Message-ID: <1328204105.2261.140.camel@groeck-laptop>
Subject: Re: [PATCH] gpio: New driver for the Intel 82801 (ICH) GPIO pins
From: Guenter Roeck <guenter.roeck@ericsson.com>
Reply-To: guenter.roeck@ericsson.com
To: Jean Delvare <khali@linux-fr.org>
CC: Grant Likely <grant.likely@secretlab.ca>,
        LKML <linux-kernel@vger.kernel.org>, Peter Tyser <ptyser@xes-inc.com>
Date: Thu, 2 Feb 2012 09:35:05 -0800
In-Reply-To: <20120202084909.2adf0f50@endymion.delvare>
References: <20110419145303.111aead7@endymion.delvare>
	 <20120202023129.GA19535@ericsson.com>
	 <20120202084909.2adf0f50@endymion.delvare>
Organization: Ericsson
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On Thu, 2012-02-02 at 02:49 -0500, Jean Delvare wrote:
> On Wed, 1 Feb 2012 18:31:29 -0800, Guenter Roeck wrote:
> > On Tue, Apr 19, 2011 at 08:53:03AM -0400, Jean Delvare wrote:
> > > I need this to handle SMBus multiplexing on my Asus Z8NA-D6 board. It
> > > has an ICH10, I've added support for older ICH chips in case someone
> > > needs it, as it was relatively simply to do that.
> > > 
> > > Signed-off-by: Jean Delvare <khali@linux-fr.org>
> > > Cc: Grant Likely <grant.likely@secretlab.ca>
> > > ---
> > > Note 1: On early ICH chips, some pins are exclusively inputs or
> > > outputs. The driver doesn't currently enforce this.
> > > 
> > > Note 2: I'm not yet sure if we want a module alias for this driver.
> > > Many systems have the device but only a few of them will need the
> > > driver (and an ACPI resource conflict will be reported for many
> > > others, especially laptops I suspect.) So it might make more sense to
> > > let consumer drivers request the i801_gpio driver as needed (which they
> > > should do anyway, as you can't assume udev is always up and running on
> > > all systems.)
> > > 
> > > Note 3: This is my first GPIO driver, so while it works fine for me, it
> > > might not be perfect. I welcome comments on how to improve it.
> > > 
> > >  drivers/gpio/Kconfig     |    7
> > >  drivers/gpio/Makefile    |    1
> > >  drivers/gpio/i801_gpio.c |  432 ++++++++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 440 insertions(+)
> >
> > Did this or an alternate patch for gpio support on the recent Intel ICHs go anywhere ?
> > 
> > I found another patch which is using a different approach, but I don't see anything
> > in the latest kernel.
> 
> I don't think any driver made it into the kernel, at least I can't find
> any in 3.3-rc2 nor linux-next. I'm not surprised, as neither driver was
> using the MFD framework while this would really be the right thing to
> do here. I never took the time to convert my driver to MFD and
> apparently Peter did not either. This is still on my to-do list but you
> know how long it is. If anyone is faster than me at getting the code is
> a shape suitable for upstream, I'll be happy to help with review and
> testing.
> 
I'd love to take this on, but unfortunately my task list isn't getting
shorter either. Just bad that this doesn't seem to make it in.

One reason of course may be that at least Peter's version tried to
accomplish too much. Looking through the comments, seems there was a
disagreement on unrelated issues such as if there should be a new
"unknown" gpio direction or not. Maybe it would make more sense to
separate the core patch to add ICH gpio support from the rest of Peter's
proposed changes.

Peter, do you have any plans to work on this in the near future ?

Thanks,
Guenter


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