Message-Id: <20201129215306.2209938-1-me@jackdoan.com>
Date:   Sun, 29 Nov 2020 15:53:04 -0600
From:   Jack Doan <me@...kdoan.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Jack Doan <me@...kdoan.com>, Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Jonathan Corbet <corbet@....net>, linux-hwmon@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] This is a driver for the HXi series of Corsair ATX power supplies.

It is based on Marius Zachmann's <mail@...iuszachmann.de> corsair-cpro
driver, since it follows a similar communication pattern, just with a
different protocol.

The devices:
Corsair's HXi line of "smart" power supplies that provide monitoring
data via a proprietary USB-HID interface. The protocol strongly
resembles PMBus, and gives access to voltage, current, and power
measurements for each of the PSU's rails.

The driver:
Again, I based this heavily on the corsair-cpro driver as the
requirements are very similar (weird USB-HID communication, maintaining
compatibility with existing userspace tools, providing hardware
monitoring data). I've tested the driver pretty thoroughly on my HX850i,
and existing userspace tools show that the protocol is common to all HXi
series PSUs. I'm looking to acquire some more Corsair PSU variants (RMi,
and AXi), to see if support can be expanded to them as well.

I do not work for Corsair and I intend to keep this driver maintainted
as long as I feasibly can.
Signed-off-by: Jack Doan <me@...kdoan.com>
---
 Documentation/hwmon/corsair-hxi-psu.rst |  50 +++
 Documentation/hwmon/index.rst           |   1 +
 MAINTAINERS                             |   6 +
 drivers/hwmon/Kconfig                   |  10 +
 drivers/hwmon/Makefile                  |   1 +
 drivers/hwmon/corsair-hxi-psu.c         | 504 ++++++++++++++++++++++++
 6 files changed, 572 insertions(+)
 create mode 100644 Documentation/hwmon/corsair-hxi-psu.rst
 create mode 100644 drivers/hwmon/corsair-hxi-psu.c

diff --git a/Documentation/hwmon/corsair-hxi-psu.rst b/Documentation/hwmon/corsair-hxi-psu.rst
new file mode 100644
index 000000000000..91d6beb36f88
--- /dev/null
+++ b/Documentation/hwmon/corsair-hxi-psu.rst
@@ -0,0 +1,50 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver corsair-hxi-psu
+==========================
+
+Supported devices:
+
+  * Corsair HXi ATX power supplies (HX750i, HX850i, HX1000i and HX1200i)
+
+Author: Jack Doan
+
+Description
+-----------
+
+This driver provides a sysfs interface for the Corsair HXi series of ATX
+power supplies.
+
+Usage Notes
+-----------
+
+Since it is a USB device, hot-swapping is possible. The device is auto-detected.
+
+Sysfs entries
+-------------
+
+* in0_input / in0_label    Voltage on ATX_12V
+* in1_input / in1_label    Voltage on ATX_5V
+* in2_input / in2_label    Voltage on ATX_3V
+* in3_input / in3_label    Input AC voltage
+
+* curr0_input / curr0_label    Current on ATX_12V
+* curr1_input / curr1_label    Current on ATX_5V
+* curr2_input / curr2_label    Current on ATX_3V
+
+* power1_input / power1_label    Power on ATX_12V
+* power2_input / power2_label    Power on ATX_5V
+* power3_input / power3_label    Power on ATX_3V
+* power4_input / power4_label    Total AC Power
+
+* temp1_input   Temperature before PSU fan
+* temp2_input   Temperature after PSU fan
+
+Future work
+------------
+
+* Adding support for monitoring and control of the fan
+* Getting and setting the overcurrent-protection mode
+* Testing on other lines of Corsair PSUs (RMi, AXi)
+* Broadening support to other "smart" ATX PSUs (NZXT, Seasonic)
+* Potentially pulling this into the PMBus code
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index b797db738225..afa598fee1e6 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -49,6 +49,7 @@ Hardware Monitoring Kernel Drivers
    bt1-pvt
    coretemp
    corsair-cpro
+   corsair-hxi-psu
    da9052
    da9055
    dell-smm-hwmon
diff --git a/MAINTAINERS b/MAINTAINERS
index 2daa6ee673f7..2c84a0820ef5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4485,6 +4485,12 @@ L:	linux-hwmon@...r.kernel.org
 S:	Maintained
 F:	drivers/hwmon/corsair-cpro.c
 
+CORSAIR-HXI-PSU HARDWARE MONITOR DRIVER
+M:	Jack Doan <me@...kdoan.com>
+L:	linux-hwmon@...r.kernel.org
+S:	Maintained
+F:	drivers/hwmon/corsair-hxi-psu.c
+
 COSA/SRP SYNC SERIAL DRIVER
 M:	Jan "Yenya" Kasprzak <kas@...muni.cz>
 S:	Maintained
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index a850e4f0e0bd..fd28bb859199 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -449,6 +449,16 @@ config SENSORS_CORSAIR_CPRO
 	  This driver can also be built as a module. If so, the module
 	  will be called corsair-cpro.
