wbec-led: Add WBEC System LED driver for WB8

Documentation/devicetree/bindings/leds/wirenboard,wbec-led.yaml

@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/wirenboard,wbec-led.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Wiren Board Embedded Controller System LED Driver
+
+maintainers:
+  - Ilia Skochilov <[email protected]>
+
+description: |
+  Enables access to the System LED on the Wiren Board Embedded Controller
+
+properties:
+  compatible:
+    const: wirenboard,wbec-led
+
+  reg:
+    const: 0
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    wbec-led@0 {
+      compatible = "wirenboard,wbec-led";
+      reg = <0>;
+    };
+...

Documentation/driver-api/wbec.rst

@@ -23,6 +23,7 @@ sub-drivers for each device connected to WBEC:
   * rtc-wbec - RTC driver
   * pwrkey-wbec - Power key driver
   * wbec-power - Power driver
+  * wbec-led - System LED driver
 
 The wbec driver also provides a set of sysfs attributes for WBEC:
 

arch/arm64/boot/dts/allwinner/sun50i-h616-wirenboard84x.dtsi

@@ -651,6 +651,11 @@
 			compatible = "wirenboard,wbec-power";
 			reg = <0>;
 		};
+
+		wbec_led: wbec-led@0 {
+			compatible = "wirenboard,wbec-led";
+			reg = <0>;
+		};
 	};
 };
 

arch/arm64/boot/dts/allwinner/sun50i-h616-wirenboard85x.dtsi

@@ -612,6 +612,11 @@
 			reg = <0>;
 			#pwm-cells = <3>;
 		};
+
+		wbec_led: wbec-led@0 {
+			compatible = "wirenboard,wbec-led";
+			reg = <0>;
+		};
 	};
 };
 

arch/arm64/configs/wb8-bootlet.config

@@ -77,6 +77,7 @@ CONFIG_RTC_DRV_WBEC=y
 CONFIG_WBEC_ADC=y
 CONFIG_WBEC_BATTERY=y
 CONFIG_PWM_WBEC=y
+CONFIG_LEDS_WBEC=y
 
 # SD3078 RTC (optional on boards without WBEC)
 CONFIG_RTC_DRV_SD3078=y

arch/arm64/configs/wb8.config

@@ -119,6 +119,7 @@ CONFIG_RTC_DRV_WBEC=y
 CONFIG_WBEC_ADC=y
 CONFIG_WBEC_BATTERY=y
 CONFIG_PWM_WBEC=y
+CONFIG_LEDS_WBEC=y
 
 # SD3078 RTC (optional on boards without WBEC)
 CONFIG_RTC_DRV_SD3078=y

drivers/leds/Kconfig

@@ -917,6 +917,13 @@ config LEDS_ACER_A500
 	  This option enables support for the Power Button LED of
 	  Acer Iconia Tab A500.
 
+config LEDS_WBEC
+	tristate "Wiren Board Embedded Controller System LED Driver"
+	depends on MFD_WBEC
+	help
+	  This option enables support for the System LED of
+	  the Wiren Board Embedded Controller.
+
 source "drivers/leds/blink/Kconfig"
 
 comment "Flash and Torch LED drivers"

drivers/leds/Makefile

@@ -87,6 +87,7 @@ obj-$(CONFIG_LEDS_TI_LMU_COMMON)	+= leds-ti-lmu-common.o
 obj-$(CONFIG_LEDS_TLC591XX)		+= leds-tlc591xx.o
 obj-$(CONFIG_LEDS_TPS6105X)		+= leds-tps6105x.o
 obj-$(CONFIG_LEDS_TURRIS_OMNIA)		+= leds-turris-omnia.o
+obj-$(CONFIG_LEDS_WBEC)			+= leds-wbec.o
 obj-$(CONFIG_LEDS_WM831X_STATUS)	+= leds-wm831x-status.o
 obj-$(CONFIG_LEDS_WM8350)		+= leds-wm8350.o
 obj-$(CONFIG_LEDS_WRAP)			+= leds-wrap.o

