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/platform_data/cros_ec_commands.h>
26 #include <linux/platform_data/cros_ec_proto.h>
27 
28 #include <asm/unaligned.h>
29 
30 #define MAX_NUM_TOP_ROW_KEYS   15
31 
32 /**
33  * struct cros_ec_keyb - Structure representing EC keyboard device
34  *
35  * @rows: Number of rows in the keypad
36  * @cols: Number of columns in the keypad
37  * @row_shift: log2 or number of rows, rounded up
38  * @keymap_data: Matrix keymap data used to convert to keyscan values
39  * @ghost_filter: true to enable the matrix key-ghosting filter
40  * @valid_keys: bitmap of existing keys for each matrix column
41  * @old_kb_state: bitmap of keys pressed last scan
42  * @dev: Device pointer
43  * @ec: Top level ChromeOS device to use to talk to EC
44  * @idev: The input device for the matrix keys.
45  * @bs_idev: The input device for non-matrix buttons and switches (or NULL).
46  * @notifier: interrupt event notifier for transport devices
47  * @function_row_physmap: An array of the encoded rows/columns for the top
48  *                        row function keys, in an order from left to right
49  * @num_function_row_keys: The number of top row keys in a custom keyboard
50  */
51 struct cros_ec_keyb {
52 	unsigned int rows;
53 	unsigned int cols;
54 	int row_shift;
55 	const struct matrix_keymap_data *keymap_data;
56 	bool ghost_filter;
57 	uint8_t *valid_keys;
58 	uint8_t *old_kb_state;
59 
60 	struct device *dev;
61 	struct cros_ec_device *ec;
62 
63 	struct input_dev *idev;
64 	struct input_dev *bs_idev;
65 	struct notifier_block notifier;
66 
67 	u16 function_row_physmap[MAX_NUM_TOP_ROW_KEYS];
68 	size_t num_function_row_keys;
69 };
70 
71 /**
72  * struct cros_ec_bs_map - Mapping between Linux keycodes and EC button/switch
73  *	bitmap #defines
74  *
75  * @ev_type: The type of the input event to generate (e.g., EV_KEY).
76  * @code: A linux keycode
77  * @bit: A #define like EC_MKBP_POWER_BUTTON or EC_MKBP_LID_OPEN
78  * @inverted: If the #define and EV_SW have opposite meanings, this is true.
79  *            Only applicable to switches.
80  */
81 struct cros_ec_bs_map {
82 	unsigned int ev_type;
83 	unsigned int code;
84 	u8 bit;
85 	bool inverted;
86 };
87 
88 /* cros_ec_keyb_bs - Map EC button/switch #defines into kernel ones */
89 static const struct cros_ec_bs_map cros_ec_keyb_bs[] = {
90 	/* Buttons */
91 	{
92 		.ev_type	= EV_KEY,
93 		.code		= KEY_POWER,
94 		.bit		= EC_MKBP_POWER_BUTTON,
95 	},
96 	{
97 		.ev_type	= EV_KEY,
98 		.code		= KEY_VOLUMEUP,
99 		.bit		= EC_MKBP_VOL_UP,
100 	},
101 	{
102 		.ev_type	= EV_KEY,
103 		.code		= KEY_VOLUMEDOWN,
104 		.bit		= EC_MKBP_VOL_DOWN,
105 	},
106 
107 	/* Switches */
108 	{
109 		.ev_type	= EV_SW,
110 		.code		= SW_LID,
111 		.bit		= EC_MKBP_LID_OPEN,
112 		.inverted	= true,
113 	},
114 	{
115 		.ev_type	= EV_SW,
116 		.code		= SW_TABLET_MODE,
117 		.bit		= EC_MKBP_TABLET_MODE,
118 	},
119 };
120 
121 /*
122  * Returns true when there is at least one combination of pressed keys that
123  * results in ghosting.
124  */
125 static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
126 {
127 	int col1, col2, buf1, buf2;
128 	struct device *dev = ckdev->dev;
129 	uint8_t *valid_keys = ckdev->valid_keys;
130 
131 	/*
132 	 * Ghosting happens if for any pressed key X there are other keys
133 	 * pressed both in the same row and column of X as, for instance,
134 	 * in the following diagram:
135 	 *
136 	 * . . Y . g .
