media: i2c: imx335: Enable regulator supplies

Provide support for enabling and disabling regulator supplies to control
power to the camera sensor.

While updating the power on function, document that a sleep is
represented as 'T4' in the datasheet power on sequence.
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/i2c/imx335.c

@@ -75,6 +75,12 @@ struct imx335_reg_list {
 	const struct imx335_reg *regs;
 };
 
+static const char * const imx335_supply_name[] = {
+	"avdd", /* Analog (2.9V) supply */
+	"ovdd", /* Digital I/O (1.8V) supply */
+	"dvdd", /* Digital Core (1.2V) supply */
+};
+
 /**
  * struct imx335_mode - imx335 sensor mode structure
  * @width: Frame width
@@ -108,6 +114,7 @@ struct imx335_mode {
  * @sd: V4L2 sub-device
  * @pad: Media pad. Only one pad supported
  * @reset_gpio: Sensor reset gpio
+ * @supplies: Regulator supplies to handle power control
  * @inclk: Sensor input clock
  * @ctrl_handler: V4L2 control handler
  * @link_freq_ctrl: Pointer to link frequency control
@@ -126,6 +133,8 @@ struct imx335 {
 	struct v4l2_subdev sd;
 	struct media_pad pad;
 	struct gpio_desc *reset_gpio;
+	struct regulator_bulk_data supplies[ARRAY_SIZE(imx335_supply_name)];
+
 	struct clk *inclk;
 	struct v4l2_ctrl_handler ctrl_handler;
 	struct v4l2_ctrl *link_freq_ctrl;
@@ -781,6 +790,17 @@ static int imx335_parse_hw_config(struct imx335 *imx335)
 		return PTR_ERR(imx335->reset_gpio);
 	}
 
+	for (i = 0; i < ARRAY_SIZE(imx335_supply_name); i++)
+		imx335->supplies[i].supply = imx335_supply_name[i];
+
+	ret = devm_regulator_bulk_get(imx335->dev,
+				      ARRAY_SIZE(imx335_supply_name),
+				      imx335->supplies);
+	if (ret) {
+		dev_err(imx335->dev, "Failed to get regulators\n");
+		return ret;
+	}
+
 	/* Get sensor input clock */
 	imx335->inclk = devm_clk_get(imx335->dev, NULL);
 	if (IS_ERR(imx335->inclk)) {
@@ -866,6 +886,17 @@ static int imx335_power_on(struct device *dev)
 	struct imx335 *imx335 = to_imx335(sd);
 	int ret;
 
+	ret = regulator_bulk_enable(ARRAY_SIZE(imx335_supply_name),
+				    imx335->supplies);
+	if (ret) {
+		dev_err(dev, "%s: failed to enable regulators\n",
+			__func__);
+		return ret;
+	}
+
+	usleep_range(500, 550); /* Tlow */
+
+	/* Set XCLR */
 	gpiod_set_value_cansleep(imx335->reset_gpio, 1);
 
 	ret = clk_prepare_enable(imx335->inclk);
@@ -874,12 +905,13 @@ static int imx335_power_on(struct device *dev)
 		goto error_reset;
 	}
 
-	usleep_range(20, 22);
+	usleep_range(20, 22); /* T4 */
 
 	return 0;
 
 error_reset:
 	gpiod_set_value_cansleep(imx335->reset_gpio, 0);
+	regulator_bulk_disable(ARRAY_SIZE(imx335_supply_name), imx335->supplies);
 
 	return ret;
 }
@@ -896,8 +928,8 @@ static int imx335_power_off(struct device *dev)
 	struct imx335 *imx335 = to_imx335(sd);
 
 	gpiod_set_value_cansleep(imx335->reset_gpio, 0);
-
 	clk_disable_unprepare(imx335->inclk);
+	regulator_bulk_disable(ARRAY_SIZE(imx335_supply_name), imx335->supplies);
 
 	return 0;
 }