drivers/leds/leds-wbec.c

@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * led-wbec.c - Wiren Board Embedded Controller System LED driver
+ *
+ * Copyright (c) 2024 Wiren Board LLC
+ *
+ * Author: Ilia Skochilov <[email protected]>
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/mfd/wbec.h>
+
+enum led_mode {
+    WBEC_LED_OFF,
+    WBEC_LED_ON,
+    WBEC_LED_BLINK,
+};
+
+struct wbec_led {
+	struct regmap *regmap;
+	struct led_classdev cdev;
+	unsigned long blink_delay_on;
+	unsigned long blink_delay_off;
+};
+
+static void wbec_led_set(struct led_classdev *led_cdev, enum led_brightness brightness)
+{
+    struct wbec_led *wbec_led = container_of(led_cdev, struct wbec_led, cdev);
+	int value;
+	if (brightness > 0) {
+		value = WBEC_LED_ON;
+	} else {
+		value = WBEC_LED_OFF;
+	}
+    regmap_write(wbec_led->regmap, WBEC_REG_EC_SYSTEM_LED, value);
+}
+
+static int wbec_blink_set(struct led_classdev *led_cdev,
+                          unsigned long *delay_on,
+                          unsigned long *delay_off)
+{
+    struct wbec_led *wbec_led = container_of(led_cdev, struct wbec_led, cdev);
+    int err;
+
+    err = regmap_write(wbec_led->regmap, WBEC_REG_EC_SYSTEM_LED, WBEC_LED_BLINK);
+    if (err) {
+        return err;
+    }
+
+    err = regmap_write(wbec_led->regmap, WBEC_REG_EC_SYSTEM_LED_ON_MS, *delay_on);
+    if (err) {
+        return err;
+    }
+
+    err = regmap_write(wbec_led->regmap, WBEC_REG_EC_SYSTEM_LED_OFF_MS, *delay_off);
+    if (err) {
+        return err;
+    }
+
+	wbec_led->blink_delay_on = *delay_on;
+	wbec_led->blink_delay_off = *delay_off;
+
+    return 0;
+}
+
+static ssize_t blink_on_show(struct device *dev,
+                             struct device_attribute *attr, char *buf)
+{
+    struct led_classdev *led_cdev = dev_get_drvdata(dev);
+    struct wbec_led *wbec_led = container_of(led_cdev, struct wbec_led, cdev);
+
+    return sprintf(buf, "%lu\n", wbec_led->blink_delay_on);
+}
+
+static ssize_t blink_on_store(struct device *dev,
+                              struct device_attribute *attr,
+                              const char *buf, size_t size)
+{
+    struct led_classdev *led_cdev = dev_get_drvdata(dev);
+    struct wbec_led *wbec_led = container_of(led_cdev, struct wbec_led, cdev);
+    unsigned long value;
+    int ret;
+
+    ret = kstrtoul(buf, 10, &value);
+    if (ret) {
+        return ret;
+    }
+
+    wbec_led->blink_delay_on = value;
+    wbec_blink_set(led_cdev, &wbec_led->blink_delay_on, &wbec_led->blink_delay_off);
+
+    return size;
+}
+
+static ssize_t blink_off_show(struct device *dev,
+                              struct device_attribute *attr, char *buf)
+{
+    struct led_classdev *led_cdev = dev_get_drvdata(dev);
+    struct wbec_led *wbec_led = container_of(led_cdev, struct wbec_led, cdev);
+
+    return sprintf(buf, "%lu\n", wbec_led->blink_delay_off);
+}
+
+static ssize_t blink_off_store(struct device *dev,
+                               struct device_attribute *attr,
+                               const char *buf, size_t size)
+{
+    struct led_classdev *led_cdev = dev_get_drvdata(dev);
+    struct wbec_led *wbec_led = container_of(led_cdev, struct wbec_led, cdev);
+    unsigned long value;
+    int ret;
+
+    ret = kstrtoul(buf, 10, &value);