137 	 * . . . . . .
138 	 * . . . . . .
139 	 * . . X . Z .
140 	 *
141 	 * In this case only X, Y, and Z are pressed, but g appears to be
142 	 * pressed too (see Wikipedia).
143 	 */
144 	for (col1 = 0; col1 < ckdev->cols; col1++) {
145 		buf1 = buf[col1] & valid_keys[col1];
146 		for (col2 = col1 + 1; col2 < ckdev->cols; col2++) {
147 			buf2 = buf[col2] & valid_keys[col2];
148 			if (hweight8(buf1 & buf2) > 1) {
149 				dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x",
150 					col1, buf1, col2, buf2);
151 				return true;
152 			}
153 		}
154 	}
155 
156 	return false;
157 }
158 
159 
160 /*
161  * Compares the new keyboard state to the old one and produces key
162  * press/release events accordingly.  The keyboard state is 13 bytes (one byte
163  * per column)
164  */
165 static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
166 			 uint8_t *kb_state, int len)
167 {
168 	struct input_dev *idev = ckdev->idev;
169 	int col, row;
170 	int new_state;
171 	int old_state;
172 
173 	if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
174 		/*
175 		 * Simple-minded solution: ignore this state. The obvious
176 		 * improvement is to only ignore changes to keys involved in
177 		 * the ghosting, but process the other changes.
178 		 */
179 		dev_dbg(ckdev->dev, "ghosting found\n");
180 		return;
181 	}
182 
183 	for (col = 0; col < ckdev->cols; col++) {
184 		for (row = 0; row < ckdev->rows; row++) {
185 			int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
186 			const unsigned short *keycodes = idev->keycode;
187 
188 			new_state = kb_state[col] & (1 << row);
189 			old_state = ckdev->old_kb_state[col] & (1 << row);
190 			if (new_state != old_state) {
191 				dev_dbg(ckdev->dev,
192 					"changed: [r%d c%d]: byte %02x\n",
193 					row, col, new_state);
194 
195 				input_event(idev, EV_MSC, MSC_SCAN, pos);
196 				input_report_key(idev, keycodes[pos],
197 						 new_state);
198 			}
199 		}
200 		ckdev->old_kb_state[col] = kb_state[col];
201 	}
202 	input_sync(ckdev->idev);
203 }
204 
205 /**
206  * cros_ec_keyb_report_bs - Report non-matrixed buttons or switches
207  *
208  * This takes a bitmap of buttons or switches from the EC and reports events,
209  * syncing at the end.
210  *
211  * @ckdev: The keyboard device.
212  * @ev_type: The input event type (e.g., EV_KEY).
213  * @mask: A bitmap of buttons from the EC.
214  */
215 static void cros_ec_keyb_report_bs(struct cros_ec_keyb *ckdev,
216 				   unsigned int ev_type, u32 mask)
217 
218 {
219 	struct input_dev *idev = ckdev->bs_idev;
220 	int i;
221 
222 	for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
223 		const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
224 
225 		if (map->ev_type != ev_type)
226 			continue;
227 
228 		input_event(idev, ev_type, map->code,
229 			    !!(mask & BIT(map->bit)) ^ map->inverted);
230 	}
231 	input_sync(idev);
232 }
233 
234 static int cros_ec_keyb_work(struct notifier_block *nb,
235 			     unsigned long queued_during_suspend, void *_notify)
236 {
237 	struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
238 						  notifier);
239 	u32 val;
240 	unsigned int ev_type;
241 
242 	/*
243 	 * If not wake enabled, discard key state changes during
244 	 * suspend. Switches will be re-checked in
245 	 * cros_ec_keyb_resume() to be sure nothing is lost.
