sonomkr-card-driver

how to add driver to rpi kernel source :

1. add the device tree overlay source file :

arch/arm/boot/dts/overlays/sonomkr-card-overlay.dts

2. add the resulting dtbo to the Makefile :

arch/arm/boot/dts/overlays/Makefile

• add the following line (for 4.9 kernel) :

sonomkr-card.dtbo \

• or the following line (for 4.4 kernel) :

dtbo-$(RPI_DT_OVERLAYS) += sonomkr-card.dtbo

3. add sonomkr as a vendor in :

Documentation/devicetree/bindings/vendor-prefixes.txt

• add the following line :

sonomkr        SonoMKR Project Team

4. add the new bcm sound driver :

sound/soc/bcm/sonomkr-card.c

5. add the resulting .o file to the Makefile :

sound/soc/bcm/Makefile

• add these two lines at the right place :

snd-soc-sonomkr-card-objs := sonomkr-card.o

obj-$(CONFIG_SND_SONOMKR_CARD) += snd-soc-sonomkr-card.o

6. add the associated config element in Kconfig :

sound/soc/bcm/Kconfig

• add the following lines:

config SND_SONOMKR_CARD
	tristate "Support for the SonoMKR Audio Card"
	depends on SND_BCM2708_SOC_I2S || SND_BCM2835_SOC_I2S
	select SND_SOC_WM8782
	help
	  Say Y or M if you want to add support for SonoMKR Audio Card.

7. edit both bcm2709 and bcmrpi defconfig :

arch/arm/configs/bcm2709_defconfig

arch/arm/configs/bcmrpi_defconfig

• add the following line to both files

CONFIG_SND_SONOMKR_CARD=m