Hi Guennadi, thanks for the patches and sorry for the delay. I've tested them a few minutes ago and they are working fine.
2 minor things/questions: 1.) Why not always balance v4l2_clk_enable/disable() calls ? 2.) For someone who reads the code it likely looks a bit odd that if the flag "unbalanced_power" is set, soc_camera balances v4l2_clk_enable/disable but not power on/off calls (ssdd->power() calls). So maybe "balance_clk" or "clk_balancing_needed" would be a better name for the flag ? Ok, let's summarize what we need: - the 3 fake clock patches patches - em28xx patch "make sure that all subdevices are powered on when needed" - these 2 patches All patches need to marked for stable (3.11). Can you pick up my me28xx patch and send Mauro a pull request ? Regards, Frank Am 21.10.2013 11:28, schrieb Guennadi Liakhovetski: > Some non soc-camera drivers, e.g. em28xx, use subdevice drivers, originally > written for soc-camera, which use soc_camera_power_on() and > soc_camera_power_off() helpers to implement their .s_power() methods. Those > helpers in turn can enable and disable a clock, if it is supplied to them > as a parameter. This works well when camera host drivers balance their > calls to subdevices' .s_power() methods. However, some such drivers fail to > do that, which leads to unbalanced calls to v4l2_clk_enable() / > v4l2_clk_disable(), which then in turn produce kernel warnings. Such > behaviour is wrong and should be fixed, however, sometimes it is difficult, > because some of those drivers are rather old and use lots of subdevices, > which all should be tested after such a fix. To support such drivers this > patch adds a work-around, allowing host drivers or platforms to set a flag, > in which case soc-camera helpers will only enable the clock, if it is > disabled, and disable it only once on the first call to .s_power(0). > > Signed-off-by: Guennadi Liakhovetski <[email protected]> > --- > > As promised yesterday, this is an alternative approach to fixing the > em28xx problem, compile tested only. > > drivers/media/platform/soc_camera/soc_camera.c | 22 ++++++++++++++++------ > include/media/soc_camera.h | 14 ++++++++++++++ > 2 files changed, 30 insertions(+), 6 deletions(-) > > diff --git a/drivers/media/platform/soc_camera/soc_camera.c > b/drivers/media/platform/soc_camera/soc_camera.c > index 387a232..21136a2 100644 > --- a/drivers/media/platform/soc_camera/soc_camera.c > +++ b/drivers/media/platform/soc_camera/soc_camera.c > @@ -71,11 +71,21 @@ static int video_dev_create(struct soc_camera_device > *icd); > int soc_camera_power_on(struct device *dev, struct soc_camera_subdev_desc > *ssdd, > struct v4l2_clk *clk) > { > - int ret = clk ? v4l2_clk_enable(clk) : 0; > - if (ret < 0) { > - dev_err(dev, "Cannot enable clock: %d\n", ret); > - return ret; > + int ret; > + bool clock_toggle; > + > + if (clk && (!ssdd->unbalanced_power || > + !test_and_set_bit(0, &ssdd->clock_state))) { > + ret = v4l2_clk_enable(clk); > + if (ret < 0) { > + dev_err(dev, "Cannot enable clock: %d\n", ret); > + return ret; > + } > + clock_toggle = true; > + } else { > + clock_toggle = false; > } > + > ret = regulator_bulk_enable(ssdd->num_regulators, > ssdd->regulators); > if (ret < 0) { > @@ -98,7 +108,7 @@ epwron: > regulator_bulk_disable(ssdd->num_regulators, > ssdd->regulators); > eregenable: > - if (clk) > + if (clock_toggle) > v4l2_clk_disable(clk); > > return ret; > @@ -127,7 +137,7 @@ int soc_camera_power_off(struct device *dev, struct > soc_camera_subdev_desc *ssdd > ret = ret ? : err; > } > > - if (clk) > + if (clk && (!ssdd->unbalanced_power || test_and_clear_bit(0, > &ssdd->clock_state))) > v4l2_clk_disable(clk); > > return ret; > diff --git a/include/media/soc_camera.h b/include/media/soc_camera.h > index 34d2414..5678a39 100644 > --- a/include/media/soc_camera.h > +++ b/include/media/soc_camera.h > @@ -150,6 +150,15 @@ struct soc_camera_subdev_desc { > struct regulator_bulk_data *regulators; > int num_regulators; > > + /* > + * Set unbalanced_power to true to deal with legacy drivers, failing to > + * balance their calls to subdevice's .s_power() method. clock_state is > + * then used internally by helper functions, it shouldn't be touched by > + * drivers or the platform code. > + */ > + bool unbalanced_power; > + unsigned long clock_state; > + > /* Optional callbacks to power on or off and reset the sensor */ > int (*power)(struct device *, int); > int (*reset)(struct device *); > @@ -206,6 +215,11 @@ struct soc_camera_link { > struct regulator_bulk_data *regulators; > int num_regulators; > > + /* Set by platforms to handle misbehaving drivers */ > + bool unbalanced_power; > + /* Used by soc-camera helper functions */ > + unsigned long clock_state; > + > /* Optional callbacks to power on or off and reset the sensor */ > int (*power)(struct device *, int); > int (*reset)(struct device *); -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
