summaryrefslogtreecommitdiff
path: root/drivers/hid/hid-google-hammer.c
blob: 4f64f93ddfcb974407d33fecd9099aed1e48fbc5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
// SPDX-License-Identifier: GPL-2.0+
/*
 *  HID driver for Google Hammer device.
 *
 *  Copyright (c) 2017 Google Inc.
 *  Author: Wei-Ning Huang <wnhuang@google.com>
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/acpi.h>
#include <linux/hid.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_device.h>
#include <linux/pm_wakeup.h>
#include <asm/unaligned.h>

#include "hid-ids.h"

/*
 * C(hrome)B(ase)A(ttached)S(witch) - switch exported by Chrome EC and reporting
 * state of the "Whiskers" base - attached or detached. Whiskers USB device also
 * reports position of the keyboard - folded or not. Combining base state and
 * position allows us to generate proper "Tablet mode" events.
 */
struct cbas_ec {
	struct device *dev;	/* The platform device (EC) */
	struct input_dev *input;
	bool base_present;
	bool base_folded;
	struct notifier_block notifier;
};

static struct cbas_ec cbas_ec;
static DEFINE_SPINLOCK(cbas_ec_lock);
static DEFINE_MUTEX(cbas_ec_reglock);

static bool cbas_parse_base_state(const void *data)
{
	u32 switches = get_unaligned_le32(data);

	return !!(switches & BIT(EC_MKBP_BASE_ATTACHED));
}

static int cbas_ec_query_base(struct cros_ec_device *ec_dev, bool get_state,
				  bool *state)
{
	struct ec_params_mkbp_info *params;
	struct cros_ec_command *msg;
	int ret;

	msg = kzalloc(sizeof(*msg) + max(sizeof(u32), sizeof(*params)),
		      GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	msg->command = EC_CMD_MKBP_INFO;
	msg->version = 1;
	msg->outsize = sizeof(*params);
	msg->insize = sizeof(u32);
	params = (struct ec_params_mkbp_info *)msg->data;
	params->info_type = get_state ?
		EC_MKBP_INFO_CURRENT : EC_MKBP_INFO_SUPPORTED;
	params->event_type = EC_MKBP_EVENT_SWITCH;

	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
	if (ret >= 0) {
		if (ret != sizeof(u32)) {
			dev_warn(ec_dev->dev, "wrong result size: %d != %zu\n",
				 ret, sizeof(u32));
			ret = -EPROTO;
		} else {
			*state = cbas_parse_base_state(msg->data);
			ret = 0;
		}
	}

	kfree(msg);

	return ret;
}

static int cbas_ec_notify(struct notifier_block *nb,
			      unsigned long queued_during_suspend,
			      void *_notify)
{
	struct cros_ec_device *ec = _notify;
	unsigned long flags;
	bool base_present;

	if (ec->event_data.event_type == EC_MKBP_EVENT_SWITCH) {
		base_present = cbas_parse_base_state(
					&ec->event_data.data.switches);
		dev_dbg(cbas_ec.dev,
			"%s: base: %d\n", __func__, base_present);

		if (device_may_wakeup(cbas_ec.dev) ||
		    !queued_during_suspend) {

			pm_wakeup_event(cbas_ec.dev, 0);

			spin_lock_irqsave(&cbas_ec_lock, flags);

			/*
			 * While input layer dedupes the events, we do not want
			 * to disrupt the state reported by the base by
			 * overriding it with state reported by the LID. Only
			 * report changes, as we assume that on attach the base
			 * is not folded.
			 */
			if (base_present != cbas_ec.base_present) {
				input_report_switch(cbas_ec.input,
						    SW_TABLET_MODE,
						    !base_present);
				input_sync(cbas_ec.input);
				cbas_ec.base_present = base_present;
			}

			spin_unlock_irqrestore(&cbas_ec_lock, flags);
		}
	}

	return NOTIFY_OK;
}

static __maybe_unused int cbas_ec_resume(struct device *dev)
{
	struct cros_ec_device *ec = dev_get_drvdata(dev->parent);
	bool base_present;
	int error;

	error = cbas_ec_query_base(ec, true, &base_present);
	if (error) {
		dev_warn(dev, "failed to fetch base state on resume: %d\n",
			 error);
	} else {
		spin_lock_irq(&cbas_ec_lock);

		cbas_ec.base_present = base_present;

		/*
		 * Only report if base is disconnected. If base is connected,
		 * it will resend its state on resume, and we'll update it
		 * in hammer_event().
		 */
		if (!cbas_ec.base_present) {
			input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
			input_sync(cbas_ec.input);
		}

		spin_unlock_irq(&cbas_ec_lock);
	}

	return 0;
}

static SIMPLE_DEV_PM_OPS(cbas_ec_pm_ops, NULL, cbas_ec_resume);

static void cbas_ec_set_input(struct input_dev *input)
{
	/* Take the lock so hammer_event() does not race with us here */
	spin_lock_irq(&cbas_ec_lock);
	cbas_ec.input = input;
	spin_unlock_irq(&cbas_ec_lock);
}

static int __cbas_ec_probe(struct platform_device *pdev)
{
	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
	struct input_dev *input;
	bool base_supported;
	int error;

	error = cbas_ec_query_base(ec, false, &base_supported);
	if (error)
		return error;

	if (!base_supported)
		return -ENXIO;

	input = devm_input_allocate_device(&pdev->dev);
	if (!input)
		return -ENOMEM;

	input->name = "Whiskers Tablet Mode Switch";
	input->id.bustype = BUS_HOST;

	input_set_capability(input, EV_SW, SW_TABLET_MODE);

	error = input_register_device(input);
	if (error) {
		dev_err(&pdev->dev, "cannot register input device: %d\n",
			error);
		return error;
	}

	/* Seed the state */
	error = cbas_ec_query_base(ec, true, &cbas_ec.base_present);
	if (error) {
		dev_err(&pdev->dev, "cannot query base state: %d\n", error);
		return error;
	}

	if (!cbas_ec.base_present)
		cbas_ec.base_folded = false;

	dev_dbg(&pdev->dev, "%s: base: %d, folded: %d\n", __func__,
		cbas_ec.base_present, cbas_ec.base_folded);

	input_report_switch(input, SW_TABLET_MODE,
			    !cbas_ec.base_present || cbas_ec.base_folded);

	cbas_ec_set_input(input);

	cbas_ec.dev = &pdev->dev;
	cbas_ec.notifier.notifier_call = cbas_ec_notify;
	error = blocking_notifier_chain_register(&ec->event_notifier,
						 &cbas_ec.notifier);
	if (error) {
		dev_err(&pdev->dev, "cannot register notifier: %d\n", error);
		cbas_ec_set_input(NULL);
		return error;
	}

	device_init_wakeup(&pdev->dev, true);
	return 0;
}

static int cbas_ec_probe(struct platform_device *pdev)
{
	int retval;

	mutex_lock(&cbas_ec_reglock);

	if (cbas_ec.input) {
		retval = -EBUSY;
		goto out;
	}

	retval = __cbas_ec_probe(pdev);

out:
	mutex_unlock(&cbas_ec_reglock);
	return retval;
}

static int cbas_ec_remove(struct platform_device *pdev)
{
	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);

	mutex_lock(&cbas_ec_reglock);

	blocking_notifier_chain_unregister(&ec->event_notifier,
					   &cbas_ec.notifier);
	cbas_ec_set_input(NULL);

	mutex_unlock(&cbas_ec_reglock);
	return 0;
}

static const struct acpi_device_id cbas_ec_acpi_ids[] = {
	{ "GOOG000B", 0 },
	{ }
};
MODULE_DEVICE_TABLE(acpi, cbas_ec_acpi_ids);

static struct platform_driver cbas_ec_driver = {
	.probe = cbas_ec_probe,
	.remove = cbas_ec_remove,
	.driver = {
		.name = "cbas_ec",
		.acpi_match_table = ACPI_PTR(cbas_ec_acpi_ids),
		.pm = &cbas_ec_pm_ops,
	},
};

#define MAX_BRIGHTNESS 100

struct hammer_kbd_leds {
	struct led_classdev cdev;
	struct hid_device *hdev;
	u8 buf[2] ____cacheline_aligned;
};

static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
		enum led_brightness br)
{
	struct hammer_kbd_leds *led = container_of(cdev,
						   struct hammer_kbd_leds,
						   cdev);
	int ret;

	led->buf[0] = 0;
	led->buf[1] = br;

	/*
	 * Request USB HID device to be in Full On mode, so that sending
	 * hardware output report and hardware raw request won't fail.
	 */
	ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
	if (ret < 0) {
		hid_err(led->hdev, "failed: device not resumed %d\n", ret);
		return ret;
	}

	ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
	if (ret == -ENOSYS)
		ret = hid_hw_raw_request(led->hdev, 0, led->buf,
					 sizeof(led->buf),
					 HID_OUTPUT_REPORT,
					 HID_REQ_SET_REPORT);
	if (ret < 0)
		hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
			ret);

	/* Request USB HID device back to Normal Mode. */
	hid_hw_power(led->hdev, PM_HINT_NORMAL);

	return ret;
}

static int hammer_register_leds(struct hid_device *hdev)
{
	struct hammer_kbd_leds *kbd_backlight;
	int error;

	kbd_backlight = kzalloc(sizeof(*kbd_backlight), GFP_KERNEL);
	if (!kbd_backlight)
		return -ENOMEM;

	kbd_backlight->hdev = hdev;
	kbd_backlight->cdev.name = "hammer::kbd_backlight";
	kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
	kbd_backlight->cdev.brightness_set_blocking =
		hammer_kbd_brightness_set_blocking;
	kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;

	/* Set backlight to 0% initially. */
	hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);

	error = led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
	if (error)
		goto err_free_mem;

	hid_set_drvdata(hdev, kbd_backlight);
	return 0;

err_free_mem:
	kfree(kbd_backlight);
	return error;
}

static void hammer_unregister_leds(struct hid_device *hdev)
{
	struct hammer_kbd_leds *kbd_backlight = hid_get_drvdata(hdev);

	if (kbd_backlight) {
		led_classdev_unregister(&kbd_backlight->cdev);
		kfree(kbd_backlight);
	}
}

#define HID_UP_GOOGLEVENDOR	0xffd10000
#define HID_VD_KBD_FOLDED	0x00000019
#define WHISKERS_KBD_FOLDED	(HID_UP_GOOGLEVENDOR | HID_VD_KBD_FOLDED)

/* HID usage for keyboard backlight (Alphanumeric display brightness) */
#define HID_AD_BRIGHTNESS	0x00140046

static int hammer_input_mapping(struct hid_device *hdev, struct hid_input *hi,
				struct hid_field *field,
				struct hid_usage *usage,
				unsigned long **bit, int *max)
{
	if (hdev->product == USB_DEVICE_ID_GOOGLE_WHISKERS &&
	    usage->hid == WHISKERS_KBD_FOLDED) {
		/*
		 * We do not want to have this usage mapped as it will get
		 * mixed in with "base attached" signal and delivered over
		 * separate input device for tablet switch mode.
		 */
		return -1;
	}

	return 0;
}

static int hammer_event(struct hid_device *hid, struct hid_field *field,
			struct hid_usage *usage, __s32 value)
{
	unsigned long flags;

	if (hid->product == USB_DEVICE_ID_GOOGLE_WHISKERS &&
	    usage->hid == WHISKERS_KBD_FOLDED) {
		spin_lock_irqsave(&cbas_ec_lock, flags);

		cbas_ec.base_folded = value;
		hid_dbg(hid, "%s: base: %d, folded: %d\n", __func__,
			cbas_ec.base_present, cbas_ec.base_folded);

		/*
		 * We should not get event if base is detached, but in case
		 * we happen to service HID and EC notifications out of order
		 * let's still check the "base present" flag.
		 */
		if (cbas_ec.input && cbas_ec.base_present) {
			input_report_switch(cbas_ec.input,
					    SW_TABLET_MODE, value);
			input_sync(cbas_ec.input);
		}

		spin_unlock_irqrestore(&cbas_ec_lock, flags);
		return 1; /* We handled this event */
	}

	return 0;
}

static bool hammer_is_keyboard_interface(struct hid_device *hdev)
{
	struct hid_report_enum *re = &hdev->report_enum[HID_INPUT_REPORT];
	struct hid_report *report;

	list_for_each_entry(report, &re->report_list, list)
		if (report->application == HID_GD_KEYBOARD)
			return true;

	return false;
}

static bool hammer_has_backlight_control(struct hid_device *hdev)
{
	struct hid_report_enum *re = &hdev->report_enum[HID_OUTPUT_REPORT];
	struct hid_report *report;
	int i, j;

	list_for_each_entry(report, &re->report_list, list) {
		if (report->application != HID_GD_KEYBOARD)
			continue;

		for (i = 0; i < report->maxfield; i++) {
			struct hid_field *field = report->field[i];

			for (j = 0; j < field->maxusage; j++)
				if (field->usage[j].hid == HID_AD_BRIGHTNESS)
					return true;
		}
	}

	return false;
}

static int hammer_probe(struct hid_device *hdev,
			const struct hid_device_id *id)
{
	int error;

	error = hid_parse(hdev);
	if (error)
		return error;

	error = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
	if (error)
		return error;

	/*
	 * We always want to poll for, and handle tablet mode events from
	 * Whiskers, even when nobody has opened the input device. This also
	 * prevents the hid core from dropping early tablet mode events from
	 * the device.
	 */
	if (hdev->product == USB_DEVICE_ID_GOOGLE_WHISKERS &&
	    hammer_is_keyboard_interface(hdev)) {
		hdev->quirks |= HID_QUIRK_ALWAYS_POLL;
		error = hid_hw_open(hdev);
		if (error)
			return error;
	}

	if (hammer_has_backlight_control(hdev)) {
		error = hammer_register_leds(hdev);
		if (error)
			hid_warn(hdev,
				"Failed to register keyboard backlight: %d\n",
				error);
	}

	return 0;
}

static void hammer_remove(struct hid_device *hdev)
{
	if (hdev->product == USB_DEVICE_ID_GOOGLE_WHISKERS &&
			hammer_is_keyboard_interface(hdev))
		hid_hw_close(hdev);

	hammer_unregister_leds(hdev);
	hid_hw_stop(hdev);
}

static const struct hid_device_id hammer_devices[] = {
	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WHISKERS) },
	{ }
};
MODULE_DEVICE_TABLE(hid, hammer_devices);

static struct hid_driver hammer_driver = {
	.name = "hammer",
	.id_table = hammer_devices,
	.probe = hammer_probe,
	.remove = hammer_remove,
	.input_mapping = hammer_input_mapping,
	.event = hammer_event,
};

static int __init hammer_init(void)
{
	int error;

	error = platform_driver_register(&cbas_ec_driver);
	if (error)
		return error;

	error = hid_register_driver(&hammer_driver);
	if (error) {
		platform_driver_unregister(&cbas_ec_driver);
		return error;
	}

	return 0;
}
module_init(hammer_init);

static void __exit hammer_exit(void)
{
	hid_unregister_driver(&hammer_driver);
	platform_driver_unregister(&cbas_ec_driver);
}
module_exit(hammer_exit);

MODULE_LICENSE("GPL");