Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | /* |
| 3 | * Common/core components for the Surface System Aggregator Module (SSAM) HID |
| 4 | * transport driver. Provides support for integrated HID devices on Microsoft |
| 5 | * Surface models. |
| 6 | * |
| 7 | * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com> |
| 8 | */ |
| 9 | |
| 10 | #include <asm/unaligned.h> |
| 11 | #include <linux/hid.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/types.h> |
| 15 | #include <linux/usb/ch9.h> |
| 16 | |
| 17 | #include <linux/surface_aggregator/controller.h> |
| 18 | |
| 19 | #include "surface_hid_core.h" |
| 20 | |
| 21 | |
Maximilian Luz | 2c2c3a0 | 2022-05-27 04:34:42 +0200 | [diff] [blame] | 22 | /* -- Utility functions. ---------------------------------------------------- */ |
| 23 | |
| 24 | static bool surface_hid_is_hot_removed(struct surface_hid_device *shid) |
| 25 | { |
| 26 | /* |
| 27 | * Non-ssam client devices, i.e. platform client devices, cannot be |
| 28 | * hot-removed. |
| 29 | */ |
| 30 | if (!is_ssam_device(shid->dev)) |
| 31 | return false; |
| 32 | |
| 33 | return ssam_device_is_hot_removed(to_ssam_device(shid->dev)); |
| 34 | } |
| 35 | |
| 36 | |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 37 | /* -- Device descriptor access. --------------------------------------------- */ |
| 38 | |
| 39 | static int surface_hid_load_hid_descriptor(struct surface_hid_device *shid) |
| 40 | { |
| 41 | int status; |
| 42 | |
Maximilian Luz | 2c2c3a0 | 2022-05-27 04:34:42 +0200 | [diff] [blame] | 43 | if (surface_hid_is_hot_removed(shid)) |
| 44 | return -ENODEV; |
| 45 | |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 46 | status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_HID, |
| 47 | (u8 *)&shid->hid_desc, sizeof(shid->hid_desc)); |
| 48 | if (status) |
| 49 | return status; |
| 50 | |
| 51 | if (shid->hid_desc.desc_len != sizeof(shid->hid_desc)) { |
| 52 | dev_err(shid->dev, "unexpected HID descriptor length: got %u, expected %zu\n", |
| 53 | shid->hid_desc.desc_len, sizeof(shid->hid_desc)); |
| 54 | return -EPROTO; |
| 55 | } |
| 56 | |
| 57 | if (shid->hid_desc.desc_type != HID_DT_HID) { |
| 58 | dev_err(shid->dev, "unexpected HID descriptor type: got %#04x, expected %#04x\n", |
| 59 | shid->hid_desc.desc_type, HID_DT_HID); |
| 60 | return -EPROTO; |
| 61 | } |
| 62 | |
| 63 | if (shid->hid_desc.num_descriptors != 1) { |
| 64 | dev_err(shid->dev, "unexpected number of descriptors: got %u, expected 1\n", |
| 65 | shid->hid_desc.num_descriptors); |
| 66 | return -EPROTO; |
| 67 | } |
| 68 | |
| 69 | if (shid->hid_desc.report_desc_type != HID_DT_REPORT) { |
| 70 | dev_err(shid->dev, "unexpected report descriptor type: got %#04x, expected %#04x\n", |
| 71 | shid->hid_desc.report_desc_type, HID_DT_REPORT); |
| 72 | return -EPROTO; |
| 73 | } |
| 74 | |
| 75 | return 0; |
| 76 | } |
| 77 | |
| 78 | static int surface_hid_load_device_attributes(struct surface_hid_device *shid) |
| 79 | { |
| 80 | int status; |
| 81 | |
Maximilian Luz | 2c2c3a0 | 2022-05-27 04:34:42 +0200 | [diff] [blame] | 82 | if (surface_hid_is_hot_removed(shid)) |
| 83 | return -ENODEV; |
| 84 | |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 85 | status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_ATTRS, |
| 86 | (u8 *)&shid->attrs, sizeof(shid->attrs)); |
| 87 | if (status) |
| 88 | return status; |
| 89 | |
| 90 | if (get_unaligned_le32(&shid->attrs.length) != sizeof(shid->attrs)) { |
| 91 | dev_err(shid->dev, "unexpected attribute length: got %u, expected %zu\n", |
| 92 | get_unaligned_le32(&shid->attrs.length), sizeof(shid->attrs)); |
| 93 | return -EPROTO; |
| 94 | } |
| 95 | |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | |
| 100 | /* -- Transport driver (common). -------------------------------------------- */ |
| 101 | |
| 102 | static int surface_hid_start(struct hid_device *hid) |
| 103 | { |
| 104 | struct surface_hid_device *shid = hid->driver_data; |
| 105 | |
