From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
"Jan Sebastian Götte" <linux@jaseg.net>,
"Phil Reid" <preid@electromag.com.au>,
"Nishad Kamdar" <nishadkamdar@gmail.com>
Subject: Re: [PATCH v1 1/2] fbtft: Rectify GPIO handling
Date: Fri, 16 Apr 2021 14:51:59 +0200 [thread overview]
Message-ID: <YHmIb2YrwfzZa7Wh@kroah.com> (raw)
In-Reply-To: <20210416123117.4993-1-andriy.shevchenko@linux.intel.com>
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]: https://learn.adafruit.com/adafruit-2-8-and-3-2-color-tft-touchscreen-breakout-v2/downloads
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 :(
thanks,
greg k-h
next prev parent reply other threads:[~2021-04-16 12:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 12:31 [PATCH v1 1/2] fbtft: Rectify GPIO handling Andy Shevchenko
2021-04-16 12:31 ` [PATCH v1 2/2] fbtft: Don't spam logs when probe is deferred Andy Shevchenko
2021-04-16 12:51 ` Greg Kroah-Hartman [this message]
2021-04-16 13:37 ` [PATCH v1 1/2] fbtft: Rectify GPIO handling Andy Shevchenko
2021-04-16 13:41 ` Andy Shevchenko
2021-04-16 14:20 ` Andy Shevchenko
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