[PATCH] hwmon: Add System76 Thelio Io driver

["Jeremy Soller" <jeremy@system76.com>]

This driver allows fan control using System76 Thelio Io.

Signed-off-by: Jeremy Soller <jeremy@system76.com>
---
 MAINTAINERS                        |   9 +-
 drivers/hwmon/Kconfig              |  10 +
 drivers/hwmon/Makefile             |   1 +
 drivers/hwmon/system76-thelio-io.c | 424 +++++++++++++++++++++++++++++
 4 files changed, 443 insertions(+), 1 deletion(-)
 create mode 100644 drivers/hwmon/system76-thelio-io.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 48abe1a281f2..7e43d1937cfa 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20733,11 +20733,18 @@ F:	include/uapi/linux/stm.h
 
 SYSTEM76 ACPI DRIVER
 M:	Jeremy Soller <jeremy@system76.com>
-M:	System76 Product Development <productdev@system76.com>
+M:	System76 <info@system76.com>
 L:	platform-driver-x86@vger.kernel.org
 S:	Maintained
 F:	drivers/platform/x86/system76_acpi.c
 
+SYSTEM76 THELIO IO DRIVER
+M:	Jeremy Soller <jeremy@system76.com>
+M:	System76 <info@system76.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	drivers/hwmon/system76-thelio-io.c
+
 SYSV FILESYSTEM
 S:	Orphan
 F:	Documentation/filesystems/sysv-fs.rst
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 307477b8a371..108c87667c96 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2433,6 +2433,16 @@ config SENSORS_HP_WMI
 	  This driver can also be built as a module. If so, the module
 	  will be called hp_wmi_sensors.
 
+config SENSORS_SYSTEM76_THELIO_IO
+	tristate "System76 Thelio Io controller"
+	depends on HID
+	help
+	  If you say yes here you get support for the System76 Thelio Io
+	  controller.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called system76-thelio-io.
+
 endif # ACPI
 