| 106 | return ssam_notifier_register(shid->ctrl, &shid->notif); |
| 107 | } |
| 108 | |
| 109 | static void surface_hid_stop(struct hid_device *hid) |
| 110 | { |
| 111 | struct surface_hid_device *shid = hid->driver_data; |
Maximilian Luz | 2c2c3a0 | 2022-05-27 04:34:42 +0200 | [diff] [blame] | 112 | bool hot_removed; |
| 113 | |
| 114 | /* |
| 115 | * Communication may fail for devices that have been hot-removed. This |
| 116 | * also includes unregistration of HID events, so we need to check this |
| 117 | * here. Only if the device has not been marked as hot-removed, we can |
| 118 | * safely disable events. |
| 119 | */ |
| 120 | hot_removed = surface_hid_is_hot_removed(shid); |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 121 | |
| 122 | /* Note: This call will log errors for us, so ignore them here. */ |
Maximilian Luz | 2c2c3a0 | 2022-05-27 04:34:42 +0200 | [diff] [blame] | 123 | __ssam_notifier_unregister(shid->ctrl, &shid->notif, !hot_removed); |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 124 | } |
| 125 | |
| 126 | static int surface_hid_open(struct hid_device *hid) |
| 127 | { |
| 128 | return 0; |
| 129 | } |
| 130 | |
| 131 | static void surface_hid_close(struct hid_device *hid) |
| 132 | { |
| 133 | } |
| 134 | |
| 135 | static int surface_hid_parse(struct hid_device *hid) |
| 136 | { |
| 137 | struct surface_hid_device *shid = hid->driver_data; |
| 138 | size_t len = get_unaligned_le16(&shid->hid_desc.report_desc_len); |
| 139 | u8 *buf; |
| 140 | int status; |
| 141 | |
Maximilian Luz | 2c2c3a0 | 2022-05-27 04:34:42 +0200 | [diff] [blame] | 142 | if (surface_hid_is_hot_removed(shid)) |
| 143 | return -ENODEV; |
| 144 | |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 145 | buf = kzalloc(len, GFP_KERNEL); |
| 146 | if (!buf) |
| 147 | return -ENOMEM; |
| 148 | |
| 149 | status = shid->ops.get_descriptor(shid, SURFACE_HID_DESC_REPORT, buf, len); |
| 150 | if (!status) |
| 151 | status = hid_parse_report(hid, buf, len); |
| 152 | |
| 153 | kfree(buf); |
| 154 | return status; |
| 155 | } |
| 156 | |
| 157 | static int surface_hid_raw_request(struct hid_device *hid, unsigned char reportnum, u8 *buf, |
| 158 | size_t len, unsigned char rtype, int reqtype) |
| 159 | { |
| 160 | struct surface_hid_device *shid = hid->driver_data; |
| 161 | |
Maximilian Luz | 2c2c3a0 | 2022-05-27 04:34:42 +0200 | [diff] [blame] | 162 | if (surface_hid_is_hot_removed(shid)) |
| 163 | return -ENODEV; |
| 164 | |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 165 | if (rtype == HID_OUTPUT_REPORT && reqtype == HID_REQ_SET_REPORT) |
| 166 | return shid->ops.output_report(shid, reportnum, buf, len); |
| 167 | |
| 168 | else if (rtype == HID_FEATURE_REPORT && reqtype == HID_REQ_GET_REPORT) |
| 169 | return shid->ops.get_feature_report(shid, reportnum, buf, len); |
| 170 | |
| 171 | else if (rtype == HID_FEATURE_REPORT && reqtype == HID_REQ_SET_REPORT) |
| 172 | return shid->ops.set_feature_report(shid, reportnum, buf, len); |
| 173 | |
| 174 | return -EIO; |
| 175 | } |
| 176 | |
Thomas Weißschuh | dd350af | 2023-01-30 03:59:42 +0000 | [diff] [blame] | 177 | static const struct hid_ll_driver surface_hid_ll_driver = { |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 178 | .start = surface_hid_start, |
| 179 | .stop = surface_hid_stop, |
| 180 | .open = surface_hid_open, |
| 181 | .close = surface_hid_close, |
| 182 | .parse = surface_hid_parse, |
| 183 | .raw_request = surface_hid_raw_request, |
| 184 | }; |
| 185 | |
| 186 | |
| 187 | /* -- Common device setup. -------------------------------------------------- */ |
| 188 | |
| 189 | int surface_hid_device_add(struct surface_hid_device *shid) |
| 190 | { |
| 191 | int status; |
| 192 | |
| 193 | status = surface_hid_load_hid_descriptor(shid); |
| 194 | if (status) |
| 195 | return status; |
| 196 | |
| 197 | status = surface_hid_load_device_attributes(shid); |
| 198 | if (status) |
| 199 | return status; |
| 200 | |
| 201 | shid->hid = hid_allocate_device(); |
| 202 | if (IS_ERR(shid->hid)) |
