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authorMike Dunn <mikedunn@newsguy.com>2013-01-07 13:55:12 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-17 08:44:08 -0800
commite2abf662bcedc0be6f73e7575cc203a5e3c9262c (patch)
tree1414164fda1b2b8fa8745bf0f2bfb0ebdb5b7839 /sound/arm
parent639fd95292222bf03e1bb8616437b261321e1536 (diff)
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ALSA: pxa27x: fix ac97 cold reset
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound/arm')
-rw-r--r--sound/arm/pxa2xx-ac97-lib.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/sound/arm/pxa2xx-ac97-lib.c b/sound/arm/pxa2xx-ac97-lib.c
index 88eec38..05bdcb2 100644
--- a/sound/arm/pxa2xx-ac97-lib.c
+++ b/sound/arm/pxa2xx-ac97-lib.c
@@ -146,6 +146,8 @@ 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 */
@@ -155,8 +157,10 @@ 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