dm: led: Support toggling LEDs

Add support for toggling an LED into the uclass interface. This can be
efficiently implemented by the driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ziping Chen <techping.chan@gmail.com>

drivers/led/led_gpio.c

@@ -21,6 +21,7 @@ struct led_gpio_priv {
 static int gpio_led_set_state(struct udevice *dev, enum led_state_t state)
 {
 	struct led_gpio_priv *priv = dev_get_priv(dev);
+	int ret;
 
 	if (!dm_gpio_is_valid(&priv->gpio))
 		return -EREMOTEIO;
@@ -28,6 +29,12 @@ static int gpio_led_set_state(struct udevice *dev, enum led_state_t state)
 	case LEDST_OFF:
 	case LEDST_ON:
 		break;
+	case LEDST_TOGGLE:
+		ret = dm_gpio_get_value(&priv->gpio);
+		if (ret < 0)
+			return ret;
+		state = !ret;
+		break;
 	default:
 		return -ENOSYS;
 	}

include/led.h

@@ -20,6 +20,7 @@ struct led_uc_plat {
 enum led_state_t {
 	LEDST_OFF = 0,
 	LEDST_ON = 1,
+	LEDST_TOGGLE,
 
 	LEDST_COUNT,
 };

test/dm/led.c

@@ -53,6 +53,31 @@ static int dm_test_led_gpio(struct unit_test_state *uts)
 }
 DM_TEST(dm_test_led_gpio, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
 
+/* Test that we can toggle LEDs */
+static int dm_test_led_toggle(struct unit_test_state *uts)
+{
+	const int offset = 1;
+	struct udevice *dev, *gpio;
+
+	/*
+	 * Check that we can manipulate an LED. LED 1 is connected to GPIO
+	 * bank gpio_a, offset 1.
+	 */
+	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_assertok(led_set_state(dev, LEDST_TOGGLE));
+	ut_asserteq(1, sandbox_gpio_get_value(gpio, offset));
+	ut_asserteq(LEDST_ON, led_get_state(dev));
+
+	ut_assertok(led_set_state(dev, LEDST_TOGGLE));
+	ut_asserteq(0, sandbox_gpio_get_value(gpio, offset));
+	ut_asserteq(LEDST_OFF, led_get_state(dev));
+
+	return 0;
+}
+DM_TEST(dm_test_led_toggle, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
 /* Test obtaining an LED by label */
 static int dm_test_led_label(struct unit_test_state *uts)
 {