1// SPDX-License-Identifier: GPL-2.0
2// ChromeOS EC keyboard driver
3//
4// Copyright (C) 2012 Google, Inc.
5//
6// This driver uses the ChromeOS EC byte-level message-based protocol for
7// communicating the keyboard state (which keys are pressed) from a keyboard EC
8// to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
9// but everything else (including deghosting) is done here. The main
10// motivation for this is to keep the EC firmware as simple as possible, since
11// it cannot be easily upgraded and EC flash/IRAM space is relatively
12// expensive.
13
14#include <linux/module.h>
15#include <linux/bitops.h>
16#include <linux/i2c.h>
17#include <linux/input.h>
18#include <linux/interrupt.h>
19#include <linux/kernel.h>
20#include <linux/notifier.h>
21#include <linux/platform_device.h>
22#include <linux/slab.h>
23#include <linux/sysrq.h>
24#include <linux/input/matrix_keypad.h>
25#include <linux/mfd/cros_ec.h>
26#include <linux/mfd/cros_ec_commands.h>
27
28#include <asm/unaligned.h>
29
30/*
31 * @rows: Number of rows in the keypad
32 * @cols: Number of columns in the keypad
33 * @row_shift: log2 or number of rows, rounded up
34 * @keymap_data: Matrix keymap data used to convert to keyscan values
35 * @ghost_filter: true to enable the matrix key-ghosting filter
36 * @valid_keys: bitmap of existing keys for each matrix column
37 * @old_kb_state: bitmap of keys pressed last scan
38 * @dev: Device pointer
39 * @ec: Top level ChromeOS device to use to talk to EC
40 * @idev: The input device for the matrix keys.
41 * @bs_idev: The input device for non-matrix buttons and switches (or NULL).
42 * @notifier: interrupt event notifier for transport devices
43 */
44struct cros_ec_keyb {
45 unsigned int rows;
46 unsigned int cols;
47 int row_shift;
48 const struct matrix_keymap_data *keymap_data;
49 bool ghost_filter;
50 uint8_t *valid_keys;
51 uint8_t *old_kb_state;
52
53 struct device *dev;
54 struct cros_ec_device *ec;
55
56 struct input_dev *idev;
57 struct input_dev *bs_idev;
58 struct notifier_block notifier;
59};
60
61
62/**
63 * cros_ec_bs_map - Struct mapping Linux keycodes to EC button/switch bitmap
64 * #defines
65 *
66 * @ev_type: The type of the input event to generate (e.g., EV_KEY).
67 * @code: A linux keycode
68 * @bit: A #define like EC_MKBP_POWER_BUTTON or EC_MKBP_LID_OPEN
69 * @inverted: If the #define and EV_SW have opposite meanings, this is true.
70 * Only applicable to switches.
71 */
72struct cros_ec_bs_map {
73 unsigned int ev_type;
74 unsigned int code;
75 u8 bit;
76 bool inverted;
77};
78
79/* cros_ec_keyb_bs - Map EC button/switch #defines into kernel ones */
80static const struct cros_ec_bs_map cros_ec_keyb_bs[] = {
81 /* Buttons */
82 {
83 .ev_type = EV_KEY,
84 .code = KEY_POWER,
85 .bit = EC_MKBP_POWER_BUTTON,
86 },
87 {
88 .ev_type = EV_KEY,
89 .code = KEY_VOLUMEUP,
90 .bit = EC_MKBP_VOL_UP,
91 },
92 {
93 .ev_type = EV_KEY,
94 .code = KEY_VOLUMEDOWN,
95 .bit = EC_MKBP_VOL_DOWN,
96 },
97
98 /* Switches */
99 {
100 .ev_type = EV_SW,
101 .code = SW_LID,
102 .bit = EC_MKBP_LID_OPEN,
103 .inverted = true,
104 },
105 {
106 .ev_type = EV_SW,
107 .code = SW_TABLET_MODE,
108 .bit = EC_MKBP_TABLET_MODE,
109 },
110};
111
112/*
113 * Returns true when there is at least one combination of pressed keys that
114 * results in ghosting.
115 */
116static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
117{
118 int col1, col2, buf1, buf2;
119 struct device *dev = ckdev->dev;
120 uint8_t *valid_keys = ckdev->valid_keys;
121
122 /*
123 * Ghosting happens if for any pressed key X there are other keys
124 * pressed both in the same row and column of X as, for instance,
125 * in the following diagram:
126 *
127 * . . Y . g .
