feat: Implement LED driver for WB Embedded-controller

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 LED Driver
+
+maintainers:
+  - Vitalii Gaponov <[email protected]>
+
+description: |
+  Enables access to the LED on the Wiren Board Embedded Controller.
+
+properties:
+  compatible:
+    const: wirenboard,wbec-led
+
+  reg:
+    const: 0
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    wbec_led: wbec-led@0 {
+      compatible = "wirenboard,wbec-led";
+      reg = <0>;
+    };
+...

Documentation/devicetree/bindings/mfd/wirenboard,wbec.yaml

@@ -12,7 +12,8 @@ maintainers:
 description: |
   Wiren Board Embedded Controller (WB EC, wbec) is an MCU with special firmware
   installed on Wiren Board Automation Controller since HW revision 7.4.
-  WB EC is MFD device and provides such function as RTC, WDT, GPIO, ADC, PWRKEY.
+  WB EC is MFD device and provides such function as RTC, WDT, GPIO, ADC, LED,
+  PWRKEY.
 
 properties:
   compatible:
@@ -79,6 +80,11 @@ examples:
           #io-channel-cells = <1>;
         };
 
+        wbec_led: wbec-led@0 {
+          compatible = "wirenboard,wbec-led";
+          reg = <0>;
+        };
+
         vin: wbec-power@0 {
           compatible = "wirenboard,wbec-power";
           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
+  * leds-wbec - LED driver
 
 The wbec driver also provides a set of sysfs attributes for WBEC:
 

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

@@ -647,6 +647,11 @@
 			#io-channel-cells = <1>;
 		};
 
+		wbec_led: wbec-led@0 {
+			compatible = "wirenboard,wbec-led";
+			reg = <0>;
+		};
+
 		vin: wbec-power@0 {
 			compatible = "wirenboard,wbec-power";
 			reg = <0>;

arch/arm64/configs/wb8.config

@@ -117,6 +117,7 @@ CONFIG_WBEC_POWER=y
 CONFIG_WBEC_WATCHDOG=y
 CONFIG_RTC_DRV_WBEC=y
 CONFIG_WBEC_ADC=y
+CONFIG_LEDS_WBEC=y
 
 # SD3078 RTC (optional on boards without WBEC)
 CONFIG_RTC_DRV_SD3078=y

drivers/leds/Kconfig

@@ -545,6 +545,15 @@ config LEDS_PCA995X
 	  LED driver chips accessed via the I2C bus. Supported
 	  devices include PCA9955BTW, PCA9952TW and PCA9955TW.
 
+config LEDS_WBEC
+	tristate "Wiren Board Embedded Controller LED Driver"
+	depends on LEDS_CLASS
+	depends on SPI
+	depends on MFD_WBEC
+	help
+	  This option enables support for LED connected to the
+	  Wiren Board Embedded Controller accessed via the SPI bus.
+
 config LEDS_WM831X_STATUS
 	tristate "LED support for status LEDs on WM831x PMICs"
 	depends on LEDS_CLASS

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 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * led-wbec.c - Wiren Board Embedded Controller LED driver
+ *
+ * Copyright (c) 2024 Wiren Board LLC
+ *
+ * Author: Vitalii Gaponov <[email protected]>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/mfd/wbec.h>
+
+
+
+struct wbec_led {
+    struct led_classdev cdev;
+    struct regmap *regmap;
+};
+
+static void wbec_led_set(struct led_classdev *led_cdev,
+                         enum led_brightness value)
+{
+    struct wbec_led *wbec_led = container_of(led_cdev, struct wbec_led, cdev);
+    regmap_write(wbec_led->regmap, WBEC_REG_LED_CTRL, value ? WBEC_REG_LED_CTRL_STATE_MSK : 0);
+}
+
+static int wbec_led_probe(struct platform_device *pdev)
+{
+    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(&pdev->dev, sizeof(struct wbec_led), GFP_KERNEL);
+    if (!wbec_led)
+        return -ENOMEM;
+
+    platform_set_drvdata(pdev, wbec_led);
+    wbec_led->regmap = wbec->regmap;
+    wbec_led->cdev.name = "wbec-led";
+    wbec_led->cdev.brightness_set = wbec_led_set;
+
+    err = devm_led_classdev_register(&pdev->dev, &wbec_led->cdev);
+	if (err) {
+		dev_err(&pdev->dev, "Couldn't register LED: %d", err);
+		return err;
+	}
+
+    dev_info(&pdev->dev, "WBEC LED device initialized successfully");
+
+    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,
+};
+module_platform_driver(wbec_led_driver);
+
+MODULE_AUTHOR("Vitalii Gaponov <[email protected]>");
+MODULE_DESCRIPTION("Wiren Board 7 Embedded Controller LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wbec-led");

drivers/mfd/wbec.c

@@ -62,6 +62,11 @@ static const struct mfd_cell wbec_cells[] = {
 		.id = PLATFORM_DEVID_NONE,
 		.of_compatible = "wirenboard,wbec-rtc"
 	},
+	{
+		.name = "wbec-led",
+		.id = PLATFORM_DEVID_NONE,
+		.of_compatible = "wirenboard,wbec-led"
+	},
 	{
 		.name = "wbec-pwrkey",
 		.id = PLATFORM_DEVID_NONE,

include/linux/mfd/wbec.h

@@ -86,6 +86,8 @@
 #define WBEC_REG_PWR_STATUS                                 0xC0
    #define WBEC_REG_PWR_STATUS_POWERED_FROM_WBMZ_MSK        BIT(0)
 
+#define WBEC_REG_LED_CTRL                                   0xD0
+   #define WBEC_REG_LED_CTRL_STATE_MSK                      BIT(0)
 
 struct wbec {
 	struct device *dev;