[PATCH v3 01/11] media: ov5640: Use runtime PM to control sensor power

[Pratyush Yadav]

Calling s_power subdev callback is discouraged. Instead, the subdevs
should use runtime PM to control its power. Use runtime PM callbacks to
control sensor power. The pm counter is incremented when the stream is
started and decremented when the stream is stopped.

Refactor s_stream() a bit to make this new control flow easier. Add a
helper to choose whether mipi or dvp set_stream needs to be called. The
logic flow is also changed to make it a bit clearer.

Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>

---

Changes in v3:
- Clean up the logic in ov5640_s_stream() a bit.
- Use pm_runtime_resume_and_get() instead of pm_runtime_get_sync().
- Rename the label error_pm to disable_pm.

Changes in v2:
- New in v2.

 drivers/media/i2c/Kconfig  |   2 +-
 drivers/media/i2c/ov5640.c | 127 +++++++++++++++++++++++--------------
 2 files changed, 79 insertions(+), 50 deletions(-)

diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 588f8eb95984..8f43a4d7bcc1 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -929,7 +929,7 @@ config VIDEO_OV2740
 
 config VIDEO_OV5640
 	tristate "OmniVision OV5640 sensor support"
-	depends on OF
+	depends on OF && PM
 	depends on GPIOLIB && VIDEO_V4L2 && I2C
 	select MEDIA_CONTROLLER
 	select VIDEO_V4L2_SUBDEV_API
diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
index f6e1e51e0375..2b7fd8631ad1 100644
--- a/drivers/media/i2c/ov5640.c
+++ b/drivers/media/i2c/ov5640.c
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/types.h>
@@ -238,8 +239,6 @@ struct ov5640_dev {
 	/* lock to protect all members below */
 	struct mutex lock;
 
-	int power_count;
-
 	struct v4l2_mbus_framefmt fmt;
 	bool pending_fmt_change;
 
@@ -1277,6 +1276,14 @@ static int ov5640_set_stream_mipi(struct ov5640_dev *sensor, bool on)
 				on ? 0x00 : 0x0f);
 }
 
+static int ov5640_set_stream(struct ov5640_dev *sensor, bool on)
+{
+	if (sensor->ep.bus_type == V4L2_MBUS_CSI2_DPHY)
+		return ov5640_set_stream_mipi(sensor, on);
+	else
+		return ov5640_set_stream_dvp(sensor, on);
+}
+
 static int ov5640_get_sysclk(struct ov5640_dev *sensor)
 {
 	 /* calculate sysclk */
@@ -2155,37 +2162,6 @@ static int ov5640_set_power(struct ov5640_dev *sensor, bool on)
 
 /* --------------- Subdev Operations --------------- */
 
-static int ov5640_s_power(struct v4l2_subdev *sd, int on)
-{
-	struct ov5640_dev *sensor = to_ov5640_dev(sd);
-	int ret = 0;
-
-	mutex_lock(&sensor->lock);
-
-	/*
-	 * If the power count is modified from 0 to != 0 or from != 0 to 0,
-	 * update the power state.
-	 */
-	if (sensor->power_count == !on) {
-		ret = ov5640_set_power(sensor, !!on);
-		if (ret)
-			goto out;
-	}
-
-	/* Update the power count. */
-	sensor->power_count += on ? 1 : -1;
-	WARN_ON(sensor->power_count < 0);
-out:
-	mutex_unlock(&sensor->lock);
-
-	if (on && !ret && sensor->power_count == 1) {
-		/* restore controls */
-		ret = v4l2_ctrl_handler_setup(&sensor->ctrls.handler);
-	}
-
-	return ret;
-}
-
 static int ov5640_try_frame_interval(struct ov5640_dev *sensor,
 				     struct v4l2_fract *fi,
 				     u32 width, u32 height)
@@ -2681,6 +2657,7 @@ static int ov5640_s_ctrl(struct v4l2_ctrl *ctrl)
 {
 	struct v4l2_subdev *sd = ctrl_to_sd(ctrl);
 	struct ov5640_dev *sensor = to_ov5640_dev(sd);
+	struct device *dev = &sensor->i2c_client->dev;
 	int ret;
 
 	/* v4l2_ctrl_lock() locks our own mutex */
@@ -2690,7 +2667,7 @@ static int ov5640_s_ctrl(struct v4l2_ctrl *ctrl)
 	 * not apply any controls to H/W at this time. Instead
 	 * the controls will be restored right after power-up.
 	 */
-	if (sensor->power_count == 0)
+	if (pm_runtime_suspended(dev))
 		return 0;
 
 	switch (ctrl->id) {
@@ -2939,39 +2916,57 @@ static int ov5640_enum_mbus_code(struct v4l2_subdev *sd,
 static int ov5640_s_stream(struct v4l2_subdev *sd, int enable)
 {
 	struct ov5640_dev *sensor = to_ov5640_dev(sd);
+	struct device *dev = &sensor->i2c_client->dev;
 	int ret = 0;
 
 	mutex_lock(&sensor->lock);
 
