linux/Documentation/devicetree/bindings/sound/pcm512x.txt
Peter Rosin f086ba9d53 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>
2015-01-28 19:28:53 +00:00

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PCM512x audio CODECs
These devices support both I2C and SPI (configured with pin strapping
on the board).
Required properties:
- compatible : One of "ti,pcm5121", "ti,pcm5122", "ti,pcm5141" or
"ti,pcm5142"
- reg : the I2C address of the device for I2C, the chip select
number for SPI.
- AVDD-supply, DVDD-supply, and CPVDD-supply : power supplies for the
device, as covered in bindings/regulator/regulator.txt
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. 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.
- 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";
reg = <0x4c>;
AVDD-supply = <&reg_3v3_analog>;
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>;
};