2 * ChromeOS EC keyboard driver
4 * Copyright (C) 2012 Google, Inc
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * This driver uses the Chrome OS EC byte-level message-based protocol for
16 * communicating the keyboard state (which keys are pressed) from a keyboard EC
17 * to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
18 * but everything else (including deghosting) is done here. The main
19 * motivation for this is to keep the EC firmware as simple as possible, since
20 * it cannot be easily upgraded and EC flash/IRAM space is relatively
24 #include <linux/module.h>
25 #include <linux/bitops.h>
26 #include <linux/i2c.h>
27 #include <linux/input.h>
28 #include <linux/interrupt.h>
29 #include <linux/kernel.h>
30 #include <linux/notifier.h>
31 #include <linux/platform_device.h>
32 #include <linux/slab.h>
33 #include <linux/sysrq.h>
34 #include <linux/input/matrix_keypad.h>
35 #include <linux/mfd/cros_ec.h>
36 #include <linux/mfd/cros_ec_commands.h>
38 #include <asm/unaligned.h>
41 * @rows: Number of rows in the keypad
42 * @cols: Number of columns in the keypad
43 * @row_shift: log2 or number of rows, rounded up
44 * @keymap_data: Matrix keymap data used to convert to keyscan values
45 * @ghost_filter: true to enable the matrix key-ghosting filter
46 * @valid_keys: bitmap of existing keys for each matrix column
47 * @old_kb_state: bitmap of keys pressed last scan
48 * @dev: Device pointer
49 * @ec: Top level ChromeOS device to use to talk to EC
50 * @idev: The input device for the matrix keys.
51 * @bs_idev: The input device for non-matrix buttons and switches (or NULL).
52 * @notifier: interrupt event notifier for transport devices
58 const struct matrix_keymap_data *keymap_data;
61 uint8_t *old_kb_state;
64 struct cros_ec_device *ec;
66 struct input_dev *idev;
67 struct input_dev *bs_idev;
68 struct notifier_block notifier;
73 * cros_ec_bs_map - Struct mapping Linux keycodes to EC button/switch bitmap
76 * @ev_type: The type of the input event to generate (e.g., EV_KEY).
77 * @code: A linux keycode
78 * @bit: A #define like EC_MKBP_POWER_BUTTON or EC_MKBP_LID_OPEN
79 * @inverted: If the #define and EV_SW have opposite meanings, this is true.
80 * Only applicable to switches.
82 struct cros_ec_bs_map {
89 /* cros_ec_keyb_bs - Map EC button/switch #defines into kernel ones */
90 static const struct cros_ec_bs_map cros_ec_keyb_bs[] = {
95 .bit = EC_MKBP_POWER_BUTTON,
100 .bit = EC_MKBP_VOL_UP,
104 .code = KEY_VOLUMEDOWN,
105 .bit = EC_MKBP_VOL_DOWN,
112 .bit = EC_MKBP_LID_OPEN,
117 .code = SW_TABLET_MODE,
118 .bit = EC_MKBP_TABLET_MODE,
123 * Returns true when there is at least one combination of pressed keys that
124 * results in ghosting.
126 static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
128 int col1, col2, buf1, buf2;
129 struct device *dev = ckdev->dev;
130 uint8_t *valid_keys = ckdev->valid_keys;
133 * Ghosting happens if for any pressed key X there are other keys
134 * pressed both in the same row and column of X as, for instance,
135 * in the following diagram:
142 * In this case only X, Y, and Z are pressed, but g appears to be
143 * pressed too (see Wikipedia).
145 for (col1 = 0; col1 < ckdev->cols; col1++) {
146 buf1 = buf[col1] & valid_keys[col1];
147 for (col2 = col1 + 1; col2 < ckdev->cols; col2++) {
148 buf2 = buf[col2] & valid_keys[col2];
149 if (hweight8(buf1 & buf2) > 1) {
150 dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x",
151 col1, buf1, col2, buf2);
162 * Compares the new keyboard state to the old one and produces key
163 * press/release events accordingly. The keyboard state is 13 bytes (one byte
166 static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
167 uint8_t *kb_state, int len)
169 struct input_dev *idev = ckdev->idev;
177 if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
179 * Simple-minded solution: ignore this state. The obvious
180 * improvement is to only ignore changes to keys involved in
181 * the ghosting, but process the other changes.
