[PATCH v3 3/9] led: implement LED boot API

[Christian Marangi <ansuelsmth@gmail.com>]

Implement LED boot API to signal correct boot of the system.

led_boot_on/off/blink() are introduced to turn ON, OFF and BLINK the
designated boot LED.

New Kconfig are introduced, CONFIG_LED_BOOT_ENABLE to enable the feature.
This makes use of the /config property "u-boot,boot-led" to the define
the boot LED.
It's also introduced a new /config property "u-boot,boot-led-period" to
define the default period when the LED is set to blink mode.

If "u-boot,boot-led-period" is not defined, the value of 250 (ms) is
used by default.

If CONFIG_LED_BLINK or CONFIG_LED_SW_BLINK is not enabled,
led_boot_blink call will fallback to simple LED ON.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 doc/device-tree-bindings/config.txt |  3 ++
 drivers/led/Kconfig                 | 20 +++++++++
 include/led.h                       | 64 +++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+)

diff --git a/doc/device-tree-bindings/config.txt b/doc/device-tree-bindings/config.txt
index f50c68bbdc3..68edd177040 100644
--- a/doc/device-tree-bindings/config.txt
+++ b/doc/device-tree-bindings/config.txt
@@ -31,6 +31,9 @@ u-boot,error-led (string)
 	This is used to specify the label for an LED to indicate an error and
 	a successful boot, on supported hardware.
 
+u-boot,boot-led-period (int)
+	This is used to specify the default period for an LED in blink mode.
+
 bootsecure (int)
 	Indicates that U-Boot should use secure_boot_cmd() to run commands,
 	rather than the normal CLI. This can be used in production images, to
diff --git a/drivers/led/Kconfig b/drivers/led/Kconfig
index bee74b25751..fd9442edaf3 100644
--- a/drivers/led/Kconfig
+++ b/drivers/led/Kconfig
@@ -9,6 +9,26 @@ config LED
 	  can provide access to board-specific LEDs. Use of the device tree
 	  for configuration is encouraged.
 
+config LED_BOOT_ENABLE
+	bool "Enable LED boot support"
+	help
+	  Enable LED boot support.
+
+	  LED boot is a specific LED assigned to signal boot operation status.
+
+config LED_BOOT_LABEL
+	string "LED boot label"
+	depends on LED_BOOT_ENABLE
+	help
+	  LED label defined in DT to assign for LED boot usage.
+
+config LED_BOOT_PERIOD
+	int "LED boot period"
+	depends on LED_BOOT_ENABLE && (LED_BLINK || LED_SW_BLINK)
+	default 2
+	help
+	  LED boot blink period in ms.
+
 config LED_BCM6328
 	bool "LED Support for BCM6328"
 	depends on LED && ARCH_BMIPS
diff --git a/include/led.h b/include/led.h
index c1f3380f253..2d3b89674e2 100644
--- a/include/led.h
+++ b/include/led.h
@@ -9,6 +9,7 @@
 
 #include <stdbool.h>
 #include <cyclic.h>
+#include <dm/ofnode.h>
 
 struct udevice;
 
@@ -159,4 +160,67 @@ int led_sw_set_period(struct udevice *dev, int period_ms);
 bool led_sw_is_blinking(struct udevice *dev);
 bool led_sw_on_state_change(struct udevice *dev, enum led_state_t state);
 
+#ifdef CONFIG_LED_BOOT_ENABLE
+
+/**
+ * led_boot_on() - turn ON the designated LED for booting
+ *
+ * Return: 0 if OK, -ve on error
+ */
+static inline int led_boot_on(void)
+{
+	const char *led_name;
+
+	led_name = ofnode_conf_read_str("u-boot,boot-led");
+	if (!led_name)
+		return -ENOENT;
+
+	return led_set_state_by_label(led_name, LEDST_ON);
+}
+
+/**
+ * led_boot_off() - turn OFF the designated LED for booting
+ *
+ * Return: 0 if OK, -ve on error
+ */
+static inline int led_boot_off(void)
+{
+	const char *led_name;
+
+	led_name = ofnode_conf_read_str("u-boot,boot-led");
+	if (!led_name)
+		return -ENOENT;
+
+	return led_set_state_by_label(CONFIG_LED_BOOT_LABEL, LEDST_OFF);
+}
+
+#if defined(CONFIG_LED_BLINK) || defined(CONFIG_LED_SW_BLINK)
+/**
+ * led_boot_blink() - turn ON the designated LED for booting
+ *
+ * Return: 0 if OK, -ve on error
+ */
+static inline int led_boot_blink(void)
+{
+	const char *led_name;
+	int led_period, ret;
+
+	led_name = ofnode_conf_read_str("u-boot,boot-led");
+	if (!led_name)
+		return -ENOENT;
+
+	led_period = ofnode_conf_read_int("u-boot,boot-led-period", 250);
+
+	ret = led_set_period_by_label(led_name, led_period);
+	if (ret)
+		return ret;
+
+	return led_set_state_by_label(led_name, LEDST_BLINK);
+}
+#else
+/* If LED BLINK is not supported/enabled, fallback to LED ON */
+#define led_boot_blink led_boot_on
+#endif
+#endif
+
 #endif
-- 
2.45.2