dm: led: Add support for blinking LEDs

Allow LEDs to be blinked if the driver supports it. Enable this for
sandbox so that the tests run.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ziping Chen <techping.chan@gmail.com>
diff --git a/test/dm/led.c b/test/dm/led.c
index 2cc2412..fde700b 100644
--- a/test/dm/led.c
+++ b/test/dm/led.c
@@ -98,3 +98,27 @@
 	return 0;
 }
 DM_TEST(dm_test_led_label, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
+/* Test LED blinking */
+#ifdef CONFIG_LED_BLINK
+static int dm_test_led_blink(struct unit_test_state *uts)
+{
+	const int offset = 1;
+	struct udevice *dev, *gpio;
+
+	/*
+	 * Check that we get an error when trying to blink an LED, since it is
+	 * not supported by the GPIO LED driver.
+	 */
+	ut_assertok(uclass_get_device(UCLASS_LED, 1, &dev));
+	ut_assertok(uclass_get_device(UCLASS_GPIO, 1, &gpio));
+	ut_asserteq(0, sandbox_gpio_get_value(gpio, offset));
+	ut_asserteq(-ENOSYS, led_set_state(dev, LEDST_BLINK));
+	ut_asserteq(0, sandbox_gpio_get_value(gpio, offset));
+	ut_asserteq(LEDST_OFF, led_get_state(dev));
+	ut_asserteq(-ENOSYS, led_set_period(dev, 100));
+
+	return 0;
+}
+DM_TEST(dm_test_led_blink, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+#endif