1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * HID driver for Google Hammer device.
4 *
5 * Copyright (c) 2017 Google Inc.
6 * Author: Wei-Ning Huang <wnhuang@google.com>
7 */
8
9 /*
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 */
15
16 #include <linux/acpi.h>
17 #include <linux/hid.h>
18 #include <linux/input/vivaldi-fmap.h>
19 #include <linux/leds.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/platform_data/cros_ec_commands.h>
23 #include <linux/platform_data/cros_ec_proto.h>
24 #include <linux/platform_device.h>
25 #include <linux/pm_wakeup.h>
26 #include <linux/unaligned.h>
27
28 #include "hid-ids.h"
29 #include "hid-vivaldi-common.h"
30
31 /*
32 * C(hrome)B(ase)A(ttached)S(witch) - switch exported by Chrome EC and reporting
33 * state of the "Whiskers" base - attached or detached. Whiskers USB device also
34 * reports position of the keyboard - folded or not. Combining base state and
35 * position allows us to generate proper "Tablet mode" events.
36 */
37 struct cbas_ec {
38 struct device *dev; /* The platform device (EC) */
39 struct input_dev *input;
40 bool base_present;
41 bool base_folded;
42 struct notifier_block notifier;
43 };
44
45 static struct cbas_ec cbas_ec;
46 static DEFINE_SPINLOCK(cbas_ec_lock);
47 static DEFINE_MUTEX(cbas_ec_reglock);
48
cbas_parse_base_state(const void * data)49 static bool cbas_parse_base_state(const void *data)
50 {
51 u32 switches = get_unaligned_le32(data);
52
53 return !!(switches & BIT(EC_MKBP_BASE_ATTACHED));
54 }
55
cbas_ec_query_base(struct cros_ec_device * ec_dev,bool get_state,bool * state)56 static int cbas_ec_query_base(struct cros_ec_device *ec_dev, bool get_state,
57 bool *state)
58 {
59 struct ec_params_mkbp_info *params;
60 struct cros_ec_command *msg;
61 int ret;
62
63 msg = kzalloc(struct_size(msg, data, max(sizeof(u32), sizeof(*params))),
64 GFP_KERNEL);
65 if (!msg)
66 return -ENOMEM;
67
68 msg->command = EC_CMD_MKBP_INFO;
69 msg->version = 1;
70 msg->outsize = sizeof(*params);
71 msg->insize = sizeof(u32);
72 params = (struct ec_params_mkbp_info *)msg->data;
73 params->info_type = get_state ?
74 EC_MKBP_INFO_CURRENT : EC_MKBP_INFO_SUPPORTED;
75 params->event_type = EC_MKBP_EVENT_SWITCH;
76
77 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
78 if (ret >= 0) {
79 if (ret != sizeof(u32)) {
80 dev_warn(ec_dev->dev, "wrong result size: %d != %zu\n",
81 ret, sizeof(u32));
82 ret = -EPROTO;
83 } else {
84 *state = cbas_parse_base_state(msg->data);
85 ret = 0;
86 }
87 }
88
89 kfree(msg);
90
91 return ret;
92 }
93
cbas_ec_notify(struct notifier_block * nb,unsigned long queued_during_suspend,void * _notify)94 static int cbas_ec_notify(struct notifier_block *nb,
95 unsigned long queued_during_suspend,
96 void *_notify)
97 {
98 struct cros_ec_device *ec = _notify;
99 unsigned long flags;
100 bool base_present;
101
102 if (ec->event_data.event_type == EC_MKBP_EVENT_SWITCH) {
103 base_present = cbas_parse_base_state(
104 &ec->event_data.data.switches);
105 dev_dbg(cbas_ec.dev,
106 "%s: base: %d\n", __func__, base_present);
107
108 if (device_may_wakeup(cbas_ec.dev) ||
109 !queued_during_suspend) {
110
111 pm_wakeup_event(cbas_ec.dev, 0);
112
113 spin_lock_irqsave(&cbas_ec_lock, flags);
114
115 /*
116 * While input layer dedupes the events, we do not want
117 * to disrupt the state reported by the base by
118 * overriding it with state reported by the LID. Only
119 * report changes, as we assume that on attach the base
120 * is not folded.
