[RFC v3] hwmon: add Corsair Commander Pro driver

[Marius Zachmann]

This is v3 of a driver for the Corsair Commander Pro.
It provides sysfs attributes for:
- Reading fan speed
- Reading temp sensors
- Reading voltage values
- Writing pwm and reading last written pwm
- Reading fan and temp connection status

I still need to add it to hid_ignore_list in hid-quirks.h,
but for now I don't want to spam another mailing list.

Signed-off-by: Marius Zachmann <mail@xxxxxxxxxxxxxxxxx>
---
Changes from v2
- add corsair-cpro to Documentation/hwmon/index.rst
- add SPDX license identifier to corsair-cpro.rst
- remove fanX_enable from Documentation and driver
- changed comment style
- clarified protocol in comments
- add get_temp_cnct for reading temperature sensor
  connection status
- added temp_cnct and temp_label in ccp_device
- added tempX_label, showing connection status
- renamed get_fan_mode_label to get_fan_cnct
- get_temp_cnct and get_fan_cnct only called in probe
- send_usb_cmd checks errors in the device response
- send_usb_cmd clears the buffer and sets the
  command
- inlined get_fan_rpm and get_voltage and removed
  functions
- more reverse christmas tree
- add device ids to hid_ignore_list in hid-quirks.h

Changes from v1:
- Style issues
- Changed to USB driver
- Clarify reading pwm
- Fixed attribute name number in Documentation
- MODULE_LICENSE now "GPL"
- Removed unneccesary hwmondev in ccp_device
- Moved buffer to ccp_device and mutex out of send_usb_cmd
- No more replacing or ignoring error codes
- Use DIV_ROUND_CLOSEST in set_pwm
- Changed fan_label when unknown to "fanX other"
- Only accept 0 or 1 for fan_enable
- Check for ERR_PTR in ccp_probe
---
 Documentation/hwmon/corsair-cpro.rst |  40 +++
 Documentation/hwmon/index.rst        |   1 +
 MAINTAINERS                          |   6 +
 drivers/hwmon/Kconfig                |  10 +
 drivers/hwmon/Makefile               |   1 +
 drivers/hwmon/corsair-cpro.c         | 497 +++++++++++++++++++++++++++
 6 files changed, 555 insertions(+)
 create mode 100644 Documentation/hwmon/corsair-cpro.rst
 create mode 100644 drivers/hwmon/corsair-cpro.c

diff --git a/Documentation/hwmon/corsair-cpro.rst b/Documentation/hwmon/corsair-cpro.rst
new file mode 100644
index 000000000000..2383c6f72115
--- /dev/null
+++ b/Documentation/hwmon/corsair-cpro.rst
@@ -0,0 +1,40 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver corsair-cpro
+==========================
+
+Supported devices:
+
+  * Corsair Commander Pro
+  * Corsair Commander Pro (1000D)
+
+Author: Marius Zachmann
+
+Description
+-----------
+
+This driver implements the sysfs interface for the Corsair Commander Pro.
+The Corsair Commander Pro is a USB device with 6 fan connectors,
+4 temperature sensor connectors and 2 Corsair LED connectors.
+It can read the voltage levels on the SATA power connector.
+
+Usage Notes
+-----------
+
+Since it is a USB device, hotswapping is possible. The device is autodetected.
+
+Sysfs entries
+-------------
+
+======================= =====================================================================
+in0_input		Voltage on SATA 12v
+in1_input		Voltage on SATA 5v
+in2_input		Voltage on SATA 3.3v
+temp[1-4]_input		Temperature on connected temperature sensors
+temp[1-4] label		Shows "nc" after name, when not connected
+fan[1-6]_input		Connected fan rpm.
+fan[1-6]_label		Shows connection status of the fan as detected by the device.
+pwm[1-6]		Sets the fan speed. Values from 0-255.
+			When reading, it reports the last value if it was set by the driver.
+			Otherwise returns 0.
+======================= =====================================================================
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 55ff4b7c5349..750d3a975d82 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -47,6 +47,7 @@ Hardware Monitoring Kernel Drivers
    bel-pfe
    bt1-pvt
    coretemp
+   corsair-cpro
    da9052
    da9055
    dell-smm-hwmon
diff --git a/MAINTAINERS b/MAINTAINERS
index f08f290df174..169530c7eede 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4386,6 +4386,12 @@ S:	Maintained
 F:	Documentation/hwmon/coretemp.rst
 F:	drivers/hwmon/coretemp.c
 
