[deliverable/linux.git] / drivers / input / keyboard / cros_ec_keyb.c

/*
 * ChromeOS EC keyboard driver
 *
 * Copyright (C) 2012 Google, Inc
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * This driver uses the Chrome OS EC byte-level message-based protocol for
 * communicating the keyboard state (which keys are pressed) from a keyboard EC
 * to the AP over some bus (such as i2c, lpc, spi).  The EC does debouncing,
 * but everything else (including deghosting) is done here.  The main
 * motivation for this is to keep the EC firmware as simple as possible, since
 * it cannot be easily upgraded and EC flash/IRAM space is relatively
 * expensive.
 */

#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/input/matrix_keypad.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>

/*
 * @rows: Number of rows in the keypad
 * @cols: Number of columns in the keypad
 * @row_shift: log2 or number of rows, rounded up
 * @keymap_data: Matrix keymap data used to convert to keyscan values
 * @ghost_filter: true to enable the matrix key-ghosting filter
 * @valid_keys: bitmap of existing keys for each matrix column
 * @old_kb_state: bitmap of keys pressed last scan
 * @dev: Device pointer
 * @idev: Input device
 * @ec: Top level ChromeOS device to use to talk to EC
 */
struct cros_ec_keyb {
	unsigned int rows;
	unsigned int cols;
	int row_shift;
	const struct matrix_keymap_data *keymap_data;
	bool ghost_filter;
	uint8_t *valid_keys;
	uint8_t *old_kb_state;

	struct device *dev;
	struct input_dev *idev;
	struct cros_ec_device *ec;
};


/*
 * Returns true when there is at least one combination of pressed keys that
 * results in ghosting.
 */
static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
{
	int col1, col2, buf1, buf2;
	struct device *dev = ckdev->dev;
	uint8_t *valid_keys = ckdev->valid_keys;

	/*
	 * Ghosting happens if for any pressed key X there are other keys
	 * pressed both in the same row and column of X as, for instance,
	 * in the following diagram:
	 *
	 * . . Y . g .
	 * . . . . . .
	 * . . . . . .
	 * . . X . Z .
	 *
	 * In this case only X, Y, and Z are pressed, but g appears to be
	 * pressed too (see Wikipedia).
	 */
	for (col1 = 0; col1 < ckdev->cols; col1++) {
		buf1 = buf[col1] & valid_keys[col1];
		for (col2 = col1 + 1; col2 < ckdev->cols; col2++) {
			buf2 = buf[col2] & valid_keys[col2];
			if (hweight8(buf1 & buf2) > 1) {
				dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x",
					col1, buf1, col2, buf2);
				return true;
			}
		}
	}

	return false;
}


/*
 * Compares the new keyboard state to the old one and produces key
 * press/release events accordingly.  The keyboard state is 13 bytes (one byte
 * per column)
 */
static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
			 uint8_t *kb_state, int len)
{
	struct input_dev *idev = ckdev->idev;
	int col, row;
	int new_state;
	int old_state;
	int num_cols;

	num_cols = len;

	if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
		/*
		 * Simple-minded solution: ignore this state. The obvious
		 * improvement is to only ignore changes to keys involved in
		 * the ghosting, but process the other changes.
		 */
		dev_dbg(ckdev->dev, "ghosting found\n");
		return;
	}

	for (col = 0; col < ckdev->cols; col++) {
		for (row = 0; row < ckdev->rows; row++) {
			int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
			const unsigned short *keycodes = idev->keycode;

			new_state = kb_state[col] & (1 << row);
			old_state = ckdev->old_kb_state[col] & (1 << row);
			if (new_state != old_state) {
				dev_dbg(ckdev->dev,
					"changed: [r%d c%d]: byte %02x\n",
					row, col, new_state);

				input_report_key(idev, keycodes[pos],
						 new_state);
			}
		}
		ckdev->old_kb_state[col] = kb_state[col];
	}
	input_sync(ckdev->idev);
}

static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state)
{
	struct cros_ec_command msg = {
		.version = 0,
		.command = EC_CMD_MKBP_STATE,
		.outdata = NULL,
		.outsize = 0,
		.indata = kb_state,
		.insize = ckdev->cols,
	};

	return cros_ec_cmd_xfer(ckdev->ec, &msg);
}

static irqreturn_t cros_ec_keyb_irq(int irq, void *data)
{
	struct cros_ec_keyb *ckdev = data;
	struct cros_ec_device *ec = ckdev->ec;
	int ret;
	uint8_t kb_state[ckdev->cols];

	if (device_may_wakeup(ec->dev))
		pm_wakeup_event(ec->dev, 0);

