hwmon: Add driver for Gigabyte AORUS Waterforce AIO coolers

diff --git a/Documentation/hwmon/gigabyte_waterforce.rst b/Documentation/hwmon/gigabyte_waterforce.rst
new file mode 100644
index 000000000000..d47f3e8516ee
--- /dev/null
+++ b/Documentation/hwmon/gigabyte_waterforce.rst
@@ -0,0 +1,47 @@ 
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver gigabyte_waterforce
+=================================
+
+Supported devices:
+
+* Gigabyte AORUS WATERFORCE X240
+* Gigabyte AORUS WATERFORCE X280
+* Gigabyte AORUS WATERFORCE X360
+
+Author: Aleksa Savic
+
+Description
+-----------
+
+This driver enables hardware monitoring support for the listed Gigabyte Waterforce
+all-in-one CPU liquid coolers. Available sensors are pump and fan speed in RPM, as
+well as coolant temperature. Also available through debugfs is the firmware version.
+
+Attaching a fan is optional and allows it to be controlled from the device. If
+it's not connected, the fan-related sensors will report zeroes.
+
+The addressable RGB LEDs and LCD screen are not supported in this driver and should
+be controlled through userspace tools.
+
+Usage notes
+-----------
+
+As these are USB HIDs, the driver can be loaded automatically by the kernel and
+supports hot swapping.
+
+Sysfs entries
+-------------
+
+=========== =============================================
+fan1_input  Fan speed (in rpm)
+fan2_input  Pump speed (in rpm)
+temp1_input Coolant temperature (in millidegrees Celsius)
+=========== =============================================
+
+Debugfs entries
+---------------
+
+================ =======================
+firmware_version Device firmware version
+================ =======================
diff --git a/MAINTAINERS b/MAINTAINERS
index 44d394dc97c7..5757e08b6d77 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8795,6 +8795,13 @@  F:	Documentation/filesystems/gfs2*
 F:	fs/gfs2/
 F:	include/uapi/linux/gfs2_ondisk.h
 
+GIGABYTE WATERFORCE SENSOR DRIVER
+M:	Aleksa Savic <savicaleksa83@gmail.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/hwmon/gigabyte_waterforce.rst
+F:	drivers/hwmon/gigabyte_waterforce.c
+
 GIGABYTE WMI DRIVER
 M:	Thomas Weißschuh <thomas@weissschuh.net>
 L:	platform-driver-x86@vger.kernel.org
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e36f58b01f2d..83f10a5bc91d 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -663,6 +663,16 @@  config SENSORS_FTSTEUTATES
 	  This driver can also be built as a module. If so, the module
 	  will be called ftsteutates.
 
+config SENSORS_GIGABYTE_WATERFORCE
+	tristate "Gigabyte Waterforce X240/X280/X360 AIO CPU coolers"
+	depends on USB_HID
+	help
+	  If you say yes here you get support for hardware monitoring for the
+	  Gigabyte Waterforce X240/X280/X360 all-in-one CPU liquid coolers.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called gigabyte_waterforce.
+
 config SENSORS_GL518SM
 	tristate "Genesys Logic GL518SM"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 019189500e5d..b62f808935d0 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -80,6 +80,7 @@  obj-$(CONFIG_SENSORS_FSCHMD)	+= fschmd.o
 obj-$(CONFIG_SENSORS_FTSTEUTATES) += ftsteutates.o
 obj-$(CONFIG_SENSORS_G760A)	+= g760a.o
 obj-$(CONFIG_SENSORS_G762)	+= g762.o
+obj-$(CONFIG_SENSORS_GIGABYTE_WATERFORCE) += gigabyte_waterforce.o
 obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o
 obj-$(CONFIG_SENSORS_GL520SM)	+= gl520sm.o
 obj-$(CONFIG_SENSORS_GSC)	+= gsc-hwmon.o
diff --git a/drivers/hwmon/gigabyte_waterforce.c b/drivers/hwmon/gigabyte_waterforce.c
new file mode 100644
index 000000000000..2d8ef27e331a
--- /dev/null
+++ b/drivers/hwmon/gigabyte_waterforce.c
@@ -0,0 +1,439 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * hwmon driver for Gigabyte AORUS Waterforce AIO CPU coolers: X240, X280 and X360.
