hwmon: add driver for Aquacomputer D5 Next

This driver exposes hardware sensors of the Aquacomputer D5 Next
watercooling pump, which communicates through a proprietary USB HID
protocol.

Available sensors are pump and fan speed, power, voltage and current, as
well as coolant temperature. Also available through debugfs are the serial
number, firmware version and power-on count.

Attaching a fan is optional and allows it to be controlled using
temperature curves directly from the pump. If it's not connected,
the fan-related sensors will report zeroes.

The pump can be configured either through software or via its physical
interface. Configuring the pump through this driver is not implemented,
as it seems to require sending it a complete configuration. That
includes addressable RGB LEDs, for which there is no standard sysfs
interface. Thus, that task is better suited for userspace tools.

This driver has been tested on x86_64, both in-kernel and as a module.

Signed-off-by: Aleksa Savic <savicaleksa83@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

3 files changed, 374 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 64533141ea4a..c4578e8f34bb 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -254,6 +254,16 @@ config SENSORS_AHT10
 	  This driver can also be built as a module. If so, the module
 	  will be called aht10.
 
+config SENSORS_AQUACOMPUTER_D5NEXT
+	tristate "Aquacomputer D5 Next watercooling pump"
+	depends on USB_HID
+	help
+	  If you say yes here you get support for the Aquacomputer D5 Next
+	  watercooling pump sensors.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called aquacomputer_d5next.
+
 config SENSORS_AS370
 	tristate "Synaptics AS370 SoC hardware monitoring driver"
 	help
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 4b33421746c0..162940270661 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_SENSORS_ADT7470)	+= adt7470.o
 obj-$(CONFIG_SENSORS_ADT7475)	+= adt7475.o
 obj-$(CONFIG_SENSORS_AHT10)	+= aht10.o
 obj-$(CONFIG_SENSORS_APPLESMC)	+= applesmc.o
+obj-$(CONFIG_SENSORS_AQUACOMPUTER_D5NEXT) += aquacomputer_d5next.o
 obj-$(CONFIG_SENSORS_ARM_SCMI)	+= scmi-hwmon.o
 obj-$(CONFIG_SENSORS_ARM_SCPI)	+= scpi-hwmon.o
 obj-$(CONFIG_SENSORS_AS370)	+= as370-hwmon.o
diff --git a/drivers/hwmon/aquacomputer_d5next.c b/drivers/hwmon/aquacomputer_d5next.c
new file mode 100644
index 000000000000..fb9341a53051
--- /dev/null
+++ b/drivers/hwmon/aquacomputer_d5next.c
@@ -0,0 +1,363 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * hwmon driver for Aquacomputer D5 Next watercooling pump
+ *
+ * The D5 Next sends HID reports (with ID 0x01) every second to report sensor values
+ * (coolant temperature, pump and fan speed, voltage, current and power). It responds to
+ * Get_Report requests, but returns a dummy value of no use.
+ *
+ * Copyright 2021 Aleksa Savic <savicaleksa83@gmail.com>
+ */
+
+#include <asm/unaligned.h>
+#include <linux/debugfs.h>
+#include <linux/hid.h>
+#include <linux/hwmon.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+
+#define DRIVER_NAME			"aquacomputer-d5next"
+
+#define D5NEXT_STATUS_REPORT_ID	0x01
+#define D5NEXT_STATUS_UPDATE_INTERVAL	(2 * HZ) /* In seconds */
+
+/* Register offsets for the D5 Next pump */
+
+#define D5NEXT_SERIAL_FIRST_PART	3
+#define D5NEXT_SERIAL_SECOND_PART	5
+#define D5NEXT_FIRMWARE_VERSION	13
+#define D5NEXT_POWER_CYCLES		24
+
+#define D5NEXT_COOLANT_TEMP		87
+
+#define D5NEXT_PUMP_SPEED		116
+#define D5NEXT_FAN_SPEED		103
+
+#define D5NEXT_PUMP_POWER		114
+#define D5NEXT_FAN_POWER		101
+
+#define D5NEXT_PUMP_VOLTAGE		110
+#define D5NEXT_FAN_VOLTAGE		97
+#define D5NEXT_5V_VOLTAGE		57
+
+#define D5NEXT_PUMP_CURRENT		112
+#define D5NEXT_FAN_CURRENT		99
+
+/* Labels for provided values */
