[PATCH 5/5] leds: add driver for AAEON devices

[aaeon.asus@xxxxxxxxx]

From: Kunyang_Fan <kunyang_fan@xxxxxxxx>

This patch adds support for the led devices which can
be controlled from sysfs through ASUS WMI interface.

Signed-off-by: Kunyang_Fan <kunyang_fan@xxxxxxxx>
---
 drivers/leds/Kconfig      |  11 +++
 drivers/leds/Makefile     |   1 +
 drivers/leds/leds-aaeon.c | 142 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 154 insertions(+)
 create mode 100644 drivers/leds/leds-aaeon.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index be4536eef1fe..34d1b80855af 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -49,6 +49,17 @@ config LEDS_88PM860X
 	  This option enables support for on-chip LED drivers found on Marvell
 	  Semiconductor 88PM8606 PMIC.
 
+config LEDS_AAEON
+	tristate "AAEON LED driver"
+	depends on X86
+	select MFD_AAEON
+	help
+	  This led driver adds support for LED brightness control on Single
+	  Board Computers produced by AAEON.
+
+	  This driver leverages the ASUS WMI interface to access device
+	  resources.
+
 config LEDS_AAT1290
 	tristate "LED support for the AAT1290"
 	depends on LEDS_CLASS_FLASH
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index d6b8a792c936..a8a77acc5e11 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_LEDS_TRIGGERS)		+= led-triggers.o
 
 # LED Platform Drivers (keep this sorted, M-| sort)
 obj-$(CONFIG_LEDS_88PM860X)		+= leds-88pm860x.o
+obj-$(CONFIG_LEDS_AAEON)		+= leds-aaeon.o
 obj-$(CONFIG_LEDS_AAT1290)		+= leds-aat1290.o
 obj-$(CONFIG_LEDS_ADP5520)		+= leds-adp5520.o
 obj-$(CONFIG_LEDS_AN30259A)		+= leds-an30259a.o
diff --git a/drivers/leds/leds-aaeon.c b/drivers/leds/leds-aaeon.c
new file mode 100644
index 000000000000..10090a4bff65
--- /dev/null
+++ b/drivers/leds/leds-aaeon.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AAEON LED driver
+ *
+ * Copyright (c) 2021, AAEON Ltd.
+ *
+ * Author: Kunyang Fan <kunyang_fan@xxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <linux/acpi.h>
+#include <linux/bitops.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_data/x86/asus-wmi.h>
+#include <linux/platform_device.h>
+
+#define DRVNAME "led_aaeon"
+#define ASUS_NB_WMI_EVENT_GUID   "0B3CBB35-E3C2-45ED-91C2-4C5A6D195D1C"
+#define AAEON_WMI_MGMT_GUID      "97845ED0-4E6D-11DE-8A39-0800200C9A66"
+
+#define GET_LED_NUMBER_ID        0x00060000
+#define GET_LED_METHOD_ID        0x00060001
+#define SET_LED_METHOD_ID        0x00060002
+#define GET_LED_NUMBER_METHOD_ID 0x10
+
+
+struct aaeon_led_data {
+	int id;
+	struct led_classdev cdev;
+};
+
+static int aaeon_led_get_number(void)
+{
+	int err, retval;
+
+	err = asus_wmi_evaluate_method(GET_LED_NUMBER_ID,
+				       GET_LED_NUMBER_METHOD_ID,
+				       0, &retval);
+	if (err)
+		return err;
+
+	return retval;
+}
+
+static enum led_brightness aaeon_led_brightness_get(struct led_classdev
+						      *cdev)
+{
+	int err, brightness;
+	struct aaeon_led_data *led =
+			container_of(cdev, struct aaeon_led_data, cdev);
+	u32 arg0;
+
+	arg0 = (u32)(led->id & 0xF);
+	err = asus_wmi_evaluate_method(GET_LED_METHOD_ID, arg0, 0, &brightness);
+	if (err)
+		return err;
+
+	return brightness;
+};
+
+static void aaeon_led_brightness_set(struct led_classdev *cdev,
+				       enum led_brightness brightness)
+{
+	int err, retval;
+	struct aaeon_led_data *led =
+			container_of(cdev, struct aaeon_led_data, cdev);
+	u32 arg0;
+
+	arg0 = (u32)(led->id & 0xF);
+	if (brightness != LED_OFF)
+		arg0 |= BIT(16);
+
+	err = asus_wmi_evaluate_method(SET_LED_METHOD_ID, arg0, 0, &retval);
+};
+
+static int __init aaeon_add_led_device(struct platform_device *pdev,
+					   int id)
+{
+	struct aaeon_led_data *led;
+
+	led = devm_kzalloc(&pdev->dev, sizeof(struct aaeon_led_data), GFP_KERNEL);
+	if (!led)
+		return -ENOMEM;
+
+	led->id = id;
+	led->cdev.brightness_get = aaeon_led_brightness_get;
+	led->cdev.brightness_set = aaeon_led_brightness_set;
+	led->cdev.name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "led:%d:", id);
+
+	if (!led->cdev.name)
+		return -ENOMEM;
+
+	return devm_led_classdev_register(&pdev->dev, &led->cdev);
+}
+
+static int aaeon_led_probe(struct platform_device *pdev)
+{
+	int err = -ENODEV, i;
+	int led_number = 0;
+
+	pr_debug("aaeon led device probe!\n");
+	/* Prevent other drivers adding this platfom device */
+	if (!wmi_has_guid(AAEON_WMI_MGMT_GUID)) {
+		pr_debug("AAEON Management GUID not found\n");
+		return -ENODEV;
+	}
+
+	/* Query the number of led devices board support */
+	led_number = aaeon_led_get_number();
+
+	/*
+	 * If the number is 0 or can't get the number of leds,
+	 * no need to register any led device node.
+	 */
+	if (led_number <= 0)
+		return -ENODEV;
+
+	for (i = 0; i < led_number; i++) {
+		err = aaeon_add_led_device(pdev, i);
+		if (err)
+			break;
+	}
+
+	return err;
+}
+
+static struct platform_driver aaeon_led_driver = {
+	.driver = {
+		.name = "leds-aaeon",
+	},
+};
+
+module_platform_driver_probe(aaeon_led_driver, aaeon_led_probe);
+
+MODULE_ALIAS("platform:leds-aaeon");
+MODULE_DESCRIPTION("AAEON LED Driver");
+MODULE_AUTHOR("Kunyang Fan <kunyang_fan@xxxxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
2.25.1