1 // SPDX-License-Identifier: GPL-2.0
2 // ChromeOS EC keyboard driver
4 // Copyright (C) 2012 Google, Inc.
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
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>
28 #include <asm/unaligned.h>
31 * struct cros_ec_keyb - Structure representing EC keyboard device
33 * @rows: Number of rows in the keypad
34 * @cols: Number of columns in the keypad
35 * @row_shift: log2 or number of rows, rounded up
36 * @keymap_data: Matrix keymap data used to convert to keyscan values
37 * @ghost_filter: true to enable the matrix key-ghosting filter
38 * @valid_keys: bitmap of existing keys for each matrix column
39 * @old_kb_state: bitmap of keys pressed last scan
40 * @dev: Device pointer
41 * @ec: Top level ChromeOS device to use to talk to EC
42 * @idev: The input device for the matrix keys.
43 * @bs_idev: The input device for non-matrix buttons and switches (or NULL).
44 * @notifier: interrupt event notifier for transport devices
50 const struct matrix_keymap_data *keymap_data;
53 uint8_t *old_kb_state;
56 struct cros_ec_device *ec;
58 struct input_dev *idev;
59 struct input_dev *bs_idev;
60 struct notifier_block notifier;
64 * struct cros_ec_bs_map - Mapping between Linux keycodes and EC button/switch
67 * @ev_type: The type of the input event to generate (e.g., EV_KEY).
68 * @code: A linux keycode
69 * @bit: A #define like EC_MKBP_POWER_BUTTON or EC_MKBP_LID_OPEN
70 * @inverted: If the #define and EV_SW have opposite meanings, this is true.
71 * Only applicable to switches.
73 struct cros_ec_bs_map {
80 /* cros_ec_keyb_bs - Map EC button/switch #defines into kernel ones */
81 static const struct cros_ec_bs_map cros_ec_keyb_bs[] = {
86 .bit = EC_MKBP_POWER_BUTTON,
91 .bit = EC_MKBP_VOL_UP,
95 .code = KEY_VOLUMEDOWN,
96 .bit = EC_MKBP_VOL_DOWN,
103 .bit = EC_MKBP_LID_OPEN,
108 .code = SW_TABLET_MODE,
109 .bit = EC_MKBP_TABLET_MODE,
114 * Returns true when there is at least one combination of pressed keys that
115 * results in ghosting.
117 static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
119 int col1, col2, buf1, buf2;
120 struct device *dev = ckdev->dev;
121 uint8_t *valid_keys = ckdev->valid_keys;
124 * Ghosting happens if for any pressed key X there are other keys
125 * pressed both in the same row and column of X as, for instance,
126 * in the following diagram:
133 * In this case only X, Y, and Z are pressed, but g appears to be
134 * pressed too (see Wikipedia).
136 for (col1 = 0; col1 < ckdev->cols; col1++) {
137 buf1 = buf[col1] & valid_keys[col1];
138 for (col2 = col1 + 1; col2 < ckdev->cols; col2++) {
139 buf2 = buf[col2] & valid_keys[col2];
140 if (hweight8(buf1 & buf2) > 1) {
141 dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x",
142 col1, buf1, col2, buf2);
153 * Compares the new keyboard state to the old one and produces key
154 * press/release events accordingly. The keyboard state is 13 bytes (one byte
157 static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
158 uint8_t *kb_state, int len)
160 struct input_dev *idev = ckdev->idev;
165 if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
167 * Simple-minded solution: ignore this state. The obvious
168 * improvement is to only ignore changes to keys involved in
169 * the ghosting, but process the other changes.
171 dev_dbg(ckdev->dev, "ghosting found\n");
175 for (col = 0; col < ckdev->cols; col++) {
176 for (row = 0; row < ckdev->rows; row++) {
177 int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
178 const unsigned short *keycodes = idev->keycode;
180 new_state = kb_state[col] & (1 << row);
181 old_state = ckdev->old_kb_state[col] & (1 << row);
182 if (new_state != old_state) {
184 "changed: [r%d c%d]: byte %02x\n",
185 row, col, new_state);
187 input_event(idev, EV_MSC, MSC_SCAN, pos);
188 input_report_key(idev, keycodes[pos],
192 ckdev->old_kb_state[col] = kb_state[col];
194 input_sync(ckdev->idev);
198 * cros_ec_keyb_report_bs - Report non-matrixed buttons or switches
200 * This takes a bitmap of buttons or switches from the EC and reports events,
201 * syncing at the end.