+
+#define L_COOLANT_TEMP			"Coolant temp"
+
+#define L_PUMP_SPEED			"Pump speed"
+#define L_FAN_SPEED			"Fan speed"
+
+#define L_PUMP_POWER			"Pump power"
+#define L_FAN_POWER			"Fan power"
+
+#define L_PUMP_VOLTAGE			"Pump voltage"
+#define L_FAN_VOLTAGE			"Fan voltage"
+#define L_5V_VOLTAGE			"+5V voltage"
+
+#define L_PUMP_CURRENT			"Pump current"
+#define L_FAN_CURRENT			"Fan current"
+
+static const char *const label_speeds[] = {
+	L_PUMP_SPEED,
+	L_FAN_SPEED,
+};
+
+static const char *const label_power[] = {
+	L_PUMP_POWER,
+	L_FAN_POWER,
+};
+
+static const char *const label_voltages[] = {
+	L_PUMP_VOLTAGE,
+	L_FAN_VOLTAGE,
+	L_5V_VOLTAGE,
+};
+
+static const char *const label_current[] = {
+	L_PUMP_CURRENT,
+	L_FAN_CURRENT,
+};
+
+struct d5next_data {
+	struct hid_device *hdev;
+	struct device *hwmon_dev;
+	struct dentry *debugfs;
+	s32 temp_input;
+	u16 speed_input[2];
+	u32 power_input[2];
+	u16 voltage_input[3];
+	u16 current_input[2];
+	u32 serial_number[2];
+	u16 firmware_version;
+	u32 power_cycles; /* How many times the device was powered on */
+	unsigned long updated;
+};
+
+static umode_t d5next_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
+				 int channel)
+{
+	return 0444;
+}
+
+static int d5next_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
+		       long *val)
+{
+	struct d5next_data *priv = dev_get_drvdata(dev);
+
+	if (time_after(jiffies, priv->updated + D5NEXT_STATUS_UPDATE_INTERVAL))
+		return -ENODATA;
+
+	switch (type) {
+	case hwmon_temp:
+		*val = priv->temp_input;
+		break;
+	case hwmon_fan:
+		*val = priv->speed_input[channel];
+		break;
+	case hwmon_power:
+		*val = priv->power_input[channel];
+		break;
+	case hwmon_in:
+		*val = priv->voltage_input[channel];
+		break;
+	case hwmon_curr:
+		*val = priv->current_input[channel];
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int d5next_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+			      int channel, const char **str)
+{
+	switch (type) {
+	case hwmon_temp:
+		*str = L_COOLANT_TEMP;
+		break;
+	case hwmon_fan:
+		*str = label_speeds[channel];
+		break;
+	case hwmon_power:
+		*str = label_power[channel];
+		break;
+	case hwmon_in:
+		*str = label_voltages[channel];
+		break;
+	case hwmon_curr:
+		*str = label_current[channel];
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_ops d5next_hwmon_ops = {
+	.is_visible = d5next_is_visible,
+	.read = d5next_read,
+	.read_string = d5next_read_string,
+};
+
+static const struct hwmon_channel_info *d5next_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(power, HWMON_P_INPUT | HWMON_P_LABEL, HWMON_P_INPUT | HWMON_P_LABEL),
+	HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL),
+	HWMON_CHANNEL_INFO(curr, HWMON_C_INPUT | HWMON_C_LABEL, HWMON_C_INPUT | HWMON_C_LABEL),
+	NULL
+};
+
+static const struct hwmon_chip_info d5next_chip_info = {
+	.ops = &d5next_hwmon_ops,
+	.info = d5next_info,
+};
+
+static int d5next_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data, int size)
+{
+	struct d5next_data *priv;
+
+	if (report->id != D5NEXT_STATUS_REPORT_ID)
+		return 0;
+
+	priv = hid_get_drvdata(hdev);
+
+	/* Info provided with every report */
+
+	priv->serial_number[0] = get_unaligned_be16(data + D5NEXT_SERIAL_FIRST_PART);
+	priv->serial_number[1] = get_unaligned_be16(data + D5NEXT_SERIAL_SECOND_PART);
+
+	priv->firmware_version = get_unaligned_be16(data + D5NEXT_FIRMWARE_VERSION);
+	priv->power_cycles = get_unaligned_be32(data + D5NEXT_POWER_CYCLES);
+
+	/* Sensor readings */
+
+	priv->temp_input = get_unaligned_be16(data + D5NEXT_COOLANT_TEMP) * 10;
+
+	priv->speed_input[0] = get_unaligned_be16(data + D5NEXT_PUMP_SPEED);
+	priv->speed_input[1] = get_unaligned_be16(data + D5NEXT_FAN_SPEED);
