Pavel, 2017-07-20 10:10 GMT+02:00 Pavel Machek <pavel at ucw.cz>: > On Mon 2017-07-17 23:28:11, Enric Balletbo i Serra wrote: >> The minnie devices comes with an AUO B101EAN01 panel which is different >> from default veyron devices, thus the power on/off timing sequence is >> slightly different. The datasheet specifies a pwm delay of 200 ms, so >> update the PMW delay proprieties accordingly. > > Wait a wait a moment! > >> --- a/arch/arm/boot/dts/rk3288-veyron-minnie.dts >> +++ b/arch/arm/boot/dts/rk3288-veyron-minnie.dts >> @@ -123,6 +123,8 @@ >> 240 241 242 243 244 245 246 247 >> 248 249 250 251 252 253 254 255>; >> power-supply = <&backlight_regulator>; >> + post-pwm-on-delay-us = <20000>; > > -us = <20 000>; > > This is not 200 msec. > Oops, good catch. > Plus, it is quite anti-social to do udelay(200 000). > > Plus, it is very anti-socifal to use udelay_range(200msec, > 400msec). > > Whoever told you udelay_range is good thing to use -- it is not, and > it is certainly not worth making user wait 200msec more! > Checked again some datasheets and seems that or not require a delay or the delays are 10ms+, so according to [1] I'll use msleep instead. [1] https://www.kernel.org/doc/Documentation/timers/timers-howto.txt Thanks, Enric > Pavel > -- > (english) http://www.livejournal.com/~pavelmachek > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
