diff options
| author | Daniel Mack <zonque@gmail.com> | 2012-12-10 10:30:04 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@opensource.wolfsonmicro.com> | 2012-12-24 16:53:28 +0100 |
| commit | fd23fb9f6bfd43a6e62b2646d18d5ca3edc3ebe3 (patch) | |
| tree | a1033cbc88a3ccba164e8d0f6c7469f9efd6713a /Documentation/devicetree | |
| parent | Merge branch 'asoc-fix-cs4271' into asoc-cs4271 (diff) | |
| download | linux-fd23fb9f6bfd43a6e62b2646d18d5ca3edc3ebe3.tar.xz linux-fd23fb9f6bfd43a6e62b2646d18d5ca3edc3ebe3.zip | |
ALSA: ASoC: cs4271: add optional soft reset workaround
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 patch adds a new flag to both the DT bindings as well as to the
platform data to enable that workaround.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Alexander Sverdlin <subaparts@yandex.ru>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Diffstat (limited to 'Documentation/devicetree')
| -rw-r--r-- | Documentation/devicetree/bindings/sound/cs4271.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/sound/cs4271.txt b/Documentation/devicetree/bindings/sound/cs4271.txt index a850fb9c88ea..e2cd1d7539e5 100644 --- 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: |