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>

configs/sandbox_defconfig

@@ -83,6 +83,7 @@ CONFIG_I2C_ARB_GPIO_CHALLENGE=y
 CONFIG_CROS_EC_KEYB=y
 CONFIG_I8042_KEYB=y
 CONFIG_LED=y
+CONFIG_LED_BLINK=y
 CONFIG_LED_GPIO=y
 CONFIG_DM_MAILBOX=y
 CONFIG_SANDBOX_MBOX=y

configs/sandbox_noblk_defconfig

@@ -92,6 +92,7 @@ CONFIG_I2C_ARB_GPIO_CHALLENGE=y
 CONFIG_CROS_EC_KEYB=y
 CONFIG_I8042_KEYB=y
 CONFIG_LED=y
+CONFIG_LED_BLINK=y
 CONFIG_LED_GPIO=y
 CONFIG_CROS_EC=y
 CONFIG_CROS_EC_I2C=y

configs/sandbox_spl_defconfig

@@ -94,6 +94,7 @@ CONFIG_I2C_ARB_GPIO_CHALLENGE=y
 CONFIG_CROS_EC_KEYB=y
 CONFIG_I8042_KEYB=y
 CONFIG_LED=y
+CONFIG_LED_BLINK=y
 CONFIG_LED_GPIO=y
 CONFIG_DM_MAILBOX=y
 CONFIG_SANDBOX_MBOX=y

drivers/led/Kconfig

@@ -9,6 +9,15 @@ config LED
 	  can provide access to board-specific LEDs. Use of the device tree
 	  for configuration is encouraged.
 
+config LED_BLINK
+	bool "Support LED blinking"
+	depends on LED
+	help
+	  Some drivers can support automatic blinking of LEDs with a given
+	  period, without needing timers or extra code to handle the timing.
+	  This option enables support for this which adds slightly to the
+	  code size.
+
 config SPL_LED
 	bool "Enable LED support in SPL"
 	depends on SPL && SPL_DM

drivers/led/led-uclass.c

@@ -52,6 +52,18 @@ enum led_state_t led_get_state(struct udevice *dev)
 	return ops->get_state(dev);
 }
 
+#ifdef CONFIG_LED_BLINK
+int led_set_period(struct udevice *dev, int period_ms)
+{
+	struct led_ops *ops = led_get_ops(dev);
+
+	if (!ops->set_period)
+		return -ENOSYS;
+
+	return ops->set_period(dev, period_ms);
+}
+#endif
+
 UCLASS_DRIVER(led) = {
 	.id		= UCLASS_LED,
 	.name		= "led",

include/led.h

@@ -17,10 +17,22 @@ struct led_uc_plat {
 	const char *label;
 };
 
+/**
+ * struct led_uc_priv - Private data the uclass stores about each device
+ *
+ * @period_ms:	Flash period in milliseconds
+ */
+struct led_uc_priv {
+	int period_ms;
+};
+
 enum led_state_t {
 	LEDST_OFF = 0,
 	LEDST_ON = 1,
 	LEDST_TOGGLE,
+#ifdef CONFIG_LED_BLINK
+	LEDST_BLINK,
+#endif
 
 	LEDST_COUNT,
 };
@@ -42,6 +54,20 @@ struct led_ops {
 	 * @return LED state led_state_t, or -ve on error
 	 */
 	enum led_state_t (*get_state)(struct udevice *dev);
+
+#ifdef CONFIG_LED_BLINK
+	/**
+	 * led_set_period() - set the blink period of an LED
+	 *
+	 * Thie records the period if supported, or returns -ENOSYS if not.
+	 * To start the LED blinking, use set_state().
+	 *
+	 * @dev:	LED device to change
+	 * @period_ms:	LED blink period in milliseconds
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*set_period)(struct udevice *dev, int period_ms);
+#endif
 };
 
 #define led_get_ops(dev)	((struct led_ops *)(dev)->driver->ops)
@@ -72,4 +98,13 @@ int led_set_state(struct udevice *dev, enum led_state_t state);
  */
 enum led_state_t led_get_state(struct udevice *dev);
 
+/**
+ * led_set_period() - set the blink period of an LED
+ *
+ * @dev:	LED device to change
+ * @period_ms:	LED blink period in milliseconds
+ * @return 0 if OK, -ve on error
+ */
+int led_set_period(struct udevice *dev, int period_ms);
+
 #endif

test/dm/led.c

@@ -98,3 +98,27 @@ static int dm_test_led_label(struct unit_test_state *uts)
 	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