boards: arm: stm32h735g_disco: Enable ADC support

Enable ADC support for the stm32h735g_disco board in devicetree

Signed-off-by: Ben Marsh <ben.marsh@helvar.com>

boards/arm/stm32h735g_disco/doc/index.rst

@@ -63,6 +63,8 @@ The current Zephyr stm32h735g_disco board configuration supports the following h
 +-----------+------------+-------------------------------------+
 | FMC       | on-chip    | memc (SDRAM)                        |
 +-----------+------------+-------------------------------------+
+| ADC       | on-chip    | ADC Controller                      |
++-----------+------------+-------------------------------------+
 
 
 Other hardware features are not yet supported on Zephyr porting.

boards/arm/stm32h735g_disco/stm32h735g_disco.dts

@@ -106,6 +106,12 @@
 	status = "okay";
 };
 
+&adc1 {
+	pinctrl-0 = <&adc1_inp0_pa0_c>;
+	pinctrl-names = "default";
+	status = "okay";
+};
+
 &mac {
 	pinctrl-0 = <&eth_mdc_pc1
 		     &eth_rxd0_pc4

boards/arm/stm32h735g_disco/stm32h735g_disco.yaml

@@ -13,3 +13,4 @@ supported:
   - gpio
   - netif:eth
   - memc
+  - adc

samples/drivers/adc/boards/stm32h735g_disco.overlay

@@ -0,0 +1,24 @@
+/* Copyright (c) 2021 STMicroelectronics
+   SPDX-License-Identifier: Apache-2.0 */
+
+#include <zephyr/dt-bindings/adc/adc.h>
+
+ / {
+	zephyr,user {
+		/* adjust channel number according to pinmux in board.dts */
+		io-channels = <&adc1 0>;
+	};
+};
+
+&adc1 {
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	channel@0 {
+		reg = <0>;
+		zephyr,gain = "ADC_GAIN_1";
+		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
+		zephyr,resolution = <16>;
+	};
+};

samples/drivers/adc/sample.yaml

@@ -4,8 +4,8 @@ tests:
   sample.drivers.adc:
     tags: ADC
     depends_on: adc
-    platform_allow: nucleo_l073rz disco_l475_iot1 cc3220sf_launchxl
+    platform_allow: nucleo_l073rz disco_l475_iot1 cc3220sf_launchxl cc3235sf_launchxl
-        cc3235sf_launchxl stm32l496g_disco nrf51dk_nrf51422 nrf52840dk_nrf52840
+        stm32l496g_disco stm32h735g_disco nrf51dk_nrf51422 nrf52840dk_nrf52840
         mec172xevb_assy6906 gd32f350r_eval gd32f450i_eval gd32vf103v_eval gd32f403z_eval
         esp32 esp32s2_saola esp32c3_devkitm gd32l233r_eval
     integration_platforms:

tests/drivers/adc/adc_api/src/test_adc.c

@@ -239,6 +239,14 @@
 /* Some F3 series SOCs do not have channel 0 connected to an external GPIO. */
 #define ADC_1ST_CHANNEL_ID	1
 
+#elif defined(CONFIG_BOARD_STM32H735G_DISCO)
+#define ADC_DEVICE_NODE         DT_INST(0, st_stm32_adc)
+#define ADC_RESOLUTION		16
+#define ADC_GAIN		ADC_GAIN_1
+#define ADC_REFERENCE		ADC_REF_INTERNAL
+#define ADC_ACQUISITION_TIME	ADC_ACQ_TIME_DEFAULT
+#define ADC_1ST_CHANNEL_ID	0
+
 #elif defined(CONFIG_BOARD_NUCLEO_L476RG) || \
 	defined(CONFIG_BOARD_BLACKPILL_F411CE) || \
 	defined(CONFIG_BOARD_STM32F401_MINI) || \