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Commit 41b645c8 authored by Mike Dunn's avatar Mike Dunn Committed by Mark Brown
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ALSA: pxa27x: fix ac97 cold reset 



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: default avatarMike Dunn <mikedunn@newsguy.com>
Acked-by: default avatarIgor Grinberg <grinberg@compulab.co.il>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org
parent d1c3ed66

sound/arm/pxa2xx-ac97-lib.c

+6 −2
Original line number Diff line number Diff line
@@ -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