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| author | Mike Dunn <mikedunn@newsguy.com> | 2013-01-08 01:55:13 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-17 20:50:55 +0400 |
| commit | 1d757c9abbfb218c89d6b0586ff89b4032a3601d (patch) | |
| tree | 2fcdd14c67c2cf5994399db59fc0fb5a20c88197 /arch/arm/mach-pxa | |
| parent | b66c35dd91a7476f42134fb44250d24f68181c7b (diff) | |
| download | linux-1d757c9abbfb218c89d6b0586ff89b4032a3601d.tar.xz | |
ALSA: pxa27x: fix ac97 warm reset
commit 3b4bc7bccc7857274705b05cf81a0c72cfd0b0dd upstream.
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_nRESET
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 fb1bf8cd
([ARM] pxa: introduce processor specific pxa27x_assert_ac97reset())
which changed the mfp to a GPIO input instead of a high output.
The fix requires the ac97 controller to obtain the gpio via gpio_request_one(),
with arguments that configure the gpio as an output initially driven high.
Tested on a palm treo 680 machine. Reportedly, this broken code only prevents a
warm reset on hardware that lacks a pull-up on the line, which appears to be the
case for me.
Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm/mach-pxa')
| -rw-r--r-- | arch/arm/mach-pxa/include/mach/mfp-pxa27x.h | 3 | ||||
| -rw-r--r-- | 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 a65867209aa0..b4eb3daf037b 100644 --- a/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h +++ b/arch/arm/mach-pxa/include/mach/mfp-pxa27x.h @@ -462,6 +462,9 @@ 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, DEFAULT) +#define GPIO95_AC97_nRESET_GPIO_HIGH MFP_CFG_OUT(GPIO95, AF0, DEFAULT) 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 4726c246dcdc..a2fe795bae14 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, }; |