arm64: dts: allwinner: pinephone: Add support for Bluetooth audio

The PinePhone has a Bluetooth chip with its PCM interface connected to
AIF3. Add the DAI link so headeset audio can be routed in hardware.

Even though the link is 16 bit PCM, configuring the link a 32-bit slot
is required for compatibility with AIF2, which also uses a 32-bit slot,
and which shares clock dividers with AIF3. Using equal clock frequencies
allows the modem and headset to be used at the same time.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210430035859.3487-7-samuel@sholland.org

arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi

@@ -25,6 +25,11 @@ backlight: backlight {
 		/* Backlight configuration differs per PinePhone revision. */
 	};
 
+	bt_sco_codec: bt-sco-codec {
+		#sound-dai-cells = <1>;
+		compatible = "linux,bt-sco";
+	};
+
 	chosen {
 		stdout-path = "serial0:115200n8";
 	};
@@ -91,6 +96,8 @@ vibrator {
 };
 
 &codec {
+	pinctrl-names = "default";
+	pinctrl-0 = <&aif3_pins>;
 	status = "okay";
 };
 
@@ -447,6 +454,23 @@ &sound {
 			"MIC1", "Internal Microphone",
 			"Headset Microphone", "HBIAS",
 			"MIC2", "Headset Microphone";
+
+	simple-audio-card,dai-link@2 {
+		format = "dsp_a";
+		frame-master = <&link2_codec>;
+		bitclock-master = <&link2_codec>;
+		bitclock-inversion;
+
+		link2_cpu: cpu {
+			sound-dai = <&bt_sco_codec 0>;
+		};
+
+		link2_codec: codec {
+			sound-dai = <&codec 2>;
+			dai-tdm-slot-num = <1>;
+			dai-tdm-slot-width = <32>;
+		};
+	};
 };
 
 &uart0 {