boards: mimxrt1020_evk: Enable ADC on RT1020 EVK

Enables ADC1 on the RT1020 evaluation board. Channels 10 and 11 of this
ADC are exposed as pins 1 and 2 of J18 on the evk.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>

boards/arm/mimxrt1020_evk/doc/index.rst

@@ -90,6 +90,8 @@ features:
 +-----------+------------+-------------------------------------+
 | USB       | on-chip    | USB device                          |
 +-----------+------------+-------------------------------------+
+| ADC       | on-chip    | adc                                 |
++-----------+------------+-------------------------------------+
 
 The default configuration can be found in the defconfig file:
 ``boards/arm/mimxrt1020_evk/mimxrt1020_evk_defconfig``
@@ -164,6 +166,10 @@ The MIMXRT1020 SoC has five pairs of pinmux/gpio controllers.
 +---------------+-----------------+---------------------------+
 | GPIO_SD_B0_06 | USDHC1_CD_B     | SD Card                   |
 +---------------+-----------------+---------------------------+
+| GPIO_AD_B1_10 | ADC             | ADC1 Channel 10           |
++---------------+-----------------+---------------------------+
+| GPIO_AD_B1_11 | ADC             | ADC1 Channel 11           |
++---------------+-----------------+---------------------------+
 
 System Clock
 ============

boards/arm/mimxrt1020_evk/mimxrt1020_evk.dts

@@ -158,3 +158,7 @@ zephyr_udc0: &usb1 {
 	cd-gpios = <&gpio1 23 GPIO_ACTIVE_LOW>;
 	no-1-8-v;
 };
+
+&adc1 {
+	status = "okay";
+};

boards/arm/mimxrt1020_evk/mimxrt1020_evk.yaml

@@ -23,3 +23,4 @@ supported:
   - netif:eth
   - spi
   - usb_device
+  - adc

boards/arm/mimxrt1020_evk/pinmux.c

@@ -262,6 +262,21 @@ static int mimxrt1020_evk_init(const struct device *dev)
 	imxrt_usdhc_pinmux_cb_register(mimxrt1020_evk_usdhc_pinmux);
 #endif
 
+#if DT_NODE_HAS_STATUS(DT_NODELABEL(adc1), okay) && CONFIG_ADC
+	/* ADC1 Channel 10 and 11 are on pins 1 and 2 of J18 */
+	/* ADC1 Channel 10 */
+	IOMUXC_SetPinMux(IOMUXC_GPIO_AD_B1_10_GPIO1_IO26, 0U);
+	/* ADC1 Channel 11 */
+	IOMUXC_SetPinMux(IOMUXC_GPIO_AD_B1_11_GPIO1_IO27, 0U);
+
+	IOMUXC_SetPinConfig(IOMUXC_GPIO_AD_B1_10_GPIO1_IO26,
+			IOMUXC_SW_PAD_CTL_PAD_SPEED(2) |
+			IOMUXC_SW_PAD_CTL_PAD_DSE(6));
+	IOMUXC_SetPinConfig(IOMUXC_GPIO_AD_B1_11_GPIO1_IO27,
+			IOMUXC_SW_PAD_CTL_PAD_SPEED(2) |
+			IOMUXC_SW_PAD_CTL_PAD_DSE(6));
+#endif
+
 	return 0;
 }
 

samples/drivers/adc/boards/mimxrt1020_evk.overlay

@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2021 NXP
+ */
+
+/ {
+	zephyr,user {
+		/* adjust channel number according to pinmux in board.dts */
+		io-channels = <&adc1 10>;
+	};
+};

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

@@ -301,7 +301,8 @@
 	defined(CONFIG_BOARD_MIMXRT1060_EVK) || \
 	defined(CONFIG_BOARD_MIMXRT1024_EVK) || \
 	defined(CONFIG_BOARD_MIMXRT1010_EVK) || \
-	defined(CONFIG_BOARD_MIMXRT1015_EVK)
+	defined(CONFIG_BOARD_MIMXRT1015_EVK) || \
+	defined(CONFIG_BOARD_MIMXRT1020_EVK)
 #define ADC_DEVICE_NAME		DT_LABEL(DT_INST(0, nxp_mcux_12b1msps_sar))
 #define ADC_RESOLUTION		12
 #define ADC_GAIN		ADC_GAIN_1