+ *
+ * Copyright 2023 Aleksa Savic <savicaleksa83@gmail.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/hid.h>
+#include <linux/hwmon.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <asm/unaligned.h>
+
+#define DRIVER_NAME	"gigabyte_waterforce"
+
+#define USB_VENDOR_ID_GIGABYTE		0x1044
+#define USB_PRODUCT_ID_WATERFORCE	0x7a4d	/* Gigabyte AORUS WATERFORCE X240, X280 and X360 */
+
+#define STATUS_VALIDITY		(2 * 1000)	/* ms */
+#define MAX_REPORT_LENGTH	6144
+
+#define WATERFORCE_TEMP_SENSOR	0xD
+#define WATERFORCE_FAN_SPEED	0x02
+#define WATERFORCE_PUMP_SPEED	0x05
+#define WATERFORCE_FAN_DUTY	0x08
+#define WATERFORCE_PUMP_DUTY	0x09
+
+/* Control commands, inner offsets and lengths */
+static const u8 get_status_cmd[] = { 0x99, 0xDA };
+
+#define FIRMWARE_VER_START_OFFSET_1	2
+#define FIRMWARE_VER_START_OFFSET_2	3
+static const u8 get_firmware_ver_cmd[] = { 0x99, 0xD6 };
+
+/* Command lengths */
+#define GET_STATUS_CMD_LENGTH		2
+#define GET_FIRMWARE_VER_CMD_LENGTH	2
+
+static const char *const waterforce_temp_label[] = {
+	"Coolant temp"
+};
+
+static const char *const waterforce_speed_label[] = {
+	"Fan speed",
+	"Pump speed"
+};
+
+struct waterforce_data {
+	struct hid_device *hdev;
+	struct device *hwmon_dev;
+	struct dentry *debugfs;
+	/* For locking access to buffer */
+	struct mutex buffer_lock;
+	/* For queueing multiple readers */
+	struct mutex status_report_request_mutex;
+	/* For reinitializing the completion below */
+	spinlock_t status_report_request_lock;
+	struct completion status_report_received;
+	struct completion fw_version_processed;
+
+	/* Sensor data */
+	s32 temp_input[1];
+	u16 speed_input[2];	/* Fan and pump speed in RPM */
+	u8 duty_input[2];	/* Fan and pump duty in 0-100% */
+
+	u8 *buffer;
+	int firmware_version;
+	unsigned long updated;	/* jiffies */
+};
+
+static umode_t waterforce_is_visible(const void *data,
+				     enum hwmon_sensor_types type, u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_label:
+		case hwmon_temp_input:
+			return 0444;
+		default:
+			break;
+		}
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_label:
+		case hwmon_fan_input:
+			return 0444;
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+			return 0444;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/* Writes the command to the device with the rest of the report filled with zeroes */
+static int waterforce_write_expanded(struct waterforce_data *priv, const u8 *cmd, int cmd_length)
+{
+	int ret;
+
+	mutex_lock(&priv->buffer_lock);
+
+	memset(priv->buffer, 0x00, MAX_REPORT_LENGTH);
+	memcpy(priv->buffer, cmd, cmd_length);
+	ret = hid_hw_output_report(priv->hdev, priv->buffer, MAX_REPORT_LENGTH);
+
+	mutex_unlock(&priv->buffer_lock);
+	return ret;
+}
+
+static int waterforce_get_status(struct waterforce_data *priv)
+{
+	int ret;
+
+	if (!mutex_lock_interruptible(&priv->status_report_request_mutex)) {
+		if (!time_after(jiffies, priv->updated + msecs_to_jiffies(STATUS_VALIDITY))) {
+			/* Data is up to date */
+			goto unlock_and_return;
+		}
+
+		/*
+		 * Disable raw event parsing for a moment to safely reinitialize the
+		 * completion. Reinit is done because hidraw could have triggered
+		 * the raw event parsing and marked the priv->status_report_received
+		 * completion as done.
