[PATCH 1/2] arm64: dts: imx8mp-beacon-kit: Move sai3 to Audio_PLL1

[Adam Ford]

The Beacon board has an LVDS display that cannot get a proper clock rate
from Video_PLL if the DSI is operational due to the way the clock divides
the pixel clocks from video_pll.  To make the LVDS work, the LVDS needs
to use an alternative clock.

Because the clock rated needed for the LDB driving the LVDS display
isn't divisible by the clock rate needed by SAI3, move SAI3 to use
Audio_PLL1, and reconfigure the CODEC to use a 12MHz fixed clock.

Because these clocks are no longer in sync with each other, the sound
generated as the wrong pitch, so reconfigure the SAI3 to be the master
since the CODEC can internally compensate when fed a fixed clock
reference, even if it is not an even multiple of the desired rate.

This now leaves AUDIO_PLL2 completely free for the LDB without
compromising the audio sound from the codec.

Signed-off-by: Adam Ford <aford173 at gmail.com>

diff --git a/arch/arm64/boot/dts/freescale/imx8mp-beacon-kit.dts b/arch/arm64/boot/dts/freescale/imx8mp-beacon-kit.dts
index a08057410bde..1f827ef38e36 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp-beacon-kit.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mp-beacon-kit.dts
@@ -211,20 +211,20 @@ sound-wm8962 {
 
 		simple-audio-card,cpu {
 			sound-dai = <&sai3>;
+			frame-master;
+			bitclock-master;
 		};
 
 		simple-audio-card,codec {
 			sound-dai = <&wm8962>;
 			clocks = <&clk IMX8MP_CLK_IPP_DO_CLKO1>;
-			frame-master;
-			bitclock-master;
 		};
 	};
 };
 
 &audio_blk_ctrl {
-	assigned-clocks = <&clk IMX8MP_AUDIO_PLL1>, <&clk IMX8MP_AUDIO_PLL2>;
-	assigned-clock-rates = <393216000>, <135475200>;
+	assigned-clocks = <&clk IMX8MP_AUDIO_PLL1>;
+	assigned-clock-rates = <393216000>;
 };
 
 &ecspi2 {
@@ -370,8 +370,8 @@ wm8962: audio-codec at 1a {
 		pinctrl-0 = <&pinctrl_wm8962>;
 		clocks = <&clk IMX8MP_CLK_IPP_DO_CLKO1>;
 		assigned-clocks = <&clk IMX8MP_CLK_IPP_DO_CLKO1>;
-		assigned-clock-parents = <&clk IMX8MP_AUDIO_PLL2_OUT>;
-		assigned-clock-rates = <22576000>;
+		assigned-clock-parents = <&clk IMX8MP_CLK_24M>;
+		assigned-clock-rates = <12000000>;
 		DCVDD-supply = <&reg_audio>;
 		DBVDD-supply = <&reg_audio>;
 		AVDD-supply = <&reg_audio>;
@@ -499,10 +499,9 @@ &pcie_phy {
 &sai3 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_sai3>;
-	assigned-clocks = <&clk IMX8MP_CLK_SAI3>,
-			  <&clk IMX8MP_AUDIO_PLL2> ;
-	assigned-clock-parents = <&clk IMX8MP_AUDIO_PLL2_OUT>;
-	assigned-clock-rates = <12288000>, <361267200>;
+	assigned-clocks = <&clk IMX8MP_CLK_SAI3>;
+	assigned-clock-parents = <&clk IMX8MP_AUDIO_PLL1_OUT>;
+	assigned-clock-rates = <12288000>;
 	fsl,sai-mclk-direction-output;
 	status = "okay";
 };
-- 
2.43.0