On Thu, Mar 18, 2021 at 11:55:39AM -0700, Guenter Roeck wrote:
> On 3/18/21 9:48 AM, Jonas Malaco wrote:
> > These are "all-in-one" CPU liquid coolers that can be monitored and
> > controlled through a proprietary USB HID protocol.
> >
> > While the models have differently sized radiators and come with varying
> > numbers of fans, they are all indistinguishable at the software level.
> > > The driver exposes fan/pump speeds and coolant temperature through the
> > standard hwmon sysfs interface.
> >
> > Fan and pump control, while supported by the devices, are not currently
> > exposed. The firmware accepts up to 61 trip points per channel
> > (fan/pump), but the same set of trip temperatures has to be maintained
> > for both; with pwmX_auto_point_Y_temp attributes, users would need to
> > maintain this invariant themselves.
> >
> > Instead, fan and pump control, as well as LED control (which the device
> > also supports for 9 addressable RGB LEDs on the CPU water block) are
> > left for existing and already mature user-space tools, which can still
> > be used alongside the driver, thanks to hidraw. A link to one, which I
> > also maintain, is provided in the documentation.
> >
> > The implementation is based on USB traffic analysis. It has been
> > runtime tested on x86_64, both as a built-in driver and as a module.
> >
> > Signed-off-by: Jonas Malaco <jonas@xxxxxxxxxxxx>
> > ---
> >
> > I was not sure whether to exhaustively check type, attr and channel in
> > _is_visible/_read/_read_string. Would it be preferred if those
> > functions assumed that they would never be called for unsupported
> > combinations, since that would be a programming error?
> >
> > In practice, should kraken2_is_visible be simplified into
> >
> > static umode_t kraken2_is_visible(...)
> > {
> > return 0444;
> > }
> >
> Yes, if nothing is optional, and all permissions are 0444.
>
> > and should _read/_read_string go through similar (but not as effective)
> > simplifications?
> >
> Unless I am missing something, all the channel checks are unnecessary
> and should be removed.
I'll remove them and the checks in kraken2_read for v2.
>
> > On another note, the copyright dates back to 2019 because this driver
> > was left to mature (and then was mostly forgotten about) in an
> > out-of-tree repository.[1]
> >
> > [1] https://github.com/liquidctl/liquidtux
> >
> > Documentation/hwmon/index.rst | 1 +
> > Documentation/hwmon/nzxt-kraken2.rst | 42 ++++
> > MAINTAINERS | 7 +
> > drivers/hwmon/Kconfig | 10 +
> > drivers/hwmon/Makefile | 1 +
> > drivers/hwmon/nzxt-kraken2.c | 279 +++++++++++++++++++++++++++
> > 6 files changed, 340 insertions(+)
> > create mode 100644 Documentation/hwmon/nzxt-kraken2.rst
> > create mode 100644 drivers/hwmon/nzxt-kraken2.c
> >
> > diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> > index d4b422edbe3a..48bfa7887dd4 100644
> > --- a/Documentation/hwmon/index.rst
> > +++ b/Documentation/hwmon/index.rst
> > @@ -143,6 +143,7 @@ Hardware Monitoring Kernel Drivers
> > npcm750-pwm-fan
> > nsa320
> > ntc_thermistor
> > + nzxt-kraken2
> > occ
> > pc87360
> > pc87427
> > diff --git a/Documentation/hwmon/nzxt-kraken2.rst b/Documentation/hwmon/nzxt-kraken2.rst
> > new file mode 100644
> > index 000000000000..94025de65a81
> > --- /dev/null
> > +++ b/Documentation/hwmon/nzxt-kraken2.rst
> > @@ -0,0 +1,42 @@
> > +.. SPDX-License-Identifier: GPL-2.0-or-later
> > +
> > +Kernel driver nzxt-kraken2
> > +==========================
> > +
> > +Supported devices:
> > +
> > +* NZXT Kraken X42
> > +* NZXT Kraken X52
> > +* NZXT Kraken X62
> > +* NZXT Kraken X72
> > +
> > +Author: Jonas Malaco
> > +
> > +Description
> > +-----------
> > +
> > +This driver enables hardware monitoring support for NZXT Kraken X42/X52/X62/X72
> > +all-in-one CPU liquid coolers. Three sensors are available: fan speed, pump
> > +speed and coolant temperature.