203 * @ckdev: The keyboard device.
204 * @ev_type: The input event type (e.g., EV_KEY).
205 * @mask: A bitmap of buttons from the EC.
207 static void cros_ec_keyb_report_bs(struct cros_ec_keyb *ckdev,
208 unsigned int ev_type, u32 mask)
211 struct input_dev *idev = ckdev->bs_idev;
214 for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
215 const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
217 if (map->ev_type != ev_type)
220 input_event(idev, ev_type, map->code,
221 !!(mask & BIT(map->bit)) ^ map->inverted);
226 static int cros_ec_keyb_work(struct notifier_block *nb,
227 unsigned long queued_during_suspend, void *_notify)
229 struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
232 unsigned int ev_type;
235 * If not wake enabled, discard key state changes during
236 * suspend. Switches will be re-checked in
237 * cros_ec_keyb_resume() to be sure nothing is lost.
239 if (queued_during_suspend && !device_may_wakeup(ckdev->dev))
242 switch (ckdev->ec->event_data.event_type) {
243 case EC_MKBP_EVENT_KEY_MATRIX:
244 pm_wakeup_event(ckdev->dev, 0);
246 if (ckdev->ec->event_size != ckdev->cols) {
248 "Discarded incomplete key matrix event.\n");
252 cros_ec_keyb_process(ckdev,
253 ckdev->ec->event_data.data.key_matrix,
254 ckdev->ec->event_size);
257 case EC_MKBP_EVENT_SYSRQ:
258 pm_wakeup_event(ckdev->dev, 0);
260 val = get_unaligned_le32(&ckdev->ec->event_data.data.sysrq);
261 dev_dbg(ckdev->dev, "sysrq code from EC: %#x\n", val);
265 case EC_MKBP_EVENT_BUTTON:
266 case EC_MKBP_EVENT_SWITCH:
267 pm_wakeup_event(ckdev->dev, 0);
269 if (ckdev->ec->event_data.event_type == EC_MKBP_EVENT_BUTTON) {
270 val = get_unaligned_le32(
271 &ckdev->ec->event_data.data.buttons);
274 val = get_unaligned_le32(
275 &ckdev->ec->event_data.data.switches);
278 cros_ec_keyb_report_bs(ckdev, ev_type, val);
289 * Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW. Used by
290 * ghosting logic to ignore NULL or virtual keys.
292 static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
295 int row_shift = ckdev->row_shift;
296 unsigned short *keymap = ckdev->idev->keycode;
299 BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap));
301 for (col = 0; col < ckdev->cols; col++) {
302 for (row = 0; row < ckdev->rows; row++) {
303 code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
304 if (code && (code != KEY_BATTERY))
305 ckdev->valid_keys[col] |= 1 << row;
307 dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n",
308 col, ckdev->valid_keys[col]);
313 * cros_ec_keyb_info - Wrap the EC command EC_CMD_MKBP_INFO
315 * This wraps the EC_CMD_MKBP_INFO, abstracting out all of the marshalling and
316 * unmarshalling and different version nonsense into something simple.
318 * @ec_dev: The EC device
319 * @info_type: Either EC_MKBP_INFO_SUPPORTED or EC_MKBP_INFO_CURRENT.
320 * @event_type: Either EC_MKBP_EVENT_BUTTON or EC_MKBP_EVENT_SWITCH. Actually
321 * in some cases this could be EC_MKBP_EVENT_KEY_MATRIX or
322 * EC_MKBP_EVENT_HOST_EVENT too but we don't use in this driver.
323 * @result: Where we'll store the result; a union
324 * @result_size: The size of the result. Expected to be the size of one of
325 * the elements in the union.
327 * Returns 0 if no error or -error upon error.
329 static int cros_ec_keyb_info(struct cros_ec_device *ec_dev,
330 enum ec_mkbp_info_type info_type,
331 enum ec_mkbp_event event_type,
332 union ec_response_get_next_data *result,
335 struct ec_params_mkbp_info *params;
336 struct cros_ec_command *msg;
339 msg = kzalloc(sizeof(*msg) + max_t(size_t, result_size,
340 sizeof(*params)), GFP_KERNEL);
344 msg->command = EC_CMD_MKBP_INFO;
346 msg->outsize = sizeof(*params);
347 msg->insize = result_size;
348 params = (struct ec_params_mkbp_info *)msg->data;
349 params->info_type = info_type;
350 params->event_type = event_type;
352 ret = cros_ec_cmd_xfer_status(ec_dev, msg);
353 if (ret == -ENOTSUPP) {
354 /* With older ECs we just return 0 for everything */
355 memset(result, 0, result_size);
357 } else if (ret < 0) {
358 dev_warn(ec_dev->dev, "Transfer error %d/%d: %d\n",
359 (int)info_type, (int)event_type, ret);
360 } else if (ret != result_size) {
361 dev_warn(ec_dev->dev, "Wrong size %d/%d: %d != %zu\n",
362 (int)info_type, (int)event_type,
366 memcpy(result, msg->data, result_size);
376 * cros_ec_keyb_query_switches - Query the state of switches and report
378 * This will ask the EC about the current state of switches and report to the
379 * kernel. Note that we don't query for buttons because they are more
380 * transitory and we'll get an update on the next release / press.
382 * @ckdev: The keyboard device
384 * Returns 0 if no error or -error upon error.
386 static int cros_ec_keyb_query_switches(struct cros_ec_keyb *ckdev)
388 struct cros_ec_device *ec_dev = ckdev->ec;
389 union ec_response_get_next_data event_data = {};
392 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_CURRENT,
393 EC_MKBP_EVENT_SWITCH, &event_data,
394 sizeof(event_data.switches));
398 cros_ec_keyb_report_bs(ckdev, EV_SW,
399 get_unaligned_le32(&event_data.switches));
405 * cros_ec_keyb_resume - Resume the keyboard
407 * We use the resume notification as a chance to query the EC for switches.
409 * @dev: The keyboard device
411 * Returns 0 if no error or -error upon error.
413 static __maybe_unused int cros_ec_keyb_resume(struct device *dev)
415 struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
418 return cros_ec_keyb_query_switches(ckdev);
424 * cros_ec_keyb_register_bs - Register non-matrix buttons/switches
426 * Handles all the bits of the keyboard driver related to non-matrix buttons
427 * and switches, including asking the EC about which are present and telling
428 * the kernel to expect them.
430 * If this device has no support for buttons and switches we'll return no error
431 * but the ckdev->bs_idev will remain NULL when this function exits.
433 * @ckdev: The keyboard device
435 * Returns 0 if no error or -error upon error.
437 static int cros_ec_keyb_register_bs(struct cros_ec_keyb *ckdev)
439 struct cros_ec_device *ec_dev = ckdev->ec;
440 struct device *dev = ckdev->dev;
441 struct input_dev *idev;
442 union ec_response_get_next_data event_data = {};
449 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
450 EC_MKBP_EVENT_BUTTON, &event_data,
451 sizeof(event_data.buttons));
454 buttons = get_unaligned_le32(&event_data.buttons);
456 ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
457 EC_MKBP_EVENT_SWITCH, &event_data,
458 sizeof(event_data.switches));
461 switches = get_unaligned_le32(&event_data.switches);
463 if (!buttons && !switches)
467 * We call the non-matrix buttons/switches 'input1', if present.