| 203 | return PTR_ERR(shid->hid); |
| 204 | |
| 205 | shid->hid->dev.parent = shid->dev; |
| 206 | shid->hid->bus = BUS_HOST; |
Maximilian Luz | b0d713c | 2021-04-11 13:34:02 +0200 | [diff] [blame] | 207 | shid->hid->vendor = get_unaligned_le16(&shid->attrs.vendor); |
| 208 | shid->hid->product = get_unaligned_le16(&shid->attrs.product); |
| 209 | shid->hid->version = get_unaligned_le16(&shid->hid_desc.hid_version); |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 210 | shid->hid->country = shid->hid_desc.country_code; |
| 211 | |
| 212 | snprintf(shid->hid->name, sizeof(shid->hid->name), "Microsoft Surface %04X:%04X", |
| 213 | shid->hid->vendor, shid->hid->product); |
| 214 | |
| 215 | strscpy(shid->hid->phys, dev_name(shid->dev), sizeof(shid->hid->phys)); |
| 216 | |
| 217 | shid->hid->driver_data = shid; |
| 218 | shid->hid->ll_driver = &surface_hid_ll_driver; |
| 219 | |
| 220 | status = hid_add_device(shid->hid); |
| 221 | if (status) |
| 222 | hid_destroy_device(shid->hid); |
| 223 | |
| 224 | return status; |
| 225 | } |
| 226 | EXPORT_SYMBOL_GPL(surface_hid_device_add); |
| 227 | |
| 228 | void surface_hid_device_destroy(struct surface_hid_device *shid) |
| 229 | { |
| 230 | hid_destroy_device(shid->hid); |
| 231 | } |
| 232 | EXPORT_SYMBOL_GPL(surface_hid_device_destroy); |
| 233 | |
| 234 | |
| 235 | /* -- PM ops. --------------------------------------------------------------- */ |
| 236 | |
| 237 | #ifdef CONFIG_PM_SLEEP |
| 238 | |
| 239 | static int surface_hid_suspend(struct device *dev) |
| 240 | { |
| 241 | struct surface_hid_device *d = dev_get_drvdata(dev); |
| 242 | |
Benjamin Tissoires | 9e35620 | 2021-12-02 10:53:33 +0100 | [diff] [blame] | 243 | return hid_driver_suspend(d->hid, PMSG_SUSPEND); |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 244 | } |
| 245 | |
| 246 | static int surface_hid_resume(struct device *dev) |
| 247 | { |
| 248 | struct surface_hid_device *d = dev_get_drvdata(dev); |
| 249 | |
Benjamin Tissoires | 9e35620 | 2021-12-02 10:53:33 +0100 | [diff] [blame] | 250 | return hid_driver_resume(d->hid); |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 251 | } |
| 252 | |
| 253 | static int surface_hid_freeze(struct device *dev) |
| 254 | { |
| 255 | struct surface_hid_device *d = dev_get_drvdata(dev); |
| 256 | |
Benjamin Tissoires | 9e35620 | 2021-12-02 10:53:33 +0100 | [diff] [blame] | 257 | return hid_driver_suspend(d->hid, PMSG_FREEZE); |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 258 | } |
| 259 | |
| 260 | static int surface_hid_poweroff(struct device *dev) |
| 261 | { |
| 262 | struct surface_hid_device *d = dev_get_drvdata(dev); |
| 263 | |
Benjamin Tissoires | 9e35620 | 2021-12-02 10:53:33 +0100 | [diff] [blame] | 264 | return hid_driver_suspend(d->hid, PMSG_HIBERNATE); |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 265 | } |
| 266 | |
| 267 | static int surface_hid_restore(struct device *dev) |
| 268 | { |
| 269 | struct surface_hid_device *d = dev_get_drvdata(dev); |
| 270 | |
Benjamin Tissoires | 9e35620 | 2021-12-02 10:53:33 +0100 | [diff] [blame] | 271 | return hid_driver_reset_resume(d->hid); |
Maximilian Luz | b05ff10 | 2021-03-10 23:53:28 +0100 | [diff] [blame] | 272 | } |
| 273 | |
| 274 | const struct dev_pm_ops surface_hid_pm_ops = { |
| 275 | .freeze = surface_hid_freeze, |
| 276 | .thaw = surface_hid_resume, |
| 277 | .suspend = surface_hid_suspend, |
| 278 | .resume = surface_hid_resume, |
| 279 | .poweroff = surface_hid_poweroff, |
| 280 | .restore = surface_hid_restore, |
| 281 | }; |
| 282 | EXPORT_SYMBOL_GPL(surface_hid_pm_ops); |
| 283 | |
| 284 | #else /* CONFIG_PM_SLEEP */ |
| 285 | |
| 286 | const struct dev_pm_ops surface_hid_pm_ops = { }; |
| 287 | EXPORT_SYMBOL_GPL(surface_hid_pm_ops); |
| 288 | |
| 289 | #endif /* CONFIG_PM_SLEEP */ |
| 290 | |
| 291 | MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>"); |
| 292 | MODULE_DESCRIPTION("HID transport driver core for Surface System Aggregator Module"); |
| 293 | MODULE_LICENSE("GPL"); |