183 dev_dbg(ckdev->dev, "ghosting found\n");
187 for (col = 0; col < ckdev->cols; col++) {
188 for (row = 0; row < ckdev->rows; row++) {
189 int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
190 const unsigned short *keycodes = idev->keycode;
192 new_state = kb_state[col] & (1 << row);
193 old_state = ckdev->old_kb_state[col] & (1 << row);
194 if (new_state != old_state) {
196 "changed: [r%d c%d]: byte %02x\n",
197 row, col, new_state);
199 input_event(idev, EV_MSC, MSC_SCAN, pos);
200 input_report_key(idev, keycodes[pos],
204 ckdev->old_kb_state[col] = kb_state[col];
206 input_sync(ckdev->idev);
210 * cros_ec_keyb_report_bs - Report non-matrixed buttons or switches
212 * This takes a bitmap of buttons or switches from the EC and reports events,
213 * syncing at the end.
215 * @ckdev: The keyboard device.
216 * @ev_type: The input event type (e.g., EV_KEY).
217 * @mask: A bitmap of buttons from the EC.
219 static void cros_ec_keyb_report_bs(struct cros_ec_keyb *ckdev,
220 unsigned int ev_type, u32 mask)
223 struct input_dev *idev = ckdev->bs_idev;
226 for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
227 const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
229 if (map->ev_type != ev_type)
232 input_event(idev, ev_type, map->code,
233 !!(mask & BIT(map->bit)) ^ map->inverted);
238 static int cros_ec_keyb_work(struct notifier_block *nb,
239 unsigned long queued_during_suspend, void *_notify)
241 struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
244 unsigned int ev_type;
246 switch (ckdev->ec->event_data.event_type) {
247 case EC_MKBP_EVENT_KEY_MATRIX:
249 * If EC is not the wake source, discard key state changes
252 if (queued_during_suspend)
255 if (ckdev->ec->event_size != ckdev->cols) {
257 "Discarded incomplete key matrix event.\n");
260 cros_ec_keyb_process(ckdev,
261 ckdev->ec->event_data.data.key_matrix,
262 ckdev->ec->event_size);
265 case EC_MKBP_EVENT_SYSRQ:
266 val = get_unaligned_le32(&ckdev->ec->event_data.data.sysrq);
267 dev_dbg(ckdev->dev, "sysrq code from EC: %#x\n", val);
271 case EC_MKBP_EVENT_BUTTON:
272 case EC_MKBP_EVENT_SWITCH:
274 * If EC is not the wake source, discard key state
275 * changes during suspend. Switches will be re-checked in
276 * cros_ec_keyb_resume() to be sure nothing is lost.
278 if (queued_during_suspend)
281 if (ckdev->ec->event_data.event_type == EC_MKBP_EVENT_BUTTON) {
282 val = get_unaligned_le32(
283 &ckdev->ec->event_data.data.buttons);
286 val = get_unaligned_le32(
287 &ckdev->ec->event_data.data.switches);
290 cros_ec_keyb_report_bs(ckdev, ev_type, val);
301 * Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW. Used by
302 * ghosting logic to ignore NULL or virtual keys.
304 static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
307 int row_shift = ckdev->row_shift;
308 unsigned short *keymap = ckdev->idev->keycode;
311 BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap));
313 for (col = 0; col < ckdev->cols; col++) {
314 for (row = 0; row < ckdev->rows; row++) {
315 code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
316 if (code && (code != KEY_BATTERY))
317 ckdev->valid_keys[col] |= 1 << row;
319 dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n",
320 col, ckdev->valid_keys[col]);
325 * cros_ec_keyb_info - Wrap the EC command EC_CMD_MKBP_INFO
327 * This wraps the EC_CMD_MKBP_INFO, abstracting out all of the marshalling and
328 * unmarshalling and different version nonsense into something simple.
330 * @ec_dev: The EC device
331 * @info_type: Either EC_MKBP_INFO_SUPPORTED or EC_MKBP_INFO_CURRENT.
332 * @event_type: Either EC_MKBP_EVENT_BUTTON or EC_MKBP_EVENT_SWITCH. Actually
333 * in some cases this could be EC_MKBP_EVENT_KEY_MATRIX or
334 * EC_MKBP_EVENT_HOST_EVENT too but we don't use in this driver.