 
+config SENSORS_CORSAIR_HXI_PSU
+	tristate "Corsair HXi power supplies"
+	depends on HID
+	help
+	  If you say yes here you get monitoring support for the Corsair HXi series
+	  of ATX power supplies
+
+	  This driver can also be built as a module. If so, the module
+	  will be called corsair-hxi-psu.
+
 config SENSORS_DRIVETEMP
 	tristate "Hard disk drives with temperature sensors"
 	depends on SCSI && ATA
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 9db2903b61e5..8924270c60b7 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_SENSORS_AXI_FAN_CONTROL) += axi-fan-control.o
 obj-$(CONFIG_SENSORS_BT1_PVT)	+= bt1-pvt.o
 obj-$(CONFIG_SENSORS_CORETEMP)	+= coretemp.o
 obj-$(CONFIG_SENSORS_CORSAIR_CPRO) += corsair-cpro.o
+obj-$(CONFIG_SENSORS_CORSAIR_HXI_PSU) += corsair-hxi-psu.o
 obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o
 obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o
 obj-$(CONFIG_SENSORS_DELL_SMM)	+= dell-smm-hwmon.o
diff --git a/drivers/hwmon/corsair-hxi-psu.c b/drivers/hwmon/corsair-hxi-psu.c
new file mode 100644
index 000000000000..9b46656e03f8
--- /dev/null
+++ b/drivers/hwmon/corsair-hxi-psu.c
@@ -0,0 +1,504 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * corsair-cpro.c - Linux driver for Corsair HX 850i
+ * Copyright (C) 2020 Jack Doan <me@...kdoan.com>
+ * Copyright (C) 2020 Marius Zachmann <mail@...iuszachmann.de>
+ * Copyright (C) 2017-2019  Sean Nelson <audiohacked@...il.com>
+ *
+ * Supported devices:
+ * Corsair HXi ATX power supplies (HX750i, HX850i, HX1000i and HX1200i)
+ *
+ * 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 simultaneously, reports could be switched.
+ *
+ * Broadly speaking, this power supply communicates with a sort of
+ * PMBUS-over-USBHID protocol.