246 	 */
247 	if (queued_during_suspend && !device_may_wakeup(ckdev->dev))
248 		return NOTIFY_OK;
249 
250 	switch (ckdev->ec->event_data.event_type) {
251 	case EC_MKBP_EVENT_KEY_MATRIX:
252 		pm_wakeup_event(ckdev->dev, 0);
253 
254 		if (ckdev->ec->event_size != ckdev->cols) {
255 			dev_err(ckdev->dev,
256 				"Discarded incomplete key matrix event.\n");
257 			return NOTIFY_OK;
258 		}
259 
260 		cros_ec_keyb_process(ckdev,
261 				     ckdev->ec->event_data.data.key_matrix,
262 				     ckdev->ec->event_size);
263 		break;
264 
265 	case EC_MKBP_EVENT_SYSRQ:
266 		pm_wakeup_event(ckdev->dev, 0);
267 
268 		val = get_unaligned_le32(&ckdev->ec->event_data.data.sysrq);
269 		dev_dbg(ckdev->dev, "sysrq code from EC: %#x\n", val);
270 		handle_sysrq(val);
271 		break;
272 
273 	case EC_MKBP_EVENT_BUTTON:
274 	case EC_MKBP_EVENT_SWITCH:
275 		pm_wakeup_event(ckdev->dev, 0);
276 
277 		if (ckdev->ec->event_data.event_type == EC_MKBP_EVENT_BUTTON) {
278 			val = get_unaligned_le32(
279 					&ckdev->ec->event_data.data.buttons);
280 			ev_type = EV_KEY;
281 		} else {
282 			val = get_unaligned_le32(
283 					&ckdev->ec->event_data.data.switches);
284 			ev_type = EV_SW;
285 		}
286 		cros_ec_keyb_report_bs(ckdev, ev_type, val);
287 		break;
288 
289 	default:
290 		return NOTIFY_DONE;
291 	}
292 
293 	return NOTIFY_OK;
294 }
295 
296 /*
297  * Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW.  Used by
298  * ghosting logic to ignore NULL or virtual keys.
299  */
300 static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
301 {
302 	int row, col;
303 	int row_shift = ckdev->row_shift;
304 	unsigned short *keymap = ckdev->idev->keycode;
305 	unsigned short code;
306 
307 	BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap));
308 
309 	for (col = 0; col < ckdev->cols; col++) {
310 		for (row = 0; row < ckdev->rows; row++) {
311 			code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
312 			if (code && (code != KEY_BATTERY))
313 				ckdev->valid_keys[col] |= 1 << row;
314 		}
315 		dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n",
316 			col, ckdev->valid_keys[col]);
317 	}
318 }
319 
320 /**
321  * cros_ec_keyb_info - Wrap the EC command EC_CMD_MKBP_INFO
322  *
323  * This wraps the EC_CMD_MKBP_INFO, abstracting out all of the marshalling and
324  * unmarshalling and different version nonsense into something simple.
325  *
326  * @ec_dev: The EC device
327  * @info_type: Either EC_MKBP_INFO_SUPPORTED or EC_MKBP_INFO_CURRENT.
328  * @event_type: Either EC_MKBP_EVENT_BUTTON or EC_MKBP_EVENT_SWITCH.  Actually
329  *              in some cases this could be EC_MKBP_EVENT_KEY_MATRIX or
330  *              EC_MKBP_EVENT_HOST_EVENT too but we don't use in this driver.
331  * @result: Where we'll store the result; a union
332  * @result_size: The size of the result.  Expected to be the size of one of
333  *               the elements in the union.
334  *
335  * Returns 0 if no error or -error upon error.
336  */
337 static int cros_ec_keyb_info(struct cros_ec_device *ec_dev,
338 			     enum ec_mkbp_info_type info_type,
339 			     enum ec_mkbp_event event_type,
340 			     union ec_response_get_next_data *result,
341 			     size_t result_size)
342 {
343 	struct ec_params_mkbp_info *params;
344 	struct cros_ec_command *msg;
345 	int ret;
346 
347 	msg = kzalloc(sizeof(*msg) + max_t(size_t, result_size,
348 					   sizeof(*params)), GFP_KERNEL);
349 	if (!msg)
350 		return -ENOMEM;
351 
352 	msg->command = EC_CMD_MKBP_INFO;
353 	msg->version = 1;
354 	msg->outsize = sizeof(*params);
355 	msg->insize = result_size;
356 	params = (struct ec_params_mkbp_info *)msg->data;
357 	params->info_type = info_type;
358 	params->event_type = event_type;
359 
360 	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
361 	if (ret == -ENOPROTOOPT) {
362 		/* With older ECs we just return 0 for everything */
363 		memset(result, 0, result_size);
364 		ret = 0;
365 	} else if (ret < 0) {
366 		dev_warn(ec_dev->dev, "Transfer error %d/%d: %d\n",
367 			 (int)info_type, (int)event_type, ret);
368 	} else if (ret != result_size) {
369 		dev_warn(ec_dev->dev, "Wrong size %d/%d: %d != %zu\n",
370 			 (int)info_type, (int)event_type,
371 			 ret, result_size);
372 		ret = -EPROTO;
373 	} else {
374 		memcpy(result, msg->data, result_size);
375 		ret = 0;
376 	}
377 
378 	kfree(msg);
379 
380 	return ret;
381 }
382 
383 /**
384  * cros_ec_keyb_query_switches - Query the state of switches and report
385  *
386  * This will ask the EC about the current state of switches and report to the
387  * kernel.  Note that we don't query for buttons because they are more
388  * transitory and we'll get an update on the next release / press.