128 * . . . . . .
129 * . . . . . .
130 * . . X . Z .
131 *
132 * In this case only X, Y, and Z are pressed, but g appears to be
133 * pressed too (see Wikipedia).
134 */
135 for (col1 = 0; col1 < ckdev->cols; col1++) {
136 buf1 = buf[col1] & valid_keys[col1];
137 for (col2 = col1 + 1; col2 < ckdev->cols; col2++) {
138 buf2 = buf[col2] & valid_keys[col2];
139 if (hweight8(buf1 & buf2) > 1) {
140 dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x",
141 col1, buf1, col2, buf2);
142 return true;
143 }
144 }
145 }
146
147 return false;
148}
149
150
151/*
152 * Compares the new keyboard state to the old one and produces key
153 * press/release events accordingly. The keyboard state is 13 bytes (one byte
154 * per column)
155 */
156static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
157 uint8_t *kb_state, int len)
158{
159 struct input_dev *idev = ckdev->idev;
160 int col, row;
161 int new_state;
162 int old_state;
163
164 if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
165 /*
166 * Simple-minded solution: ignore this state. The obvious
167 * improvement is to only ignore changes to keys involved in
168 * the ghosting, but process the other changes.
169 */
170 dev_dbg(ckdev->dev, "ghosting found\n");
171 return;
172 }
173
174 for (col = 0; col < ckdev->cols; col++) {
175 for (row = 0; row < ckdev->rows; row++) {
176 int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
177 const unsigned short *keycodes = idev->keycode;
178
179 new_state = kb_state[col] & (1 << row);
180 old_state = ckdev->old_kb_state[col] & (1 << row);
181 if (new_state != old_state) {
182 dev_dbg(ckdev->dev,
183 "changed: [r%d c%d]: byte %02x\n",
184 row, col, new_state);
185
186 input_report_key(idev, keycodes[pos],
187 new_state);
188 }
189 }
190 ckdev->old_kb_state[col] = kb_state[col];
191 }
192 input_sync(ckdev->idev);
193}
194
195/**
196 * cros_ec_keyb_report_bs - Report non-matrixed buttons or switches
197 *
198 * This takes a bitmap of buttons or switches from the EC and reports events,
199 * syncing at the end.
200 *
201 * @ckdev: The keyboard device.
202 * @ev_type: The input event type (e.g., EV_KEY).
203 * @mask: A bitmap of buttons from the EC.
204 */
205static void cros_ec_keyb_report_bs(struct cros_ec_keyb *ckdev,
206 unsigned int ev_type, u32 mask)
207
208{
209 struct input_dev *idev = ckdev->bs_idev;
210 int i;
211
212 for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
213 const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
214
215 if (map->ev_type != ev_type)
216 continue;
217
218 input_event(idev, ev_type, map->code,
219 !!(mask & BIT(map->bit)) ^ map->inverted);
220 }
221 input_sync(idev);
222}
223
224static int cros_ec_keyb_work(struct notifier_block *nb,
225 unsigned long queued_during_suspend, void *_notify)
226{
227 struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
228 notifier);
229 u32 val;
230 unsigned int ev_type;
231
232 /*
233 * If not wake enabled, discard key state changes during
234 * suspend. Switches will be re-checked in
235 * cros_ec_keyb_resume() to be sure nothing is lost.
236 */
237 if (queued_during_suspend && !device_may_wakeup(ckdev->dev))
238 return NOTIFY_OK;
239
240 switch (ckdev->ec->event_data.event_type) {
241 case EC_MKBP_EVENT_KEY_MATRIX:
242 pm_wakeup_event(ckdev->dev, 0);
243
244 if (ckdev->ec->event_size != ckdev->cols) {
245 dev_err(ckdev->dev,
246 "Discarded incomplete key matrix event.\n");
247 return NOTIFY_OK;
248 }
249
250 cros_ec_keyb_process(ckdev,
251 ckdev->ec->event_data.data.key_matrix,
252 ckdev->ec->event_size);
253 break;
254
255 case EC_MKBP_EVENT_SYSRQ:
256 pm_wakeup_event(ckdev->dev, 0);
257
258 val = get_unaligned_le32(&ckdev->ec->event_data.data.sysrq);
259 dev_dbg(ckdev->dev, "sysrq code from EC: %#x\n", val);
260 handle_sysrq(val);
261 break;
262
263 case EC_MKBP_EVENT_BUTTON:
264 case EC_MKBP_EVENT_SWITCH:
265 pm_wakeup_event(ckdev->dev, 0);
266
267 if (ckdev->ec->event_data.event_type == EC_MKBP_EVENT_BUTTON) {
268 val = get_unaligned_le32(
269 &ckdev->ec->event_data.data.buttons);
270 ev_type = EV_KEY;
271 } else {
272 val = get_unaligned_le32(
273 &ckdev->ec->event_data.data.switches);
274 ev_type = EV_SW;
275 }
276 cros_ec_keyb_report_bs(ckdev, ev_type, val);
277 break;
278
279 default:
280 return NOTIFY_DONE;
281 }
282
283 return NOTIFY_OK;
284}
285
286/*
287 * Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW. Used by
288 * ghosting logic to ignore NULL or virtual keys.