+ *
+ * Support has been added for reading:
+ *      * both temperature sensors
+ *      * voltage, current, and power for 12V, 5V, 3.3V rails
+ *      * input (wall) voltage
+ *      * total input (wall) power
+ * Supposedly, the PSU supports the following functionality that is not yet
+ * supported by this driver:
+ *      * changing the fan control mode from automatic to manual
+ *      * setting fan speed
+ *      * reading/writing different overcurrent-protection modes
+ */
+
+#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/types.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jack Doan <me@...kdoan.com>");
+
+#define USB_VENDOR_ID_CORSAIR            0x1b1c
+#define USB_PRODUCT_ID_CORSAIR_HX750i    0x1c05
+#define USB_PRODUCT_ID_CORSAIR_HX850i    0x1c06
+#define USB_PRODUCT_ID_CORSAIR_HX1000i    0x1c07
+#define USB_PRODUCT_ID_CORSAIR_HX1200i    0x1c08
+
+#define OUT_BUFFER_SIZE 63
+#define IN_BUFFER_SIZE 16
+#define LABEL_LENGTH 8
+#define REQ_TIMEOUT 300
+#define NUM_RAILS 4
+
+enum hxi_sensor_id {
+	SENSOR_12V = 0x0,
+	SENSOR_5V = 0x1,
+	SENSOR_3V = 0x2,
+	UNSWITCHED = 0xFE // do not send a sensor switch msg
+};
+
+enum hxi_sensor_cmd {
+	SIG_VOLTS = 0x8B,
+	SIG_WALL_VOLTS = 0x88,
+	SIG_AMPS = 0x8C,
+	SIG_TEMPERATURE_1 = 0x8D,
+	SIG_TEMPERATURE_2 = 0x8E,
+	SIG_WATTS = 0x96,
+	SIG_TOTAL_WATTS = 0xEE,
+};
+
+struct hxi_rail {
+	enum hxi_sensor_id sensor;
+	enum hxi_sensor_cmd volt_cmd;
+	enum hxi_sensor_cmd amp_cmd;
+	enum hxi_sensor_cmd power_cmd;
+	char label[LABEL_LENGTH];
+};
+
+struct hxi_device {
+	struct hid_device *hdev;
+	struct device *hwmon_dev;
+	struct completion wait_input_report;
+	struct mutex mutex; /* whenever buffer is used, lock before send_usb_cmd */
+	u8 *buffer;
+	struct hxi_rail rails[NUM_RAILS];
+};
+
+/* send command, check for error in response, response in hxi->buffer */
+static int send_usb_cmd(struct hxi_device *hxi, u8 command, u8 b1, u8 b2)
+{
+	unsigned long t;
+	int ret;
+
+	memset(hxi->buffer, 0x00, OUT_BUFFER_SIZE);
+	hxi->buffer[0] = command;
+	hxi->buffer[1] = b1;
+	hxi->buffer[2] = b2;
+
+	reinit_completion(&hxi->wait_input_report);
+
+	ret = hid_hw_output_report(hxi->hdev, hxi->buffer, OUT_BUFFER_SIZE);
+	if (ret < 0)
+		goto exit;
+	else
+		ret = 0;
+	t = wait_for_completion_timeout(&hxi->wait_input_report, msecs_to_jiffies(REQ_TIMEOUT));
+	if (!t)
+		ret = -ETIMEDOUT;
+
+exit:
+	return ret;
+}
+
+static int hxi_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data, int size)
+{
+	struct hxi_device *hxi = hid_get_drvdata(hdev);
+
+	/* only copy buffer when requested */
+	if (completion_done(&hxi->wait_input_report))
+		goto exit;
+
+	memcpy(hxi->buffer, data, min(IN_BUFFER_SIZE, size));
+	complete(&hxi->wait_input_report);
+
+exit:
+	return 0;
+}
+
+/*
+ * Gets one of the two temperature sensors in the PSU
+ * This code is different enough from the other sensors to justify pulling it out into it's own
+ * function to improve readability.
+ */
+static int get_temperature(struct hxi_device *hxi, int channel)
+{
+	int ret;
+	u8 cmd = SIG_TEMPERATURE_1;
+
+	if (channel == 1)
+		cmd = SIG_TEMPERATURE_2;
+
+	mutex_lock(&hxi->mutex);
+	ret = send_usb_cmd(hxi, 0x03, cmd, 0);
+	if (ret)
+		ret = -ENODATA;
+	else
+		ret = (hxi->buffer[2] << 8) + hxi->buffer[3];
+	mutex_unlock(&hxi->mutex);
+
+	return ret;
+}
+
+/*
+ * The PSU reports voltage/current/power measurements in this 16-bit
+ * floating-point format as described in the
+ * PMBUS spec, v1.2, Part II, section 8.3.1
+ *
+ * There is already code for this in the PMBus section of hwmon, but I didn't
+ * want this module to depend on any of the PMBus components because PMBus is
+ * so heavily tied in with I2C, and this is a USBHID driver.
+ */
+static int decode_corsair_float(u16 input)
+{
+	int ret;
+	int exponent = input >> 11;
+	int fraction = input & 2047;
+
+	if (exponent > 15)
+		exponent = -(32 - exponent);
+	if (fraction > 1023)
+		fraction = -(2048 - fraction);
+	if (fraction & 1)
+		fraction++;
+	/* scale to milli-units */
+	fraction = fraction * 1000;
+	if (exponent < 0)
+		ret = fraction >> ((~exponent) + 1);
+	else
+		ret = fraction << exponent;
+	return ret;
+}
+
+/*
+ * Requests and returns single data values depending on channel.