+CORSAIR-CPRO HARDWARE MONITOR DRIVER
+M:	Marius Zachmann <mail@xxxxxxxxxxxxxxxxx>
+L:	linux-hwmon@xxxxxxxxxxxxxxx
+S:	Maintained
+F:	drivers/hwmon/corsair-cpro.c
+
 COSA/SRP SYNC SERIAL DRIVER
 M:	Jan "Yenya" Kasprzak <kas@xxxxxxxxxx>
 S:	Maintained
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 288ae9f63588..8b046a5dfa40 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -439,6 +439,16 @@ config SENSORS_BT1_PVT_ALARMS
 	  the data conversion will be periodically performed and the data will be
 	  saved in the internal driver cache.
 
+config SENSORS_CORSAIR_CPRO
+	tristate "Corsair Commander Pro controller"
+	depends on USB
+	help
+	  If you say yes here you get support for the Corsair Commander Pro
+	  controller.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called corsair-cpro.
+
 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 3e32c21f5efe..18e1ef74ade7 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_SENSORS_ATXP1)	+= atxp1.o
 obj-$(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_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-cpro.c b/drivers/hwmon/corsair-cpro.c
new file mode 100644
index 000000000000..c4852829f90f
--- /dev/null
+++ b/drivers/hwmon/corsair-cpro.c
@@ -0,0 +1,497 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * corsair-cpro.c - Linux driver for Corsair Commander Pro
+ * Copyright (C) 2020 Marius Zachmann <mail@xxxxxxxxxxxxxxxxx>
+ */
+
+#include <linux/kernel.h>
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#define USB_VENDOR_ID_CORSAIR               0x1b1c
+#define USB_PRODUCT_ID_CORSAIR_COMMANDERPRO 0x0c10
+#define USB_PRODUCT_ID_CORSAIR_1000D	    0x1d00
+
+#define OUT_BUFFER_SIZE	63
+#define IN_BUFFER_SIZE	16
+#define LABEL_LENGTH	12
+
+#define CTL_GET_TMP_CNCT 0x10 /*
+			       * returns in bytes 1-4 for each temp sensor:
+			       * 0 not connected
+			       * 1 connected
+			       */
+#define CTL_GET_TMP	 0x11 /*
+			       * send: byte 1 is channel, rest zero
+			       * rcv:  returns temp for channel in bytes 1 and 2
+			       * returns 17 in byte 0 if no sensor is connected
+			       */
+#define CTL_GET_VOLT	 0x12 /*
+			       * send: byte 1 is rail number: 0 = 12v, 1 = 5v, 2 = 3.3v
+			       * rcv:  returns volt in bytes 1,2
+			       */
+#define CTL_GET_FAN_CNCT 0x20 /*
+			       * returns in bytes 1-6 for each fan:
+			       * 0 not connected
+			       * 1 3pin
+			       * 2 4pin
+			       */
+#define CTL_GET_FAN_RPM	 0x21 /*
+			       * send: byte 1 is channel, rest zero
+			       * rcv:  returns rpm in bytes 1,2
+			       */
+#define CTL_SET_FAN_FPWM 0x23 /*
+			       * set fixed pwm
+			       * send: byte 1 is fan number
+			       * send: byte 2 is percentage from 0 - 100
+			       */
+
+struct ccp_device {
+	struct usb_device *udev;
+	struct mutex mutex; /* whenever buffer is used, lock before send_usb_cmd */
+	u8 *buffer;
+	int pwm[6];
+	char fan_label[6][LABEL_LENGTH];
+	int temp_cnct[4];
+	char temp_label[4][LABEL_LENGTH];
+};
+
+/* send command, check for error in response, response in ccp->buffer */
+static int send_usb_cmd(struct ccp_device *ccp, u8 command, u8 byte1, u8 byte2)
+{
+	int actual_length;
+	int ret;
+
+	memset(ccp->buffer, 0x00, OUT_BUFFER_SIZE);
+	ccp->buffer[0] = command;
+	ccp->buffer[1] = byte1;
+	ccp->buffer[2] = byte2;
+
+	ret = usb_bulk_msg(ccp->udev, usb_sndintpipe(ccp->udev, 2), ccp->buffer, OUT_BUFFER_SIZE,
+			   &actual_length, 1000);
+	if (ret) {
+		dev_err(&ccp->udev->dev, "usb_bulk_msg send failed: %d", ret);
+		return ret;
+	}
+
+	/* response needs to be received every time */
