[PATCH v2 5/5] media: i2c: lm3560: Add support for PM features

[Svyatoslav Ryhel <clamor95@gmail.com>]

Add support for power management features to better control the LM3560
within the media framework. To achieve the desired PM support, the HWEN
GPIO and VIN power supply were added and configured into power on/off
sequences. Media device deregistration helpers were grouped into a
separate function to simplify the probe/remove process. Added PM
operations along with the PM configuration setup.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
---
 drivers/media/i2c/lm3560.c | 135 +++++++++++++++++++++++++++++++++----
 1 file changed, 123 insertions(+), 12 deletions(-)

diff --git a/drivers/media/i2c/lm3560.c b/drivers/media/i2c/lm3560.c
index 022a6a76befb..8f5156a80a99 100644
--- a/drivers/media/i2c/lm3560.c
+++ b/drivers/media/i2c/lm3560.c
@@ -11,12 +11,15 @@
 
 #include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <linux/mod_devicetable.h>
 #include <linux/mutex.h>
+#include <linux/pm_runtime.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/videodev2.h>
 #include <media/i2c/lm3560.h>
 #include <media/v4l2-ctrls.h>
@@ -47,6 +50,8 @@ enum led_enable {
  * @dev: pointer to &struct device
  * @regmap: reg. map for i2c
  * @lock: muxtex for serial access.
+ * @hwen_gpio: line connected to HWEN pin
+ * @vin_supply: line connected to IN supply (2.5V - 5.5V)
  * @led_mode: V4L2 LED mode
  * @ctrls_led: V4L2 controls
  * @subdev_led: V4L2 subdev
@@ -60,6 +65,9 @@ struct lm3560_flash {
 	struct regmap *regmap;
 	struct mutex lock;
 
+	struct gpio_desc *hwen_gpio;
+	struct regulator *vin_supply;
+
 	enum v4l2_flash_led_mode led_mode;
 	struct v4l2_ctrl_handler ctrls_led[LM3560_LED_MAX];
 	struct v4l2_subdev subdev_led[LM3560_LED_MAX];
@@ -172,12 +180,17 @@ static int lm3560_get_ctrl(struct v4l2_ctrl *ctrl, enum lm3560_led_id led_no)
 	struct lm3560_flash *flash = to_lm3560_flash(ctrl, led_no);
 	int rval = -EINVAL;
 
+	if (!pm_runtime_get_if_in_use(flash->dev))
+		return 0;
+
 	if (ctrl->id == V4L2_CID_FLASH_FAULT) {
 		s32 fault = 0;
 		unsigned int reg_val;
 		rval = regmap_read(flash->regmap, REG_FLAG, &reg_val);
-		if (rval < 0)
+		if (rval < 0) {
+			pm_runtime_put(flash->dev);
 			return rval;
+		}
 		if (reg_val & FAULT_SHORT_CIRCUIT)
 			fault |= V4L2_FLASH_FAULT_SHORT_CIRCUIT;
 		if (reg_val & FAULT_OVERTEMP)
@@ -187,6 +200,8 @@ static int lm3560_get_ctrl(struct v4l2_ctrl *ctrl, enum lm3560_led_id led_no)
 		ctrl->cur.val = fault;
 	}
 
+	pm_runtime_put(flash->dev);
+
 	return rval;
 }
 
@@ -196,6 +211,9 @@ static int lm3560_set_ctrl(struct v4l2_ctrl *ctrl, enum lm3560_led_id led_no)
 	u8 tout_bits;
 	int rval = -EINVAL;
 
+	if (!pm_runtime_get_if_in_use(flash->dev))
+		return 0;
+
 	switch (ctrl->id) {
 	case V4L2_CID_FLASH_LED_MODE:
 		flash->led_mode = ctrl->val;
@@ -241,6 +259,8 @@ static int lm3560_set_ctrl(struct v4l2_ctrl *ctrl, enum lm3560_led_id led_no)
 		break;
 	}
 
+	pm_runtime_put(flash->dev);
+
 	return rval;
 }
 
@@ -403,6 +423,60 @@ static int lm3560_init_device(struct lm3560_flash *flash)
 	return rval;
 }
 