289 */
290static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
291{
292 int row, col;
293 int row_shift = ckdev->row_shift;
294 unsigned short *keymap = ckdev->idev->keycode;
295 unsigned short code;
296
297 BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap));
298
299 for (col = 0; col < ckdev->cols; col++) {
300 for (row = 0; row < ckdev->rows; row++) {
301 code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
302 if (code && (code != KEY_BATTERY))
303 ckdev->valid_keys[col] |= 1 << row;
304 }
305 dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n",
306 col, ckdev->valid_keys[col]);
307 }
308}
309
310/**
311 * cros_ec_keyb_info - Wrap the EC command EC_CMD_MKBP_INFO
312 *
313 * This wraps the EC_CMD_MKBP_INFO, abstracting out all of the marshalling and
314 * unmarshalling and different version nonsense into something simple.
315 *
316 * @ec_dev: The EC device
317 * @info_type: Either EC_MKBP_INFO_SUPPORTED or EC_MKBP_INFO_CURRENT.
318 * @event_type: Either EC_MKBP_EVENT_BUTTON or EC_MKBP_EVENT_SWITCH. Actually
319 * in some cases this could be EC_MKBP_EVENT_KEY_MATRIX or
320 * EC_MKBP_EVENT_HOST_EVENT too but we don't use in this driver.
321 * @result: Where we'll store the result; a union
322 * @result_size: The size of the result. Expected to be the size of one of
323 * the elements in the union.
324 *
325 * Returns 0 if no error or -error upon error.
326 */
327static int cros_ec_keyb_info(struct cros_ec_device *ec_dev,
328 enum ec_mkbp_info_type info_type,
329 enum ec_mkbp_event event_type,
330 union ec_response_get_next_data *result,
331 size_t result_size)
332{
333 struct ec_params_mkbp_info *params;
334 struct cros_ec_command *msg;
335 int ret;
336
337 msg = kzalloc(sizeof(*msg) + max_t(size_t, result_size,
338 sizeof(*params)), GFP_KERNEL);
339 if (!msg)
340 return -ENOMEM;
341
342 msg->command = EC_CMD_MKBP_INFO;
343 msg->version = 1;
344 msg->outsize = sizeof(*params);
345 msg->insize = result_size;
346 params = (struct ec_params_mkbp_info *)msg->data;
347 params->info_type = info_type;
348 params->event_type = event_type;
349
350 ret = cros_ec_cmd_xfer(ec_dev, msg);
351 if (ret < 0) {
352 dev_warn(ec_dev->dev, "Transfer error %d/%d: %d\n",
353 (int)info_type, (int)event_type, ret);
354 } else if (msg->result == EC_RES_INVALID_VERSION) {
355 /* With older ECs we just return 0 for everything */
356 memset(result, 0, result_size);
357 ret = 0;
358 } else if (msg->result != EC_RES_SUCCESS) {
359 dev_warn(ec_dev->dev, "Error getting info %d/%d: %d\n",
360 (int)info_type, (int)event_type, msg->result);
361 ret = -EPROTO;
362 } else if (ret != result_size) {
363 dev_warn(ec_dev->dev, "Wrong size %d/%d: %d != %zu\n",
364 (int)info_type, (int)event_type,
365 ret, result_size);
366 ret = -EPROTO;
367 } else {
368 memcpy(result, msg->data, result_size);
369 ret = 0;
370 }
371
372 kfree(msg);
373
374 return ret;
375}
376
377/**
378 * cros_ec_keyb_query_switches - Query the state of switches and report
379 *
380 * This will ask the EC about the current state of switches and report to the
381 * kernel. Note that we don't query for buttons because they are more
382 * transitory and we'll get an update on the next release / press.
