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Message-ID: <20230811201406.4096210-5-contact@jookia.org>
Date: Sat, 12 Aug 2023 06:14:03 +1000
From: John Watts <contact@...kia.org>
To: alsa-devel@...a-project.org
Cc: Liam Girdwood <lgirdwood@...il.com>,
Mark Brown <broonie@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>,
Chen-Yu Tsai <wens@...e.org>,
Jernej Skrabec <jernej.skrabec@...il.com>,
Samuel Holland <samuel@...lland.org>,
Jaroslav Kysela <perex@...ex.cz>,
Takashi Iwai <tiwai@...e.com>, John Watts <contact@...kia.org>,
Uwe Kleine-König
<u.kleine-koenig@...gutronix.de>,
Maxime Ripard <mripard@...nel.org>, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: [RFC PATCH 4/7] ASoC: sunxi: sun4i-i2s: Use channel-slots device tree property
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@...kia.org>
---
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
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