ALSA: ASoC: cs4271: add optional soft reset workaround

[karo-tx-linux.git] / Documentation / devicetree / bindings / sound / cs4271.txt

diff --git a/Documentation/devicetree/bindings/sound/cs4271.txt b/Documentation/devicetree/bindings/sound/cs4271.txt
index a850fb9c88eab2156ec89f0c76d8ca59073540f8..e2cd1d7539e527897cc34566508ed56f070a60cb 100644 (file)
--- a/Documentation/devicetree/bindings/sound/cs4271.txt
+++ b/Documentation/devicetree/bindings/sound/cs4271.txt
@@ -20,6 +20,18 @@ Optional properties:
                !RESET pin
  - cirrus,amuteb-eq-bmutec:    When given, the Codec's AMUTEB=BMUTEC flag
                                is enabled.
+ - cirrus,enable-soft-reset:
+       The CS4271 requires its LRCLK and MCLK to be stable before its RESET
+       line is de-asserted. That also means that clocks cannot be changed
+       without putting the chip back into hardware reset, which also requires
+       a complete re-initialization of all registers.
+
+       One (undocumented) workaround is to assert and de-assert the PDN bit
+       in the MODE2 register. This workaround can be enabled with this DT
+       property.
+
+       Note that this is not needed in case the clocks are stable
+       throughout the entire runtime of the codec.
 
 Examples: