_hwcfg(&client->dev);
> +	imx355->hwcfg = imx355_get_hwcfg(&client->dev, imx355);
>  	if (!imx355->hwcfg) {
>  		dev_err(&client->dev, "failed to get hwcfg");
>  		ret = -ENODEV;
>  		goto error_probe;
>  	}
>  
> +	ret = imx355_power_on(&client->dev);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to power on sensor: %d", ret);
> +		goto error_probe;
> +	}
> +
> +	/* Check module identity */
> +	ret = imx355_identify_module(imx355);
> +	if (ret) {
> +		dev_err(&client->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(&client->dev, "failed to init controls: %d", ret);
> -		goto error_probe;
> +		goto error_power_off;
>  	}
>  
>  	/* Initialize subdev */
> @@ -1754,6 +1848,9 @@ 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(&client->dev);
> +
>  error_probe:
>  	mutex_destroy(&imx355->mutex);
>  
> @@ -1770,7 +1867,11 @@ static void imx355_remove(struct i2c_client *client)
>  	v4l2_ctrl_handler_free(sd->ctrl_handler);
>  
>  	pm_runtime_disable(&client->dev);
> -	pm_runtime_set_suspended(&client->dev);
> +
> +	if (!pm_runtime_status_suspended(&client->dev)) {
> +		imx355_power_off(&client->dev);
> +		pm_runtime_set_suspended(&client->dev);
> +	}
>  
>  	mutex_destroy(&imx355->mutex);
>  }
> @@ -1781,10 +1882,18 @@ 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 = of_match_ptr(imx355_match_table),

Please don't use of_match_ptr() on drivers that can also be used on ACPI --
it renders the pointer NULL if OF is disabled.

> +		.pm = &imx355_pm_ops,
>  	},
>  	.probe = imx355_probe,
>  	.remove = imx355_remove,

-- 
Kind regards,

Sakari Ailus