iio: adc: Add driver for Renesas RZ/G2L A/D converter

Add ADC driver support for Renesas RZ/G2L A/D converter in SW
trigger mode.

A/D Converter block is a successive approximation analog-to-digital
converter with a 12-bit accuracy and supports a maximum of 8 input
channels.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210804202118.25745-3-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -15856,6 +15856,14 @@ L:	linux-renesas-soc@vger.kernel.org
 S:	Maintained
 F:	drivers/phy/renesas/phy-rcar-gen3-usb*.c
 
+RENESAS RZ/G2L A/D DRIVER
+M:	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
+L:	linux-iio@vger.kernel.org
+L:	linux-renesas-soc@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/iio/adc/renesas,rzg2l-adc.yaml
+F:	drivers/iio/adc/rzg2l_adc.c
+
 RESET CONTROLLER FRAMEWORK
 M:	Philipp Zabel <p.zabel@pengutronix.de>
 S:	Maintained

drivers/iio/adc/Kconfig

@@ -887,6 +887,16 @@ config ROCKCHIP_SARADC
 	  To compile this driver as a module, choose M here: the
 	  module will be called rockchip_saradc.
 
+config RZG2L_ADC
+	tristate "Renesas RZ/G2L ADC driver"
+	depends on ARCH_R9A07G044 || COMPILE_TEST
+	help
+	  Say yes here to build support for the ADC found in Renesas
+	  RZ/G2L family.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rzg2l_adc.
+
 config SC27XX_ADC
 	tristate "Spreadtrum SC27xx series PMICs ADC"
 	depends on MFD_SC27XX_PMIC || COMPILE_TEST

drivers/iio/adc/Makefile

@@ -82,6 +82,7 @@ obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
 obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
 obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
 obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
 obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
 obj-$(CONFIG_STX104) += stx104.o