Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / Documentation / devicetree / bindings / sound / cs4271.txt

diff --git a/kernel/Documentation/devicetree/bindings/sound/cs4271.txt b/kernel/Documentation/devicetree/bindings/sound/cs4271.txt
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+Cirrus Logic CS4271 DT bindings
+
+This driver supports both the I2C and the SPI bus.
+
+Required properties:
+
+ - compatible: "cirrus,cs4271"
+
+For required properties on SPI, please consult
+Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Required properties on I2C:
+
+ - reg: the i2c address
+
+
+Optional properties:
+
+ - reset-gpio:         a GPIO spec to define which pin is connected to the chip's
+               !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:
+
+       codec_i2c: cs4271@10 {
+               compatible = "cirrus,cs4271";
+               reg = <0x10>;
+               reset-gpio = <&gpio 23 0>;
+       };
+
+       codec_spi: cs4271@0 {
+               compatible = "cirrus,cs4271";
+               reg = <0x0>;
+               reset-gpio = <&gpio 23 0>;
+               spi-max-frequency = <6000000>;
+       };
+