389  *
390  * @ckdev: The keyboard device
391  *
392  * Returns 0 if no error or -error upon error.
393  */
394 static int cros_ec_keyb_query_switches(struct cros_ec_keyb *ckdev)
395 {
396 	struct cros_ec_device *ec_dev = ckdev->ec;
397 	union ec_response_get_next_data event_data = {};
398 	int ret;
399 
400 	ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_CURRENT,
401 				EC_MKBP_EVENT_SWITCH, &event_data,
402 				sizeof(event_data.switches));
403 	if (ret)
404 		return ret;
405 
406 	cros_ec_keyb_report_bs(ckdev, EV_SW,
407 			       get_unaligned_le32(&event_data.switches));
408 
409 	return 0;
410 }
411 
412 /**
413  * cros_ec_keyb_resume - Resume the keyboard
414  *
415  * We use the resume notification as a chance to query the EC for switches.
416  *
417  * @dev: The keyboard device
418  *
419  * Returns 0 if no error or -error upon error.
420  */
421 static __maybe_unused int cros_ec_keyb_resume(struct device *dev)
422 {
423 	struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
424 
425 	if (ckdev->bs_idev)
426 		return cros_ec_keyb_query_switches(ckdev);
427 
428 	return 0;
429 }
430 
431 /**
432  * cros_ec_keyb_register_bs - Register non-matrix buttons/switches
433  *
434  * Handles all the bits of the keyboard driver related to non-matrix buttons
435  * and switches, including asking the EC about which are present and telling
436  * the kernel to expect them.
437  *
438  * If this device has no support for buttons and switches we'll return no error
439  * but the ckdev->bs_idev will remain NULL when this function exits.
440  *
441  * @ckdev: The keyboard device
442  *
443  * Returns 0 if no error or -error upon error.
444  */
445 static int cros_ec_keyb_register_bs(struct cros_ec_keyb *ckdev)
446 {
447 	struct cros_ec_device *ec_dev = ckdev->ec;
448 	struct device *dev = ckdev->dev;
449 	struct input_dev *idev;
450 	union ec_response_get_next_data event_data = {};
451 	const char *phys;
452 	u32 buttons;
453 	u32 switches;
454 	int ret;
455 	int i;
456 
457 	ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
458 				EC_MKBP_EVENT_BUTTON, &event_data,
459 				sizeof(event_data.buttons));
460 	if (ret)
461 		return ret;
462 	buttons = get_unaligned_le32(&event_data.buttons);
463 
464 	ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
465 				EC_MKBP_EVENT_SWITCH, &event_data,
466 				sizeof(event_data.switches));
467 	if (ret)
468 		return ret;
469 	switches = get_unaligned_le32(&event_data.switches);
470 
471 	if (!buttons && !switches)
472 		return 0;
473 
474 	/*
475 	 * We call the non-matrix buttons/switches 'input1', if present.
476 	 * Allocate phys before input dev, to ensure correct tear-down
477 	 * ordering.