383 *
384 * @ckdev: The keyboard device
385 *
386 * Returns 0 if no error or -error upon error.
387 */
388static int cros_ec_keyb_query_switches(struct cros_ec_keyb *ckdev)
389{
390 struct cros_ec_device *ec_dev = ckdev->ec;
391 union ec_response_get_next_data event_data = {};
392 int ret;
393
394 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_CURRENT,
395 EC_MKBP_EVENT_SWITCH, &event_data,
396 sizeof(event_data.switches));
397 if (ret)
398 return ret;
399
400 cros_ec_keyb_report_bs(ckdev, EV_SW,
401 get_unaligned_le32(&event_data.switches));
402
403 return 0;
404}
405
406/**
407 * cros_ec_keyb_resume - Resume the keyboard
408 *
409 * We use the resume notification as a chance to query the EC for switches.
410 *
411 * @dev: The keyboard device
412 *
413 * Returns 0 if no error or -error upon error.
414 */
415static __maybe_unused int cros_ec_keyb_resume(struct device *dev)
416{
417 struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
418
419 if (ckdev->bs_idev)
420 return cros_ec_keyb_query_switches(ckdev);
421
422 return 0;
423}
424
425/**
426 * cros_ec_keyb_register_bs - Register non-matrix buttons/switches
427 *
428 * Handles all the bits of the keyboard driver related to non-matrix buttons
429 * and switches, including asking the EC about which are present and telling
430 * the kernel to expect them.
431 *
432 * If this device has no support for buttons and switches we'll return no error
433 * but the ckdev->bs_idev will remain NULL when this function exits.
434 *
435 * @ckdev: The keyboard device
436 *
437 * Returns 0 if no error or -error upon error.
438 */
439static int cros_ec_keyb_register_bs(struct cros_ec_keyb *ckdev)
440{
441 struct cros_ec_device *ec_dev = ckdev->ec;
442 struct device *dev = ckdev->dev;
443 struct input_dev *idev;
444 union ec_response_get_next_data event_data = {};
445 const char *phys;
446 u32 buttons;
447 u32 switches;
448 int ret;
449 int i;
450
451 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
452 EC_MKBP_EVENT_BUTTON, &event_data,
453 sizeof(event_data.buttons));
454 if (ret)
455 return ret;
456 buttons = get_unaligned_le32(&event_data.buttons);
457
458 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
459 EC_MKBP_EVENT_SWITCH, &event_data,
460 sizeof(event_data.switches));
461 if (ret)
462 return ret;
463 switches = get_unaligned_le32(&event_data.switches);
464
465 if (!buttons && !switches)
466 return 0;
467
468 /*
469 * We call the non-matrix buttons/switches 'input1', if present.
470 * Allocate phys before input dev, to ensure correct tear-down
471 * ordering.
472 */
473 phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input1", ec_dev->phys_name);
474 if (!phys)
475 return -ENOMEM;
476
477 idev = devm_input_allocate_device(dev);
478 if (!idev)
479 return -ENOMEM;
480
481 idev->name = "cros_ec_buttons";
482 idev->phys = phys;
483 __set_bit(EV_REP, idev->evbit);
484
485 idev->id.bustype = BUS_VIRTUAL;
486 idev->id.version = 1;
487 idev->id.product = 0;
488 idev->dev.parent = dev;
489
490 input_set_drvdata(idev, ckdev);
491 ckdev->bs_idev = idev;
492
493 for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
494 const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
495
496 if ((map->ev_type == EV_KEY && (buttons & BIT(map->bit))) ||
497 (map->ev_type == EV_SW && (switches & BIT(map->bit))))
498 input_set_capability(idev, map->ev_type, map->code);
499 }
500
501 ret = cros_ec_keyb_query_switches(ckdev);
502 if (ret) {
503 dev_err(dev, "cannot query switches\n");
504 return ret;
505 }
506
507 ret = input_register_device(ckdev->bs_idev);
508 if (ret) {
509 dev_err(dev, "cannot register input device\n");
510 return ret;
511 }
512
513 return 0;
514}
515
516/**
517 * cros_ec_keyb_register_bs - Register matrix keys
518 *
519 * Handles all the bits of the keyboard driver related to matrix keys.
520 *
521 * @ckdev: The keyboard device
522 *
523 * Returns 0 if no error or -error upon error.