468 * Allocate phys before input dev, to ensure correct tear-down
471 phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input1", ec_dev->phys_name);
475 idev = devm_input_allocate_device(dev);
479 idev->name = "cros_ec_buttons";
481 __set_bit(EV_REP, idev->evbit);
483 idev->id.bustype = BUS_VIRTUAL;
484 idev->id.version = 1;
485 idev->id.product = 0;
486 idev->dev.parent = dev;
488 input_set_drvdata(idev, ckdev);
489 ckdev->bs_idev = idev;
491 for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
492 const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
494 if ((map->ev_type == EV_KEY && (buttons & BIT(map->bit))) ||
495 (map->ev_type == EV_SW && (switches & BIT(map->bit))))
496 input_set_capability(idev, map->ev_type, map->code);
499 ret = cros_ec_keyb_query_switches(ckdev);
501 dev_err(dev, "cannot query switches\n");
505 ret = input_register_device(ckdev->bs_idev);
507 dev_err(dev, "cannot register input device\n");
515 * cros_ec_keyb_register_bs - Register matrix keys
517 * Handles all the bits of the keyboard driver related to matrix keys.
519 * @ckdev: The keyboard device
521 * Returns 0 if no error or -error upon error.
523 static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
525 struct cros_ec_device *ec_dev = ckdev->ec;
526 struct device *dev = ckdev->dev;
527 struct input_dev *idev;
531 err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols);
535 ckdev->valid_keys = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
536 if (!ckdev->valid_keys)
539 ckdev->old_kb_state = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL);
540 if (!ckdev->old_kb_state)
544 * We call the keyboard matrix 'input0'. Allocate phys before input
545 * dev, to ensure correct tear-down ordering.
547 phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input0", ec_dev->phys_name);
551 idev = devm_input_allocate_device(dev);
555 idev->name = CROS_EC_DEV_NAME;
557 __set_bit(EV_REP, idev->evbit);
559 idev->id.bustype = BUS_VIRTUAL;
560 idev->id.version = 1;
561 idev->id.product = 0;
562 idev->dev.parent = dev;
564 ckdev->ghost_filter = of_property_read_bool(dev->of_node,
565 "google,needs-ghost-filter");
567 err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
570 dev_err(dev, "cannot build key matrix\n");
574 ckdev->row_shift = get_count_order(ckdev->cols);
576 input_set_capability(idev, EV_MSC, MSC_SCAN);
577 input_set_drvdata(idev, ckdev);
579 cros_ec_keyb_compute_valid_keys(ckdev);
581 err = input_register_device(ckdev->idev);
583 dev_err(dev, "cannot register input device\n");
590 static int cros_ec_keyb_probe(struct platform_device *pdev)
592 struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
593 struct device *dev = &pdev->dev;
594 struct cros_ec_keyb *ckdev;
600 ckdev = devm_kzalloc(dev, sizeof(*ckdev), GFP_KERNEL);
606 dev_set_drvdata(dev, ckdev);
608 err = cros_ec_keyb_register_matrix(ckdev);
610 dev_err(dev, "cannot register matrix inputs: %d\n", err);
614 err = cros_ec_keyb_register_bs(ckdev);
616 dev_err(dev, "cannot register non-matrix inputs: %d\n", err);
620 ckdev->notifier.notifier_call = cros_ec_keyb_work;
621 err = blocking_notifier_chain_register(&ckdev->ec->event_notifier,
624 dev_err(dev, "cannot register notifier: %d\n", err);
628 device_init_wakeup(ckdev->dev, true);
632 static int cros_ec_keyb_remove(struct platform_device *pdev)
634 struct cros_ec_keyb *ckdev = dev_get_drvdata(&pdev->dev);
636 blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
643 static const struct of_device_id cros_ec_keyb_of_match[] = {
644 { .compatible = "google,cros-ec-keyb" },
647 MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
650 static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);
652 static struct platform_driver cros_ec_keyb_driver = {
653 .probe = cros_ec_keyb_probe,
654 .remove = cros_ec_keyb_remove,
656 .name = "cros-ec-keyb",
657 .of_match_table = of_match_ptr(cros_ec_keyb_of_match),
658 .pm = &cros_ec_keyb_pm_ops,
662 module_platform_driver(cros_ec_keyb_driver);
664 MODULE_LICENSE("GPL v2");
665 MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
666 MODULE_ALIAS("platform:cros-ec-keyb");