478 	 */
479 	phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input1", ec_dev->phys_name);
480 	if (!phys)
481 		return -ENOMEM;
482 
483 	idev = devm_input_allocate_device(dev);
484 	if (!idev)
485 		return -ENOMEM;
486 
487 	idev->name = "cros_ec_buttons";
488 	idev->phys = phys;
489 	__set_bit(EV_REP, idev->evbit);
490 
491 	idev->id.bustype = BUS_VIRTUAL;
492 	idev->id.version = 1;
493 	idev->id.product = 0;
494 	idev->dev.parent = dev;
495 
496 	input_set_drvdata(idev, ckdev);
497 	ckdev->bs_idev = idev;
498 
499 	for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
500 		const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
501 
502 		if ((map->ev_type == EV_KEY && (buttons & BIT(map->bit))) ||
503 		    (map->ev_type == EV_SW && (switches & BIT(map->bit))))
504 			input_set_capability(idev, map->ev_type, map->code);
505 	}
506 
507 	ret = cros_ec_keyb_query_switches(ckdev);
508 	if (ret) {
509 		dev_err(dev, "cannot query switches\n");
510 		return ret;
511 	}
512 
513 	ret = input_register_device(ckdev->bs_idev);
514 	if (ret) {
515 		dev_err(dev, "cannot register input device\n");
516 		return ret;
517 	}
518 
519 	return 0;
520 }
521 
522 /**
523  * cros_ec_keyb_register_bs - Register matrix keys
524  *
525  * Handles all the bits of the keyboard driver related to matrix keys.
526  *
527  * @ckdev: The keyboard device
528  *
529  * Returns 0 if no error or -error upon error.
530  */
531 static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
532 {
533 	struct cros_ec_device *ec_dev = ckdev->ec;
534 	struct device *dev = ckdev->dev;
535 	struct input_dev *idev;
536 	const char *phys;
537 	int err;
538 	struct property *prop;
539 	const __be32 *p;
540 	u16 *physmap;
541 	u32 key_pos;
542 	int row, col;
543 
544 	err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols);
545 	if (err)
546 		return err;
547 
548 	ckdev->valid_keys = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
549 	if (!ckdev->valid_keys)
550 		return -ENOMEM;
551 
552 	ckdev->old_kb_state = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
553 	if (!ckdev->old_kb_state)
554 		return -ENOMEM;
555 
556 	/*
557 	 * We call the keyboard matrix 'input0'. Allocate phys before input
558 	 * dev, to ensure correct tear-down ordering.
559 	 */
560 	phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input0", ec_dev->phys_name);
561 	if (!phys)
562 		return -ENOMEM;
563 
564 	idev = devm_input_allocate_device(dev);
565 	if (!idev)
566 		return -ENOMEM;
567 
568 	idev->name = CROS_EC_DEV_NAME;
569 	idev->phys = phys;
570 	__set_bit(EV_REP, idev->evbit);
571 
572 	idev->id.bustype = BUS_VIRTUAL;
573 	idev->id.version = 1;
574 	idev->id.product = 0;
575 	idev->dev.parent = dev;
576 
577 	ckdev->ghost_filter = of_property_read_bool(dev->of_node,
578 					"google,needs-ghost-filter");
579 
580 	err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
581 					 NULL, idev);
582 	if (err) {
583 		dev_err(dev, "cannot build key matrix\n");
584 		return err;
585 	}
586 
587 	ckdev->row_shift = get_count_order(ckdev->cols);
588 
589 	input_set_capability(idev, EV_MSC, MSC_SCAN);
590 	input_set_drvdata(idev, ckdev);
591 	ckdev->idev = idev;
592 	cros_ec_keyb_compute_valid_keys(ckdev);
593 
594 	physmap = ckdev->function_row_physmap;
595 	of_property_for_each_u32(dev->of_node, "function-row-physmap",
596 				 prop, p, key_pos) {
597 		if (ckdev->num_function_row_keys == MAX_NUM_TOP_ROW_KEYS) {
598 			dev_warn(dev, "Only support up to %d top row keys\n",
599 				 MAX_NUM_TOP_ROW_KEYS);
600 			break;
601 		}
602 		row = KEY_ROW(key_pos);
603 		col = KEY_COL(key_pos);
604 		*physmap = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
605 		physmap++;
606 		ckdev->num_function_row_keys++;
607 	}
608 