121 */
122 if (base_present != cbas_ec.base_present) {
123 input_report_switch(cbas_ec.input,
124 SW_TABLET_MODE,
125 !base_present);
126 input_sync(cbas_ec.input);
127 cbas_ec.base_present = base_present;
128 }
129
130 spin_unlock_irqrestore(&cbas_ec_lock, flags);
131 }
132 }
133
134 return NOTIFY_OK;
135 }
136
cbas_ec_resume(struct device * dev)137 static __maybe_unused int cbas_ec_resume(struct device *dev)
138 {
139 struct cros_ec_device *ec = dev_get_drvdata(dev->parent);
140 bool base_present;
141 int error;
142
143 error = cbas_ec_query_base(ec, true, &base_present);
144 if (error) {
145 dev_warn(dev, "failed to fetch base state on resume: %d\n",
146 error);
147 } else {
148 spin_lock_irq(&cbas_ec_lock);
149
150 cbas_ec.base_present = base_present;
151
152 /*
153 * Only report if base is disconnected. If base is connected,
154 * it will resend its state on resume, and we'll update it
155 * in hammer_event().
156 */
157 if (!cbas_ec.base_present) {
158 input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
159 input_sync(cbas_ec.input);
160 }
161
162 spin_unlock_irq(&cbas_ec_lock);
163 }
164
165 return 0;
166 }
167
168 static SIMPLE_DEV_PM_OPS(cbas_ec_pm_ops, NULL, cbas_ec_resume);
169
cbas_ec_set_input(struct input_dev * input)170 static void cbas_ec_set_input(struct input_dev *input)
171 {
172 /* Take the lock so hammer_event() does not race with us here */
173 spin_lock_irq(&cbas_ec_lock);
174 cbas_ec.input = input;
175 spin_unlock_irq(&cbas_ec_lock);
176 }
177
__cbas_ec_probe(struct platform_device * pdev)178 static int __cbas_ec_probe(struct platform_device *pdev)
179 {
180 struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
181 struct input_dev *input;
182 bool base_supported;
183 int error;
184
185 error = cbas_ec_query_base(ec, false, &base_supported);
186 if (error)
187 return error;
188
189 if (!base_supported)
190 return -ENXIO;
191
192 input = devm_input_allocate_device(&pdev->dev);
193 if (!input)
194 return -ENOMEM;
195
196 input->name = "Whiskers Tablet Mode Switch";
197 input->id.bustype = BUS_HOST;
198
199 input_set_capability(input, EV_SW, SW_TABLET_MODE);
200
201 error = input_register_device(input);
202 if (error) {
203 dev_err(&pdev->dev, "cannot register input device: %d\n",
204 error);
205 return error;
206 }
207
208 /* Seed the state */
209 error = cbas_ec_query_base(ec, true, &cbas_ec.base_present);
210 if (error) {
211 dev_err(&pdev->dev, "cannot query base state: %d\n", error);
212 return error;
213 }
214
215 if (!cbas_ec.base_present)
216 cbas_ec.base_folded = false;
217
218 dev_dbg(&pdev->dev, "%s: base: %d, folded: %d\n", __func__,
219 cbas_ec.base_present, cbas_ec.base_folded);
220
221 input_report_switch(input, SW_TABLET_MODE,
222 !cbas_ec.base_present || cbas_ec.base_folded);
223
224 cbas_ec_set_input(input);
225
226 cbas_ec.dev = &pdev->dev;
227 cbas_ec.notifier.notifier_call = cbas_ec_notify;
228 error = blocking_notifier_chain_register(&ec->event_notifier,
229 &cbas_ec.notifier);
230 if (error) {
231 dev_err(&pdev->dev, "cannot register notifier: %d\n", error);
232 cbas_ec_set_input(NULL);
233 return error;
234 }
235
236 device_init_wakeup(&pdev->dev, true);
237 return 0;
238 }
239
cbas_ec_probe(struct platform_device * pdev)240 static int cbas_ec_probe(struct platform_device *pdev)
241 {
242 int retval;
243
244 mutex_lock(&cbas_ec_reglock);
245
246 if (cbas_ec.input) {
247 retval = -EBUSY;
248 goto out;
249 }
250
251 retval = __cbas_ec_probe(pdev);
252
253 out:
254 mutex_unlock(&cbas_ec_reglock);
255 return retval;
256 }
257
cbas_ec_remove(struct platform_device * pdev)258 static void cbas_ec_remove(struct platform_device *pdev)
259 {
260 struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
261