	ret = cros_ec_keyb_get_state(ckdev, kb_state);
	if (ret >= 0)
		cros_ec_keyb_process(ckdev, kb_state, ret);
	else
		dev_err(ec->dev, "failed to get keyboard state: %d\n", ret);

	return IRQ_HANDLED;
}

static int cros_ec_keyb_open(struct input_dev *dev)
{
	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
	struct cros_ec_device *ec = ckdev->ec;

	return request_threaded_irq(ec->irq, NULL, cros_ec_keyb_irq,
					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
					"cros_ec_keyb", ckdev);
}

static void cros_ec_keyb_close(struct input_dev *dev)
{
	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
	struct cros_ec_device *ec = ckdev->ec;

	free_irq(ec->irq, ckdev);
}

/*
 * Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW.  Used by
 * ghosting logic to ignore NULL or virtual keys.
 */
static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
{
	int row, col;
	int row_shift = ckdev->row_shift;
	unsigned short *keymap = ckdev->idev->keycode;
	unsigned short code;

	BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap));

	for (col = 0; col < ckdev->cols; col++) {
		for (row = 0; row < ckdev->rows; row++) {
			code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
			if (code && (code != KEY_BATTERY))
				ckdev->valid_keys[col] |= 1 << row;
		}
		dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n",
			col, ckdev->valid_keys[col]);
	}
}

static int cros_ec_keyb_probe(struct platform_device *pdev)
{
	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
	struct device *dev = ec->dev;
	struct cros_ec_keyb *ckdev;
	struct input_dev *idev;
	struct device_node *np;
	int err;

	np = pdev->dev.of_node;
	if (!np)
		return -ENODEV;

	ckdev = devm_kzalloc(&pdev->dev, sizeof(*ckdev), GFP_KERNEL);
	if (!ckdev)
		return -ENOMEM;
	err = matrix_keypad_parse_of_params(&pdev->dev, &ckdev->rows,
					    &ckdev->cols);
	if (err)
		return err;

	ckdev->valid_keys = devm_kzalloc(&pdev->dev, ckdev->cols, GFP_KERNEL);
	if (!ckdev->valid_keys)
		return -ENOMEM;

	ckdev->old_kb_state = devm_kzalloc(&pdev->dev, ckdev->cols, GFP_KERNEL);
	if (!ckdev->old_kb_state)
		return -ENOMEM;

	idev = devm_input_allocate_device(&pdev->dev);
	if (!idev)
		return -ENOMEM;

	if (!ec->irq) {
		dev_err(dev, "no EC IRQ specified\n");
		return -EINVAL;
	}

	ckdev->ec = ec;
	ckdev->dev = dev;
	dev_set_drvdata(&pdev->dev, ckdev);

	idev->name = ec->ec_name;
	idev->phys = ec->phys_name;
	__set_bit(EV_REP, idev->evbit);

	idev->id.bustype = BUS_VIRTUAL;
	idev->id.version = 1;
	idev->id.product = 0;
	idev->dev.parent = &pdev->dev;
	idev->open = cros_ec_keyb_open;
	idev->close = cros_ec_keyb_close;

	ckdev->ghost_filter = of_property_read_bool(np,
					"google,needs-ghost-filter");

	err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
					 NULL, idev);
	if (err) {
		dev_err(dev, "cannot build key matrix\n");
		return err;
	}

	ckdev->row_shift = get_count_order(ckdev->cols);

	input_set_capability(idev, EV_MSC, MSC_SCAN);
	input_set_drvdata(idev, ckdev);
	ckdev->idev = idev;
	cros_ec_keyb_compute_valid_keys(ckdev);

	err = input_register_device(ckdev->idev);
	if (err) {
		dev_err(dev, "cannot register input device\n");
		return err;
	}

	return 0;
}

#ifdef CONFIG_PM_SLEEP
/* Clear any keys in the buffer */
static void cros_ec_keyb_clear_keyboard(struct cros_ec_keyb *ckdev)
{
	uint8_t old_state[ckdev->cols];
	uint8_t new_state[ckdev->cols];
	unsigned long duration;
	int i, ret;

	/*
	 * Keep reading until we see that the scan state does not change.
	 * That indicates that we are done.
	 *
	 * Assume that the EC keyscan buffer is at most 32 deep.
	 */
	duration = jiffies;
	ret = cros_ec_keyb_get_state(ckdev, new_state);
	for (i = 1; !ret && i < 32; i++) {
		memcpy(old_state, new_state, sizeof(old_state));
		ret = cros_ec_keyb_get_state(ckdev, new_state);
		if (0 == memcmp(old_state, new_state, sizeof(old_state)))
			break;
	}
	duration = jiffies - duration;
	dev_info(ckdev->dev, "Discarded %d keyscan(s) in %dus\n", i,
		jiffies_to_usecs(duration));
}

static int cros_ec_keyb_resume(struct device *dev)
{
	struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);

