Messages in this thread | | | Date | Tue, 11 Oct 2022 07:06:40 -0700 | From | Dmitry Torokhov <> | Subject | Re: [PATCH 1/4] ARM: dts: omap3-n900: fix LCD reset line polarity |
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Hi Sebastian,
On Tue, Oct 11, 2022 at 02:37:26PM +0200, Sebastian Reichel wrote: > Hi, > > On Tue, Oct 11, 2022 at 08:45:54AM +0300, Tony Lindgren wrote: > > * Dmitry Torokhov <dmitry.torokhov@gmail.com> [221004 21:26]: > > > The LCD driver (panel-sony-acx565akm), when probing, starts with line > > > driven low, and then toggles it to high and keeps it there. Also, the > > > line is driven low when powering off the device, and ls released when > > > powering it back on. This means that the reset line should be described > > > as "active low" in DTS. This will be important when the driver is > > > converted to gpiod API which respects the polarity declared in DTS. > > > > We should ensure these patches get merged together with the driver > > change to avoid breaking LCD for booting. Probably no need to have > > the driver quirk handling for inverted polartity in this case. > > > > It's probably easiest to have an immutable branch for the driver > > changes I can base the dts changes on. Or I can ack the dts changes > > if they get merged with the driver. > > Both drivers are already using gpiod API: > > drivers/gpu/drm/panel/panel-sony-acx565akm.c > drivers/gpu/drm/panel/panel-dsi-cm.c
I was looking at
drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c drivers/video/fbdev/omap2/omapfb/displays/panel-dsi-cm.c
which are not using gpiod. Should they be retired?
> > So this just breaks things.
I missed the drivers in drivers/gpu/... and I see that they essentially abuse gpiod API as gpiod_set_value() operates on logical level (active/inactive) and not absolute (high/low). They should either use the gpiod_*_raw() variants, or they should be adjusted to do the proper thing together with the accompanying DTS change.
What are your preferences?
Thanks.
-- Dmitry
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