262 mutex_lock(&cbas_ec_reglock);
263
264 blocking_notifier_chain_unregister(&ec->event_notifier,
265 &cbas_ec.notifier);
266 cbas_ec_set_input(NULL);
267
268 mutex_unlock(&cbas_ec_reglock);
269 }
270
271 static const struct acpi_device_id cbas_ec_acpi_ids[] = {
272 { "GOOG000B", 0 },
273 { }
274 };
275 MODULE_DEVICE_TABLE(acpi, cbas_ec_acpi_ids);
276
277 #ifdef CONFIG_OF
278 static const struct of_device_id cbas_ec_of_match[] = {
279 { .compatible = "google,cros-cbas" },
280 { },
281 };
282 MODULE_DEVICE_TABLE(of, cbas_ec_of_match);
283 #endif
284
285 static struct platform_driver cbas_ec_driver = {
286 .probe = cbas_ec_probe,
287 .remove_new = cbas_ec_remove,
288 .driver = {
289 .name = "cbas_ec",
290 .acpi_match_table = ACPI_PTR(cbas_ec_acpi_ids),
291 .of_match_table = of_match_ptr(cbas_ec_of_match),
292 .pm = &cbas_ec_pm_ops,
293 },
294 };
295
296 #define MAX_BRIGHTNESS 100
297
298 struct hammer_kbd_leds {
299 struct led_classdev cdev;
300 struct hid_device *hdev;
301 u8 buf[2] ____cacheline_aligned;
302 };
303
hammer_kbd_brightness_set_blocking(struct led_classdev * cdev,enum led_brightness br)304 static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
305 enum led_brightness br)
306 {
307 struct hammer_kbd_leds *led = container_of(cdev,
308 struct hammer_kbd_leds,
309 cdev);
310 int ret;
311
312 led->buf[0] = 0;
313 led->buf[1] = br;
314
315 /*
316 * Request USB HID device to be in Full On mode, so that sending
317 * hardware output report and hardware raw request won't fail.
318 */
319 ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
320 if (ret < 0) {
321 hid_err(led->hdev, "failed: device not resumed %d\n", ret);
322 return ret;
323 }
324
325 ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
326 if (ret == -ENOSYS)
327 ret = hid_hw_raw_request(led->hdev, 0, led->buf,
328 sizeof(led->buf),
329 HID_OUTPUT_REPORT,
330 HID_REQ_SET_REPORT);
331 if (ret < 0)
332 hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
333 ret);
334
335 /* Request USB HID device back to Normal Mode. */
336 hid_hw_power(led->hdev, PM_HINT_NORMAL);
337
338 return ret;
339 }
340
hammer_register_leds(struct hid_device * hdev)341 static int hammer_register_leds(struct hid_device *hdev)
342 {
343 struct hammer_kbd_leds *kbd_backlight;
344
345 kbd_backlight = devm_kzalloc(&hdev->dev, sizeof(*kbd_backlight),
346 GFP_KERNEL);
347 if (!kbd_backlight)
348 return -ENOMEM;
349
350 kbd_backlight->hdev = hdev;
351 kbd_backlight->cdev.name = "hammer::kbd_backlight";
352 kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
353 kbd_backlight->cdev.brightness_set_blocking =
354 hammer_kbd_brightness_set_blocking;
355 kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
356
357 /* Set backlight to 0% initially. */
358 hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
359
360 return devm_led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
361 }
362
363 #define HID_UP_GOOGLEVENDOR 0xffd10000
364 #define HID_VD_KBD_FOLDED 0x00000019
365 #define HID_USAGE_KBD_FOLDED (HID_UP_GOOGLEVENDOR | HID_VD_KBD_FOLDED)
366
367 /* HID usage for keyboard backlight (Alphanumeric display brightness) */
368 #define HID_AD_BRIGHTNESS 0x00140046
369
hammer_input_mapping(struct hid_device * hdev,struct hid_input * hi,struct hid_field * field,struct hid_usage * usage,unsigned long ** bit,int * max)370 static int hammer_input_mapping(struct hid_device *hdev, struct hid_input *hi,
371 struct hid_field *field,
372 struct hid_usage *usage,
373 unsigned long **bit, int *max)
374 {
375 if (usage->hid == HID_USAGE_KBD_FOLDED) {
376 /*
377 * We do not want to have this usage mapped as it will get
378 * mixed in with "base attached" signal and delivered over
379 * separate input device for tablet switch mode.
