[ Upstream commit ec03c21043 ]
The infamous commit c440eee1a7 ("Staging: staging: fbtft: Switch to
the GPIO descriptor interface") broke GPIO handling completely.
It has already four commits to rectify and it seems not enough.
In order to fix the mess here we:
1) Set default to "inactive" for all requested pins
2) Fix CS#, RD#, and WR# pins polarity since it's active low
and GPIO descriptor interface takes it into consideration
from the Device Tree or ACPI
3) Consolidate chip activation (CS# assertion) under default
->reset() callback
To summarize the expectations about polarity for GPIOs:
RD# Low
WR# Low
CS# Low
RESET# Low
DC or RS High
RW High
Data 0 .. 15 High
See also Adafruit learning course [1] for the example of the schematics.
While at it, drop unneeded NULL checks, since GPIO API is tolerant to that.
[1]: https://learn.adafruit.com/adafruit-2-8-and-3-2-color-tft-touchscreen-breakout-v2/downloads
Fixes: 92e3e88488 ("Staging: fbtft: Fix GPIO handling")
Fixes: b918d1c270 ("Staging: fbtft: Fix reset assertion when using gpio descriptor")
Fixes: dbc4f989c8 ("Staging: fbtft: Fix probing of gpio descriptor")
Fixes: c440eee1a7 ("Staging: fbtft: Switch to the gpio descriptor interface")
Cc: Jan Sebastian Götte <linux@jaseg.net>
Cc: Nishad Kamdar <nishadkamdar@gmail.com>
Reviewed-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210503172114.27891-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
fbe80b3ee9