On Fri, 2015-03-06 at 12:04 +0100, Linus Walleij wrote: > On Wed, Feb 18, 2015 at 1:18 PM, Shobhit Kumar <shobhit.kumar@xxxxxxxxx> wrote: > > > Export Panel BACKLIGHT_EN(offset 0x51) and PANEL_EN(offset 0x52) as two > > additional GPIOs. Needed by display driver to enable the DSI panel on > > BYT platform where the Panel EN/Disable and Backlight control are > > routed thorugh CRC PMIC > > > > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx> > > Cc: Alexandre Courbot <gnurou@xxxxxxxxx> > > Cc: Thierry Reding <thierry.reding@xxxxxxxxx> > > Signed-off-by: Shobhit Kumar <shobhit.kumar@xxxxxxxxx> > > This seems very unintuitive. I have a hard time believeing this: > > > +#define GPIOPANELCTL 0x51 > > A special GPIO only designated to panel control? That is totally > counter to the *meaning* of "general purpose input/output". > It is not general purpose at all, it is special-purpose. > > If the data sheet says a special-purpose pin is a "GPIO" when > it isn't the map of the world (the datasheet terminology) is wrong, > not the world, the usage is dedicated for the panel. Look > at the usecase, not the name. > > Obviously that line is only for controlling the backlight, and you > should spin a new child device from the Inte SoC PMIC MFD hub > and put a driver for it in drivers/video/backlight or wherever this > goes. There are actually two lines for Panel Power control and Backlight enable/disable. I have already moved towards adding a new Cell device for PWM child device and a new pwm driver for the same. That will take care of backlight thingy. But for the Panel power control, I am at loss for how best to program that. It is not strictly a GPIO but behaves similarly and thought of simply extending existing gpio-crystalcove. My next implementation(not posted yet) is having that exported by adding a lookup table in PMIC MFD probe routine. Regards Shobhit > > Lee: do you agree? > > Yours, > Linus Walleij _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