609 	err = input_register_device(ckdev->idev);
610 	if (err) {
611 		dev_err(dev, "cannot register input device\n");
612 		return err;
613 	}
614 
615 	return 0;
616 }
617 
618 static ssize_t function_row_physmap_show(struct device *dev,
619 					 struct device_attribute *attr,
620 					 char *buf)
621 {
622 	ssize_t size = 0;
623 	int i;
624 	struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
625 	u16 *physmap = ckdev->function_row_physmap;
626 
627 	for (i = 0; i < ckdev->num_function_row_keys; i++)
628 		size += scnprintf(buf + size, PAGE_SIZE - size,
629 				  "%s%02X", size ? " " : "", physmap[i]);
630 	if (size)
631 		size += scnprintf(buf + size, PAGE_SIZE - size, "\n");
632 
633 	return size;
634 }
635 
636 static DEVICE_ATTR_RO(function_row_physmap);
637 
638 static struct attribute *cros_ec_keyb_attrs[] = {
639 	&dev_attr_function_row_physmap.attr,
640 	NULL,
641 };
642 
643 static umode_t cros_ec_keyb_attr_is_visible(struct kobject *kobj,
644 					    struct attribute *attr,
645 					    int n)
646 {
647 	struct device *dev = kobj_to_dev(kobj);
648 	struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
649 
650 	if (attr == &dev_attr_function_row_physmap.attr &&
651 	    !ckdev->num_function_row_keys)
652 		return 0;
653 
654 	return attr->mode;
655 }
656 
657 static const struct attribute_group cros_ec_keyb_attr_group = {
658 	.is_visible = cros_ec_keyb_attr_is_visible,
659 	.attrs = cros_ec_keyb_attrs,
660 };
661 
662 
663 static int cros_ec_keyb_probe(struct platform_device *pdev)
664 {
665 	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
666 	struct device *dev = &pdev->dev;
667 	struct cros_ec_keyb *ckdev;
668 	int err;
669 
670 	if (!dev->of_node)
671 		return -ENODEV;
672 
673 	ckdev = devm_kzalloc(dev, sizeof(*ckdev), GFP_KERNEL);
674 	if (!ckdev)
675 		return -ENOMEM;
676 
677 	ckdev->ec = ec;
678 	ckdev->dev = dev;
679 	dev_set_drvdata(dev, ckdev);
680 
681 	err = cros_ec_keyb_register_matrix(ckdev);
682 	if (err) {
683 		dev_err(dev, "cannot register matrix inputs: %d\n", err);
684 		return err;
685 	}
686 
687 	err = cros_ec_keyb_register_bs(ckdev);
688 	if (err) {
689 		dev_err(dev, "cannot register non-matrix inputs: %d\n", err);
690 		return err;
691 	}
692 
693 	err = devm_device_add_group(dev, &cros_ec_keyb_attr_group);
694 	if (err) {
695 		dev_err(dev, "failed to create attributes. err=%d\n", err);
696 		return err;
697 	}
698 
699 	ckdev->notifier.notifier_call = cros_ec_keyb_work;
700 	err = blocking_notifier_chain_register(&ckdev->ec->event_notifier,
701 					       &ckdev->notifier);
702 	if (err) {
703 		dev_err(dev, "cannot register notifier: %d\n", err);
704 		return err;
705 	}
706 
707 	device_init_wakeup(ckdev->dev, true);
708 	return 0;
709 }
710 
711 static int cros_ec_keyb_remove(struct platform_device *pdev)
712 {
713 	struct cros_ec_keyb *ckdev = dev_get_drvdata(&pdev->dev);
714 
715 	blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
716 					   &ckdev->notifier);
717 
718 	return 0;
719 }
720 
721 #ifdef CONFIG_OF
722 static const struct of_device_id cros_ec_keyb_of_match[] = {
723 	{ .compatible = "google,cros-ec-keyb" },
724 	{},
725 };
726 MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
727 #endif
728 
729 static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);
730 
731 static struct platform_driver cros_ec_keyb_driver = {
732 	.probe = cros_ec_keyb_probe,
733 	.remove = cros_ec_keyb_remove,
734 	.driver = {
735 		.name = "cros-ec-keyb",
736 		.of_match_table = of_match_ptr(cros_ec_keyb_of_match),
737 		.pm = &cros_ec_keyb_pm_ops,
738 	},
739 };
740 
741 module_platform_driver(cros_ec_keyb_driver);
742 
743 MODULE_LICENSE("GPL v2");
744 MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
745 MODULE_ALIAS("platform:cros-ec-keyb");
746