From: Sascha Hauer <s.hauer@pengutronix.de>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] gpio: add driver for SN74273 output expander
Date: Mon, 9 Sep 2019 09:23:31 +0200 [thread overview]
Message-ID: <20190909072331.4xmc6nvjgfdxged3@pengutronix.de> (raw)
In-Reply-To: <20190906140127.17396-1-a.fatoum@pengutronix.de>
On Fri, Sep 06, 2019 at 04:01:27PM +0200, Ahmad Fatoum wrote:
> The SN74273 is an octal D-Type Flip-Flop. When used as an output expander,
> N existing output signals can be turned into (N-8)*8 outputs using
> N-8 chips. Add driver to facilitate this.
The reason I haven't mainlined this driver when writing it was that
Linux also has a driver for the 74273, but in a completely different
setup. In the Linux driver the 74273 is assumed to have its inputs on
the data bus together with a separate address decoder.
The chip in this driver here instead is connected via GPIO pins. For
Using flipflops as GPIO expanders there a myriads of different ways to
implement, so I have my doubts how useful it is to even try to put them
in a generic driver.
Sascha
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next prev parent reply other threads:[~2019-09-09 7:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 14:01 Ahmad Fatoum
2019-09-09 7:23 ` Sascha Hauer [this message]
2019-09-17 9:22 ` Ahmad Fatoum
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