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From: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: linux-kernel@vger.kernel.org,
	Jerome Oufella <jerome.oufella@savoirfairelinux.com>,
	Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH v2] gpio: add TS-5500 DIO blocks support
Date: Wed, 19 Dec 2012 17:13:47 -0500 (EST)	[thread overview]
Message-ID: <1032450702.626703.1355955227194.JavaMail.root@mail.savoirfairelinux.com> (raw)
In-Reply-To: <20121219171600.7B0EF3E0C5A@localhost>

Hi Grant,

> Please take a look at either send me a follow-on patch to convert it
> to use gpio-generic, or tell my why gpio-generic isn't appropriate here.

The gpio-generic driver is not appropriate here because Technologic Systems
x86-based platforms do not use a typical GPIO implementation. 
To name a few specificities:
- The GPIOs are available through ioport and not iomem
- There are input-only/output-only/input-output lines on the same block
- The number of GPIOs differs between blocks (currently 11, 13 and 14 pins)
- A single bit in a control register drives the direction of 4 input/output
  lines, while the register's other bits have different functions.

IMHO these considerations justify a specific GPIO driver to support these
Technologic Systems pin blocks.

Regards,
Vivien

      reply	other threads:[~2012-12-19 22:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-08  2:36 [PATCH v2] gpio: add TS-5500 DIO blocks support Vivien Didelot
2012-12-10  9:55 ` Linus Walleij
2012-12-19 17:16   ` Grant Likely
2012-12-19 22:13     ` Vivien Didelot [this message]

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