[RFC PATCH 2/7] ASoC: sunxi: sun4i-i2s: Use channel-dins device tree property

[John Watts]

Instead of using DIN pin 0 for all pins, allow changing this using
the device tree property.

As an example:

&i2s2 {
	channel-dins = /bits/ 8 <0 0 1 1 2 2>;
};

This sets channels 0 and 1 to DIN pin 0, channels 1 and 2 to DIN pin 1,
and channels 3 and 4 to DIN pin 3 respectively.

Signed-off-by: John Watts <contact@xxxxxxxxxx>
---
 sound/soc/sunxi/sun4i-i2s.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
index d8f999ecaf05..cf66f21646a4 100644
--- a/sound/soc/sunxi/sun4i-i2s.c
+++ b/sound/soc/sunxi/sun4i-i2s.c
@@ -236,8 +236,33 @@ struct sun4i_i2s_clk_div {
 
 static int sun4i_i2s_read_channel_dins(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 DIN pin 0 by default */
 	memset(i2s->channel_dins, 0, sizeof(i2s->channel_dins));
+
+	if (!np)
+		return 0;
+
+	ret = of_property_read_variable_u8_array(np, "channel-dins",
+						 i2s->channel_dins,
+						 1, max_channels);
+
+	if (ret == -EINVAL)
+		return 0;
+
+	if (ret < 0)
+		return ret;
+
+	for (int i = 0; i < ret; ++i) {
+		u8 din = i2s->channel_dins[i];
+
+		if (din >= i2s->variant->num_din_pins)
+			return -EINVAL;
+	}
+
 	return 0;
 }
 
-- 
2.41.0