Re: [PATCH v1 1/2] fbtft: Rectify GPIO handling

From: Greg Kroah-Hartman
Date: Fri Apr 16 2021 - 08:52:09 EST

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:
> 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) Fix RESET pin polarity in the places missed by the commit
> b918d1c27066 ("Staging: fbtft: Fix reset assertion when using gpio descriptor")
> 4) 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.
> [1]:

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 :(


greg k-h