ASoC: pcm512x: Support mastering BCLK/LRCLK using the PLL

Using the PLL in master mode requires using an external connection
between one of the GPIO pins (configured as PLL/4 output) and the
SCK pin. It also requires the external clock to be fed to some other
GPIO pin instead of the SCK pin.

This is described for the PCM5122 chip in the answers to the forum post
"PCM5122 DAC as I2S master troubles with PLL mode" at the TI E2E
community pages (1). The clocking functionality is also much better
described in the datasheet for the chip PCM5242, which seems to be
register compatible with PCM512x and PCM514x (which both have severely
lacking datasheets).

(1) http://e2e.ti.com/support/data_converters/audio_converters/f/64/t/267830

Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 23 insertions, 2 deletions

diff --git a/Documentation/devicetree/bindings/sound/pcm512x.txt b/Documentation/devicetree/bindings/sound/pcm512x.txt
index 98e0d34915e8..3aae3b41bd8e 100644
--- a/Documentation/devicetree/bindings/sound/pcm512x.txt
+++ b/Documentation/devicetree/bindings/sound/pcm512x.txt
@@ -17,9 +17,16 @@ Required properties:
 Optional properties:
 
   - clocks : A clock specifier for the clock connected as SCLK.  If this
-    is absent the device will be configured to clock from BCLK.
+    is absent the device will be configured to clock from BCLK.  If pll-in
+    and pll-out are specified in addition to a clock, the device is
+    configured to accept clock input on a specified gpio pin.
 
-Example:
+  - pll-in, pll-out : gpio pins used to connect the pll using <1>
+    through <6>.  The device will be configured for clock input on the
+    given pll-in pin and PLL output on the given pll-out pin.  An
+    external connection from the pll-out pin to the SCLK pin is assumed.
+
+Examples:
 
 	pcm5122: pcm5122@4c {
 		compatible = "ti,pcm5122";
@@ -29,3 +36,17 @@ Example:
 		DVDD-supply = <&reg_1v8>;
 		CPVDD-supply = <&reg_3v3>;
 	};
+
+
+	pcm5142: pcm5142@4c {
+		compatible = "ti,pcm5142";
+		reg = <0x4c>;
+
+		AVDD-supply = <&reg_3v3_analog>;
+		DVDD-supply = <&reg_1v8>;
+		CPVDD-supply = <&reg_3v3>;
+
+		clocks = <&sck>;
+		pll-in = <3>;
+		pll-out = <6>;
+	};