Thierry, On 07.11.2014 16:19, Vladimir Zapolskiy wrote: > Hi Thierry, > > On 07.11.2014 15:48, Thierry Reding wrote: >> On Sat, Oct 11, 2014 at 04:46:25PM +0300, Vladimir Zapolskiy wrote: >>> Platform PWM backlight data provided by board's device tree should be >>> complete enough to successfully request a pwm device using pwm_get() API. >>> >>> Based on initial implementation done by Dmitry Eremin-Solenikov. >>> >>> Reported-by: Dmitry Eremin-Solenikov <[email protected]> >>> Signed-off-by: Vladimir Zapolskiy <[email protected]> >>> Cc: Thierry Reding <[email protected]> >>> Cc: Jingoo Han <[email protected]> >>> Cc: Bryan Wu <[email protected]> >>> Cc: Lee Jones <[email protected]> >>> --- >>> drivers/video/backlight/pwm_bl.c | 14 +++++++------- >>> 1 file changed, 7 insertions(+), 7 deletions(-) >> >> I don't really understand what this is supposed to do. The commit >> message doesn't make a very good job of explaining it either. >> >> Can you describe in more detail what problem this fixes and why it >> should be merged? > > thank you for review. > > As it is shown by the code this particular change rejects fallback to > legacy PWM device request (which itself in turn is fixed in the next > commit) for boards with supplied DTS, "pwm-backlight" compatible node > and unregistered corresponding PWM device in that node. > > I don't know if there is a good enough reason to register PWM backlight > device connected to some quite arbitrary PWM device, if no PWM device > information is given in the "pwm-backlight" compatible node, so I think > it makes sense to change the default policy. >
also please note that Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt quite fairly describes "pwms" as a required property, but right now this statement from the documentation is wrong, it is possible to register pwm-backlight device driver (using notorious pwm_request() legacy API) connected to some unspecified pwm device. I don't think that the current registration policy is correct, that's why I propose to fix the logic instead of making a documentation update. -- With best wishes, Vladimir -- To unsubscribe from this list: send the line "unsubscribe linux-pwm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
