linux-kernel - Re: [PATCH] gpio-ich: Share ownership of GPIO groups

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Date:	Tue, 11 Sep 2012 12:41:16 +0200
From:	Samuel Ortiz <sameo@...ux.intel.com>
To:	Jean Delvare <khali@...ux-fr.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Grant Likely <grant.likely@...retlab.ca>,
	Peter Tyser <ptyser@...-inc.com>,
	Aaron Sierra <asierra@...-inc.com>
Subject: Re: [PATCH] gpio-ich: Share ownership of GPIO groups

Hi Jean,

On Mon, Jul 23, 2012 at 05:34:15PM +0200, Jean Delvare wrote:
> The ICH chips have their GPIO pins organized in 2 or 3 independent
> groups of 32 GPIO pins. It can happen that the ACPI BIOS wants to make
> use of pins in one group, preventing the OS to access these. This does
> not prevent the OS from accessing the other group(s).
> 
> This is the case for example on my Asus Z8NA-D6 board. The ACPI BIOS
> wants to control GPIO 18 (group 1), while I (the OS) need to control
> GPIO 52 and 53 (group 2) for SMBus multiplexing.
> 
> So instead of checking for ACPI resource conflict on the whole I/O
> range, check on a per-group basis, and consider it a success if at
> least one of the groups is available for the OS to use.
> 
> Signed-off-by: Jean Delvare <khali@...ux-fr.org>
> Cc: Peter Tyser <ptyser@...-inc.com>
> Cc: Aaron Sierra <asierra@...-inc.com>
> Cc: Grant Likely <grant.likely@...retlab.ca>
> Cc: Samuel Ortiz <sameo@...ux.intel.com>
> ---
> That's probably not the nicest code you've seen, but everything else I
> could think of either couldn't work or was looking worse. If anyone can
> think of a better approach, I'm all ears.
> 
>  drivers/gpio/gpio-ich.c     |   79 +++++++++++++++++++++++++++++++++++++------
>  drivers/mfd/lpc_ich.c       |   29 ++++++++++++++-
>  include/linux/mfd/lpc_ich.h |    1 
>  3 files changed, 97 insertions(+), 12 deletions(-)
Applied (finally) to my for-next branch, thanks.

Cheers,
Samuel.

-- 
Intel Open Source Technology Centre
http://oss.intel.com/
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