sound: soc: rp1: First rough, somewhat working version. WIP.

Despite the name this is not an ASOC driver but an ALSA PCM one.
It probably should be rewritten/ported to the ASOC framework!
It only supports 48000Hz and lacks mmap() amongst other things.

Author: njhollinghurst

arch/arm64/configs/bcm2712_defconfig

@@ -1148,6 +1148,7 @@ CONFIG_SND_PISOUND=m
 CONFIG_SND_DACBERRY400=m
 CONFIG_SND_DESIGNWARE_I2S=m
 CONFIG_SND_DESIGNWARE_PCM=y
+CONFIG_SND_RP1_AUDIO_OUT=m
 CONFIG_SND_SOC_AD193X_SPI=m
 CONFIG_SND_SOC_AD193X_I2C=m
 CONFIG_SND_SOC_ADAU1701=m

sound/soc/Kconfig

@@ -107,6 +107,7 @@ source "sound/soc/mxs/Kconfig"
 source "sound/soc/pxa/Kconfig"
 source "sound/soc/qcom/Kconfig"
 source "sound/soc/rockchip/Kconfig"
+source "sound/soc/rp1/Kconfig"
 source "sound/soc/samsung/Kconfig"
 source "sound/soc/sh/Kconfig"
 source "sound/soc/sof/Kconfig"

sound/soc/Makefile

@@ -60,6 +60,7 @@ obj-$(CONFIG_SND_SOC)	+= kirkwood/
 obj-$(CONFIG_SND_SOC)	+= pxa/
 obj-$(CONFIG_SND_SOC)	+= qcom/
 obj-$(CONFIG_SND_SOC)	+= rockchip/
+obj-$(CONFIG_SND_SOC)   += rp1/
 obj-$(CONFIG_SND_SOC)	+= samsung/
 obj-$(CONFIG_SND_SOC)	+= sh/
 obj-$(CONFIG_SND_SOC)	+= sof/

sound/soc/rp1/Kconfig

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SND_RP1_AUDIO_OUT
+	tristate "PWM Audio Out from RP1"
+	help
+	 Say Y or M if you want to add support for digital audio
+	 output from Raspberry Pi 5.
+

sound/soc/rp1/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_SND_RP1_AUDIO_OUT) += rp1-aout.o