> > +
> > +Fan and pump control, while supported by the firmware, are not currently
> > +exposed. The addressable RGB LEDs, present in the integrated CPU water block
> > +and pump head, are not supported either. But both features can be found in
> > +existing user-space tools (e.g. `liquidctl`_).
> > +
> > +.. _liquidctl: https://github.com/liquidctl/liquidctl
> > +
> > +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)
> > +======================= ========================================================
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 0635b30e467c..b8f9fc5eaf08 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -12911,6 +12911,13 @@ L: linux-nfc@xxxxxxxxxxxx (moderated for non-subscribers)
> > S: Supported
> > F: drivers/nfc/nxp-nci
> >
> > +NZXT-KRAKEN2 HARDWARE MONITORING DRIVER
> > +M: Jonas Malaco <jonas@xxxxxxxxxxxx>
> > +L: linux-hwmon@xxxxxxxxxxxxxxx
> > +S: Maintained
> > +F: Documentation/hwmon/nzxt-kraken2.rst
> > +F: drivers/hwmon/nzxt-kraken2.c
> > +
> > OBJAGG
> > M: Jiri Pirko <jiri@xxxxxxxxxx>
> > L: netdev@xxxxxxxxxxxxxxx
> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > index 54f04e61fb83..0ddc974b102e 100644
> > --- a/drivers/hwmon/Kconfig
> > +++ b/drivers/hwmon/Kconfig
> > @@ -1492,6 +1492,16 @@ config SENSORS_NSA320
> > This driver can also be built as a module. If so, the module
> > will be called nsa320-hwmon.
> >
> > +config SENSORS_NZXT_KRAKEN2
> > + tristate "NZXT Kraken X42/X51/X62/X72 liquid coolers"
> > + depends on USB_HID
> > + help
> > + If you say yes here you get support for hardware monitoring for the
> > + NZXT Kraken X42/X52/X62/X72 all-in-one CPU liquid coolers.
> > +
> > + This driver can also be built as a module. If so, the module
> > + will be called nzxt-kraken2.
> > +
> > source "drivers/hwmon/occ/Kconfig"
> >
> > config SENSORS_PCF8591
> > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> > index fe38e8a5c979..59e78bc212cf 100644
> > --- a/drivers/hwmon/Makefile
> > +++ b/drivers/hwmon/Makefile
> > @@ -155,6 +155,7 @@ obj-$(CONFIG_SENSORS_NCT7904) += nct7904.o
> > obj-$(CONFIG_SENSORS_NPCM7XX) += npcm750-pwm-fan.o
> > obj-$(CONFIG_SENSORS_NSA320) += nsa320-hwmon.o
> > obj-$(CONFIG_SENSORS_NTC_THERMISTOR) += ntc_thermistor.o
> > +obj-$(CONFIG_SENSORS_NZXT_KRAKEN2) += nzxt-kraken2.o
> > obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
> > obj-$(CONFIG_SENSORS_PC87427) += pc87427.o
> > obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o
> > diff --git a/drivers/hwmon/nzxt-kraken2.c b/drivers/hwmon/nzxt-kraken2.c
> > new file mode 100644
> > index 000000000000..1426310d6965
> > --- /dev/null
> > +++ b/drivers/hwmon/nzxt-kraken2.c
> > @@ -0,0 +1,279 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * nzxt-kraken2.c - hwmon driver for NZXT Kraken X42/X52/X62/X72 coolers
> > + *
> > + * Copyright 2019 Jonas Malaco <jonas@xxxxxxxxxxxx>
>
> Should probably be 2019 - 2021
>
> > + */
> > +
> > +#include <asm/unaligned.h>
> > +#include <linux/hid.h>
> > +#include <linux/hwmon.h>
> > +#include <linux/module.h>
> > +#include <linux/spinlock.h>
> > +
> > +#define STATUS_REPORT_ID 0x04
> > +#define STATUS_USEFUL_SIZE 8
> > +
> > +static const char *const kraken2_temp_label[] = {
> > + "Coolant",
> > +};
> > +
> > +static const char *const kraken2_fan_label[] = {
> > + "Fan",
> > + "Pump",
> > +};
> > +
> > +struct kraken2_priv_data {
> > + struct hid_device *hid_dev;
> > + struct device *hwmon_dev;
> > +
> > + spinlock_t lock; /* protects the last received status */
> > + u8 status[STATUS_USEFUL_SIZE];
> > +};
> > +
> > +static umode_t kraken2_is_visible(const void *data,
