ASoC: rockchip: add support for pdm controller

The Pulse Density Modulation Interface Controller (PDMC) is
a PDM interface controller and decoder that support PDM format.
It integrates a clock generator driving the PDM microphone
and embeds filters which decimate the incoming bit stream to
obtain most common audio rates.

Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 39 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/sound/rockchip,pdm.txt b/Documentation/devicetree/bindings/sound/rockchip,pdm.txt
new file mode 100644
index 000000000000..921729de7346
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/rockchip,pdm.txt
@@ -0,0 +1,39 @@
+* Rockchip PDM controller
+
+Required properties:
+
+- compatible: "rockchip,pdm"
+- reg: physical base address of the controller and length of memory mapped
+  region.
+- dmas: DMA specifiers for rx dma. See the DMA client binding,
+	Documentation/devicetree/bindings/dma/dma.txt
+- dma-names: should include "rx".
+- clocks: a list of phandle + clock-specifer pairs, one for each entry in clock-names.
+- clock-names: should contain following:
+   - "pdm_hclk": clock for PDM BUS
+   - "pdm_clk" : clock for PDM controller
+- pinctrl-names: Must contain a "default" entry.
+- pinctrl-N: One property must exist for each entry in
+	     pinctrl-names. See ../pinctrl/pinctrl-bindings.txt
+	     for details of the property values.
+
+Example for rk3328 PDM controller:
+
+pdm: pdm@ff040000 {
+	compatible = "rockchip,pdm";
+	reg = <0x0 0xff040000 0x0 0x1000>;
+	clocks = <&clk_pdm>, <&clk_gates28 0>;
+	clock-names = "pdm_clk", "pdm_hclk";
+	dmas = <&pdma 16>;
+	#dma-cells = <1>;
+	dma-names = "rx";
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&pdmm0_clk
+		     &pdmm0_fsync
+		     &pdmm0_sdi0
+		     &pdmm0_sdi1
+		     &pdmm0_sdi2
+		     &pdmm0_sdi3>;
+	pinctrl-1 = <&pdmm0_sleep>;
+	status = "disabled";
+};