 endif # HWMON
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 3f4b0fda0998..7cfdabb4e66f 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -199,6 +199,7 @@ obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
 obj-$(CONFIG_SENSORS_SPARX5)	+= sparx5-temp.o
 obj-$(CONFIG_SENSORS_STTS751)	+= stts751.o
 obj-$(CONFIG_SENSORS_SY7636A)	+= sy7636a-hwmon.o
+obj-$(CONFIG_SENSORS_SYSTEM76_THELIO_IO) += system76-thelio-io.o
 obj-$(CONFIG_SENSORS_AMC6821)	+= amc6821.o
 obj-$(CONFIG_SENSORS_TC74)	+= tc74.o
 obj-$(CONFIG_SENSORS_THMC50)	+= thmc50.o
diff --git a/drivers/hwmon/system76-thelio-io.c b/drivers/hwmon/system76-thelio-io.c
new file mode 100644
index 000000000000..5796810a2997
--- /dev/null
+++ b/drivers/hwmon/system76-thelio-io.c
@@ -0,0 +1,424 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * system76-thelio-io.c - Linux driver for System76 Thelio Io
+ * Copyright (C) 2023 System76
+ *
+ * Based on:
+ * corsair-cpro.c - Linux driver for Corsair Commander Pro
+ * Copyright (C) 2020 Marius Zachmann <mail@mariuszachmann.de>
+ *
+ * This driver uses hid reports to communicate with the device to allow hidraw userspace drivers
+ * still being used. The device does not use report ids. When using hidraw and this driver
+ * simultaniously, reports could be switched.
+ */
+
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/hid.h>
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include <linux/types.h>
+
+#define BUFFER_SIZE 32
+#define REQ_TIMEOUT 300
+
+#define HID_CMD 0
+#define HID_RES 1
+#define HID_DATA 2
+
+#define CMD_FAN_GET  7
+#define CMD_FAN_SET 8
+#define CMD_LED_SET_MODE 16
+#define CMD_FAN_TACH 22
+
+struct thelio_io_device {
+	struct hid_device *hdev;
+	struct device *hwmon_dev;
+#ifdef CONFIG_PM_SLEEP
+	struct notifier_block pm_notifier;
+#endif
+	struct completion wait_input_report;
+	struct mutex mutex; /* whenever buffer is used, lock before send_usb_cmd */
+	u8 *buffer;
+};
+
+/* converts response error in buffer to errno */
+static int thelio_io_get_errno(struct thelio_io_device *thelio_io)
+{
+	switch (thelio_io->buffer[HID_RES]) {
+	case 0x00: /* success */
+		return 0;
+	default:
+		hid_err(thelio_io->hdev, "unknown response error: %d", thelio_io->buffer[HID_RES]);
+		return -EIO;
+	}
+}
+
+/* send command, check for error in response, response in thelio_io->buffer */
+static int send_usb_cmd(struct thelio_io_device *thelio_io, u8 command,
+	u8 byte1, u8 byte2, u8 byte3)
+{
+	unsigned long t;
+	int ret;
+
+	memset(thelio_io->buffer, 0x00, BUFFER_SIZE);
+	thelio_io->buffer[HID_CMD] = command;
+	thelio_io->buffer[HID_DATA] = byte1;
+	thelio_io->buffer[HID_DATA + 1] = byte2;
+	thelio_io->buffer[HID_DATA + 2] = byte3;
+
+	reinit_completion(&thelio_io->wait_input_report);
+
+	ret = hid_hw_output_report(thelio_io->hdev, thelio_io->buffer, BUFFER_SIZE);
+	if (ret < 0)
+		return ret;
+
+	t = wait_for_completion_timeout(&thelio_io->wait_input_report,
+		msecs_to_jiffies(REQ_TIMEOUT));
+	if (!t)
+		return -ETIMEDOUT;
+
+	return thelio_io_get_errno(thelio_io);
+}
+
+static int thelio_io_raw_event(struct hid_device *hdev, struct hid_report *report,
+	u8 *data, int size)
+{
+	struct thelio_io_device *thelio_io = hid_get_drvdata(hdev);
+
+	/* only copy buffer when requested */
+	if (completion_done(&thelio_io->wait_input_report))
+		return 0;
+
+	memcpy(thelio_io->buffer, data, min(BUFFER_SIZE, size));
+	complete(&thelio_io->wait_input_report);
+
+	return 0;
+}
+
+/* requests and returns single data values depending on channel */
+static int get_data(struct thelio_io_device *thelio_io, int command, int channel,
+	bool two_byte_data)
+{
+	int ret;
+
+	mutex_lock(&thelio_io->mutex);
+
+	ret = send_usb_cmd(thelio_io, command, channel, 0, 0);
+	if (ret)
+		goto out_unlock;
+
+	ret = (int)thelio_io->buffer[HID_DATA + 1];
+	if (two_byte_data)
+		ret |= (((int)thelio_io->buffer[HID_DATA + 2]) << 8);
+
+out_unlock:
+	mutex_unlock(&thelio_io->mutex);
+	return ret;
+}
+
+static int set_pwm(struct thelio_io_device *thelio_io, int channel, long val)
+{
+	int ret;
+
+	if (val < 0 || val > 255)
+		return -EINVAL;
+
+	mutex_lock(&thelio_io->mutex);
+
+	ret = send_usb_cmd(thelio_io, CMD_FAN_SET, channel, val, 0);
+
+	mutex_unlock(&thelio_io->mutex);
+	return ret;
+}
+
+static int thelio_io_read_string(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, const char **str)
+{
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_label:
+			switch (channel) {
+			case 0:
+				*str = "CPU Fan";
+				return 0;
+			case 1:
+				*str = "Intake Fan";
+				return 0;
+			case 2:
+				*str = "GPU Fan";
+				return 0;
+			case 3:
+				*str = "Aux Fan";
+				return 0;
+			default:
+				break;
+			}
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int thelio_io_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	struct thelio_io_device *thelio_io = dev_get_drvdata(dev);