> > + enum hwmon_sensor_types type,
> > + u32 attr, int channel)
> > +{
> > + switch (type) {
> > + case hwmon_temp:
> > + switch (attr) {
> > + case hwmon_temp_input:
> > + case hwmon_temp_label:
> > + if (channel == 0)
> > + return 0444;
> > + return 0;
> > + }
> > + break;
> > + case hwmon_fan:
> > + switch (attr) {
> > + case hwmon_fan_input:
> > + case hwmon_fan_label:
> > + if (channel >= 0 && channel < 2)
> > + return 0444;
> > + return 0;
> > + }
> > + break;
> > + default:
> > + break;
> > + }
> > + return 0;
> > +}
> > +
> > +static int kraken2_read(struct device *dev, enum hwmon_sensor_types type,
> > + u32 attr, int channel, long *val)
> > +{
> > + struct kraken2_priv_data *priv = dev_get_drvdata(dev);
> > + unsigned long flags;
> > +
> > + switch (type) {
> > + case hwmon_temp:
> > + switch (attr) {
> > + case hwmon_temp_input:
> > + if (channel != 0)
> > + return -EOPNOTSUPP;
> > + /*
> > + * The fractional byte has been observed to be in the
> > + * interval [1,9], but some of these steps are also
> > + * consistently skipped for certain integer parts.
> > + *
> > + * For the lack of a better idea, assume that the
> > + * resolution is 0.1°C, and that the missing steps are
> > + * artifacts of how the firmware processes the raw
> > + * sensor data.
> > + */
> > + spin_lock_irqsave(&priv->lock, flags);
>
> Why would this need to disable interrupts ?
Here and for the fan speeds they are disabled because kraken2_raw_event
is an interrupt handler (specifically, it runs in a hard IRQ context).
>
> > + *val = priv->status[1] * 1000 + priv->status[2] * 100;
> > + spin_unlock_irqrestore(&priv->lock, flags);
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > + break;
> > + case hwmon_fan:
> > + switch (attr) {
> > + case hwmon_fan_input:
> > + if (channel < 0 || channel >= 2)
> > + return -EOPNOTSUPP;
> > + spin_lock_irqsave(&priv->lock, flags);
>
> Why would this need to disable interrupts ?
>
> > + *val = get_unaligned_be16(priv->status + 3 + channel * 2);
> > + spin_unlock_irqrestore(&priv->lock, flags);
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int kraken2_read_string(struct device *dev, enum hwmon_sensor_types type,
> > + u32 attr, int channel, const char **str)
> > +{
> > + switch (type) {
> > + case hwmon_temp:
> > + switch (attr) {
> > + case hwmon_temp_label:
> > + if (channel != 0)
> > + return -EOPNOTSUPP;
> > + *str = kraken2_temp_label[channel];
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > + break;
> > + case hwmon_fan:
> > + switch (attr) {
> > + case hwmon_fan_label:
> > + if (channel < 0 || channel >= 2)
> > + return -EOPNOTSUPP;
> > + *str = kraken2_fan_label[channel];
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > + return 0;
> > +}
> > +
> > +static const struct hwmon_ops kraken2_hwmon_ops = {
> > + .is_visible = kraken2_is_visible,
> > + .read = kraken2_read,
> > + .read_string = kraken2_read_string,
> > +};
> > +
> > +static const struct hwmon_channel_info *kraken2_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),
> > + NULL
> > +};
> > +
> > +static const struct hwmon_chip_info kraken2_chip_info = {
> > + .ops = &kraken2_hwmon_ops,
> > + .info = kraken2_info,
> > +};
> > +
> > +static int kraken2_raw_event(struct hid_device *hdev,
> > + struct hid_report *report, u8 *data, int size)
> > +{
> > + struct kraken2_priv_data *priv;
> > + unsigned long flags;
> > +
> > + if (size < STATUS_USEFUL_SIZE || report->id != STATUS_REPORT_ID)
> > + return 0;
> > +
> > + priv = hid_get_drvdata(hdev);
> > +
> > + spin_lock_irqsave(&priv->lock, flags);
>
> I don't see the point of disabling interrupts here and above.
