[v7,4/8] leds: add driver for LEDs from qnap-mcu devices

diff --git a/MAINTAINERS b/MAINTAINERS
index ee6e98ba2e6f..943905cbcf62 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18682,6 +18682,7 @@  F:	drivers/media/tuners/qm1d1c0042*
 QNAP MCU DRIVER
 M:	Heiko Stuebner <heiko@sntech.de>
 S:	Maintained
+F:	drivers/leds/leds-qnap-mcu.c
 F:	drivers/mfd/qnap-mcu.c
 F:	include/linux/qnap-mcu.h
 
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 8d9d8da376e4..9a337478dd80 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -580,6 +580,17 @@  config LEDS_PCA995X
 	  LED driver chips accessed via the I2C bus. Supported
 	  devices include PCA9955BTW, PCA9952TW and PCA9955TW.
 
+config LEDS_QNAP_MCU
+	tristate "LED Support for QNAP MCU controllers"
+	depends on LEDS_CLASS
+	depends on MFD_QNAP_MCU
+	help
+	  This option enables support for LEDs available on embedded
+	  controllers used in QNAP NAS devices.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called qnap-mcu-leds.
+
 config LEDS_WM831X_STATUS
 	tristate "LED support for status LEDs on WM831x PMICs"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 18afbb5a23ee..c6f74865d729 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -79,6 +79,7 @@  obj-$(CONFIG_LEDS_PCA995X)		+= leds-pca995x.o
 obj-$(CONFIG_LEDS_PM8058)		+= leds-pm8058.o
 obj-$(CONFIG_LEDS_POWERNV)		+= leds-powernv.o
 obj-$(CONFIG_LEDS_PWM)			+= leds-pwm.o
+obj-$(CONFIG_LEDS_QNAP_MCU)		+= leds-qnap-mcu.o
 obj-$(CONFIG_LEDS_REGULATOR)		+= leds-regulator.o
 obj-$(CONFIG_LEDS_SC27XX_BLTC)		+= leds-sc27xx-bltc.o
 obj-$(CONFIG_LEDS_SUN50I_A100)		+= leds-sun50i-a100.o
diff --git a/drivers/leds/leds-qnap-mcu.c b/drivers/leds/leds-qnap-mcu.c
new file mode 100644
index 000000000000..4e4709456261
--- /dev/null
+++ b/drivers/leds/leds-qnap-mcu.c
@@ -0,0 +1,227 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for LEDs found on QNAP MCU devices
+ *
+ * Copyright (C) 2024 Heiko Stuebner <heiko@sntech.de>
+ */
+
+#include <linux/leds.h>
+#include <linux/mfd/qnap-mcu.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <uapi/linux/uleds.h>
+
+enum qnap_mcu_err_led_mode {
+	QNAP_MCU_ERR_LED_ON = 0,
+	QNAP_MCU_ERR_LED_OFF = 1,
+	QNAP_MCU_ERR_LED_BLINK_FAST = 2,
+	QNAP_MCU_ERR_LED_BLINK_SLOW = 3,
+};
+
+struct qnap_mcu_err_led {
+	struct qnap_mcu *mcu;
+	struct led_classdev cdev;
+	char name[LED_MAX_NAME_SIZE];
+	u8 num;
+	u8 mode;
+};
+
+static inline struct qnap_mcu_err_led *
+		cdev_to_qnap_mcu_err_led(struct led_classdev *led_cdev)
+{
+	return container_of(led_cdev, struct qnap_mcu_err_led, cdev);
+}
+
+static int qnap_mcu_err_led_set(struct led_classdev *led_cdev,
+				enum led_brightness brightness)
+{
+	struct qnap_mcu_err_led *err_led = cdev_to_qnap_mcu_err_led(led_cdev);
+	u8 cmd[] = { '@', 'R', '0' + err_led->num, '0' };
+
+	/* Don't disturb a possible set blink-mode if LED stays on */
+	if (brightness != 0 && err_led->mode >= QNAP_MCU_ERR_LED_BLINK_FAST)
+		return 0;
+
+	err_led->mode = brightness ? QNAP_MCU_ERR_LED_ON : QNAP_MCU_ERR_LED_OFF;
+	cmd[3] = '0' + err_led->mode;
+
+	return qnap_mcu_exec_with_ack(err_led->mcu, cmd, sizeof(cmd));
+}
+
+static int qnap_mcu_err_led_blink_set(struct led_classdev *led_cdev,
+				      unsigned long *delay_on,
+				      unsigned long *delay_off)
+{
+	struct qnap_mcu_err_led *err_led = cdev_to_qnap_mcu_err_led(led_cdev);
+	u8 cmd[] = { '@', 'R', '0' + err_led->num, '0' };
+
+	/* LED is off, nothing to do */
+	if (err_led->mode == QNAP_MCU_ERR_LED_OFF)
+		return 0;
+
+	if (*delay_on < 500) {
+		*delay_on = 100;
+		*delay_off = 100;
+		err_led->mode = QNAP_MCU_ERR_LED_BLINK_FAST;
+	} else {
+		*delay_on = 500;
+		*delay_off = 500;
+		err_led->mode = QNAP_MCU_ERR_LED_BLINK_SLOW;
+	}
+
+	cmd[3] = '0' + err_led->mode;
+
+	return qnap_mcu_exec_with_ack(err_led->mcu, cmd, sizeof(cmd));
+}
+
+static int qnap_mcu_register_err_led(struct device *dev, struct qnap_mcu *mcu, int num_err_led)
+{
+	struct qnap_mcu_err_led *err_led;
+	int ret;
+
