From: Marcus Cooper <codekip...@gmail.com>
The DAI has a loopback register which can be set and therefore routes
the transmit fifo to receive fifo. This is useful for testing the block
without the need for any external hardware.
Signed-off-by: Marcus Cooper <codekip...@gmail.com>
---
Documentation/devicetree/bindings/sound/sun4i-i2s.txt | 3 +++
sound/soc/sunxi/sun4i-i2s.c | 11 +++++++++++
2 files changed, 14 insertions(+)
diff --git a/Documentation/devicetree/bindings/sound/sun4i-i2s.txt
b/Documentation/devicetree/bindings/sound/sun4i-i2s.txt
index 3f966ac61b9e..325e3d4571f1 100644
--- a/Documentation/devicetree/bindings/sound/sun4i-i2s.txt
+++ b/Documentation/devicetree/bindings/sound/sun4i-i2s.txt
@@ -32,6 +32,9 @@ Optional properties:
- allwinner,slot-width-override:if this property is present then the dai is
configured to extend the slot width to the
value specified. Min 8, Max 32.
+- loopback: if this property is present then the dai is configured in
+ loopback mode where the output fifo is redirected to the input
+ fifo.
- allwinner,playback-channels: if this property is present then the number
of available channels is extended and the
diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
index 7cf4dfe440de..a3c33814d33e 100644
--- a/sound/soc/sunxi/sun4i-i2s.c
+++ b/sound/soc/sunxi/sun4i-i2s.c
@@ -31,6 +31,7 @@
#define SUN4I_I2S_CTRL_MODE_MASK BIT(5)
#define SUN4I_I2S_CTRL_MODE_SLAVE (1 << 5)
#define SUN4I_I2S_CTRL_MODE_MASTER (0 << 5)
+#define SUN4I_I2S_CTRL_LOOP BIT(3)
#define SUN4I_I2S_CTRL_TX_EN BIT(2)
#define SUN4I_I2S_CTRL_RX_EN BIT(1)
#define SUN4I_I2S_CTRL_GL_EN BIT(0)
@@ -195,6 +196,8 @@ struct sun4i_i2s {
const struct sun4i_i2s_quirks *variant;
+ bool loopback;
+
unsigned int slot_width;
};
@@ -639,6 +642,11 @@ static void sun4i_i2s_start_capture(struct sun4i_i2s *i2s)
regmap_update_bits(i2s->regmap, SUN4I_I2S_DMA_INT_CTRL_REG,
SUN4I_I2S_DMA_INT_CTRL_RX_DRQ_EN,
SUN4I_I2S_DMA_INT_CTRL_RX_DRQ_EN);
+
+ /* Debugging without codec */
+ if (i2s->loopback)
+ regmap_update_bits(i2s->regmap, SUN4I_I2S_CTRL_REG,
+ SUN4I_I2S_CTRL_LOOP, SUN4I_I2S_CTRL_LOOP);
}
static void sun4i_i2s_start_playback(struct sun4i_i2s *i2s)
@@ -1204,6 +1212,9 @@ static int sun4i_i2s_probe(struct platform_device *pdev)
soc_dai->playback.channels_max = val;
}
+ if (of_property_read_bool(pdev->dev.of_node, "loopback"))
+ i2s->loopback = true;
+
pm_runtime_enable(&pdev->dev);
if (!pm_runtime_enabled(&pdev->dev)) {
ret = sun4i_i2s_runtime_resume(&pdev->dev);
--
2.16.2
--
You received this message because you are subscribed to the Google Groups
"linux-sunxi" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to linux-sunxi+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