+
+	priv->power_input[0] = get_unaligned_be16(data + D5NEXT_PUMP_POWER) * 10000;
+	priv->power_input[1] = get_unaligned_be16(data + D5NEXT_FAN_POWER) * 10000;
+
+	priv->voltage_input[0] = get_unaligned_be16(data + D5NEXT_PUMP_VOLTAGE) * 10;
+	priv->voltage_input[1] = get_unaligned_be16(data + D5NEXT_FAN_VOLTAGE) * 10;
+	priv->voltage_input[2] = get_unaligned_be16(data + D5NEXT_5V_VOLTAGE) * 10;
+
+	priv->current_input[0] = get_unaligned_be16(data + D5NEXT_PUMP_CURRENT);
+	priv->current_input[1] = get_unaligned_be16(data + D5NEXT_FAN_CURRENT);
+
+	priv->updated = jiffies;
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+static int serial_number_show(struct seq_file *seqf, void *unused)
+{
+	struct d5next_data *priv = seqf->private;
+
+	seq_printf(seqf, "%05u-%05u\n", priv->serial_number[0], priv->serial_number[1]);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(serial_number);
+
+static int firmware_version_show(struct seq_file *seqf, void *unused)
+{
+	struct d5next_data *priv = seqf->private;
+
+	seq_printf(seqf, "%u\n", priv->firmware_version);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(firmware_version);
+
+static int power_cycles_show(struct seq_file *seqf, void *unused)
+{
+	struct d5next_data *priv = seqf->private;
+
+	seq_printf(seqf, "%u\n", priv->power_cycles);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(power_cycles);
+
+static void d5next_debugfs_init(struct d5next_data *priv)
+{
+	char name[32];
+
+	scnprintf(name, sizeof(name), "%s-%s", DRIVER_NAME, dev_name(&priv->hdev->dev));
+
+	priv->debugfs = debugfs_create_dir(name, NULL);
+	debugfs_create_file("serial_number", 0444, priv->debugfs, priv, &serial_number_fops);
+	debugfs_create_file("firmware_version", 0444, priv->debugfs, priv, &firmware_version_fops);
+	debugfs_create_file("power_cycles", 0444, priv->debugfs, priv, &power_cycles_fops);
+}
+
+#else
+
+static void d5next_debugfs_init(struct d5next_data *priv)
+{
+}
+
+#endif
+
+static int d5next_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct d5next_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);
+
+	priv->updated = jiffies - D5NEXT_STATUS_UPDATE_INTERVAL;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret)
+		return ret;
+
+	ret = hid_hw_open(hdev);
+	if (ret)
+		goto fail_and_stop;
+
+	priv->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "d5next", priv,
+							  &d5next_chip_info, NULL);
+
+	if (IS_ERR(priv->hwmon_dev)) {
+		ret = PTR_ERR(priv->hwmon_dev);
+		goto fail_and_close;
+	}
+
+	d5next_debugfs_init(priv);
+
+	return 0;
+
+fail_and_close:
+	hid_hw_close(hdev);
+fail_and_stop:
+	hid_hw_stop(hdev);
+	return ret;
+}
+
+static void d5next_remove(struct hid_device *hdev)
+{
+	struct d5next_data *priv = hid_get_drvdata(hdev);
+
+	debugfs_remove_recursive(priv->debugfs);
+	hwmon_device_unregister(priv->hwmon_dev);
+
+	hid_hw_close(hdev);
+	hid_hw_stop(hdev);
+}
+
+static const struct hid_device_id d5next_table[] = {
+	{ HID_USB_DEVICE(0x0c70, 0xf00e) }, /* Aquacomputer D5 Next */
+	{},
+};
+
+MODULE_DEVICE_TABLE(hid, d5next_table);
+
+static struct hid_driver d5next_driver = {
+	.name = DRIVER_NAME,
+	.id_table = d5next_table,
+	.probe = d5next_probe,
+	.remove = d5next_remove,
+	.raw_event = d5next_raw_event,
+};
+
+static int __init d5next_init(void)
+{
+	return hid_register_driver(&d5next_driver);
+}
+
+static void __exit d5next_exit(void)
+{
+	hid_unregister_driver(&d5next_driver);
+}
+
+/* Request to initialize after the HID bus to ensure it's not being loaded before */
+
+late_initcall(d5next_init);
+module_exit(d5next_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Aleksa Savic <savicaleksa83@gmail.com>");
+MODULE_DESCRIPTION("Hwmon driver for Aquacomputer D5 Next pump");