[alsa-devel] [PATCH 1/4 v3] pxa2xx-i2s: Proper hw initialization
Karl Beldan
karl.beldan at gmail.com
Thu May 14 10:25:42 CEST 2009
Make sure we are in a know good state at end of probe :
Reset FIFO logic and registers, and make sure REC and RPL functions
along with FIFO service are disabled (SACR0_RST enables REC and RPL).
Resetting loses current settings so remove reset from stream startup.
Now reset occurs only at probe.
Signed-off-by: Karl Beldan <karl.beldan at mobile-devices.fr>
---
sound/soc/pxa/pxa2xx-i2s.c | 17 ++++++++++++++---
1 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/sound/soc/pxa/pxa2xx-i2s.c b/sound/soc/pxa/pxa2xx-i2s.c
index 2f4b6e4..59cc4f5 100644
--- a/sound/soc/pxa/pxa2xx-i2s.c
+++ b/sound/soc/pxa/pxa2xx-i2s.c
@@ -106,10 +106,8 @@ static int pxa2xx_i2s_startup(struct snd_pcm_substream
*substream,
if (IS_ERR(clk_i2s))
return PTR_ERR(clk_i2s);
- if (!cpu_dai->active) {
- SACR0 |= SACR0_RST;
+ if (!cpu_dai->active)
SACR0 = 0;
- }
return 0;
}
@@ -346,6 +344,19 @@ static int pxa2xx_i2s_probe(struct platform_device *dev)
if (ret != 0)
clk_put(clk_i2s);
+ /*
+ * PXA Developer's Manual:
+ * If SACR0[ENB] is toggled in the middle of a normal operation,
+ * the SACR0[RST] bit must also be set and cleared to reset all
+ * I2S controller registers.
+ */
+ SACR0 = SACR0_RST;
+ SACR0 = 0;
+ /* Make sure RPL and REC are disabled */
+ SACR1 = SACR1_DRPL | SACR1_DREC;
+ /* Along with FIFO servicing */
+ SAIMR &= ~(SAIMR_RFS | SAIMR_TFS);
+
return ret;
}
--
1.6.3.rc1.34.g0be9b
--
Karl
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