+    if (ret) {
+        return ret;
+    }
+
+    wbec_led->blink_delay_off = value;
+    wbec_blink_set(led_cdev, &wbec_led->blink_delay_on, &wbec_led->blink_delay_off);
+
+    return size;
+}
+
+static DEVICE_ATTR_RW(blink_on);
+static DEVICE_ATTR_RW(blink_off);
+
+static struct attribute *wbec_led_attrs[] = {
+    &dev_attr_blink_on.attr,
+    &dev_attr_blink_off.attr,
+    NULL
+};
+
+ATTRIBUTE_GROUPS(wbec_led);
+
+static int wbec_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct wbec *wbec = dev_get_drvdata(pdev->dev.parent);
+	struct wbec_led *wbec_led;
+	int err;
+
+	if (!pdev->dev.parent) {
+        return -ENODEV;
+    }
+
+	wbec_led = devm_kzalloc(dev, sizeof(struct wbec_led), GFP_KERNEL);
+	if (!wbec_led) {
+        return -ENOMEM;
+    }
+
+	wbec_led->regmap = wbec->regmap;
+    if (!wbec_led->regmap) {
+        return -ENODEV;
+    }
+
+    if (!of_device_is_compatible(dev->of_node, "wirenboard,wbec-led")) {
+        dev_err(dev, "Incompatible device\n");
+        return -EINVAL;
+    }
+
+	wbec_led->cdev.name = "wbec_led";
+	wbec_led->cdev.brightness_set = wbec_led_set;
+	wbec_led->cdev.blink_set = wbec_blink_set;
+	wbec_led->cdev.groups = wbec_led_groups;
+
+	err = led_classdev_register(dev, &wbec_led->cdev);
+    if (err) {
+        dev_err(dev, "Failed to register System LED device\n");
+        return err;
+    }
+
+	platform_set_drvdata(pdev, wbec_led);
+
+	dev_info(dev, "System LED device probed successfully\n");
+	return 0;
+}
+
+static int wbec_led_remove(struct platform_device *pdev)
+{
+    struct wbec_led *wbec_led = platform_get_drvdata(pdev);
+
+    led_classdev_unregister(&wbec_led->cdev);
+
+    dev_info(&pdev->dev, "System LED device removed\n");
+
+    return 0;
+}
+
+static const struct of_device_id wbec_led_of_match[] = {
+	{ .compatible = "wirenboard,wbec-led" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, wbec_led_of_match);
+
+static struct platform_driver wbec_led_driver = {
+	.driver	= {
+		.name = "wbec-led",
+		.of_match_table = wbec_led_of_match,
+	},
+	.probe	= wbec_led_probe,
+	.remove = wbec_led_remove,
+};
+module_platform_driver(wbec_led_driver);
+
+MODULE_ALIAS("platform:wbec-led");
+MODULE_AUTHOR("Ilia Skochilov <[email protected]>");
+MODULE_DESCRIPTION("Wiren Board Embedded Controller System LED driver");
+MODULE_LICENSE("GPL");

drivers/mfd/wbec.c

@@ -82,6 +82,11 @@ static const struct mfd_cell wbec_cells[] = {
 		.id = PLATFORM_DEVID_NONE,
 		.of_compatible = "wirenboard,wbec-battery"
 	},
+	{
+		.name = "wbec-led",
+		.id = PLATFORM_DEVID_NONE,
+		.of_compatible = "wirenboard,wbec-led"
+	},
 };
 
 /* ----------------------------------------------------------------------- */

include/linux/mfd/wbec.h

@@ -57,6 +57,11 @@
 #define WBEC_REG_ADC_DATA_ADC5                              0x4A
 #define WBEC_REG_ADC_DATA_ADC6                              0x4B
 
+/* Region EC_SYSTEM_LED: RW */
+#define WBEC_REG_EC_SYSTEM_LED                              0x60
+#define WBEC_REG_EC_SYSTEM_LED_ON_MS                        0x61
+#define WBEC_REG_EC_SYSTEM_LED_OFF_MS                       0x62
+
 /* Region GPIO: RW */
 #define WBEC_REG_GPIO                                       0x80
    #define WBEC_REG_GPIO_A1_MSK                             BIT(0)