Hi Jacopo, On Wed 09 Mar 22, 14:47, Jacopo Mondi wrote: > Hi Paul, > > On Wed, Mar 09, 2022 at 08:32:32PM +0900, Paul Elder wrote: > > Switch to using runtime PM for power management. > > What happens if CONFIG_PM is not selected ? Two of the existing > sensor drivers in mainline depends on PM but not the ov5640, and I'm > not sure we should depend on PM to be able to compile the module. I think the direction for the media subsystem is to use runtime pm everywhere possible, which is not opional (like traditional PM) so I really thinks it makes sense to have the sensor driver depend on it. The alternative would probably be to keep the s_power implementation when !CONFIG_PM which is certinaly not something we want. > Also I see very few #ifdef CONFIG_PM in drivers/media/i2c so either > the CONFIG_PM dependency is not an issue or most sensor drivers don't > care. This seems like an overlook, I think drivers that rely on runtime pm do need to depend on PM in Kconfig. Cheers, Paul > Also, could you base this patch on sakari's tree master branc which > contains my ov5640 patches that will land in v5.18 to avoid future > rebases ? > https://git.linuxtv.org/sailus/media_tree.git > > > > > Signed-off-by: Paul Elder <paul.elder@xxxxxxxxxxxxxxxx> > > --- > > drivers/media/i2c/ov5640.c | 108 ++++++++++++++++++++++--------------- > > 1 file changed, 64 insertions(+), 44 deletions(-) > > > > diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c > > index ddbd71394db3..8e95096ba67b 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> > > @@ -240,7 +241,7 @@ struct ov5640_dev { > > /* lock to protect all members below */ > > struct mutex lock; > > > > - int power_count; > > + bool powered; > > 'powered' is never reset to false when the chip is powered off. > > I would avoid tracking the power state manually but rely instead > on the value returned from pm_runtime_get_if_in_use(). > > > > > struct v4l2_mbus_framefmt fmt; > > bool pending_fmt_change; > > @@ -2148,6 +2149,8 @@ static int ov5640_set_power(struct ov5640_dev *sensor, bool on) > > if (!on) > > ov5640_set_power_off(sensor); > > > > + sensor->powered = on; > > + > > return 0; > > > > power_off: > > @@ -2157,37 +2160,6 @@ 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) > > @@ -2663,6 +2635,9 @@ static int ov5640_g_volatile_ctrl(struct v4l2_ctrl *ctrl) > > > > /* v4l2_ctrl_lock() locks our own mutex */ > > > > + if (!sensor->powered) > > + return 0; > > + > > switch (ctrl->id) { > > case V4L2_CID_AUTOGAIN: > > val = ov5640_get_gain(sensor); > > @@ -2694,7 +2669,7 @@ 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 (!sensor->powered) > > return 0; > > > > switch (ctrl->id) { > > @@ -2945,6 +2920,12 @@ static int ov5640_s_stream(struct v4l2_subdev *sd, int enable) > > struct ov5640_dev *sensor = to_ov5640_dev(sd); > > int ret = 0; > > > > + if (enable) { > > + ret = pm_runtime_resume_and_get(&sensor->i2c_client->dev); > > + if (ret < 0) > > + return ret; > > + } > > + > > mutex_lock(&sensor->lock); > > > > if (sensor->streaming == !enable) { > > @@ -2969,13 +2950,17 @@ static int ov5640_s_stream(struct v4l2_subdev *sd, int enable) > > if (!ret) > > sensor->streaming = enable; > > } > > + > > out: > > mutex_unlock(&sensor->lock); > > + > > + if (!enable || ret) > > + pm_runtime_put(&sensor->i2c_client->dev); > > + > > 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, > > @@ -3019,15 +3004,11 @@ static int ov5640_check_chip_id(struct ov5640_dev *sensor) > > int ret = 0; > > u16 chip_id; > > > > - ret = ov5640_set_power_on(sensor); > > - if (ret) > > - return ret; > > - > > ret = ov5640_read_reg16(sensor, OV5640_REG_CHIP_ID, &chip_id); > > if (ret) { > > dev_err(&client->dev, "%s: failed to read chip identifier\n", > > __func__); > > - goto power_off; > > + return ret; > > } > > > > if (chip_id != 0x5640) { > > @@ -3036,8 +3017,6 @@ static int ov5640_check_chip_id(struct ov5640_dev *sensor) > > ret = -ENXIO; > > } > > > > -power_off: > > - ov5640_set_power_off(sensor); > > return ret; > > } > > > > @@ -3158,20 +3137,35 @@ static int ov5640_probe(struct i2c_client *client) > > > > mutex_init(&sensor->lock); > > > > - ret = ov5640_check_chip_id(sensor); > > + ret = ov5640_init_controls(sensor); > > if (ret) > > goto entity_cleanup; > > > > - ret = ov5640_init_controls(sensor); > > + ret = ov5640_set_power(sensor, true); > > + if (ret) > > + goto free_ctrls; > > + > > + ret = ov5640_check_chip_id(sensor); > > if (ret) > > goto entity_cleanup; > > Should you power_off if identifying the chip fails ? > > On the other hand, enabling runtime_pm before identifying the chip > might help having a simpler error handling path ? > > Something like: > > ... > pm_runtime_set_active(dev); > pm_runtime_enable(dev); > pm_runtime_get(dev); > > ret = ov5640_check_chip_id(sensor); > if (ret) > goto err_pm_runtime; > > ret = v4l2_async_register_subdev_sensor(&sensor->sd); > if (ret) > goto err_pm_runtime; > > pm_runtime_set_autosuspend_delay(dev, 1000); > pm_runtime_use_autosuspend(dev); > pm_runtime_put_autosuspend(dev); > > return 0; > > err_pm_runtime: > pm_runtime_put(dev); > pm_runtime_disable(dev); > pm_runtime_put_noidle(dev); > ... > > Tested by forcing an early return from ov5640_check_chip_id() and I > get no warnings about unbalanced runtime_pm counters. > > > > > + pm_runtime_set_active(dev); > > + pm_runtime_get_noresume(dev); > > + pm_runtime_enable(dev); > > + > > ret = v4l2_async_register_subdev_sensor(&sensor->sd); > > if (ret) > > - goto free_ctrls; > > + goto err_pm_runtime; > > + > > + pm_runtime_set_autosuspend_delay(dev, 1000); > > Is this dealy required, where does it come from ? > > Thanks > j > > > > + pm_runtime_use_autosuspend(dev); > > + pm_runtime_put_autosuspend(dev); > > > > return 0; > > > > +err_pm_runtime: > > + pm_runtime_disable(dev); > > + pm_runtime_put_noidle(dev); > > free_ctrls: > > v4l2_ctrl_handler_free(&sensor->ctrls.handler); > > entity_cleanup: > > @@ -3193,6 +3187,31 @@ static int ov5640_remove(struct i2c_client *client) > > return 0; > > } > > > > +static int __maybe_unused ov5640_sensor_suspend(struct device *dev) > > +{ > > + struct v4l2_subdev *sd = dev_get_drvdata(dev); > > + struct ov5640_dev *ov5640 = to_ov5640_dev(sd); > > + > > + return ov5640_set_power(ov5640, false); > > +} > > + > > +static int __maybe_unused ov5640_sensor_resume(struct device *dev) > > +{ > > + struct v4l2_subdev *sd = dev_get_drvdata(dev); > > + struct ov5640_dev *ov5640 = to_ov5640_dev(sd); > > + int ret; > > + > > + ret = ov5640_set_power(ov5640, true); > > + if (ret) > > + return ret; > > + > > + return v4l2_ctrl_handler_setup(&ov5640->ctrls.handler); > > +} > > + > > +static const struct dev_pm_ops ov5640_pm_ops = { > > + SET_RUNTIME_PM_OPS(ov5640_sensor_suspend, ov5640_sensor_resume, NULL) > > +}; > > + > > static const struct i2c_device_id ov5640_id[] = { > > {"ov5640", 0}, > > {}, > > @@ -3209,6 +3228,7 @@ 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, > > -- > > 2.30.2 > > -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com
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