media: ov2740: Add regulator support

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>
Acked-by: Ricardo Ribalda <ribalda@chromium.org>
Tested-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Author: jwrdegoede

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 */