+ * To maintain PMBUS-like behavior, the PSU switches "channels" when taking
+ * measurements from the 12V/5V/3.3V busses. Other sensors that have standard
+ * PMBUS commands are "unswitched"
+ */
+static int get_data(struct hxi_device *hxi, enum hxi_sensor_id sensor, enum hxi_sensor_cmd sig)
+{
+	int ret;
+
+	mutex_lock(&hxi->mutex);
+	switch (sensor) {
+	case SENSOR_12V:
+	case SENSOR_5V:
+	case SENSOR_3V:
+		ret = send_usb_cmd(hxi, 0x2, 0x0, sensor);
+		break;
+	case UNSWITCHED:
+		ret = 0;
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+	if (ret)
+		goto out_unlock;
+	switch (sig) {
+	case SIG_VOLTS:
+	case SIG_AMPS:
+	case SIG_WATTS:
+	case SIG_TOTAL_WATTS:
+	case SIG_WALL_VOLTS:
+		ret = send_usb_cmd(hxi, 0x3, sig, 0);
+		break;
+	default:
+		ret = -1;
+		break;
+	}
+	if (ret)
+		goto out_unlock;
+	/*
+	 * Note that this is different byte order from temperature.
+	 * Thanks, PMBus.
+	 */
+	ret = (hxi->buffer[3] << 8) + hxi->buffer[2];
+
+out_unlock:
+	mutex_unlock(&hxi->mutex);
+	return decode_corsair_float((u16)ret);
+}
+
+static int hxi_read_string(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, const char **str)
+{
+	int ret;
+	struct hxi_device *hxi = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_in:
+	case hwmon_curr:
+	case hwmon_power:
+		switch (attr) {
+		case hwmon_in_label: /* this includes current as well */
+		case hwmon_power_label:
+			*str = hxi->rails[channel].label;
+			ret = 0;
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+}
+
+static int hxi_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int chan, long *val)
+{
+	struct hxi_device *hxi = dev_get_drvdata(dev);
+	int ret = -EOPNOTSUPP;
+	int data;
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			data = get_temperature(hxi, chan);
+			if (data < 0) {
+				ret = -ENODATA;
+				goto exit;
+			}
+			*val = data;
+			ret = 0;
+			break;
+		default:
+			break;
+		}
+		break;
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+			data = get_data(hxi, hxi->rails[chan].sensor, hxi->rails[chan].volt_cmd);
+			if (data < 0) {
+				ret = -ENODATA;
+				goto exit;
+			}
+			*val = data;
+			ret = 0;
+			break;
+		default:
+			break;
+		}
+		break;
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_input:
+			data = get_data(hxi, hxi->rails[chan].sensor, hxi->rails[chan].amp_cmd);
+			if (data < 0) {
+				ret = -ENODATA;
+				goto exit;
+			}
+			*val = data;
+			ret = 0;
+			break;
+		default:
+			break;
+		}
+		break;
+	case hwmon_power:
+		switch (attr) {
+		case hwmon_power_input:
+			data = get_data(hxi, hxi->rails[chan].sensor, hxi->rails[chan].power_cmd);
+			if (data < 0) {
+				ret = -ENODATA;
+				goto exit;
+			}
+			/*power is reported in uW, more scaling needed */
+			*val = data * 1000;
+			ret = 0;
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+exit:
+	return ret;
+}
+
+static int hxi_write(struct device *dev, enum hwmon_sensor_types type,
+		     u32 attr, int channel, long val)
+{
+	return -EOPNOTSUPP;
+}
+
+static umode_t hxi_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel)
+{
+	return 0444;
+}
+
+static const struct hwmon_ops hxi_hwmon_ops = {
+	.is_visible = hxi_is_visible,
+	.read = hxi_read,
+	.read_string = hxi_read_string,
+	.write = hxi_write,
+};
+
