1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Surface Fan driver for Surface System Aggregator Module. It provides access 4 * 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 // SSAM 16 SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_fan_rpm_get, __le16, { 17 .target_category = SSAM_SSH_TC_FAN, 18 .command_id = 0x01, 19 }); 20 21 static int surface_fan_hwmon_read(struct device *dev, 22 enum hwmon_sensor_types type, u32 attr, 23 int channel, long *val) 24 { 25 struct ssam_device *sdev = dev_get_drvdata(dev); 26 int ret; 27 __le16 value; 28 29 ret = __ssam_fan_rpm_get(sdev, &value); 30 if (ret) 31 return ret; 32 33 *val = le16_to_cpu(value); 34 35 return 0; 36 } 37 38 static const struct hwmon_channel_info *const surface_fan_info[] = { 39 HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT), 40 NULL 41 }; 42 43 static const struct hwmon_ops surface_fan_hwmon_ops = { 44 .visible = 0444, 45 .read = surface_fan_hwmon_read, 46 }; 47 48 static const struct hwmon_chip_info surface_fan_chip_info = { 49 .ops = &surface_fan_hwmon_ops, 50 .info = surface_fan_info, 51 }; 52 53 static int surface_fan_probe(struct ssam_device *sdev) 54 { 55 struct device *hdev; 56 57 hdev = devm_hwmon_device_register_with_info(&sdev->dev, 58 "surface_fan", sdev, 59 &surface_fan_chip_info, 60 NULL); 61 62 return PTR_ERR_OR_ZERO(hdev); 63 } 64 65 static const struct ssam_device_id ssam_fan_match[] = { 66 { SSAM_SDEV(FAN, SAM, 0x01, 0x01) }, 67 {}, 68 }; 69 MODULE_DEVICE_TABLE(ssam, ssam_fan_match); 70 71 static struct ssam_device_driver surface_fan = { 72 .probe = surface_fan_probe, 73 .match_table = ssam_fan_match, 74 .driver = { 75 .name = "surface_fan", 76 .probe_type = PROBE_PREFER_ASYNCHRONOUS, 77 }, 78 }; 79 module_ssam_device_driver(surface_fan); 80 81 MODULE_AUTHOR("Ivor Wanders <ivor@iwanders.net>"); 82 MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module"); 83 MODULE_LICENSE("GPL"); 84