ASoC: codecs: Add RK3308 internal audio codec driver

Add driver for the internal audio codec of the Rockchip RK3308 SoC.

Initially based on the vendor kernel driver [0], with lots of cleanups,
fixes, improvements, conversion to DAPM and removal of some features.

[0] https://github.com/rockchip-linux/kernel/blob/develop-4.19/sound/soc/codecs/rk3308_codec.cSigned-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://msgid.link/r/20240305-rk3308-audio-codec-v4-4-312acdbe628f@bootlin.comSigned-off-by: Mark Brown <broonie@kernel.org>

MAINTAINERS

@@ -19050,6 +19050,8 @@ ROCKCHIP RK3308 INTERNAL AUDIO CODEC
 M:	Luca Ceresoli <luca.ceresoli@bootlin.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/sound/rockchip,rk3308-codec.yaml
+F:	sound/soc/codecs/rk3308_codec.c
+F:	sound/soc/codecs/rk3308_codec.h
 
 ROCKCHIP VIDEO DECODER DRIVER
 M:	Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>

sound/soc/codecs/Kconfig

@@ -180,6 +180,7 @@ config SND_SOC_ALL_CODECS
 	imply SND_SOC_PCM512x_I2C
 	imply SND_SOC_PCM512x_SPI
 	imply SND_SOC_PEB2466
+	imply SND_SOC_RK3308
 	imply SND_SOC_RK3328
 	imply SND_SOC_RK817
 	imply SND_SOC_RT274
@@ -1433,6 +1434,16 @@ config SND_SOC_PEB2466
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-soc-peb2466.
 
+config SND_SOC_RK3308
+	tristate "Rockchip RK3308 audio CODEC"
+	select REGMAP_MMIO
+	help
+	  This is a device driver for the audio codec embedded in the
+	  Rockchip RK3308 SoC.
+
+	  It has 8 24-bit ADCs and 2 24-bit DACs. The maximum supported
+	  sampling rate is 192 kHz.
+
 config SND_SOC_RK3328
 	tristate "Rockchip RK3328 audio CODEC"
 	select REGMAP_MMIO

sound/soc/codecs/Makefile

@@ -205,6 +205,7 @@ snd-soc-pcm512x-objs := pcm512x.o
 snd-soc-pcm512x-i2c-objs := pcm512x-i2c.o
 snd-soc-pcm512x-spi-objs := pcm512x-spi.o
 snd-soc-peb2466-objs := peb2466.o
+snd-soc-rk3308-objs := rk3308_codec.o
 snd-soc-rk3328-objs := rk3328_codec.o
 snd-soc-rk817-objs := rk817_codec.o
 snd-soc-rl6231-objs := rl6231.o
@@ -595,6 +596,7 @@ obj-$(CONFIG_SND_SOC_PCM512x)	+= snd-soc-pcm512x.o
 obj-$(CONFIG_SND_SOC_PCM512x_I2C)	+= snd-soc-pcm512x-i2c.o
 obj-$(CONFIG_SND_SOC_PCM512x_SPI)	+= snd-soc-pcm512x-spi.o
 obj-$(CONFIG_SND_SOC_PEB2466)	+= snd-soc-peb2466.o
+obj-$(CONFIG_SND_SOC_RK3308)	+= snd-soc-rk3308.o
 obj-$(CONFIG_SND_SOC_RK3328)	+= snd-soc-rk3328.o
 obj-$(CONFIG_SND_SOC_RK817)	+= snd-soc-rk817.o
 obj-$(CONFIG_SND_SOC_RL6231)	+= snd-soc-rl6231.o