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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@iwanders.net> Link: https://github.com/linux-surface/kernel/pull/144 Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> Reviewed-by: Armin Wolf <W_Armin@gmx.de> Link: https://lore.kernel.org/r/20240131005856.10180-2-ivor@iwanders.net [groeck: - Declare surface_fan_hwmon_is_visible() static - Add dependency on SURFACE_AGGREGATOR_BUS ] Signed-off-by: Guenter Roeck <linux@roeck-us.net>
92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Surface Fan driver for Surface System Aggregator Module. It provides access
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* to the fan's rpm through the hwmon system.
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*
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* Copyright (C) 2023 Ivor Wanders <ivor@iwanders.net>
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*/
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#include <linux/hwmon.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/surface_aggregator/device.h>
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#include <linux/types.h>
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// SSAM
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SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_fan_rpm_get, __le16, {
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.target_category = SSAM_SSH_TC_FAN,
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.command_id = 0x01,
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});
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// hwmon
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static umode_t surface_fan_hwmon_is_visible(const void *drvdata,
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enum hwmon_sensor_types type, u32 attr,
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int channel)
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{
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return 0444;
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}
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static int surface_fan_hwmon_read(struct device *dev,
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enum hwmon_sensor_types type, u32 attr,
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int channel, long *val)
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{
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struct ssam_device *sdev = dev_get_drvdata(dev);
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int ret;
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__le16 value;
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ret = __ssam_fan_rpm_get(sdev, &value);
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if (ret)
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return ret;
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*val = le16_to_cpu(value);
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return 0;
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}
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static const struct hwmon_channel_info *const surface_fan_info[] = {
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HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
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NULL
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};
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static const struct hwmon_ops surface_fan_hwmon_ops = {
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.is_visible = surface_fan_hwmon_is_visible,
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.read = surface_fan_hwmon_read,
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};
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static const struct hwmon_chip_info surface_fan_chip_info = {
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.ops = &surface_fan_hwmon_ops,
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.info = surface_fan_info,
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};
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static int surface_fan_probe(struct ssam_device *sdev)
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{
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struct device *hdev;
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hdev = devm_hwmon_device_register_with_info(&sdev->dev,
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"surface_fan", sdev,
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&surface_fan_chip_info,
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NULL);
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return PTR_ERR_OR_ZERO(hdev);
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}
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static const struct ssam_device_id ssam_fan_match[] = {
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{ SSAM_SDEV(FAN, SAM, 0x01, 0x01) },
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{},
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};
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MODULE_DEVICE_TABLE(ssam, ssam_fan_match);
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static struct ssam_device_driver surface_fan = {
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.probe = surface_fan_probe,
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.match_table = ssam_fan_match,
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.driver = {
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.name = "surface_fan",
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.probe_type = PROBE_PREFER_ASYNCHRONOUS,
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},
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};
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module_ssam_device_driver(surface_fan);
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MODULE_AUTHOR("Ivor Wanders <ivor@iwanders.net>");
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MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module");
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MODULE_LICENSE("GPL");
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