+static void lm3560_power_off(struct lm3560_flash *flash)
+{
+	gpiod_set_value_cansleep(flash->hwen_gpio, 0);
+	regulator_disable(flash->vin_supply);
+}
+
+static int lm3560_power_on(struct lm3560_flash *flash)
+{
+	int rval;
+
+	rval = regulator_enable(flash->vin_supply);
+	if (rval < 0) {
+		dev_err(flash->dev, "failed to enable vin power supply\n");
+		return rval;
+	}
+
+	gpiod_set_value_cansleep(flash->hwen_gpio, 1);
+
+	rval = lm3560_init_device(flash);
+	if (rval < 0) {
+		lm3560_power_off(flash);
+		return rval;
+	}
+
+	return 0;
+}
+
+static int __maybe_unused lm3560_pm_runtime_resume(struct device *dev)
+{
+	struct lm3560_flash *flash = dev_get_drvdata(dev);
+
+	return lm3560_power_on(flash);
+}
+
+static int __maybe_unused lm3560_pm_runtime_suspend(struct device *dev)
+{
+	struct lm3560_flash *flash = dev_get_drvdata(dev);
+
+	lm3560_power_off(flash);
+
+	return 0;
+}
+
+static void lm3560_subdev_cleanup(struct lm3560_flash *flash)
+{
+	unsigned int i;
+
+	for (i = LM3560_LED0; i < LM3560_LED_MAX; i++) {
+		v4l2_device_unregister_subdev(&flash->subdev_led[i]);
+		v4l2_ctrl_handler_free(&flash->ctrls_led[i]);
+		media_entity_cleanup(&flash->subdev_led[i].entity);
+	}
+}
+
 static int lm3560_probe(struct i2c_client *client)
 {
 	struct lm3560_flash *flash;
@@ -423,6 +497,17 @@ static int lm3560_probe(struct i2c_client *client)
 	flash->dev = &client->dev;
 	mutex_init(&flash->lock);
 
+	flash->hwen_gpio = devm_gpiod_get_optional(&client->dev, "enable",
+						   GPIOD_OUT_LOW);
+	if (IS_ERR(flash->hwen_gpio))
+		return dev_err_probe(&client->dev, PTR_ERR(flash->hwen_gpio),
+				     "failed to get hwen gpio\n");
+
+	flash->vin_supply = devm_regulator_get(&client->dev, "vin");
+	if (IS_ERR(flash->vin_supply))
+		return dev_err_probe(&client->dev, PTR_ERR(flash->vin_supply),
+				     "failed to get vin-supply\n");
+
 	flash->peak = LM3560_PEAK_1600mA;
 	rval = device_property_read_u32(flash->dev,
 					"ti,peak-current-microamp", &peak_ua);
@@ -450,10 +535,13 @@ static int lm3560_probe(struct i2c_client *client)
 				 &flash->max_flash_timeout);
 	flash->max_flash_timeout /= 1000;
 
-	rval = lm3560_init_device(flash);
+	rval = lm3560_power_on(flash);
 	if (rval < 0)
 		return rval;
 
+	pm_runtime_set_active(flash->dev);
+	pm_runtime_enable(flash->dev);
+
 	device_for_each_child_node(flash->dev, node) {
 		fwnode_property_read_u32(node, "reg", &reg);
 
@@ -467,30 +555,53 @@ static int lm3560_probe(struct i2c_client *client)
 						 &flash->max_torch_brt[reg]);
 
 			rval = lm3560_subdev_init(flash, reg, node);
-			if (rval < 0)
-				return dev_err_probe(flash->dev, rval,
-						    "failed to register led%d\n",
-						    reg);
+			if (rval < 0) {
+				dev_err(flash->dev,
+					"failed to register led%d\n", reg);
+				goto error_clean;
+			}
 		}
 	}
 
 	i2c_set_clientdata(client, flash);
 
+	pm_runtime_set_autosuspend_delay(flash->dev, 1000);
+	pm_runtime_use_autosuspend(flash->dev);
+	pm_runtime_idle(flash->dev);
+
 	return 0;
+
+error_clean:
+	pm_runtime_disable(flash->dev);
+	pm_runtime_set_suspended(flash->dev);
+	lm3560_subdev_cleanup(flash);
+	lm3560_power_off(flash);
+
+	return rval;
 }
 
 static void lm3560_remove(struct i2c_client *client)
 {
 	struct lm3560_flash *flash = i2c_get_clientdata(client);
-	unsigned int i;
 
-	for (i = LM3560_LED0; i < LM3560_LED_MAX; i++) {
-		v4l2_device_unregister_subdev(&flash->subdev_led[i]);
-		v4l2_ctrl_handler_free(&flash->ctrls_led[i]);
-		media_entity_cleanup(&flash->subdev_led[i].entity);
+	lm3560_subdev_cleanup(flash);
+
+	/*
+	 * Disable runtime PM. In case runtime PM is disabled in the kernel,
+	 * make sure to turn power off manually.
+	 */
+	pm_runtime_disable(&client->dev);
+	if (!pm_runtime_status_suspended(&client->dev)) {
+		lm3560_power_off(flash);
+		pm_runtime_set_suspended(&client->dev);
 	}
 }
 
+static const struct dev_pm_ops lm3560_pm_ops = {
+	SET_RUNTIME_PM_OPS(lm3560_pm_runtime_suspend,
+			   lm3560_pm_runtime_resume, NULL)
+};
+
 static const struct of_device_id lm3560_of_match[] = {
 	{ .compatible = "ti,lm3559" },
 	{ .compatible = "ti,lm3560" },
@@ -509,7 +620,7 @@ MODULE_DEVICE_TABLE(i2c, lm3560_id_table);
 static struct i2c_driver lm3560_i2c_driver = {
 	.driver = {
 		   .name = LM3560_NAME,
-		   .pm = NULL,
+		   .pm = &lm3560_pm_ops,
 		   .of_match_table = lm3560_of_match,
 		   },
 	.probe = lm3560_probe,
-- 
2.51.0