Adds a driver that provides read only access to the fan speed for Microsoft Surface Pro devices. The fan speed is always regulated by the EC and cannot be influenced directly. Signed-off-by: Ivor Wanders <ivor@xxxxxxxxxxxx> Link: https://github.com/linux-surface/kernel/pull/144 --- Documentation/hwmon/index.rst | 1 + Documentation/hwmon/surface_fan.rst | 27 ++++++ MAINTAINERS | 8 ++ drivers/hwmon/Kconfig | 13 +++ drivers/hwmon/Makefile | 1 + drivers/hwmon/surface_fan.c | 125 ++++++++++++++++++++++++++++ 6 files changed, 175 insertions(+) create mode 100644 Documentation/hwmon/surface_fan.rst create mode 100644 drivers/hwmon/surface_fan.c diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst index 042e1cf95..4dfb3b9bd 100644 --- a/Documentation/hwmon/index.rst +++ b/Documentation/hwmon/index.rst @@ -202,6 +202,7 @@ Hardware Monitoring Kernel Drivers smsc47m1 sparx5-temp stpddc60 + surface_fan sy7636a-hwmon tc654 tc74 diff --git a/Documentation/hwmon/surface_fan.rst b/Documentation/hwmon/surface_fan.rst new file mode 100644 index 000000000..6e27a6653 --- /dev/null +++ b/Documentation/hwmon/surface_fan.rst @@ -0,0 +1,27 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +Kernel driver surface_fan +========================= + +Supported Devices: + + * Microsoft Surface Pro 9 + +Author: Ivor Wanders <ivor@xxxxxxxxxxxx> + +Description +----------- + +This provides monitoring of the fan found in some Microsoft Surface Pro devices, +like the Surface Pro 9. The fan is always controlled by the onboard controller. + +Sysfs interface +--------------- + +======================= ======= ========================================= +Name Perm Description +======================= ======= ========================================= +``fan1_input`` RO Current fan speed in RPM. +``fan1_max`` RO Approximate maximum fan speed. +``fan1_min`` RO Minimum fan speed used by the controller. +======================= ======= ========================================= diff --git a/MAINTAINERS b/MAINTAINERS index 439cf523b..8e7870af3 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14078,6 +14078,14 @@ F: Documentation/driver-api/surface_aggregator/clients/dtx.rst F: drivers/platform/surface/surface_dtx.c F: include/uapi/linux/surface_aggregator/dtx.h +MICROSOFT SURFACE SENSOR FAN DRIVER +M: Maximilian Luz <luzmaximilian@xxxxxxxxx> +M: Ivor Wanders <ivor@xxxxxxxxxxxx> +L: linux-hwmon@xxxxxxxxxxxxxxx +S: Maintained +F: Documentation/hwmon/surface_fan.rst +F: drivers/hwmon/surface_fan.c + MICROSOFT SURFACE GPE LID SUPPORT DRIVER M: Maximilian Luz <luzmaximilian@xxxxxxxxx> L: platform-driver-x86@xxxxxxxxxxxxxxx diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 307477b8a..4b4d999af 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -1965,6 +1965,19 @@ config SENSORS_SMM665 This driver can also be built as a module. If so, the module will be called smm665. +config SENSORS_SURFACE_FAN + tristate "Surface Fan Driver" + depends on SURFACE_AGGREGATOR + help + Driver that provides monitoring of the fan on Surface Pro devices that + have a fan, like the Surface Pro 9. + + This makes the fan's current speed accessible through the hwmon + system. It does not provide control over the fan, the firmware is + responsible for that, this driver merely provides monitoring. + + Select M or Y here, if you want to be able to read the fan's speed. + config SENSORS_ADC128D818 tristate "Texas Instruments ADC128D818" depends on I2C diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index 3f4b0fda0..5ae214c06 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -198,6 +198,7 @@ obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o obj-$(CONFIG_SENSORS_SPARX5) += sparx5-temp.o obj-$(CONFIG_SENSORS_STTS751) += stts751.o +obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o obj-$(CONFIG_SENSORS_SY7636A) += sy7636a-hwmon.o obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o obj-$(CONFIG_SENSORS_TC74) += tc74.o diff --git a/drivers/hwmon/surface_fan.c b/drivers/hwmon/surface_fan.c new file mode 100644 index 000000000..7129b25ed --- /dev/null +++ b/drivers/hwmon/surface_fan.