On Fri, Apr 16, 2021 at 02:51:59PM +0200, Greg Kroah-Hartman wrote:
On Fri, Apr 16, 2021 at 03:31:16PM +0300, Andy Shevchenko wrote:
The infamous commit c440eee1a7a1 ("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:
Set default to "inactive" for all requested pins
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
Fix RESET pin polarity in the places missed by the commit b918d1c27066 ("Staging: fbtft: Fix reset assertion when using gpio descriptor")
Consolidate chip activation (CS assert) 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. At the end, update TODO to mark this job eventually done.
Shouldn't this be broken up into "one patch per thing" from your list above? Feels like you did a lot of different things all in the same patch :(
Okay, I split a bit, now it's 4 patches. (See v2).