	/*
	 * When the EC is not a wake source, then it could not have caused the
	 * resume, so we clear the EC's key scan buffer. If the EC was a
	 * wake source (e.g. the lid is open and the user might press a key to
	 * wake) then the key scan buffer should be preserved.
	 */
	if (ckdev->ec->was_wake_device)
		cros_ec_keyb_clear_keyboard(ckdev);

	return 0;
}

#endif

static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);

#ifdef CONFIG_OF
static const struct of_device_id cros_ec_keyb_of_match[] = {
	{ .compatible = "google,cros-ec-keyb" },
	{},
};
MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
#endif

static struct platform_driver cros_ec_keyb_driver = {
	.probe = cros_ec_keyb_probe,
	.driver = {
		.name = "cros-ec-keyb",
		.of_match_table = of_match_ptr(cros_ec_keyb_of_match),
		.pm	= &cros_ec_keyb_pm_ops,
	},
};

module_platform_driver(cros_ec_keyb_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
MODULE_ALIAS("platform:cros-ec-keyb");
Commit	Line	Data
6af6dc2d SG	1	/*
	2	* ChromeOS EC keyboard driver
	3	*
	4	* Copyright (C) 2012 Google, Inc
	5	*
	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.
	9	*
	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.
	14	*
	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
	21	* expensive.
	22	*/
	23
	24	#include <linux/module.h>
017f14e8	25	#include <linux/bitops.h>
6af6dc2d SG	26	#include <linux/i2c.h>
6af6dc2d SG	27	#include <linux/input.h>
d1fd345e	28	#include <linux/interrupt.h>
6af6dc2d	29	#include <linux/kernel.h>
6af6dc2d SG	30	#include <linux/platform_device.h>
	31	#include <linux/slab.h>
	32	#include <linux/input/matrix_keypad.h>
	33	#include <linux/mfd/cros_ec.h>
	34	#include <linux/mfd/cros_ec_commands.h>
	35
	36	/*
	37	* @rows: Number of rows in the keypad
	38	* @cols: Number of columns in the keypad
	39	* @row_shift: log2 or number of rows, rounded up
	40	* @keymap_data: Matrix keymap data used to convert to keyscan values
	41	* @ghost_filter: true to enable the matrix key-ghosting filter
017f14e8	42	* @valid_keys: bitmap of existing keys for each matrix column
64757eba	43	* @old_kb_state: bitmap of keys pressed last scan
6af6dc2d SG	44	* @dev: Device pointer
	45	* @idev: Input device
	46	* @ec: Top level ChromeOS device to use to talk to EC
6af6dc2d SG	47	*/
	48	struct cros_ec_keyb {
	49	unsigned int rows;
	50	unsigned int cols;
	51	int row_shift;
	52	const struct matrix_keymap_data *keymap_data;
	53	bool ghost_filter;
017f14e8	54	uint8_t *valid_keys;
64757eba	55	uint8_t *old_kb_state;
6af6dc2d SG	56
	57	struct device *dev;
	58	struct input_dev *idev;
	59	struct cros_ec_device *ec;
6af6dc2d SG	60	};
	61
	62
6af6dc2d SG	63	/*
	64	* Returns true when there is at least one combination of pressed keys that
	65	* results in ghosting.
	66	*/
	67	static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb ckdev, uint8_t buf)
	68	{
017f14e8 TB	69	int col1, col2, buf1, buf2;
	70	struct device *dev = ckdev->dev;
	71	uint8_t *valid_keys = ckdev->valid_keys;
6af6dc2d SG	72
	73	/*
	74	* Ghosting happens if for any pressed key X there are other keys
	75	* pressed both in the same row and column of X as, for instance,
	76	* in the following diagram:
	77	*
	78	* . . Y . g .
	79	* . . . . . .
	80	* . . . . . .
	81	* . . X . Z .
	82	*
	83	* In this case only X, Y, and Z are pressed, but g appears to be
	84	* pressed too (see Wikipedia).
6af6dc2d	85	*/
017f14e8 TB	86	for (col1 = 0; col1 < ckdev->cols; col1++) {
	87	buf1 = buf[col1] & valid_keys[col1];
	88	for (col2 = col1 + 1; col2 < ckdev->cols; col2++) {
	89	buf2 = buf[col2] & valid_keys[col2];
	90	if (hweight8(buf1 & buf2) > 1) {