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Surface Fan driver for Surface System Aggregator Module. It provides access + * to the fan's rpm through the hwmon system. + * + * Copyright (C) 2023 Ivor Wanders <ivor@xxxxxxxxxxxx> + */ + +#include <linux/hwmon.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/surface_aggregator/device.h> +#include <linux/types.h> + +// The minimum speed for the fan when turned on by the controller. The onboard +// controller uses this as minimum value before turning the fan on or off. +#define SURFACE_FAN_MIN_SPEED 3000 +// The maximum speed, determined by observation and rounding up to the nearest +// multiple of 500 to account for variation between individual fans. +#define SURFACE_FAN_MAX_SPEED 7500 + +// SSAM +SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_fan_rpm_get, __le16, { + .target_category = SSAM_SSH_TC_FAN, + .command_id = 0x01, +}); + +// hwmon +umode_t surface_fan_hwmon_is_visible(const void *drvdata, + enum hwmon_sensor_types type, u32 attr, + int channel) +{ + if (type != hwmon_fan) + return 0; + + switch (attr) { + case hwmon_fan_input: + case hwmon_fan_label: + case hwmon_fan_min: + case hwmon_fan_max: + return 0444; + default: + return 0; + } +} + +static int surface_fan_hwmon_read(struct device *dev, + enum hwmon_sensor_types type, u32 attr, + int channel, long *val) +{ + struct ssam_device *sdev = dev_get_drvdata(dev); + __le16 value; + int res; + + if (type != hwmon_fan) + return -EOPNOTSUPP; + + switch (attr) { + case hwmon_fan_input: + res = __ssam_fan_rpm_get(sdev, &value); + if (res) + return -EIO; + *val = le16_to_cpu(value); + return 0; + case hwmon_fan_min: + *val = SURFACE_FAN_MIN_SPEED; + return 0; + case hwmon_fan_max: + *val = SURFACE_FAN_MAX_SPEED; + return 0; + default: + return -EOPNOTSUPP; + } +} + +static const struct hwmon_channel_info *const surface_fan_info[] = { + HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_MAX | HWMON_F_MIN), + NULL +}; + +static const struct hwmon_ops surface_fan_hwmon_ops = { + .is_visible = surface_fan_hwmon_is_visible, + .read = surface_fan_hwmon_read, +}; + +static const struct hwmon_chip_info surface_fan_chip_info = { + .ops = &surface_fan_hwmon_ops, + .info = surface_fan_info, +}; + +static int surface_fan_probe(struct ssam_device *sdev) +{ + struct device *hdev; + + hdev = devm_hwmon_device_register_with_info(&sdev->dev, "fan", sdev, + &surface_fan_chip_info, + NULL); + if (IS_ERR(hdev)) + return PTR_ERR(hdev); + + ssam_device_set_drvdata(sdev, sdev); + + return 0; +} + +static const struct ssam_device_id ssam_fan_match[] = { + { SSAM_SDEV(FAN, SAM, 0x01, 0x01) }, + {}, +}; +MODULE_DEVICE_TABLE(ssam, ssam_fan_match); + +static struct ssam_device_driver surface_fan = { + .probe = surface_fan_probe, + .match_table = ssam_fan_match, + .driver = { + .name = "surface_fan", + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; +module_ssam_device_driver(surface_fan); + +MODULE_AUTHOR("Ivor Wanders <ivor@xxxxxxxxxxxx>"); +MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module"); +MODULE_LICENSE("GPL"); -- 2.17.1