380 */
381 return -1;
382 }
383
384 return 0;
385 }
386
hammer_folded_event(struct hid_device * hdev,bool folded)387 static void hammer_folded_event(struct hid_device *hdev, bool folded)
388 {
389 unsigned long flags;
390
391 spin_lock_irqsave(&cbas_ec_lock, flags);
392
393 /*
394 * If we are getting events from Whiskers that means that it
395 * is attached to the lid.
396 */
397 cbas_ec.base_present = true;
398 cbas_ec.base_folded = folded;
399 hid_dbg(hdev, "%s: base: %d, folded: %d\n", __func__,
400 cbas_ec.base_present, cbas_ec.base_folded);
401
402 if (cbas_ec.input) {
403 input_report_switch(cbas_ec.input, SW_TABLET_MODE, folded);
404 input_sync(cbas_ec.input);
405 }
406
407 spin_unlock_irqrestore(&cbas_ec_lock, flags);
408 }
409
hammer_event(struct hid_device * hid,struct hid_field * field,struct hid_usage * usage,__s32 value)410 static int hammer_event(struct hid_device *hid, struct hid_field *field,
411 struct hid_usage *usage, __s32 value)
412 {
413 if (usage->hid == HID_USAGE_KBD_FOLDED) {
414 hammer_folded_event(hid, value);
415 return 1; /* We handled this event */
416 }
417
418 return 0;
419 }
420
hammer_has_folded_event(struct hid_device * hdev)421 static bool hammer_has_folded_event(struct hid_device *hdev)
422 {
423 return !!hid_find_field(hdev, HID_INPUT_REPORT,
424 HID_GD_KEYBOARD, HID_USAGE_KBD_FOLDED);
425 }
426
hammer_has_backlight_control(struct hid_device * hdev)427 static bool hammer_has_backlight_control(struct hid_device *hdev)
428 {
429 return !!hid_find_field(hdev, HID_OUTPUT_REPORT,
430 HID_GD_KEYBOARD, HID_AD_BRIGHTNESS);
431 }
432
hammer_get_folded_state(struct hid_device * hdev)433 static void hammer_get_folded_state(struct hid_device *hdev)
434 {
435 struct hid_report *report;
436 char *buf;
437 int len, rlen;
438 int a;
439
440 report = hdev->report_enum[HID_INPUT_REPORT].report_id_hash[0x0];
441
442 if (!report || report->maxfield < 1)
443 return;
444
445 len = hid_report_len(report) + 1;
446
447 buf = kmalloc(len, GFP_KERNEL);
448 if (!buf)
449 return;
450
451 rlen = hid_hw_raw_request(hdev, report->id, buf, len, report->type, HID_REQ_GET_REPORT);
452
453 if (rlen != len) {
454 hid_warn(hdev, "Unable to read base folded state: %d (expected %d)\n", rlen, len);
455 goto out;
456 }
457
458 for (a = 0; a < report->maxfield; a++) {
459 struct hid_field *field = report->field[a];
460
461 if (field->usage->hid == HID_USAGE_KBD_FOLDED) {
462 u32 value = hid_field_extract(hdev, buf+1,
463 field->report_offset, field->report_size);
464
465 hammer_folded_event(hdev, value);
466 break;
467 }
468 }
469
470 out:
471 kfree(buf);
472 }
473
hammer_stop(void * hdev)474 static void hammer_stop(void *hdev)
475 {
476 hid_hw_stop(hdev);
477 }
478
hammer_probe(struct hid_device * hdev,const struct hid_device_id * id)479 static int hammer_probe(struct hid_device *hdev,
480 const struct hid_device_id *id)
481 {
482 struct vivaldi_data *vdata;
483 int error;
484
485 vdata = devm_kzalloc(&hdev->dev, sizeof(*vdata), GFP_KERNEL);
486 if (!vdata)
487 return -ENOMEM;
488
489 hid_set_drvdata(hdev, vdata);
490
491 error = hid_parse(hdev);
492 if (error)
493 return error;
494
495 error = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
496 if (error)
497 return error;
498
499 error = devm_add_action(&hdev->dev, hammer_stop, hdev);
500 if (error)
501 return error;
502
503 /*
504 * We always want to poll for, and handle tablet mode events from
505 * devices that have folded usage, even when nobody has opened the input
506 * device. This also prevents the hid core from dropping early tablet
507 * mode events from the device.
