[PATCH v2] arm64: dts: imx8mp: Enable SAI audio on Data Modul i.MX8M Plus eDM SBC

[Marek Vasut]

Add SAI I2S and audio bindings to Data Modul i.MX8M Plus eDM SBC.

The SGTL5000 is attached to SAI3, however the SGTL5000 codec MCLK
must be supplied even if the SAI3 is not in use and is controlled
separately by the codec. The MCLK is also used to drive the codec
I2C block, so without MCLK, I2C access to the codec would not be
possible.

To provide such flexible MCLK control, use PWM4 with period 1 and
duty cycle 50% as 12 MHz clock source, as there is no direct way
to route MX8MP CCM clock to the MCLK pin. Use codec as bitclock
and frame clock master, so that the SGTL5000 PLL can be used to
generate derived clock.

Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Conor Dooley <conor+dt at kernel.org>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt at linaro.org>
Cc: NXP Linux Team <linux-imx at nxp.com>
Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
Cc: Rob Herring <robh+dt at kernel.org>
Cc: Sascha Hauer <s.hauer at pengutronix.de>
Cc: Shawn Guo <shawnguo at kernel.org>
Cc: devicetree at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
---
V2: Reorder DT properties
---
 .../freescale/imx8mp-data-modul-edm-sbc.dts   | 64 ++++++++++++++++++-
 1 file changed, 63 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mp-data-modul-edm-sbc.dts b/arch/arm64/boot/dts/freescale/imx8mp-data-modul-edm-sbc.dts
index 5828c9d7821de..ef36b7ec65ee1 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp-data-modul-edm-sbc.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mp-data-modul-edm-sbc.dts
@@ -45,6 +45,19 @@ clk_xtal25: clock-xtal25 {
 		clock-frequency = <25000000>;
 	};
 
+	clk_pwm4: clock-pwm4 {
+		compatible = "pwm-clock";
+		#clock-cells = <0>;
+		clock-frequency = <12000000>;
+		clock-output-names = "codec-pwm4";
+		/*
+		 * 1 / 83 ns ~= 12 MHz , but since the PWM input clock is 24 MHz
+		 * and the calculated PWM period is 1 and duty cycle is 50%, the
+		 * result is exactly 12 MHz, which is fine for SGTL5000 MCLK.
+		 */
+		pwms = <&pwm4 0 83 0>;
+	};
+
 	panel: panel {
 		/* Compatible string is filled in by panel board DT Overlay. */
 		backlight = <&backlight>;
@@ -82,6 +95,24 @@ reg_usdhc2_vmmc: regulator-usdhc2-vmmc {
 		vin-supply = <&buck4>;
 	};
 
+	sound {
+		compatible = "simple-audio-card";
+		simple-audio-card,name = "SGTL5000-Card";
+		simple-audio-card,format = "i2s";
+		simple-audio-card,bitclock-master = <&codec_dai>;
+		simple-audio-card,frame-master = <&codec_dai>;
+		simple-audio-card,widgets = "Headphone", "Headphone Jack";
+		simple-audio-card,routing = "Headphone Jack", "HP_OUT";
+
+		cpu_dai: simple-audio-card,cpu {
+			sound-dai = <&sai3>;
+		};
+
+		codec_dai: simple-audio-card,codec {
+			sound-dai = <&sgtl5000>;
+		};
+	};
+
 	watchdog { /* TPS3813 */
 		compatible = "linux,wdt-gpio";
 		pinctrl-names = "default";
@@ -288,6 +319,15 @@ &i2c1 {
 	sda-gpios = <&gpio5 15 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
 	status = "okay";
 
+	sgtl5000: audio-codec at a {
+		compatible = "fsl,sgtl5000";
+		reg = <0x0a>;
+		#sound-dai-cells = <0>;
+		clocks = <&clk_pwm4>;
+		VDDA-supply = <&buck4>;
+		VDDIO-supply = <&buck4>;
+	};
+
 	usb-hub at 2c {
 		compatible = "microchip,usb2514bi";
 		reg = <0x2c>;
@@ -436,6 +476,23 @@ &pwm1 {
 	status = "disabled";
 };
 
+&pwm4 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_pwm4>;
+	status = "okay";
+};
+
+&sai3 {
+	#clock-cells = <0>;
+	#sound-dai-cells = <0>;
+	assigned-clocks = <&clk IMX8MP_CLK_SAI3>;
+	assigned-clock-parents = <&clk IMX8MP_AUDIO_PLL1_OUT>;
+	assigned-clock-rates = <12288000>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_sai3>;
+	status = "okay";
+};
+
 /* SD slot */
 &usdhc2 {
 	pinctrl-names = "default", "state_100mhz", "state_200mhz";
@@ -785,6 +842,12 @@ MX8MP_IOMUXC_GPIO1_IO03__GPIO1_IO03		0x40000090
 		>;
 	};
 
+	pinctrl_pwm4: pwm4-grp {
+		fsl,pins = <
+			MX8MP_IOMUXC_SAI3_MCLK__PWM4_OUT		0xd6
+		>;
+	};
+
 	pinctrl_rtc: rtc-grp {
 		fsl,pins = <
 			/* RTC_IRQ# */
@@ -816,7 +879,6 @@ pinctrl_sai3: sai3-grp {
 			MX8MP_IOMUXC_SAI3_TXFS__AUDIOMIX_SAI3_TX_SYNC	0xd6
 			MX8MP_IOMUXC_SAI3_TXD__AUDIOMIX_SAI3_TX_DATA00	0xd6
 			MX8MP_IOMUXC_SAI3_TXC__AUDIOMIX_SAI3_TX_BCLK	0xd6
-			MX8MP_IOMUXC_SAI3_MCLK__AUDIOMIX_SAI3_MCLK	0xd6
 			MX8MP_IOMUXC_SAI3_RXD__AUDIOMIX_SAI3_RX_DATA00	0xd6
 		>;
 	};
-- 
2.43.0