335 * @result: Where we'll store the result; a union
336 * @result_size: The size of the result. Expected to be the size of one of
337 * the elements in the union.
339 * Returns 0 if no error or -error upon error.
341 static int cros_ec_keyb_info(struct cros_ec_device *ec_dev,
342 enum ec_mkbp_info_type info_type,
343 enum ec_mkbp_event event_type,
344 union ec_response_get_next_data *result,
347 struct ec_params_mkbp_info *params;
348 struct cros_ec_command *msg;
351 msg = kzalloc(sizeof(*msg) + max_t(size_t, result_size,
352 sizeof(*params)), GFP_KERNEL);
356 msg->command = EC_CMD_MKBP_INFO;
358 msg->outsize = sizeof(*params);
359 msg->insize = result_size;
360 params = (struct ec_params_mkbp_info *)msg->data;
361 params->info_type = info_type;
362 params->event_type = event_type;
364 ret = cros_ec_cmd_xfer(ec_dev, msg);
366 dev_warn(ec_dev->dev, "Transfer error %d/%d: %d\n",
367 (int)info_type, (int)event_type, ret);
368 } else if (msg->result == EC_RES_INVALID_VERSION) {
369 /* With older ECs we just return 0 for everything */
370 memset(result, 0, result_size);
372 } else if (msg->result != EC_RES_SUCCESS) {
373 dev_warn(ec_dev->dev, "Error getting info %d/%d: %d\n",
374 (int)info_type, (int)event_type, msg->result);
376 } else if (ret != result_size) {
377 dev_warn(ec_dev->dev, "Wrong size %d/%d: %d != %zu\n",
378 (int)info_type, (int)event_type,
382 memcpy(result, msg->data, result_size);
392 * cros_ec_keyb_query_switches - Query the state of switches and report
394 * This will ask the EC about the current state of switches and report to the
395 * kernel. Note that we don't query for buttons because they are more
396 * transitory and we'll get an update on the next release / press.
398 * @ckdev: The keyboard device
400 * Returns 0 if no error or -error upon error.
402 static int cros_ec_keyb_query_switches(struct cros_ec_keyb *ckdev)
404 struct cros_ec_device *ec_dev = ckdev->ec;
405 union ec_response_get_next_data event_data = {};
408 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_CURRENT,
409 EC_MKBP_EVENT_SWITCH, &event_data,
410 sizeof(event_data.switches));
414 cros_ec_keyb_report_bs(ckdev, EV_SW,
415 get_unaligned_le32(&event_data.switches));
421 * cros_ec_keyb_resume - Resume the keyboard
423 * We use the resume notification as a chance to query the EC for switches.
425 * @dev: The keyboard device
427 * Returns 0 if no error or -error upon error.
429 static __maybe_unused int cros_ec_keyb_resume(struct device *dev)
431 struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
434 return cros_ec_keyb_query_switches(ckdev);
440 * cros_ec_keyb_register_bs - Register non-matrix buttons/switches
442 * Handles all the bits of the keyboard driver related to non-matrix buttons
443 * and switches, including asking the EC about which are present and telling
444 * the kernel to expect them.
446 * If this device has no support for buttons and switches we'll return no error
447 * but the ckdev->bs_idev will remain NULL when this function exits.
449 * @ckdev: The keyboard device
451 * Returns 0 if no error or -error upon error.
453 static int cros_ec_keyb_register_bs(struct cros_ec_keyb *ckdev)
455 struct cros_ec_device *ec_dev = ckdev->ec;
456 struct device *dev = ckdev->dev;
457 struct input_dev *idev;
458 union ec_response_get_next_data event_data = {};
465 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
466 EC_MKBP_EVENT_BUTTON, &event_data,
467 sizeof(event_data.buttons));
470 buttons = get_unaligned_le32(&event_data.buttons);
472 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
473 EC_MKBP_EVENT_SWITCH, &event_data,
474 sizeof(event_data.switches));
477 switches = get_unaligned_le32(&event_data.switches);
479 if (!buttons && !switches)
483 * We call the non-matrix buttons/switches 'input1', if present.