+		 */
+		spin_lock_bh(&priv->status_report_request_lock);
+		reinit_completion(&priv->status_report_received);
+		spin_unlock_bh(&priv->status_report_request_lock);
+
+		/* Send command for getting status */
+		ret = waterforce_write_expanded(priv, get_status_cmd, GET_STATUS_CMD_LENGTH);
+		if (ret < 0)
+			return ret;
+
+		if (wait_for_completion_interruptible_timeout
+		    (&priv->status_report_received, msecs_to_jiffies(STATUS_VALIDITY)) <= 0)
+			ret = -ENODATA;
+unlock_and_return:
+		mutex_unlock(&priv->status_report_request_mutex);
+		if (ret < 0)
+			return ret;
+	} else {
+		return -ENODATA;
+	}
+
+	return 0;
+}
+
+static int waterforce_read(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, long *val)
+{
+	int ret;
+	struct waterforce_data *priv = dev_get_drvdata(dev);
+
+	if (time_after(jiffies, priv->updated + msecs_to_jiffies(STATUS_VALIDITY))) {
+		/* Request status on demand */
+		ret = waterforce_get_status(priv);
+		if (ret < 0)
+			return -ENODATA;
+	}
+
+	switch (type) {
+	case hwmon_temp:
+		*val = priv->temp_input[channel];
+		break;
+	case hwmon_fan:
+		*val = priv->speed_input[channel];
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+			*val = DIV_ROUND_CLOSEST(priv->duty_input[channel] * 255, 100);
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		return -EOPNOTSUPP;	/* unreachable */
+	}
+
+	return 0;
+}
+
+static int waterforce_read_string(struct device *dev, enum hwmon_sensor_types type,
+				  u32 attr, int channel, const char **str)
+{
+	switch (type) {
+	case hwmon_temp:
+		*str = waterforce_temp_label[channel];
+		break;
+	case hwmon_fan:
+		*str = waterforce_speed_label[channel];
+		break;
+	default:
+		return -EOPNOTSUPP;	/* unreachable */
+	}
+
+	return 0;
+}
+
+static int waterforce_get_fw_ver(struct hid_device *hdev)
+{
+	int ret;
+	struct waterforce_data *priv = hid_get_drvdata(hdev);
+
+	ret = waterforce_write_expanded(priv, get_firmware_ver_cmd, GET_FIRMWARE_VER_CMD_LENGTH);
+	if (ret < 0)
+		return ret;
+
+	if (wait_for_completion_interruptible_timeout
+	    (&priv->fw_version_processed, msecs_to_jiffies(STATUS_VALIDITY)) <= 0)
+		return -ENODATA;
+
+	return 0;
+}
+
+static const struct hwmon_ops waterforce_hwmon_ops = {
+	.is_visible = waterforce_is_visible,
+	.read = waterforce_read,
+	.read_string = waterforce_read_string
+};
+
+static const struct hwmon_channel_info *waterforce_info[] = {
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_LABEL,
+			   HWMON_F_INPUT | HWMON_F_LABEL),
+	HWMON_CHANNEL_INFO(pwm,
+			   HWMON_PWM_INPUT,
+			   HWMON_PWM_INPUT),
+	NULL
+};
+
+static const struct hwmon_chip_info waterforce_chip_info = {
+	.ops = &waterforce_hwmon_ops,
+	.info = waterforce_info,
+};
+
+static int waterforce_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data,
+				int size)
+{
+	struct waterforce_data *priv = hid_get_drvdata(hdev);
+
+	if (data[0] == get_firmware_ver_cmd[0] && data[1] == get_firmware_ver_cmd[1]) {
+		/* Received a firmware version report */
+		priv->firmware_version =
+		    data[FIRMWARE_VER_START_OFFSET_1] * 10 + data[FIRMWARE_VER_START_OFFSET_2];
+
+		if (!completion_done(&priv->fw_version_processed))
+			complete_all(&priv->fw_version_processed);
+		return 0;
+	}
+
+	if (data[0] != get_status_cmd[0] || data[1] != get_status_cmd[1])
+		return 0;
+
+	priv->temp_input[0] = data[WATERFORCE_TEMP_SENSOR] * 1000;
+	priv->speed_input[0] = get_unaligned_le16(data + WATERFORCE_FAN_SPEED);
+	priv->speed_input[1] = get_unaligned_le16(data + WATERFORCE_PUMP_SPEED);
+	priv->duty_input[0] = data[WATERFORCE_FAN_DUTY];
+	priv->duty_input[1] = data[WATERFORCE_PUMP_DUTY];
+
+	if (!completion_done(&priv->status_report_received))
+		complete_all(&priv->status_report_received);
+
+	priv->updated = jiffies;
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+static int firmware_version_show(struct seq_file *seqf, void *unused)
+{
+	struct waterforce_data *priv = seqf->private;
+
+	if (!priv->firmware_version)
+		return -ENODATA;
+
+	seq_printf(seqf, "%u\n", priv->firmware_version);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(firmware_version);
+
+static void waterforce_debugfs_init(struct waterforce_data *priv)
+{
+	char name[64];
+
+	scnprintf(name, sizeof(name), "%s-%s", DRIVER_NAME, dev_name(&priv->hdev->dev));
+
+	priv->debugfs = debugfs_create_dir(name, NULL);
+	debugfs_create_file("firmware_version", 0444, priv->debugfs, priv, &firmware_version_fops);
+}
+
+#else
+
+static void waterforce_debugfs_init(struct waterforce_data *priv)
+{
+}
+
+#endif
+
+static int waterforce_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct waterforce_data *priv;
+	int ret;
+
+	priv = devm_kzalloc(&hdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->hdev = hdev;
+	hid_set_drvdata(hdev, priv);
+
+	/*
+	 * Initialize priv->updated to STATUS_VALIDITY seconds in the past, making
+	 * the initial empty data invalid for waterforce_read() without the need for
+	 * a special case there.