-	if (sensor->streaming == !enable) {
-		if (enable && sensor->pending_mode_change) {
+	if (sensor->streaming == enable) {
+		mutex_unlock(&sensor->lock);
+		return 0;
+	}
+
+	if (enable) {
+		ret = pm_runtime_resume_and_get(dev);
+		if (ret < 0)
+			goto err;
+
+		if (sensor->pending_mode_change) {
 			ret = ov5640_set_mode(sensor);
 			if (ret)
-				goto out;
+				goto put_pm;
 		}
 
-		if (enable && sensor->pending_fmt_change) {
+		if (sensor->pending_fmt_change) {
 			ret = ov5640_set_framefmt(sensor, &sensor->fmt);
 			if (ret)
-				goto out;
+				goto put_pm;
 			sensor->pending_fmt_change = false;
 		}
 
-		if (sensor->ep.bus_type == V4L2_MBUS_CSI2_DPHY)
-			ret = ov5640_set_stream_mipi(sensor, enable);
-		else
-			ret = ov5640_set_stream_dvp(sensor, enable);
+		ret = ov5640_set_stream(sensor, true);
+		if (ret)
+			goto put_pm;
+	} else {
+		ret = ov5640_set_stream(sensor, false);
+		if (ret)
+			goto err;
 
-		if (!ret)
-			sensor->streaming = enable;
+		pm_runtime_put(dev);
 	}
-out:
+
+	sensor->streaming = enable;
+	mutex_unlock(&sensor->lock);
+	return 0;
+
+put_pm:
+	pm_runtime_put(dev);
+err:
 	mutex_unlock(&sensor->lock);
 	return ret;
 }
 
 static const struct v4l2_subdev_core_ops ov5640_core_ops = {
-	.s_power = ov5640_s_power,
 	.log_status = v4l2_ctrl_subdev_log_status,
 	.subscribe_event = v4l2_ctrl_subdev_subscribe_event,
 	.unsubscribe_event = v4l2_event_subdev_unsubscribe,
@@ -3037,6 +3032,29 @@ static int ov5640_check_chip_id(struct ov5640_dev *sensor)
 	return ret;
 }
 
+static int ov5640_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+	struct ov5640_dev *sensor = to_ov5640_dev(subdev);
+
+	return ov5640_set_power(sensor, false);
+}
+
+static int ov5640_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+	struct ov5640_dev *sensor = to_ov5640_dev(subdev);
+	int ret = 0;
+
+	ret = ov5640_set_power(sensor, true);
+	if (ret)
+		return ret;
+
+	return __v4l2_ctrl_handler_setup(&sensor->ctrls.handler);
+}
+
 static int ov5640_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
@@ -3162,13 +3180,17 @@ static int ov5640_probe(struct i2c_client *client)
 	if (ret)
 		goto entity_cleanup;
 
+	pm_runtime_enable(dev);
+	pm_runtime_set_suspended(dev);
+
 	ret = v4l2_async_register_subdev_sensor(&sensor->sd);
 	if (ret)
-		goto free_ctrls;
+		goto pm_disable;
 
 	return 0;
 
-free_ctrls:
+pm_disable:
+	pm_runtime_disable(dev);
 	v4l2_ctrl_handler_free(&sensor->ctrls.handler);
 entity_cleanup:
 	media_entity_cleanup(&sensor->sd.entity);
@@ -3178,17 +3200,23 @@ static int ov5640_probe(struct i2c_client *client)
 
 static int ov5640_remove(struct i2c_client *client)
 {
+	struct device *dev = &client->dev;
 	struct v4l2_subdev *sd = i2c_get_clientdata(client);
 	struct ov5640_dev *sensor = to_ov5640_dev(sd);
 
 	v4l2_async_unregister_subdev(&sensor->sd);
 	media_entity_cleanup(&sensor->sd.entity);
+	pm_runtime_disable(dev);
 	v4l2_ctrl_handler_free(&sensor->ctrls.handler);
 	mutex_destroy(&sensor->lock);
 
 	return 0;
 }
 
+static const struct dev_pm_ops ov5640_pm_ops = {
+	SET_RUNTIME_PM_OPS(ov5640_suspend, ov5640_resume, NULL)
+};
+
 static const struct i2c_device_id ov5640_id[] = {
 	{"ov5640", 0},
 	{},
@@ -3205,6 +3233,7 @@ static struct i2c_driver ov5640_i2c_driver = {
 	.driver = {
 		.name  = "ov5640",
 		.of_match_table	= ov5640_dt_ids,
+		.pm = &ov5640_pm_ops,
 	},
 	.id_table = ov5640_id,
 	.probe_new = ov5640_probe,
-- 
2.30.0