+	err_led = devm_kzalloc(dev, sizeof(*err_led), GFP_KERNEL);
+	if (!err_led)
+		return -ENOMEM;
+
+	err_led->mcu = mcu;
+	err_led->num = num_err_led;
+	err_led->mode = QNAP_MCU_ERR_LED_OFF;
+
+	scnprintf(err_led->name, LED_MAX_NAME_SIZE, "hdd%d:red:status", num_err_led + 1);
+	err_led->cdev.name = err_led->name;
+
+	err_led->cdev.brightness_set_blocking = qnap_mcu_err_led_set;
+	err_led->cdev.blink_set = qnap_mcu_err_led_blink_set;
+	err_led->cdev.brightness = 0;
+	err_led->cdev.max_brightness = 1;
+
+	ret = devm_led_classdev_register(dev, &err_led->cdev);
+	if (ret)
+		return ret;
+
+	return qnap_mcu_err_led_set(&err_led->cdev, 0);
+}
+
+enum qnap_mcu_usb_led_mode {
+	QNAP_MCU_USB_LED_ON = 1,
+	QNAP_MCU_USB_LED_OFF = 3,
+	QNAP_MCU_USB_LED_BLINK = 2,
+};
+
+struct qnap_mcu_usb_led {
+	struct qnap_mcu *mcu;
+	struct led_classdev cdev;
+	u8 mode;
+};
+
+static inline struct qnap_mcu_usb_led *
+		cdev_to_qnap_mcu_usb_led(struct led_classdev *led_cdev)
+{
+	return container_of(led_cdev, struct qnap_mcu_usb_led, cdev);
+}
+
+static int qnap_mcu_usb_led_set(struct led_classdev *led_cdev,
+				enum led_brightness brightness)
+{
+	struct qnap_mcu_usb_led *usb_led = cdev_to_qnap_mcu_usb_led(led_cdev);
+	u8 cmd[] = { '@', 'C', 0 };
+
+	/* Don't disturb a possible set blink-mode if LED stays on */
+	if (brightness != 0 && usb_led->mode == QNAP_MCU_USB_LED_BLINK)
+		return 0;
+
+	usb_led->mode = brightness ? QNAP_MCU_USB_LED_ON : QNAP_MCU_USB_LED_OFF;
+
+	/*
+	 * Byte 3 is shared between the usb led target on/off/blink
+	 * and also the buzzer control (in the input driver)
+	 */
+	cmd[2] = 'D' + usb_led->mode;
+
+	return qnap_mcu_exec_with_ack(usb_led->mcu, cmd, sizeof(cmd));
+}
+
+static int qnap_mcu_usb_led_blink_set(struct led_classdev *led_cdev,
+				      unsigned long *delay_on,
+				      unsigned long *delay_off)
+{
+	struct qnap_mcu_usb_led *usb_led = cdev_to_qnap_mcu_usb_led(led_cdev);
+	u8 cmd[] = { '@', 'C', 0 };
+
+	/* LED is off, nothing to do */
+	if (usb_led->mode == QNAP_MCU_USB_LED_OFF)
+		return 0;
+
+	*delay_on = 250;
+	*delay_off = 250;
+	usb_led->mode = QNAP_MCU_USB_LED_BLINK;
+
+	/*
+	 * Byte 3 is shared between the USB LED target on/off/blink
+	 * and also the buzzer control (in the input driver)
+	 */
+	cmd[2] = 'D' + usb_led->mode;
+
+	return qnap_mcu_exec_with_ack(usb_led->mcu, cmd, sizeof(cmd));
+}
+
+static int qnap_mcu_register_usb_led(struct device *dev, struct qnap_mcu *mcu)
+{
+	struct qnap_mcu_usb_led *usb_led;
+	int ret;
+
+	usb_led = devm_kzalloc(dev, sizeof(*usb_led), GFP_KERNEL);
+	if (!usb_led)
+		return -ENOMEM;
+
+	usb_led->mcu = mcu;
+	usb_led->mode = QNAP_MCU_USB_LED_OFF;
+	usb_led->cdev.name = "usb:blue:disk";
+	usb_led->cdev.brightness_set_blocking = qnap_mcu_usb_led_set;
+	usb_led->cdev.blink_set = qnap_mcu_usb_led_blink_set;
+	usb_led->cdev.brightness = 0;
+	usb_led->cdev.max_brightness = 1;
+
+	ret = devm_led_classdev_register(dev, &usb_led->cdev);
+	if (ret)
+		return ret;
+
+	return qnap_mcu_usb_led_set(&usb_led->cdev, 0);
+}
+
+static int qnap_mcu_leds_probe(struct platform_device *pdev)
+{
+	struct qnap_mcu *mcu = dev_get_drvdata(pdev->dev.parent);
+	const struct qnap_mcu_variant *variant = pdev->dev.platform_data;
+	int ret;
+
+	for (int i = 0; i < variant->num_drives; i++) {
+		ret = qnap_mcu_register_err_led(&pdev->dev, mcu, i);
+		if (ret)
+			return dev_err_probe(&pdev->dev, ret,
+					"failed to register error LED %d\n", i);
+	}
+
+	if (variant->usb_led) {
+		ret = qnap_mcu_register_usb_led(&pdev->dev, mcu);
+		if (ret)
+			return dev_err_probe(&pdev->dev, ret,
+					"failed to register USB LED\n");
+	}
+
+	return 0;
+}
+
+static struct platform_driver qnap_mcu_leds_driver = {
+	.probe = qnap_mcu_leds_probe,
+	.driver = {
+		.name = "qnap-mcu-leds",
+	},
+};
+module_platform_driver(qnap_mcu_leds_driver);
+
+MODULE_ALIAS("platform:qnap-mcu-leds");
+MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
+MODULE_DESCRIPTION("QNAP MCU LEDs driver");
+MODULE_LICENSE("GPL");