524 */
525static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
526{
527 struct cros_ec_device *ec_dev = ckdev->ec;
528 struct device *dev = ckdev->dev;
529 struct input_dev *idev;
530 const char *phys;
531 int err;
532
533 err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols);
534 if (err)
535 return err;
536
537 ckdev->valid_keys = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
538 if (!ckdev->valid_keys)
539 return -ENOMEM;
540
541 ckdev->old_kb_state = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
542 if (!ckdev->old_kb_state)
543 return -ENOMEM;
544
545 /*
546 * We call the keyboard matrix 'input0'. Allocate phys before input
547 * dev, to ensure correct tear-down ordering.
548 */
549 phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input0", ec_dev->phys_name);
550 if (!phys)
551 return -ENOMEM;
552
553 idev = devm_input_allocate_device(dev);
554 if (!idev)
555 return -ENOMEM;
556
557 idev->name = CROS_EC_DEV_NAME;
558 idev->phys = phys;
559 __set_bit(EV_REP, idev->evbit);
560
561 idev->id.bustype = BUS_VIRTUAL;
562 idev->id.version = 1;
563 idev->id.product = 0;
564 idev->dev.parent = dev;
565
566 ckdev->ghost_filter = of_property_read_bool(dev->of_node,
567 "google,needs-ghost-filter");
568
569 err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
570 NULL, idev);
571 if (err) {
572 dev_err(dev, "cannot build key matrix\n");
573 return err;
574 }
575
576 ckdev->row_shift = get_count_order(ckdev->cols);
577
578 input_set_capability(idev, EV_MSC, MSC_SCAN);
579 input_set_drvdata(idev, ckdev);
580 ckdev->idev = idev;
581 cros_ec_keyb_compute_valid_keys(ckdev);
582
583 err = input_register_device(ckdev->idev);
584 if (err) {
585 dev_err(dev, "cannot register input device\n");
586 return err;
587 }
588
589 return 0;
590}
591
592static int cros_ec_keyb_probe(struct platform_device *pdev)
593{
594 struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
595 struct device *dev = &pdev->dev;
596 struct cros_ec_keyb *ckdev;
597 int err;
598
599 if (!dev->of_node)
600 return -ENODEV;
601
602 ckdev = devm_kzalloc(dev, sizeof(*ckdev), GFP_KERNEL);
603 if (!ckdev)
604 return -ENOMEM;
605
606 ckdev->ec = ec;
607 ckdev->dev = dev;
608 dev_set_drvdata(dev, ckdev);
609
610 err = cros_ec_keyb_register_matrix(ckdev);
611 if (err) {
612 dev_err(dev, "cannot register matrix inputs: %d\n", err);
613 return err;
614 }
615
616 err = cros_ec_keyb_register_bs(ckdev);
617 if (err) {
618 dev_err(dev, "cannot register non-matrix inputs: %d\n", err);
619 return err;
620 }
621
622 ckdev->notifier.notifier_call = cros_ec_keyb_work;
623 err = blocking_notifier_chain_register(&ckdev->ec->event_notifier,
624 &ckdev->notifier);
625 if (err) {
626 dev_err(dev, "cannot register notifier: %d\n", err);
627 return err;
628 }
629
630 device_init_wakeup(ckdev->dev, true);
631 return 0;
632}
633
634static int cros_ec_keyb_remove(struct platform_device *pdev)
635{
636 struct cros_ec_keyb *ckdev = dev_get_drvdata(&pdev->dev);
637
638 blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
639 &ckdev->notifier);
640
641 return 0;
642}
643
644#ifdef CONFIG_OF
645static const struct of_device_id cros_ec_keyb_of_match[] = {
646 { .compatible = "google,cros-ec-keyb" },
647 {},
648};
649MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
650#endif
651
652static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);
653
654static struct platform_driver cros_ec_keyb_driver = {
655 .probe = cros_ec_keyb_probe,
656 .remove = cros_ec_keyb_remove,
657 .driver = {
658 .name = "cros-ec-keyb",
659 .of_match_table = of_match_ptr(cros_ec_keyb_of_match),
660 .pm = &cros_ec_keyb_pm_ops,
661 },
662};
663
664module_platform_driver(cros_ec_keyb_driver);
665
666MODULE_LICENSE("GPL v2");
667MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
668MODULE_ALIAS("platform:cros-ec-keyb");
669