| From | Herton Ronaldo Krzesinski <> | Subject | [PATCH 34/74] ALSA: pxa27x: fix ac97 cold reset | Date | Thu, 24 Jan 2013 01:26:46 -0200 |
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3.5.7.4 -stable review patch. If anyone has any objections, please let me know.
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From: Mike Dunn <mikedunn@newsguy.com>
commit 41b645c8624df6ace020a8863ad1449d69140f7d upstream.
Cold reset on the pxa27x currently fails and
pxa2xx_ac97_try_cold_reset: cold reset timeout (GSR=0x44)
appears in the kernel log. Through trial-and-error (the pxa270 developer's manual is mostly incoherent on the topic of ac97 reset), I got cold reset to complete by setting the WARM_RST bit in the GCR register (and later noticed that pxa3xx does this for cold reset as well). Also, a timeout loop is needed to wait for the reset to complete.
Tested on a palm treo 680 machine.
Signed-off-by: Mike Dunn <mikedunn@newsguy.com> Acked-by: Igor Grinberg <grinberg@compulab.co.il> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- sound/arm/pxa2xx-ac97-lib.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/sound/arm/pxa2xx-ac97-lib.c b/sound/arm/pxa2xx-ac97-lib.c index 48d7c0a..8cfb2c0 100644 --- a/sound/arm/pxa2xx-ac97-lib.c +++ b/sound/arm/pxa2xx-ac97-lib.c @@ -148,6 +148,8 @@ static inline void pxa_ac97_warm_pxa27x(void) static inline void pxa_ac97_cold_pxa27x(void) { + unsigned int timeout; + GCR &= GCR_COLD_RST; /* clear everything but nCRST */ GCR &= ~GCR_COLD_RST; /* then assert nCRST */ @@ -157,8 +159,10 @@ static inline void pxa_ac97_cold_pxa27x(void) clk_enable(ac97conf_clk); udelay(5); clk_disable(ac97conf_clk); - GCR = GCR_COLD_RST; - udelay(50); + GCR = GCR_COLD_RST | GCR_WARM_RST; + timeout = 100; /* wait for the codec-ready bit to be set */ + while (!((GSR | gsr_bits) & (GSR_PCR | GSR_SCR)) && timeout--) + mdelay(1); } #endif -- 1.7.9.5
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