	91	dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x",
	92	col1, buf1, col2, buf2);
	93	return true;
	94	}
	95	}
	96	}
6af6dc2d SG	97
	98	return false;
	99	}
	100
017f14e8	101
6af6dc2d SG	102	/*
	103	* Compares the new keyboard state to the old one and produces key
	104	* press/release events accordingly. The keyboard state is 13 bytes (one byte
	105	* per column)
	106	*/
	107	static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
	108	uint8_t *kb_state, int len)
	109	{
	110	struct input_dev *idev = ckdev->idev;
	111	int col, row;
	112	int new_state;
64757eba	113	int old_state;
6af6dc2d SG	114	int num_cols;
	115
	116	num_cols = len;
	117
	118	if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
	119	/*
	120	* Simple-minded solution: ignore this state. The obvious
	121	* improvement is to only ignore changes to keys involved in
	122	* the ghosting, but process the other changes.
	123	*/
	124	dev_dbg(ckdev->dev, "ghosting found\n");
	125	return;
	126	}
	127
	128	for (col = 0; col < ckdev->cols; col++) {
	129	for (row = 0; row < ckdev->rows; row++) {
	130	int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
	131	const unsigned short *keycodes = idev->keycode;
6af6dc2d	132
6af6dc2d	133	new_state = kb_state[col] & (1 << row);
64757eba DA	134	old_state = ckdev->old_kb_state[col] & (1 << row);
64757eba DA	135	if (new_state != old_state) {
6af6dc2d SG	136	dev_dbg(ckdev->dev,
	137	"changed: [r%d c%d]: byte %02x\n",
	138	row, col, new_state);
	139
64757eba DA	140	input_report_key(idev, keycodes[pos],
64757eba DA	141	new_state);
6af6dc2d SG	142	}
6af6dc2d SG	143	}
64757eba	144	ckdev->old_kb_state[col] = kb_state[col];
6af6dc2d SG	145	}
	146	input_sync(ckdev->idev);
	147	}
	148
6af6dc2d SG	149	static int cros_ec_keyb_get_state(struct cros_ec_keyb ckdev, uint8_t kb_state)
6af6dc2d SG	150	{
5799f95a BR	151	struct cros_ec_command msg = {
	152	.version = 0,
	153	.command = EC_CMD_MKBP_STATE,
	154	.outdata = NULL,
	155	.outsize = 0,
	156	.indata = kb_state,
	157	.insize = ckdev->cols,
	158	};
	159
a6551a76	160	return cros_ec_cmd_xfer(ckdev->ec, &msg);
6af6dc2d SG	161	}
6af6dc2d SG	162
d1fd345e	163	static irqreturn_t cros_ec_keyb_irq(int irq, void *data)
6af6dc2d	164	{
d1fd345e AB	165	struct cros_ec_keyb *ckdev = data;
d1fd345e AB	166	struct cros_ec_device *ec = ckdev->ec;
6af6dc2d	167	int ret;
6af6dc2d SG	168	uint8_t kb_state[ckdev->cols];
6af6dc2d SG	169
d1fd345e AB	170	if (device_may_wakeup(ec->dev))
	171	pm_wakeup_event(ec->dev, 0);
	172
6af6dc2d SG	173	ret = cros_ec_keyb_get_state(ckdev, kb_state);
	174	if (ret >= 0)
	175	cros_ec_keyb_process(ckdev, kb_state, ret);
d1fd345e AB	176	else
d1fd345e AB	177	dev_err(ec->dev, "failed to get keyboard state: %d\n", ret);
6af6dc2d	178
d1fd345e AB	179	return IRQ_HANDLED;
	180	}
	181
	182	static int cros_ec_keyb_open(struct input_dev *dev)
	183	{
	184	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
	185	struct cros_ec_device *ec = ckdev->ec;
	186
	187	return request_threaded_irq(ec->irq, NULL, cros_ec_keyb_irq,
	188	IRQF_TRIGGER_LOW \| IRQF_ONESHOT,
	189	"cros_ec_keyb", ckdev);
	190	}
	191
	192	static void cros_ec_keyb_close(struct input_dev *dev)
	193	{
	194	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
	195	struct cros_ec_device *ec = ckdev->ec;
	196
	197	free_irq(ec->irq, ckdev);
6af6dc2d SG	198	}
6af6dc2d SG	199
017f14e8 TB	200	/*
	201	* Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW. Used by
	202	* ghosting logic to ignore NULL or virtual keys.
	203	*/
	204	static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
	205	{
	206	int row, col;