+	int ret;
+
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			ret = get_data(thelio_io, CMD_FAN_TACH, channel, true);
+			if (ret < 0)
+				return ret;
+			*val = ret;
+			return 0;
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+			ret = get_data(thelio_io, CMD_FAN_GET, channel, false);
+			if (ret < 0)
+				return ret;
+			*val = ret;
+			return 0;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+};
+
+static int thelio_io_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	struct thelio_io_device *thelio_io = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+			return set_pwm(thelio_io, channel, val);
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+};
+
+static umode_t thelio_io_is_visible(const void *data, enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			return 0444;
+		case hwmon_fan_label:
+			return 0444;
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+};
+
+static const struct hwmon_ops thelio_io_hwmon_ops = {
+	.is_visible = thelio_io_is_visible,
+	.read = thelio_io_read,
+	.read_string = thelio_io_read_string,
+	.write = thelio_io_write,
+};
+
+static const struct hwmon_channel_info *thelio_io_info[] = {
+	HWMON_CHANNEL_INFO(chip,
+			   HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_LABEL,
+			   HWMON_F_INPUT | HWMON_F_LABEL,
+			   HWMON_F_INPUT | HWMON_F_LABEL,
+			   HWMON_F_INPUT | HWMON_F_LABEL
+			   ),
+	HWMON_CHANNEL_INFO(pwm,
+			   HWMON_PWM_INPUT,
+			   HWMON_PWM_INPUT,
+			   HWMON_PWM_INPUT,
+			   HWMON_PWM_INPUT
+			   ),
+	NULL
+};
+
+static const struct hwmon_chip_info thelio_io_chip_info = {
+	.ops = &thelio_io_hwmon_ops,
+	.info = thelio_io_info,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int thelio_io_pm(struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct thelio_io_device *thelio_io = container_of(nb, struct thelio_io_device, pm_notifier);
+
+	switch (action) {
+	case PM_HIBERNATION_PREPARE:
+	case PM_SUSPEND_PREPARE:
+		mutex_lock(&thelio_io->mutex);
+		send_usb_cmd(thelio_io, CMD_LED_SET_MODE, 0, 1, 0);
+		mutex_unlock(&thelio_io->mutex);
+		break;
+
+	case PM_POST_HIBERNATION:
+	case PM_POST_SUSPEND:
+		mutex_lock(&thelio_io->mutex);
+		send_usb_cmd(thelio_io, CMD_LED_SET_MODE, 0, 0, 0);
+		mutex_unlock(&thelio_io->mutex);
+		break;
+
+	case PM_POST_RESTORE:
+	case PM_RESTORE_PREPARE:
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+#endif
+
+static int thelio_io_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct thelio_io_device *thelio_io;
+	int ret;
+
+	thelio_io = devm_kzalloc(&hdev->dev, sizeof(*thelio_io), GFP_KERNEL);
+	if (!thelio_io)
+		return -ENOMEM;
+
+	thelio_io->buffer = devm_kmalloc(&hdev->dev, BUFFER_SIZE, GFP_KERNEL);
+	if (!thelio_io->buffer)
+		return -ENOMEM;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret)
+		return ret;
+
+	ret = hid_hw_open(hdev);
+	if (ret)
+		goto out_hw_stop;
+
+	thelio_io->hdev = hdev;
+	hid_set_drvdata(hdev, thelio_io);
+	mutex_init(&thelio_io->mutex);
+	init_completion(&thelio_io->wait_input_report);
+
+	hid_device_io_start(hdev);
+
+	if (hdev->maxcollection == 1 && hdev->collection[0].usage == 0xFF600061) {
+		hid_info(hdev, "found command device\n");
+		thelio_io->hwmon_dev = hwmon_device_register_with_info(&hdev->dev,
+			"system76_thelio_io", thelio_io, &thelio_io_chip_info, 0);
+		if (IS_ERR(thelio_io->hwmon_dev)) {
+			ret = PTR_ERR(thelio_io->hwmon_dev);
+			goto out_hw_close;
+		}
+
+	#ifdef CONFIG_PM_SLEEP
+		thelio_io->pm_notifier.notifier_call = thelio_io_pm;
+		register_pm_notifier(&thelio_io->pm_notifier);
+	#endif
+	}
+
+	return 0;
+
+out_hw_close:
+	hid_hw_close(hdev);
+out_hw_stop:
+	hid_hw_stop(hdev);
+	return ret;
+}
+
+static void thelio_io_remove(struct hid_device *hdev)
+{
+	struct thelio_io_device *thelio_io = hid_get_drvdata(hdev);
+
+#ifdef CONFIG_PM_SLEEP
+	unregister_pm_notifier(&thelio_io->pm_notifier);
+#endif
+
+	if (thelio_io->hwmon_dev)
+		hwmon_device_unregister(thelio_io->hwmon_dev);
+
+	hid_hw_close(hdev);
+	hid_hw_stop(hdev);
+}
+
+static const struct hid_device_id thelio_io_devices[] = {
+	{ HID_USB_DEVICE(0x3384, 0x000B) }, // thelio_io_2
+	{ }
+};
+
+static struct hid_driver thelio_io_driver = {
+	.name = "system76-thelio-io",
+	.id_table = thelio_io_devices,
+	.probe = thelio_io_probe,
+	.remove = thelio_io_remove,
+	.raw_event = thelio_io_raw_event,
+};
+
+MODULE_DEVICE_TABLE(hid, thelio_io_devices);
+MODULE_LICENSE("GPL");
+
+static int __init thelio_io_init(void)
+{
+	return hid_register_driver(&thelio_io_driver);
+}
+
+static void __exit thelio_io_exit(void)
+{
+	hid_unregister_driver(&thelio_io_driver);
+}
+
+/*
+ * When compiling this driver as built-in, hwmon initcalls will get called before the
+ * hid driver and this driver would fail to register. late_initcall solves this.
+ */
+late_initcall(thelio_io_init);
+module_exit(thelio_io_exit);
-- 
2.34.1