+static const struct hwmon_channel_info *hxi_info[] = {
+	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT,
+			   HWMON_T_INPUT
+	),
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   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,
+			   HWMON_C_INPUT | HWMON_C_LABEL
+	),
+	HWMON_CHANNEL_INFO(power,
+			   HWMON_P_INPUT | HWMON_P_LABEL,
+			   HWMON_P_INPUT | HWMON_P_LABEL,
+			   HWMON_P_INPUT | HWMON_P_LABEL,
+			   HWMON_P_INPUT | HWMON_P_LABEL
+	),
+	NULL
+};
+
+static const struct hwmon_chip_info hxi_chip_info = {
+	.ops = &hxi_hwmon_ops,
+	.info = hxi_info,
+};
+
+static int hxi_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct hxi_device *hxi;
+	int ret;
+	int i;
+
+	hxi = devm_kzalloc(&hdev->dev, sizeof(*hxi), GFP_KERNEL);
+	if (!hxi) {
+		ret = -ENOMEM;
+		goto exit;
+	}
+
+	hxi->buffer = devm_kmalloc(&hdev->dev, OUT_BUFFER_SIZE, GFP_KERNEL);
+	if (!hxi->buffer) {
+		ret = -ENOMEM;
+		goto exit;
+	}
+
+	for (i = 0; i < NUM_RAILS - 1; i++) {
+		hxi->rails[i].volt_cmd = SIG_VOLTS;
+		hxi->rails[i].amp_cmd = SIG_AMPS;
+		hxi->rails[i].power_cmd = SIG_WATTS;
+	}
+
+	hxi->rails[0].sensor = SENSOR_12V;
+	hxi->rails[1].sensor = SENSOR_5V;
+	hxi->rails[2].sensor = SENSOR_3V;
+	hxi->rails[3].sensor = UNSWITCHED;
+	hxi->rails[3].volt_cmd = SIG_WALL_VOLTS;
+	hxi->rails[3].power_cmd = SIG_TOTAL_WATTS;
+
+	strncpy(hxi->rails[0].label, "12V", LABEL_LENGTH);
+	strncpy(hxi->rails[1].label, "5V", LABEL_LENGTH);
+	strncpy(hxi->rails[2].label, "3V", LABEL_LENGTH);
+	strncpy(hxi->rails[3].label, "Wall", LABEL_LENGTH);
+
+	ret = hid_parse(hdev);
+	if (ret)
+		goto exit;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret)
+		goto exit;
+
+	ret = hid_hw_open(hdev);
+	if (ret)
+		goto out_hw_stop;
+
+	hxi->hdev = hdev;
+	hid_set_drvdata(hdev, hxi);
+	mutex_init(&hxi->mutex);
+	init_completion(&hxi->wait_input_report);
+
+	hid_device_io_start(hdev);
+
+	hxi->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "hxipsu",
+							 hxi, &hxi_chip_info, 0);
+	if (IS_ERR(hxi->hwmon_dev)) {
+		ret = (int)PTR_ERR(hxi->hwmon_dev);
+		goto out_hw_close;
+	}
+
+	ret = 0;
+	goto exit;
+
+out_hw_close:
+	hid_hw_close(hdev);
+out_hw_stop:
+	hid_hw_stop(hdev);
+exit:
+	return ret;
+}
+
+static void hxi_remove(struct hid_device *hdev)
+{
+	struct hxi_device *hxi = hid_get_drvdata(hdev);
+
+	hwmon_device_unregister(hxi->hwmon_dev);
+	hid_hw_close(hdev);
+	hid_hw_stop(hdev);
+}
+
+static const struct hid_device_id hxi_devices[] = {
+	{HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_HX750i)},
+	{HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_HX850i)},
+	{HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_HX1000i)},
+	{HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_HX1200i)},
+	{}
+};
+
+static struct hid_driver hxi_driver = {
+	.name = "corsair-hxi",
+	.id_table = hxi_devices,
+	.probe = hxi_probe,
+	.remove = hxi_remove,
+	.raw_event = hxi_raw_event,
+};
+
+MODULE_DEVICE_TABLE(hid, hxi_devices);
+
+static int __init hxi_init(void)
+{
+	return hid_register_driver(&hxi_driver);
+}
+
+static void __exit hxi_exit(void)
+{
+	hid_unregister_driver(&hxi_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(hxi_init);
+
+module_exit(hxi_exit);
-- 
2.29.2

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