From: Marcus Cooper <codekipper@xxxxxxxxx> 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 <codekipper@xxxxxxxxx> --- 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 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel