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 <asm/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 */
37struct 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
45static struct cbas_ec cbas_ec;
46static DEFINE_SPINLOCK(cbas_ec_lock);
47static DEFINE_MUTEX(cbas_ec_reglock);
48
49static 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
56static 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
94static 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
137static __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
168static SIMPLE_DEV_PM_OPS(cbas_ec_pm_ops, NULL, cbas_ec_resume);
169
170static 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
178static 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
240static 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
253out:
254	mutex_unlock(&cbas_ec_reglock);
255	return retval;
256}
257
258static int 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	return 0;
270}
271
272static const struct acpi_device_id cbas_ec_acpi_ids[] = {
273	{ "GOOG000B", 0 },
274	{ }
275};
276MODULE_DEVICE_TABLE(acpi, cbas_ec_acpi_ids);
277
278#ifdef CONFIG_OF
279static const struct of_device_id cbas_ec_of_match[] = {
280	{ .compatible = "google,cros-cbas" },
281	{ },
282};
283MODULE_DEVICE_TABLE(of, cbas_ec_of_match);
284#endif
285
286static struct platform_driver cbas_ec_driver = {
287	.probe = cbas_ec_probe,
288	.remove = cbas_ec_remove,
289	.driver = {
290		.name = "cbas_ec",
291		.acpi_match_table = ACPI_PTR(cbas_ec_acpi_ids),
292		.of_match_table = of_match_ptr(cbas_ec_of_match),
293		.pm = &cbas_ec_pm_ops,
294	},
295};
296
297#define MAX_BRIGHTNESS 100
298
299struct hammer_kbd_leds {
300	struct led_classdev cdev;
301	struct hid_device *hdev;
302	u8 buf[2] ____cacheline_aligned;
303};
304
305static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
306		enum led_brightness br)
307{
308	struct hammer_kbd_leds *led = container_of(cdev,
309						   struct hammer_kbd_leds,
310						   cdev);
311	int ret;
312
313	led->buf[0] = 0;
314	led->buf[1] = br;
315
316	/*
317	 * Request USB HID device to be in Full On mode, so that sending
318	 * hardware output report and hardware raw request won't fail.
319	 */
320	ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
321	if (ret < 0) {
322		hid_err(led->hdev, "failed: device not resumed %d\n", ret);
323		return ret;
324	}
325
326	ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
327	if (ret == -ENOSYS)
328		ret = hid_hw_raw_request(led->hdev, 0, led->buf,
329					 sizeof(led->buf),
330					 HID_OUTPUT_REPORT,
331					 HID_REQ_SET_REPORT);
332	if (ret < 0)
333		hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
334			ret);
335
336	/* Request USB HID device back to Normal Mode. */
337	hid_hw_power(led->hdev, PM_HINT_NORMAL);
338
339	return ret;
340}
341
342static int hammer_register_leds(struct hid_device *hdev)
343{
344	struct hammer_kbd_leds *kbd_backlight;
345
346	kbd_backlight = devm_kzalloc(&hdev->dev, sizeof(*kbd_backlight),
347				     GFP_KERNEL);
348	if (!kbd_backlight)
349		return -ENOMEM;
350
351	kbd_backlight->hdev = hdev;
352	kbd_backlight->cdev.name = "hammer::kbd_backlight";
353	kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
354	kbd_backlight->cdev.brightness_set_blocking =
355		hammer_kbd_brightness_set_blocking;
356	kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
357
358	/* Set backlight to 0% initially. */
359	hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
360
361	return devm_led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
362}
363
364#define HID_UP_GOOGLEVENDOR	0xffd10000
365#define HID_VD_KBD_FOLDED	0x00000019
366#define HID_USAGE_KBD_FOLDED	(HID_UP_GOOGLEVENDOR | HID_VD_KBD_FOLDED)
367
368/* HID usage for keyboard backlight (Alphanumeric display brightness) */
369#define HID_AD_BRIGHTNESS	0x00140046
370
371static int hammer_input_mapping(struct hid_device *hdev, struct hid_input *hi,
372				struct hid_field *field,
373				struct hid_usage *usage,
374				unsigned long **bit, int *max)
375{
376	if (usage->hid == HID_USAGE_KBD_FOLDED) {
377		/*
378		 * We do not want to have this usage mapped as it will get
379		 * mixed in with "base attached" signal and delivered over
380		 * separate input device for tablet switch mode.
381		 */
382		return -1;
383	}
384
385	return 0;
386}
387
388static void hammer_folded_event(struct hid_device *hdev, bool folded)
389{
390	unsigned long flags;
391
392	spin_lock_irqsave(&cbas_ec_lock, flags);
393
394	/*
395	 * If we are getting events from Whiskers that means that it
396	 * is attached to the lid.
397	 */
398	cbas_ec.base_present = true;
399	cbas_ec.base_folded = folded;
400	hid_dbg(hdev, "%s: base: %d, folded: %d\n", __func__,
401		cbas_ec.base_present, cbas_ec.base_folded);
402
403	if (cbas_ec.input) {
404		input_report_switch(cbas_ec.input, SW_TABLET_MODE, folded);
405		input_sync(cbas_ec.input);
406	}
407
408	spin_unlock_irqrestore(&cbas_ec_lock, flags);
409}
410
411static int hammer_event(struct hid_device *hid, struct hid_field *field,
412			struct hid_usage *usage, __s32 value)
413{
414	if (usage->hid == HID_USAGE_KBD_FOLDED) {
415		hammer_folded_event(hid, value);
416		return 1; /* We handled this event */
417	}
418
419	return 0;
420}
421
422static bool hammer_has_usage(struct hid_device *hdev, unsigned int report_type,
423			unsigned application, unsigned usage)
424{
425	struct hid_report_enum *re = &hdev->report_enum[report_type];
426	struct hid_report *report;
427	int i, j;
428
429	list_for_each_entry(report, &re->report_list, list) {
430		if (report->application != application)
431			continue;
432
433		for (i = 0; i < report->maxfield; i++) {
434			struct hid_field *field = report->field[i];
435
436			for (j = 0; j < field->maxusage; j++)
437				if (field->usage[j].hid == usage)
438					return true;
439		}
440	}
441
442	return false;
443}
444
445static bool hammer_has_folded_event(struct hid_device *hdev)
446{
447	return hammer_has_usage(hdev, HID_INPUT_REPORT,
448				HID_GD_KEYBOARD, HID_USAGE_KBD_FOLDED);
449}
450
451static bool hammer_has_backlight_control(struct hid_device *hdev)
452{
453	return hammer_has_usage(hdev, HID_OUTPUT_REPORT,
454				HID_GD_KEYBOARD, HID_AD_BRIGHTNESS);
455}
456
457static void hammer_get_folded_state(struct hid_device *hdev)
458{
459	struct hid_report *report;
460	char *buf;
461	int len, rlen;
462	int a;
463
464	report = hdev->report_enum[HID_INPUT_REPORT].report_id_hash[0x0];
465
466	if (!report || report->maxfield < 1)
467		return;
468
469	len = hid_report_len(report) + 1;
470
471	buf = kmalloc(len, GFP_KERNEL);
472	if (!buf)
473		return;
474
475	rlen = hid_hw_raw_request(hdev, report->id, buf, len, report->type, HID_REQ_GET_REPORT);
476
477	if (rlen != len) {
478		hid_warn(hdev, "Unable to read base folded state: %d (expected %d)\n", rlen, len);
479		goto out;
480	}
481
482	for (a = 0; a < report->maxfield; a++) {
483		struct hid_field *field = report->field[a];
484
485		if (field->usage->hid == HID_USAGE_KBD_FOLDED) {
486			u32 value = hid_field_extract(hdev, buf+1,
487					field->report_offset, field->report_size);
488
489			hammer_folded_event(hdev, value);
490			break;
491		}
492	}
493
494out:
495	kfree(buf);
496}
497
498static void hammer_stop(void *hdev)
499{
500	hid_hw_stop(hdev);
501}
502
503static int hammer_probe(struct hid_device *hdev,
504			const struct hid_device_id *id)
505{
506	struct vivaldi_data *vdata;
507	int error;
508
509	vdata = devm_kzalloc(&hdev->dev, sizeof(*vdata), GFP_KERNEL);
510	if (!vdata)
511		return -ENOMEM;
512
513	hid_set_drvdata(hdev, vdata);
514
515	error = hid_parse(hdev);
516	if (error)
517		return error;
518
519	error = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
520	if (error)
521		return error;
522
523	error = devm_add_action(&hdev->dev, hammer_stop, hdev);
524	if (error)
525		return error;
526
527	/*
528	 * We always want to poll for, and handle tablet mode events from
529	 * devices that have folded usage, even when nobody has opened the input
530	 * device. This also prevents the hid core from dropping early tablet
531	 * mode events from the device.
532	 */
533	if (hammer_has_folded_event(hdev)) {
534		hdev->quirks |= HID_QUIRK_ALWAYS_POLL;
535		error = hid_hw_open(hdev);
536		if (error)
537			return error;
538
539		hammer_get_folded_state(hdev);
540	}
541
542	if (hammer_has_backlight_control(hdev)) {
543		error = hammer_register_leds(hdev);
544		if (error)
545			hid_warn(hdev,
546				"Failed to register keyboard backlight: %d\n",
547				error);
548	}
549
550	return 0;
551}
552
553static void hammer_remove(struct hid_device *hdev)
554{
555	unsigned long flags;
556
557	if (hammer_has_folded_event(hdev)) {
558		hid_hw_close(hdev);
559
560		/*
561		 * If we are disconnecting then most likely Whiskers is
562		 * being removed. Even if it is not removed, without proper
563		 * keyboard we should not stay in clamshell mode.
564		 *
565		 * The reason for doing it here and not waiting for signal
566		 * from EC, is that on some devices there are high leakage
567		 * on Whiskers pins and we do not detect disconnect reliably,
568		 * resulting in devices being stuck in clamshell mode.
569		 */
570		spin_lock_irqsave(&cbas_ec_lock, flags);
571		if (cbas_ec.input && cbas_ec.base_present) {
572			input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
573			input_sync(cbas_ec.input);
574		}
575		cbas_ec.base_present = false;
576		spin_unlock_irqrestore(&cbas_ec_lock, flags);
577	}
578
579	/* Unregistering LEDs and stopping the hardware is done via devm */
580}
581
582static const struct hid_device_id hammer_devices[] = {
583	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
584		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_DON) },
585	{ HID_DEVICE(BUS_USB, HID_GROUP_VIVALDI,
586		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_EEL) },
587	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
588		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
589	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
590		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_JEWEL) },
591	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
592		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MAGNEMITE) },
593	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
594		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MASTERBALL) },
595	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
596		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MOONBALL) },
597	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
598		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
599	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
600		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
601	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
602		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WHISKERS) },
603	{ }
604};
605MODULE_DEVICE_TABLE(hid, hammer_devices);
606
607static struct hid_driver hammer_driver = {
608	.name = "hammer",
609	.id_table = hammer_devices,
610	.probe = hammer_probe,
611	.remove = hammer_remove,
612	.feature_mapping = vivaldi_feature_mapping,
613	.input_mapping = hammer_input_mapping,
614	.event = hammer_event,
615	.driver = {
616		.dev_groups = vivaldi_attribute_groups,
617	},
618};
619
620static int __init hammer_init(void)
621{
622	int error;
623
624	error = platform_driver_register(&cbas_ec_driver);
625	if (error)
626		return error;
627
628	error = hid_register_driver(&hammer_driver);
629	if (error) {
630		platform_driver_unregister(&cbas_ec_driver);
631		return error;
632	}
633
634	return 0;
635}
636module_init(hammer_init);
637
638static void __exit hammer_exit(void)
639{
640	hid_unregister_driver(&hammer_driver);
641	platform_driver_unregister(&cbas_ec_driver);
642}
643module_exit(hammer_exit);
644
645MODULE_LICENSE("GPL");
646