WIP tests/drivers/gpio: generalize gpio specification solution

Provide board-specific overlays that specify which pins to use for the
test, rather than use aliases in the board device tree.  This uses a
binding that's specifically documented for use in GPIO applications.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>

dts/bindings/misc/test,scope-pins.yaml

@@ -0,0 +1,29 @@
+#
+# Copyright (c) 2019 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+title: GPIO pin definitions for tests
+
+description: >
+    Identify accessible board pins that can be used for GPIO signals.
+
+    Most development boards expose several GPIO pins on a header.  These
+    may be used as signals to a logic analyzer, or to simulate an
+    external device.  This binding provides a board-independent
+    description of pins that can be made available for this purpose.
+
+compatible: "test,scope-pins"
+
+properties:
+    gpios:
+        type: compound
+        required: true
+        description: >
+          Accessible pins used for GPIO-based instrumentation and
+          testing.
+
+          Any number of pins may be provided, on multiple GPIO devices.
+          However at least two entries must be present, and the first
+          two must be on the same GPIO device.

tests/drivers/gpio/gpio_basic_api/efr32mg_sltb004a.overlay

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2019 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	scope-pins {
+		compatible = "test,scope-pins";
+		gpios = <&gpiof 6 0>, <&gpiof 5 0>;
+	};
+};

tests/drivers/gpio/gpio_basic_api/frdm_k64f.overlay

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2019 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	scope-pins {
+		compatible = "test,scope-pins";
+		gpios =
+			<&gpioc 16 0>, <&gpioc 17 0>,
+			<&gpioc 2 0>, <&gpioc 3 0>,
+			<&gpioc 1 0>, <&gpioc 8 0>,
+			<&gpioc 9 0>, <&gpioc 0 0>,
+			<&gpioc 7 0>, <&gpioc 5 0>;
+
+	};
+};

tests/drivers/gpio/gpio_basic_api/nrf52840_pca10056.overlay

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2019 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	scope-pins {
+		compatible = "test,scope-pins";
+		/* Use pins on P3 (Arduino D0) header. */
+		gpios =
+			<&gpio1 1 0>, <&gpio1 2 0>,
+			<&gpio1 3 0>, <&gpio1 4 0>,
+			<&gpio1 5 0>, <&gpio1 6 0>,
+			<&gpio1 7 0>, <&gpio1 8 0>;
+	};
+};

tests/drivers/gpio/gpio_basic_api/prj.conf

@@ -2,3 +2,4 @@ CONFIG_GPIO=y
 CONFIG_ZTEST=y
 CONFIG_ENTROPY_GENERATOR=y
 CONFIG_TEST_RANDOM_GENERATOR=y
+#CONFIG_TEST_USERSPACE=y

tests/drivers/gpio/gpio_basic_api/src/main.c

@@ -7,8 +7,29 @@
 
 #include "test_gpio.h"
 
+/* Grotesque hack for pinmux boards */
+#ifdef CONFIG_BOARD_FRDM_K64F
+#include <drivers/pinmux.h>
+#include <fsl_port.h>
+#endif
+
+static void board_setup(void)
+{
+#ifdef CONFIG_BOARD_FRDM_K64F
+	printk("Setting up pinmux for K64F\n");
+	const char *pmx_name = "portc";
+	struct device *pmx = device_get_binding(pmx_name);
+	printk("pmx %s for %s: %p\n", pmx_name, DEV_NAME, pmx);
+	int rc = pinmux_pin_set(pmx, PIN_OUT, PORT_PCR_MUX(kPORT_MuxAsGpio));
+	printk("pmx pin %u: %d\n", PIN_OUT, rc);
+	rc = pinmux_pin_set(pmx, PIN_IN, PORT_PCR_MUX(kPORT_MuxAsGpio));
+	printk("pmx pin %u: %d\n", PIN_IN, rc);
+#endif
+}
+
 void test_main(void)
 {
+	board_setup();
 	ztest_test_suite(gpio_basic_test,
 			 ztest_unit_test(test_gpio_port),
 			 ztest_unit_test(test_gpio_pin_read_write),

tests/drivers/gpio/gpio_basic_api/src/test_gpio.h

@@ -12,7 +12,11 @@
 #include <sys/util.h>
 #include <ztest.h>
 
-#if defined(DT_ALIAS_GPIO_0_LABEL)
+#ifdef DT_INST_0_TEST_SCOPE_PINS
+#define DEV_NAME DT_INST_0_TEST_SCOPE_PINS_GPIOS_CONTROLLER_0
+#define PIN_OUT DT_TEST_SCOPE_PINS_SCOPE_PINS_GPIOS_PIN_0
+#define PIN_IN DT_TEST_SCOPE_PINS_SCOPE_PINS_GPIOS_PIN_1
+#elif defined(DT_ALIAS_GPIO_0_LABEL)
 #define DEV_NAME DT_ALIAS_GPIO_0_LABEL
 #elif defined(DT_ALIAS_GPIO_1_LABEL)
 #define DEV_NAME DT_ALIAS_GPIO_1_LABEL
@@ -22,9 +26,10 @@
 #error Unsupported board
 #endif
 
+#ifndef PIN_OUT
 #define PIN_OUT 2
 #define PIN_IN 3
-
+#endif /* PIN_OUT */
 
 #define MAX_INT_CNT 3
 struct drv_data {