From mboxrd@z Thu Jan  1 00:00:00 1970
From: grinberg@compulab.co.il (Igor Grinberg)
Date: Mon, 31 Dec 2012 11:56:11 +0200
Subject: [PATCH Resend] ARM: pxa27x: fix ac97 controller warm reset code
In-Reply-To: <1356728815-14410-1-git-send-email-mikedunn@newsguy.com>
References: <1356728815-14410-1-git-send-email-mikedunn@newsguy.com>
Message-ID: <50E1613B.9040403@compulab.co.il>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 12/28/12 23:06, Mike Dunn wrote:
> This patch fixes some code that implements a work-around to a hardware bug in
> the ac97 controller on the pxa27x.  A bug in the controller's warm reset
> functionality requires that the mfp used by the controller as the AC97_RESET_n
> line be temporarily reconfigured as a generic output gpio (AF0) and manually
> held high for the duration of the warm reset cycle.  This is what was done in
> the original code, but it was broken long ago by commit
> fb1bf8cd13bfa7ed0364ab0d82f717fc020d35f6 
> ([ARM] pxa: introduce processor specific pxa27x_assert_ac97reset())
> which changed the mfp to a GPIO input instead of a high output.

Apparently, it is broken only on boards with no external pullups on these lines.

> 
> Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
> ---
>  arch/arm/mach-pxa/pxa27x.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c
> index 8047ee0..76221e4 100644
> --- a/arch/arm/mach-pxa/pxa27x.c
> +++ b/arch/arm/mach-pxa/pxa27x.c
> @@ -47,9 +47,9 @@ void pxa27x_clear_otgph(void)
>  EXPORT_SYMBOL(pxa27x_clear_otgph);
> 
>  static unsigned long ac97_reset_config[] = {
> -	GPIO113_GPIO,
> +	MFP_CFG_OUT(GPIO113, AF0, DRIVE_HIGH),
>  	GPIO113_AC97_nRESET,
> -	GPIO95_GPIO,
> +	MFP_CFG_OUT(GPIO95, AF0, DRIVE_HIGH),

It was always discouraged to code the above directly.
How about one of the below:
1)
GPIO113_GPIO | MFP_PULL_HIGH,
GPIO95_GPIO  | MFP_PULL_HIGH,

or

2) introduce something like:
GPIO113_AC97_nRESET_GPIO_HIGH
GPIO95_AC97_nRESET_GPIO_HIGH
in the mfp-pxa27x.h file and use them in the structure above.


>  	GPIO95_AC97_nRESET,
>  };
> 
> --
> 1.7.8.6
> 
> 
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> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

-- 
Regards,
Igor.