linux-kernel - Re: [PATCH 2/3] gpio: 104-dio-48e: Add Counter/Timer support

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Message-ID: <ZGub8Gyu773b+V92@fedora>
Date:   Mon, 22 May 2023 12:44:32 -0400
From:   William Breathitt Gray <william.gray@...aro.org>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Bartosz Golaszewski <brgl@...ev.pl>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-gpio@...r.kernel.org
Subject: Re: [PATCH 2/3] gpio: 104-dio-48e: Add Counter/Timer support

On Sat, May 20, 2023 at 09:28:15PM +0200, Linus Walleij wrote:
> On Sun, Apr 16, 2023 at 7:37 PM William Breathitt Gray
> <william.gray@...aro.org> wrote:
> 
> > The 104-DIO-48E features an 8254 Counter/Timer chip providing three
> > counter/timers which can be used for frequency measurement, frequency
> > output, pulse width modulation, pulse width measurement, event count,
> > etc. The counter/timers use the same addresses as PPI 0 (addresses 0x0
> > to 0x3), so a raw_spinlock_t is used to synchronize operations between
> > the two regmap mappings to prevent clobbering.
> >
> > Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
> 
> Very interesting development here.
> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
> 
> Yours,
> Linus Walleij

With this patch, we should now have complete support for every feature
available on this device. A nice milestone as well after first
introducing basic GPIO support for the ACCES 104-DIO-48E in 2016.

Given that there is also Intel 8255 support, it would be fun to route
back one of the device's GPIO outputs into the Intel 8254 timer gate and
hook up a simple speaker; we could get some nice beep generation going
and party like it's 1989! B-)

William Breathitt Gray

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