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authorMisael Lopez Cruz <misael.lopez@ti.com>2015-06-08 16:03:47 +0300
committerMark Brown <broonie@kernel.org>2015-06-08 18:51:26 +0100
commit19db62ea0558d71844847cdf4c65a655df2ab69f (patch)
tree901b33c14404a775c414e4ee905063c4396afec1 /sound/soc/davinci
parent518f6bab13842a5f25bd8f89b1cae32aa8adf91f (diff)
ASoC: davinci-mcasp: Logic low for inactive output slots
The default state when serializers are in inactive slots is Hi-Z. In some cases, there are no additional components driving the data lines to a safe state so they might have noise. While in inactive slots, the McASP AXR pins configured as outputs can be driven low through the serializer pin drive mode setting (DISMOD) to prevent such noise. Signed-off-by: Misael Lopez Cruz <misael.lopez@ti.com> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'sound/soc/davinci')
-rw-r--r--sound/soc/davinci/davinci-mcasp.c2
-rw-r--r--sound/soc/davinci/davinci-mcasp.h5
2 files changed, 6 insertions, 1 deletions
diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
index 56da8ce1faf3..68356f2c78f8 100644
--- a/sound/soc/davinci/davinci-mcasp.c
+++ b/sound/soc/davinci/davinci-mcasp.c
@@ -686,6 +686,8 @@ static int mcasp_common_hw_param(struct davinci_mcasp *mcasp, int stream,
if (mcasp->serial_dir[i] == TX_MODE &&
tx_ser < max_active_serializers) {
mcasp_set_bits(mcasp, DAVINCI_MCASP_PDIR_REG, AXR(i));
+ mcasp_mod_bits(mcasp, DAVINCI_MCASP_XRSRCTL_REG(i),
+ DISMOD_LOW, DISMOD_MASK);
tx_ser++;
} else if (mcasp->serial_dir[i] == RX_MODE &&
rx_ser < max_active_serializers) {
diff --git a/sound/soc/davinci/davinci-mcasp.h b/sound/soc/davinci/davinci-mcasp.h
index 79dc511180bf..a3be108a8c17 100644
--- a/sound/soc/davinci/davinci-mcasp.h
+++ b/sound/soc/davinci/davinci-mcasp.h
@@ -215,7 +215,10 @@
* DAVINCI_MCASP_XRSRCTL_BASE_REG - Serializer Control Register Bits
*/
#define MODE(val) (val)
-#define DISMOD (val)(val<<2)
+#define DISMOD_3STATE (0x0)
+#define DISMOD_LOW (0x2 << 2)
+#define DISMOD_HIGH (0x3 << 2)
+#define DISMOD_MASK DISMOD_HIGH
#define TXSTATE BIT(4)
#define RXSTATE BIT(5)
#define SRMOD_MASK 3