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 // hwmon 22 static 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 29 static 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 46 static const struct hwmon_channel_info *const surface_fan_info[] = { 47 HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT), 48 NULL 49 }; 50 51 static const struct hwmon_ops surface_fan_hwmon_ops = { 52 .is_visible = surface_fan_hwmon_is_visible, 53 .read = surface_fan_hwmon_read, 54 }; 55 56 static const struct hwmon_chip_info surface_fan_chip_info = { 57 .ops = &surface_fan_hwmon_ops, 58 .info = surface_fan_info, 59 }; 60 61 static 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 73 static const struct ssam_device_id ssam_fan_match[] = { 74 { SSAM_SDEV(FAN, SAM, 0x01, 0x01) }, 75 {}, 76 }; 77 MODULE_DEVICE_TABLE(ssam, ssam_fan_match); 78 79 static 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 }; 87 module_ssam_device_driver(surface_fan); 88 89 MODULE_AUTHOR("Ivor Wanders <ivor@iwanders.net>"); 90 MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module"); 91 MODULE_LICENSE("GPL"); 92