test: dm: add a test for class button

Add a test to confirm that we can read button state
using the button-gpio driver.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/test/dm/button.c b/test/dm/button.c
new file mode 100644
index 0000000..890f470
--- /dev/null
+++ b/test/dm/button.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Philippe Reynes <philippe.reynes@softathome.com>
+ *
+ * Based on led.c
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <button.h>
+#include <asm/gpio.h>
+#include <dm/test.h>
+#include <test/ut.h>
+
+/* Base test of the button uclass */
+static int dm_test_button_base(struct unit_test_state *uts)
+{
+	struct udevice *dev;
+
+	/* Get the top-level device */
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 0, &dev));
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 1, &dev));
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 2, &dev));
+	ut_asserteq(-ENODEV, uclass_get_device(UCLASS_BUTTON, 3, &dev));
+
+	return 0;
+}
+DM_TEST(dm_test_button_base, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
+/* Test of the button uclass using the button_gpio driver */
+static int dm_test_button_gpio(struct unit_test_state *uts)
+{
+	const int offset = 3;
+	struct udevice *dev, *gpio;
+
+	/*
+	 * Check that we can manipulate an BUTTON. BUTTON 1 is connected to GPIO
+	 * bank gpio_a, offset 3.
+	 */
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 1, &dev));
+	ut_assertok(uclass_get_device(UCLASS_GPIO, 1, &gpio));
+
+	ut_asserteq(0, sandbox_gpio_set_value(gpio, offset, 0));
+	ut_asserteq(0, sandbox_gpio_get_value(gpio, offset));
+	ut_asserteq(BUTTON_OFF, button_get_state(dev));
+
+	ut_asserteq(0, sandbox_gpio_set_value(gpio, offset, 1));
+	ut_asserteq(1, sandbox_gpio_get_value(gpio, offset));
+	ut_asserteq(BUTTON_ON, button_get_state(dev));
+
+	return 0;
+}
+DM_TEST(dm_test_button_gpio, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
+/* Test obtaining an BUTTON by label */
+static int dm_test_button_label(struct unit_test_state *uts)
+{
+	struct udevice *dev, *cmp;
+
+	ut_assertok(button_get_by_label("summer", &dev));
+	ut_asserteq(1, device_active(dev));
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 1, &cmp));
+	ut_asserteq_ptr(dev, cmp);
+
+	ut_assertok(button_get_by_label("christmas", &dev));
+	ut_asserteq(1, device_active(dev));
+	ut_assertok(uclass_get_device(UCLASS_BUTTON, 2, &cmp));
+	ut_asserteq_ptr(dev, cmp);
+
+	ut_asserteq(-ENODEV, button_get_by_label("spring", &dev));
+
+	return 0;
+}
+DM_TEST(dm_test_button_label, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);