+	ret = usb_bulk_msg(ccp->udev, usb_rcvintpipe(ccp->udev, 1), ccp->buffer, IN_BUFFER_SIZE,
+			   &actual_length, 1000);
+	if (ret) {
+		dev_err(&ccp->udev->dev, "usb_bulk_msg receive failed: %d", ret);
+		return ret;
+	}
+
+	/* first byte of response is error code */
+	if (ccp->buffer[0] != 0x00) {
+		dev_err(&ccp->udev->dev, "device response error: %d", ccp->buffer[0]);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/* for commands, which return just a number depending on a channel: */
+static int get_data(struct ccp_device *ccp, int command, int channel, long *val)
+{
+	int ret;
+
+	mutex_lock(&ccp->mutex);
+
+	ret = send_usb_cmd(ccp, command, channel, 0);
+	if (ret)
+		goto exit;
+
+	*val = (ccp->buffer[1] << 8) + ccp->buffer[2];
+
+exit:
+	mutex_unlock(&ccp->mutex);
+	return ret;
+}
+
+static int set_pwm(struct ccp_device *ccp, int channel, long val)
+{
+	int ret;
+
+	if (val < 0 || val > 255)
+		return -EINVAL;
+
+	ccp->pwm[channel] = val;
+
+	/* The Corsair Commander Pro uses values from 0-100 */
+	val = DIV_ROUND_CLOSEST(val * 100, 255);
+
+	mutex_lock(&ccp->mutex);
+
+	ret = send_usb_cmd(ccp, CTL_SET_FAN_FPWM, channel, val);
+
+	mutex_unlock(&ccp->mutex);
+	return ret;
+}
+
+/* read fan connection status and set labels */
+static int get_fan_cnct(struct ccp_device *ccp)
+{
+	int channel;
+	int mode;
+	int ret;
+
+	mutex_lock(&ccp->mutex);
+
+	ret = send_usb_cmd(ccp, CTL_GET_FAN_CNCT, 0, 0);
+	if (ret)
+		goto exit;
+
+	for (channel = 0; channel < 6; channel++) {
+		mode = ccp->buffer[channel + 1];
+
+		switch (mode) {
+		case 0:
+			scnprintf(ccp->fan_label[channel], LABEL_LENGTH,
+				  "fan%d nc", channel + 1);
+			break;
+		case 1:
+			scnprintf(ccp->fan_label[channel], LABEL_LENGTH,
+				  "fan%d 3pin", channel + 1);
+			break;
+		case 2:
+			scnprintf(ccp->fan_label[channel], LABEL_LENGTH,
+				  "fan%d 4pin", channel + 1);
+			break;
+		default:
+			scnprintf(ccp->fan_label[channel], LABEL_LENGTH,
+				  "fan%d other", channel + 1);
+			break;
+		}
+	}
+
+exit:
+	mutex_unlock(&ccp->mutex);
+	return ret;
+}
+
+/* read temp sensor connection status and set labels */
+static int get_temp_cnct(struct ccp_device *ccp)
+{
+	int channel;
+	int mode;
+	int ret;
+
+	mutex_lock(&ccp->mutex);
+
+	ret = send_usb_cmd(ccp, CTL_GET_TMP_CNCT, 0, 0);
+	if (ret)
+		goto exit;
+
+	for (channel = 0; channel < 4; channel++) {
+		mode = ccp->buffer[channel + 1];
+		ccp->temp_cnct[channel] = mode;
+
+		switch (mode) {
+		case 0:
+			scnprintf(ccp->temp_label[channel], LABEL_LENGTH,
+				  "temp%d nc", channel + 1);
+			break;
+		case 1:
+			scnprintf(ccp->temp_label[channel], LABEL_LENGTH,
+				  "temp%d", channel + 1);
+			break;
+		default:
+			scnprintf(ccp->temp_label[channel], LABEL_LENGTH,
+				  "temp%d other", channel + 1);
+			break;
+		}
+	}
+
+exit:
+	mutex_unlock(&ccp->mutex);
+	return ret;
+}
+
+static int get_temp(struct ccp_device *ccp, int channel, long *val)
+{
+	int ret;
+
+	if (ccp->temp_cnct[channel] != 1)
+		return -ENODATA;
+
+	ret = get_data(ccp, CTL_GET_TMP, channel, val);
+	*val = *val * 10;
+
+	return ret;
+}
+
+static int ccp_read_string(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, const char **str)
+{
+	struct ccp_device *ccp = dev_get_drvdata(dev);
+	int ret = 0;
+
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_label:
+			*str = ccp->fan_label[channel];
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_label:
+			*str = ccp->temp_label[channel];
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+}
+
+static int ccp_read(struct device *dev, enum hwmon_sensor_types type,
+		    u32 attr, int channel, long *val)
+{