484 * Allocate phys before input dev, to ensure correct tear-down
487 phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input1", ec_dev->phys_name);
491 idev = devm_input_allocate_device(dev);
495 idev->name = "cros_ec_buttons";
497 __set_bit(EV_REP, idev->evbit);
499 idev->id.bustype = BUS_VIRTUAL;
500 idev->id.version = 1;
501 idev->id.product = 0;
502 idev->dev.parent = dev;
504 input_set_drvdata(idev, ckdev);
505 ckdev->bs_idev = idev;
507 for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
508 const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
510 if ((map->ev_type == EV_KEY && (buttons & BIT(map->bit))) ||
511 (map->ev_type == EV_SW && (switches & BIT(map->bit))))
512 input_set_capability(idev, map->ev_type, map->code);
515 ret = cros_ec_keyb_query_switches(ckdev);
517 dev_err(dev, "cannot query switches\n");
521 ret = input_register_device(ckdev->bs_idev);
523 dev_err(dev, "cannot register input device\n");
531 * cros_ec_keyb_register_bs - Register matrix keys
533 * Handles all the bits of the keyboard driver related to matrix keys.
535 * @ckdev: The keyboard device
537 * Returns 0 if no error or -error upon error.
539 static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
541 struct cros_ec_device *ec_dev = ckdev->ec;
542 struct device *dev = ckdev->dev;
543 struct input_dev *idev;
547 err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols);
551 ckdev->valid_keys = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
552 if (!ckdev->valid_keys)
555 ckdev->old_kb_state = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
556 if (!ckdev->old_kb_state)
560 * We call the keyboard matrix 'input0'. Allocate phys before input
561 * dev, to ensure correct tear-down ordering.
563 phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input0", ec_dev->phys_name);
567 idev = devm_input_allocate_device(dev);
571 idev->name = CROS_EC_DEV_NAME;
573 __set_bit(EV_REP, idev->evbit);
575 idev->id.bustype = BUS_VIRTUAL;
576 idev->id.version = 1;
577 idev->id.product = 0;
578 idev->dev.parent = dev;
580 ckdev->ghost_filter = of_property_read_bool(dev->of_node,
581 "google,needs-ghost-filter");
583 err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
586 dev_err(dev, "cannot build key matrix\n");
590 ckdev->row_shift = get_count_order(ckdev->cols);
592 input_set_capability(idev, EV_MSC, MSC_SCAN);
593 input_set_drvdata(idev, ckdev);
595 cros_ec_keyb_compute_valid_keys(ckdev);
597 err = input_register_device(ckdev->idev);
599 dev_err(dev, "cannot register input device\n");
606 static int cros_ec_keyb_probe(struct platform_device *pdev)
608 struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
609 struct device *dev = &pdev->dev;
610 struct cros_ec_keyb *ckdev;
616 ckdev = devm_kzalloc(dev, sizeof(*ckdev), GFP_KERNEL);
622 dev_set_drvdata(dev, ckdev);
624 err = cros_ec_keyb_register_matrix(ckdev);
626 dev_err(dev, "cannot register matrix inputs: %d\n", err);
630 err = cros_ec_keyb_register_bs(ckdev);
632 dev_err(dev, "cannot register non-matrix inputs: %d\n", err);
636 ckdev->notifier.notifier_call = cros_ec_keyb_work;
637 err = blocking_notifier_chain_register(&ckdev->ec->event_notifier,
640 dev_err(dev, "cannot register notifier: %d\n", err);
647 static int cros_ec_keyb_remove(struct platform_device *pdev)
649 struct cros_ec_keyb *ckdev = dev_get_drvdata(&pdev->dev);
651 blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
658 static const struct of_device_id cros_ec_keyb_of_match[] = {
659 { .compatible = "google,cros-ec-keyb" },
662 MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
665 static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);
667 static struct platform_driver cros_ec_keyb_driver = {
668 .probe = cros_ec_keyb_probe,
669 .remove = cros_ec_keyb_remove,
671 .name = "cros-ec-keyb",
672 .of_match_table = of_match_ptr(cros_ec_keyb_of_match),
673 .pm = &cros_ec_keyb_pm_ops,
677 module_platform_driver(cros_ec_keyb_driver);
679 MODULE_LICENSE("GPL");
680 MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
681 MODULE_ALIAS("platform:cros-ec-keyb");