On R329 I2S variants with multiple pins it's useful to read from
multiple devices within a single TDM slot. Allow changing the
assignment of slots through a device tree property.
As an example:
&i2s2 {
channel-dins = /bits/ 8 <0 0 1 1 2 2>;
channel-slots = /bits/ 8 <0 1 0 1 0 1>;
};
In addition to configuring the first 6 channels to use different
DIN pins for three separate ADCs, the addition of channel-slots allows
all three ADCs to be sampled within the first two TDM slots.
Signed-off-by: John Watts <contact@xxxxxxxxxx>
---
sound/soc/sunxi/sun4i-i2s.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
index 627bf319e1cc..019a4856c90b 100644
--- a/sound/soc/sunxi/sun4i-i2s.c
+++ b/sound/soc/sunxi/sun4i-i2s.c
@@ -269,12 +269,27 @@ static int sun4i_i2s_read_channel_dins(struct device *dev, struct sun4i_i2s *i2s
static int sun4i_i2s_read_channel_slots(struct device *dev, struct sun4i_i2s *i2s)
{
+ struct device_node *np = dev->of_node;
int max_channels = ARRAY_SIZE(i2s->channel_dins);
+ int ret;
/* Use a 1:1 mapping by default */
for (int i = 0; i < max_channels; ++i)
i2s->channel_slots[i] = i;
+ if (!np)
+ return 0;
+
+ ret = of_property_read_variable_u8_array(np, "channel-slots",
+ i2s->channel_slots,
+ 1, max_channels);
+
+ if (ret == -EINVAL)
+ return 0;
+
+ if (ret < 0)
+ return ret;
+
return 0;
}
--
2.41.0