+	struct ccp_device *ccp = dev_get_drvdata(dev);
+	int ret = 0;
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			ret = get_temp(ccp, channel, val);
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			ret = get_data(ccp, CTL_GET_FAN_RPM, channel, val);
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+			/* how to read pwm values from the device is currently unknown */
+			/* driver returns last set value or 0		               */
+			*val = ccp->pwm[channel];
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+			ret = get_data(ccp, CTL_GET_VOLT, channel, val);
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+};
+
+static int ccp_write(struct device *dev, enum hwmon_sensor_types type,
+		     u32 attr, int channel, long val)
+{
+	struct ccp_device *ccp = dev_get_drvdata(dev);
+	int ret = 0;
+
+	switch (type) {
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+			ret = set_pwm(ccp, channel, val);
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+};
+
+static umode_t ccp_is_visible(const void *data, enum hwmon_sensor_types type,
+			      u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_chip:
+		switch (attr) {
+		case hwmon_chip_update_interval:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			return 0444;
+		case hwmon_temp_label:
+			return 0444;
+		default:
+			break;
+		}
+		break;
+	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;
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+			return 0444;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+};
+
+static const struct hwmon_ops ccp_hwmon_ops = {
+	.is_visible = ccp_is_visible,
+	.read = ccp_read,
+	.read_string = ccp_read_string,
+	.write = ccp_write,
+};
+
+static const struct hwmon_channel_info *ccp_info[] = {
+	HWMON_CHANNEL_INFO(chip,
+			   HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL
+			   ),
+	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_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,
+			   HWMON_PWM_INPUT,
+			   HWMON_PWM_INPUT
+			   ),
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT,
+			   HWMON_I_INPUT,
+			   HWMON_I_INPUT
+			   ),
+	NULL
+};
+
+static const struct hwmon_chip_info ccp_chip_info = {
+	.ops = &ccp_hwmon_ops,
+	.info = ccp_info,
+};
+
+static int ccp_probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+	struct device *hwmon_dev;
+	struct ccp_device *ccp;
+	int ret;
+
+	ccp = devm_kzalloc(&intf->dev, sizeof(struct ccp_device), GFP_KERNEL);
+	if (!ccp)
+		return -ENOMEM;
+
+	ccp->buffer = devm_kmalloc(&intf->dev, OUT_BUFFER_SIZE, GFP_KERNEL);
+	if (!ccp->buffer)
+		return -ENOMEM;
+
+	mutex_init(&ccp->mutex);
+
+	ccp->udev = interface_to_usbdev(intf);
+
+	/* temp and fan connection status only updates, when device is powered on */
+	ret = get_temp_cnct(ccp);
+	if (ret)
+		return ret;
+
+	ret = get_fan_cnct(ccp);
+	if (ret)
+		return ret;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&intf->dev, "corsaircpro", ccp,
+							 &ccp_chip_info, 0);
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+void ccp_disconnect(struct usb_interface *intf)
+{
+}
+
+static const struct usb_device_id ccp_devices[] = {
+	{ USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_COMMANDERPRO) },
+	{ USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_1000D) },
+	{ }
+};
+
+static struct usb_driver ccp_driver = {
+	.name = "corsair-cpro",
+	.probe = ccp_probe,
+	.disconnect = ccp_disconnect,
+	.id_table = ccp_devices
+};
+
+MODULE_DEVICE_TABLE(usb, ccp_devices);
+MODULE_LICENSE("GPL");
+
+module_usb_driver(ccp_driver);
-- 
2.27.0


-------------------------------------------------------------