Re: [PATCH v2 05/18] media: ov5640: Use runtime PM to control sensor power
From: Tomi Valkeinen
Date: Fri May 28 2021 - 02:44:53 EST
On 26/05/2021 18:22, Pratyush Yadav wrote:
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 v2:
- New in v2.
drivers/media/i2c/Kconfig | 2 +-
drivers/media/i2c/ov5640.c | 124 +++++++++++++++++++++++--------------
2 files changed, 77 insertions(+), 49 deletions(-)
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 462c0e059754..5588fc1cc14a 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -914,7 +914,7 @@ 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 5b9cc71df473..4ed5758e2398 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 +2916,56 @@ 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)
+ goto out;
+
+ if (enable) {
+ ret = pm_runtime_get_sync(dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(dev);
+ goto out;
+ }
There now seems to be a function to do the above steps:
pm_runtime_resume_and_get.
+
+ 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, enable);
+ if (ret)
+ goto put_pm;
+ } else {
+ ret = ov5640_set_stream(sensor, enable);
Instead of using "enable" here (and in the enable path above), just use
true/false. It'll be more readable.
+ if (ret)
+ goto out;
- if (!ret)
- sensor->streaming = enable;
+ pm_runtime_put(dev);
}
+
+ sensor->streaming = enable;
+ goto out;
+
+put_pm:
+ pm_runtime_put(dev);
out:
mutex_unlock(&sensor->lock);
return ret;
}
The flow in the above function is quite confusing. I think you should
either 1) have a separate error paths via gotos and a return 0 before
the error labels, or 2) common error and success path, without that
final "goto out" you have above.
Maybe if you move the code in the "if (enable) {} else {}" to the
ov5640_set_stream(), the flow will be easier to manage.
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 +3031,29 @@ 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 +3179,17 @@ 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 error_pm;
return 0;
-free_ctrls:
+error_pm:
+ pm_runtime_disable(dev);
The label style used here seems to be the
"label-tells-what-will-be-done", so I think instead of "error_pm", it
should be, perhaps, "pm_disable".
v4l2_ctrl_handler_free(&sensor->ctrls.handler);
entity_cleanup:
media_entity_cleanup(&sensor->sd.entity);
@@ -3178,17 +3199,23 @@ 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 +3232,7 @@ 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,