[RFC PATCH 4/7] ASoC: sunxi: sun4i-i2s: Use channel-slots device tree property
flat view
STALE1141d
From: John Watts <hidden>
Date: 2023-08-11 20:14:59
Also in:
alsa-devel, linux-arm-kernel, linux-sunxi, lkml
Subsystem:
sound, sound - soc layer / dynamic audio power management (asoc), the rest · Maintainers:
Jaroslav Kysela, Takashi Iwai, Liam Girdwood, Mark Brown, Linus Torvalds
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 <redacted>
---
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