508 */
509 if (hammer_has_folded_event(hdev)) {
510 hdev->quirks |= HID_QUIRK_ALWAYS_POLL;
511 error = hid_hw_open(hdev);
512 if (error)
513 return error;
514
515 hammer_get_folded_state(hdev);
516 }
517
518 if (hammer_has_backlight_control(hdev)) {
519 error = hammer_register_leds(hdev);
520 if (error)
521 hid_warn(hdev,
522 "Failed to register keyboard backlight: %d\n",
523 error);
524 }
525
526 return 0;
527 }
528
hammer_remove(struct hid_device * hdev)529 static void hammer_remove(struct hid_device *hdev)
530 {
531 unsigned long flags;
532
533 if (hammer_has_folded_event(hdev)) {
534 hid_hw_close(hdev);
535
536 /*
537 * If we are disconnecting then most likely Whiskers is
538 * being removed. Even if it is not removed, without proper
539 * keyboard we should not stay in clamshell mode.
540 *
541 * The reason for doing it here and not waiting for signal
542 * from EC, is that on some devices there are high leakage
543 * on Whiskers pins and we do not detect disconnect reliably,
544 * resulting in devices being stuck in clamshell mode.
545 */
546 spin_lock_irqsave(&cbas_ec_lock, flags);
547 if (cbas_ec.input && cbas_ec.base_present) {
548 input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
549 input_sync(cbas_ec.input);
550 }
551 cbas_ec.base_present = false;
552 spin_unlock_irqrestore(&cbas_ec_lock, flags);
553 }
554
555 /* Unregistering LEDs and stopping the hardware is done via devm */
556 }
557
558 static const struct hid_device_id hammer_devices[] = {
559 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
560 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_DON) },
561 { HID_DEVICE(BUS_USB, HID_GROUP_VIVALDI,
562 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_EEL) },
563 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
564 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
565 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
566 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_JEWEL) },
567 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
568 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MAGNEMITE) },
569 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
570 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MASTERBALL) },
571 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
572 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MOONBALL) },
573 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
574 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
575 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
576 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
577 { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
578 USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WHISKERS) },
579 { }
580 };
581 MODULE_DEVICE_TABLE(hid, hammer_devices);
582
583 static struct hid_driver hammer_driver = {
584 .name = "hammer",
585 .id_table = hammer_devices,
586 .probe = hammer_probe,
587 .remove = hammer_remove,
588 .feature_mapping = vivaldi_feature_mapping,
589 .input_mapping = hammer_input_mapping,
590 .event = hammer_event,
591 .driver = {
592 .dev_groups = vivaldi_attribute_groups,
593 },
594 };
595
hammer_init(void)596 static int __init hammer_init(void)
597 {
598 int error;
599
600 error = platform_driver_register(&cbas_ec_driver);
601 if (error)
602 return error;
603
604 error = hid_register_driver(&hammer_driver);
605 if (error) {
606 platform_driver_unregister(&cbas_ec_driver);
607 return error;
608 }
609
610 return 0;
611 }
612 module_init(hammer_init);
613
hammer_exit(void)614 static void __exit hammer_exit(void)
615 {
616 hid_unregister_driver(&hammer_driver);
617 platform_driver_unregister(&cbas_ec_driver);
618 }
619 module_exit(hammer_exit);
620
621 MODULE_DESCRIPTION("HID driver for Google Hammer device.");
622 MODULE_LICENSE("GPL");
623