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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Surface Fan driver for Surface System Aggregator Module. It provides access4 * to the fan's rpm through the hwmon system.5 *6 * Copyright (C) 2023 Ivor Wanders <ivor@iwanders.net>7 */8 9#include <linux/hwmon.h>10#include <linux/kernel.h>11#include <linux/module.h>12#include <linux/surface_aggregator/device.h>13#include <linux/types.h>14 15// SSAM16SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_fan_rpm_get, __le16, {17 .target_category = SSAM_SSH_TC_FAN,18 .command_id = 0x01,19});20 21// hwmon22static umode_t surface_fan_hwmon_is_visible(const void *drvdata,23 enum hwmon_sensor_types type, u32 attr,24 int channel)25{26 return 0444;27}28 29static int surface_fan_hwmon_read(struct device *dev,30 enum hwmon_sensor_types type, u32 attr,31 int channel, long *val)32{33 struct ssam_device *sdev = dev_get_drvdata(dev);34 int ret;35 __le16 value;36 37 ret = __ssam_fan_rpm_get(sdev, &value);38 if (ret)39 return ret;40 41 *val = le16_to_cpu(value);42 43 return 0;44}45 46static const struct hwmon_channel_info *const surface_fan_info[] = {47 HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),48 NULL49};50 51static const struct hwmon_ops surface_fan_hwmon_ops = {52 .is_visible = surface_fan_hwmon_is_visible,53 .read = surface_fan_hwmon_read,54};55 56static const struct hwmon_chip_info surface_fan_chip_info = {57 .ops = &surface_fan_hwmon_ops,58 .info = surface_fan_info,59};60 61static int surface_fan_probe(struct ssam_device *sdev)62{63 struct device *hdev;64 65 hdev = devm_hwmon_device_register_with_info(&sdev->dev,66 "surface_fan", sdev,67 &surface_fan_chip_info,68 NULL);69 70 return PTR_ERR_OR_ZERO(hdev);71}72 73static const struct ssam_device_id ssam_fan_match[] = {74 { SSAM_SDEV(FAN, SAM, 0x01, 0x01) },75 {},76};77MODULE_DEVICE_TABLE(ssam, ssam_fan_match);78 79static struct ssam_device_driver surface_fan = {80 .probe = surface_fan_probe,81 .match_table = ssam_fan_match,82 .driver = {83 .name = "surface_fan",84 .probe_type = PROBE_PREFER_ASYNCHRONOUS,85 },86};87module_ssam_device_driver(surface_fan);88 89MODULE_AUTHOR("Ivor Wanders <ivor@iwanders.net>");90MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module");91MODULE_LICENSE("GPL");92