Re: [PATCH 4/4] media: ov2740: Add regulator support

[Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>]

On Thu, Nov 28, 2024 at 04:23:38PM +0100, Hans de Goede wrote:
> On some designs the regulators for the AVDD / DOVDD / DVDD power rails
> are controlled by Linux.
> 
> Add support to the driver for getting regulators for these 3 rails and
> for enabling these regulators when necessary.
> 
> The datasheet specifies a delay of 0ns between enabling the regulators,
> IOW they can all 3 be enabled at the same time. This allows using the bulk
> regulator API.
> 
> The regulator core will provide dummy regulators for the 3 power-rails
> when necessary.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>

>  drivers/media/i2c/ov2740.c | 30 +++++++++++++++++++++++++++---
>  1 file changed, 27 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c
> index 14d0a0588cc2..c766c1f83e12 100644
> --- a/drivers/media/i2c/ov2740.c
> +++ b/drivers/media/i2c/ov2740.c
> @@ -11,6 +11,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/nvmem-provider.h>
>  #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-device.h>
>  #include <media/v4l2-fwnode.h>
> @@ -76,6 +77,14 @@
>  /* OTP registers from sensor */
>  #define OV2740_REG_OTP_CUSTOMER		0x7010
>  
> +static const char * const ov2740_supply_name[] = {
> +	"AVDD",
> +	"DOVDD",
> +	"DVDD",
> +};
> +
> +#define OV2740_NUM_SUPPLIES ARRAY_SIZE(ov2740_supply_name)
> +
>  struct nvm_data {
>  	struct nvmem_device *nvmem;
>  	struct regmap *regmap;
> @@ -523,10 +532,11 @@ struct ov2740 {
>  	struct v4l2_ctrl *hblank;
>  	struct v4l2_ctrl *exposure;
>  
> -	/* GPIOs, clocks */
> +	/* GPIOs, clocks, regulators */
>  	struct gpio_desc *reset_gpio;
>  	struct gpio_desc *powerdown_gpio;
>  	struct clk *clk;
> +	struct regulator_bulk_data supplies[OV2740_NUM_SUPPLIES];
>  
>  	/* Current mode */
>  	const struct ov2740_mode *cur_mode;
> @@ -1309,6 +1319,7 @@ static int ov2740_suspend(struct device *dev)
>  	gpiod_set_value_cansleep(ov2740->reset_gpio, 1);
>  	gpiod_set_value_cansleep(ov2740->powerdown_gpio, 1);
>  	clk_disable_unprepare(ov2740->clk);
> +	regulator_bulk_disable(OV2740_NUM_SUPPLIES, ov2740->supplies);
>  	return 0;
>  }
>  
> @@ -1318,10 +1329,16 @@ static int ov2740_resume(struct device *dev)
>  	struct ov2740 *ov2740 = to_ov2740(sd);
>  	int ret;
>  
> -	ret = clk_prepare_enable(ov2740->clk);
> +	ret = regulator_bulk_enable(OV2740_NUM_SUPPLIES, ov2740->supplies);
>  	if (ret)
>  		return ret;
>  
> +	ret = clk_prepare_enable(ov2740->clk);
> +	if (ret) {
> +		regulator_bulk_disable(OV2740_NUM_SUPPLIES, ov2740->supplies);
> +		return ret;
> +	}
> +
>  	gpiod_set_value_cansleep(ov2740->powerdown_gpio, 0);
>  	gpiod_set_value_cansleep(ov2740->reset_gpio, 0);
>  	msleep(20);
> @@ -1334,7 +1351,7 @@ static int ov2740_probe(struct i2c_client *client)
>  	struct device *dev = &client->dev;
>  	struct ov2740 *ov2740;
>  	bool full_power;
> -	int ret;
> +	int i, ret;
>  
>  	ov2740 = devm_kzalloc(&client->dev, sizeof(*ov2740), GFP_KERNEL);
>  	if (!ov2740)
> @@ -1372,6 +1389,13 @@ static int ov2740_probe(struct i2c_client *client)
>  		return dev_err_probe(dev, PTR_ERR(ov2740->clk),
>  				     "failed to get clock\n");
>  
> +	for (i = 0; i < OV2740_NUM_SUPPLIES; i++)
> +		ov2740->supplies[i].supply = ov2740_supply_name[i];
> +
> +	ret = devm_regulator_bulk_get(dev, OV2740_NUM_SUPPLIES, ov2740->supplies);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to get regulators\n");
> +
>  	full_power = acpi_dev_state_d0(&client->dev);
>  	if (full_power) {
>  		/* ACPI does not always clear the reset GPIO / enable the clock */
> -- 
> 2.47.0
> 
>