[PATCH v2] ARM: pxa27x: fix ac97 controller warm reset code
Igor Grinberg
grinberg at compulab.co.il
Fri Jan 4 01:50:21 EST 2013
On 01/03/13 16:39, Mike Dunn wrote:
> Change log:
> v2: Heed Igor's admonishment to define a macro instead of using MFP_CFG_OUT
> directly. Thanks.
Usually, the change log is not useful after applying the patch, so
it should go below the scissors line ("---").
>
> 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.
>
> Signed-off-by: Mike Dunn <mikedunn at newsguy.com>
Thanks!
Acked-by: Igor Grinberg <grinberg at compulab.co.il>
> ---
> arch/arm/mach-pxa/include/mach/mfp-pxa27x.h | 3 +++
> arch/arm/mach-pxa/pxa27x.c | 4 ++--
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h b/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h
> index a611ad3..8281e17 100644
> --- a/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h
> +++ b/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h
> @@ -463,6 +463,9 @@
> GPIO76_LCD_PCLK, \
> GPIO77_LCD_BIAS
>
> +/* these enable a work-around for a hw bug in pxa27x during ac97 warm reset */
> +#define GPIO113_AC97_nRESET_GPIO_HIGH MFP_CFG_OUT(GPIO113, AF0, DRIVE_HIGH)
> +#define GPIO95_AC97_nRESET_GPIO_HIGH MFP_CFG_OUT(GPIO95, AF0, DRIVE_HIGH)
>
> extern int keypad_set_wake(unsigned int on);
> #endif /* __ASM_ARCH_MFP_PXA27X_H */
> diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c
> index 8047ee0..616cb87 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,
> + GPIO113_AC97_nRESET_GPIO_HIGH,
> GPIO113_AC97_nRESET,
> - GPIO95_GPIO,
> + GPIO95_AC97_nRESET_GPIO_HIGH,
> GPIO95_AC97_nRESET,
> };
>
--
Regards,
Igor.
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