Before they were disabled because this runs in a hard IRQ context. But
that also means that, indeed, it wasn't necessary to disable them here.
>
> Either case, the spinlocks are overkill. It would be much easier to
> convert raw readings here into temperature and fan speed and store
> the resulting values in struct kraken2_priv_data, and then to
> just report it in the read functions. That would be much less costly
> because the spinlock would not be needed at all, and calculations
> would be done only once per event.
Oddly enough, this is very close to how the code read last week.
But I was storing the values in kraken2_priv_data as longs, and I'm not
sure that storing and loading longs is atomic on all architectures.
Was that safe, or should I use something else instead of longs?
>
> > + memcpy(priv->status, data, STATUS_USEFUL_SIZE);
> > + spin_unlock_irqrestore(&priv->lock, flags);
> > +
> > + return 0;
> > +}
>
> For my education: What triggers those events ? Are they reported
> by the hardware autonomously whenever something changes ?
> A comment at the top of the driver explaining how this works
> might be useful.
The device autonomously sends these status reports twice a second.
I'll add the comment for v2.
>
> Also, is there a way to initialize values during probe ? Otherwise
> the driver would report values of 0 until the hardware reports
> something.
The device doesn't respond to HID Get_Report, so we can't get valid
initial values.
The best we can do is identify the situation and report it to
user-space. Am I right that ENODATA should be used for this?
Thanks,
Jonas
>
> > +
> > +static int kraken2_probe(struct hid_device *hdev,
> > + const struct hid_device_id *id)
> > +{
> > + struct kraken2_priv_data *priv;
> > + int ret;
> > +
> > + priv = devm_kzalloc(&hdev->dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + priv->hid_dev = hdev;
> > + spin_lock_init(&priv->lock);
> > + hid_set_drvdata(hdev, priv);
> > +
> > + 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->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "kraken2",
> > + priv, &kraken2_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;
> > + }
> > +
> > + return 0;
> > +
> > +fail_and_close:
> > + hid_hw_close(hdev);
> > +fail_and_stop:
> > + hid_hw_stop(hdev);
> > + return ret;
> > +}
> > +
> > +static void kraken2_remove(struct hid_device *hdev)
> > +{
> > + struct kraken2_priv_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 kraken2_table[] = {
> > + { HID_USB_DEVICE(0x1e71, 0x170e) }, /* NZXT Kraken X42/X52/X62/X72 */
> > + { }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(hid, kraken2_table);
> > +
> > +static struct hid_driver kraken2_driver = {
> > + .name = "nzxt-kraken2",
> > + .id_table = kraken2_table,
> > + .probe = kraken2_probe,
> > + .remove = kraken2_remove,
> > + .raw_event = kraken2_raw_event,
> > +};
> > +
> > +static int __init kraken2_init(void)
> > +{
> > + return hid_register_driver(&kraken2_driver);
> > +}
> > +
> > +static void __exit kraken2_exit(void)
> > +{
> > + hid_unregister_driver(&kraken2_driver);
> > +}
> > +
> > +/*
> > + * When compiled into the kernel, initialize after the hid bus.
> > + */
> > +late_initcall(kraken2_init);
> > +module_exit(kraken2_exit);
> > +
> > +MODULE_LICENSE("GPL");
> > +MODULE_AUTHOR("Jonas Malaco <jonas@xxxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("Hwmon driver for NZXT Kraken X42/X52/X62/X72 coolers");
> >
> > base-commit: d8a08585259268e7b5305d04422a59d713719ccb
> >
>