+	 */
+	priv->updated = jiffies - msecs_to_jiffies(STATUS_VALIDITY);
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "hid parse failed with %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Enable hidraw so existing user-space tools can continue to work.
+	 */
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret) {
+		hid_err(hdev, "hid hw start failed with %d\n", ret);
+		goto fail_and_stop;
+	}
+
+	ret = hid_hw_open(hdev);
+	if (ret) {
+		hid_err(hdev, "hid hw open failed with %d\n", ret);
+		goto fail_and_close;
+	}
+
+	priv->buffer = devm_kzalloc(&hdev->dev, MAX_REPORT_LENGTH, GFP_KERNEL);
+	if (!priv->buffer) {
+		ret = -ENOMEM;
+		goto fail_and_close;
+	}
+
+	mutex_init(&priv->status_report_request_mutex);
+	mutex_init(&priv->buffer_lock);
+	spin_lock_init(&priv->status_report_request_lock);
+	init_completion(&priv->status_report_received);
+	init_completion(&priv->fw_version_processed);
+
+	priv->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "waterforce",
+							  priv, &waterforce_chip_info, NULL);
+	if (IS_ERR(priv->hwmon_dev)) {
+		ret = PTR_ERR(priv->hwmon_dev);
+		hid_err(hdev, "hwmon registration failed with %d\n", ret);
+		goto fail_and_close;
+	}
+
+	hid_device_io_start(hdev);
+	ret = waterforce_get_fw_ver(hdev);
+	if (ret < 0)
+		hid_warn(hdev, "fw version request failed with %d\n", ret);
+	hid_device_io_stop(hdev);
+
+	waterforce_debugfs_init(priv);
+
+	return 0;
+
+fail_and_close:
+	hid_hw_close(hdev);
+fail_and_stop:
+	hid_hw_stop(hdev);
+	return ret;
+}
+
+static void waterforce_remove(struct hid_device *hdev)
+{
+	struct waterforce_data *priv = hid_get_drvdata(hdev);
+
+	hwmon_device_unregister(priv->hwmon_dev);
+
+	hid_hw_close(hdev);
+	hid_hw_stop(hdev);
+}
+
+static const struct hid_device_id waterforce_table[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GIGABYTE, USB_PRODUCT_ID_WATERFORCE) },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(hid, waterforce_table);
+
+static struct hid_driver waterforce_driver = {
+	.name = "waterforce",
+	.id_table = waterforce_table,
+	.probe = waterforce_probe,
+	.remove = waterforce_remove,
+	.raw_event = waterforce_raw_event,
+};
+
+static int __init waterforce_init(void)
+{
+	return hid_register_driver(&waterforce_driver);
+}
+
+static void __exit waterforce_exit(void)
+{
+	hid_unregister_driver(&waterforce_driver);
+}
+
+/* When compiled into the kernel, initialize after the HID bus */
+late_initcall(waterforce_init);
+module_exit(waterforce_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Aleksa Savic <savicaleksa83@gmail.com>");
+MODULE_DESCRIPTION("Hwmon driver for Gigabyte AORUS Waterforce AIO coolers");