	207	int row_shift = ckdev->row_shift;
	208	unsigned short *keymap = ckdev->idev->keycode;
	209	unsigned short code;
	210
	211	BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap));
	212
	213	for (col = 0; col < ckdev->cols; col++) {
	214	for (row = 0; row < ckdev->rows; row++) {
	215	code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
	216	if (code && (code != KEY_BATTERY))
	217	ckdev->valid_keys[col] \|= 1 << row;
	218	}
	219	dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n",
	220	col, ckdev->valid_keys[col]);
	221	}
	222	}
	223
6af6dc2d SG	224	static int cros_ec_keyb_probe(struct platform_device *pdev)
	225	{
	226	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
	227	struct device *dev = ec->dev;
	228	struct cros_ec_keyb *ckdev;
	229	struct input_dev *idev;
	230	struct device_node *np;
	231	int err;
	232
	233	np = pdev->dev.of_node;
	234	if (!np)
	235	return -ENODEV;
	236
	237	ckdev = devm_kzalloc(&pdev->dev, sizeof(*ckdev), GFP_KERNEL);
	238	if (!ckdev)
	239	return -ENOMEM;
	240	err = matrix_keypad_parse_of_params(&pdev->dev, &ckdev->rows,
	241	&ckdev->cols);
	242	if (err)
	243	return err;
017f14e8 TB	244
	245	ckdev->valid_keys = devm_kzalloc(&pdev->dev, ckdev->cols, GFP_KERNEL);
	246	if (!ckdev->valid_keys)
	247	return -ENOMEM;
	248
64757eba DA	249	ckdev->old_kb_state = devm_kzalloc(&pdev->dev, ckdev->cols, GFP_KERNEL);
	250	if (!ckdev->old_kb_state)
	251	return -ENOMEM;
6af6dc2d SG	252
	253	idev = devm_input_allocate_device(&pdev->dev);
	254	if (!idev)
	255	return -ENOMEM;
	256
d1fd345e AB	257	if (!ec->irq) {
	258	dev_err(dev, "no EC IRQ specified\n");
	259	return -EINVAL;
	260	}
	261
6af6dc2d	262	ckdev->ec = ec;
6af6dc2d SG	263	ckdev->dev = dev;
	264	dev_set_drvdata(&pdev->dev, ckdev);
	265
	266	idev->name = ec->ec_name;
	267	idev->phys = ec->phys_name;
	268	__set_bit(EV_REP, idev->evbit);
	269
	270	idev->id.bustype = BUS_VIRTUAL;
	271	idev->id.version = 1;
	272	idev->id.product = 0;
	273	idev->dev.parent = &pdev->dev;
	274	idev->open = cros_ec_keyb_open;
	275	idev->close = cros_ec_keyb_close;
	276
	277	ckdev->ghost_filter = of_property_read_bool(np,
	278	"google,needs-ghost-filter");
	279
	280	err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
	281	NULL, idev);
	282	if (err) {
	283	dev_err(dev, "cannot build key matrix\n");
	284	return err;
	285	}
	286
	287	ckdev->row_shift = get_count_order(ckdev->cols);
	288
	289	input_set_capability(idev, EV_MSC, MSC_SCAN);
	290	input_set_drvdata(idev, ckdev);
	291	ckdev->idev = idev;
017f14e8 TB	292	cros_ec_keyb_compute_valid_keys(ckdev);
017f14e8 TB	293
6af6dc2d SG	294	err = input_register_device(ckdev->idev);
	295	if (err) {
	296	dev_err(dev, "cannot register input device\n");
	297	return err;
	298	}
	299
	300	return 0;
	301	}
	302
	303	#ifdef CONFIG_PM_SLEEP
03832aa8 GU	304	/* Clear any keys in the buffer */
	305	static void cros_ec_keyb_clear_keyboard(struct cros_ec_keyb *ckdev)
	306	{
	307	uint8_t old_state[ckdev->cols];
	308	uint8_t new_state[ckdev->cols];
	309	unsigned long duration;
	310	int i, ret;
	311
	312	/*
	313	* Keep reading until we see that the scan state does not change.
	314	* That indicates that we are done.
	315	*
	316	* Assume that the EC keyscan buffer is at most 32 deep.
	317	*/
	318	duration = jiffies;
	319	ret = cros_ec_keyb_get_state(ckdev, new_state);
	320	for (i = 1; !ret && i < 32; i++) {
	321	memcpy(old_state, new_state, sizeof(old_state));
	322	ret = cros_ec_keyb_get_state(ckdev, new_state);
	323	if (0 == memcmp(old_state, new_state, sizeof(old_state)))
	324	break;
	325	}
	326	duration = jiffies - duration;
	327	dev_info(ckdev->dev, "Discarded %d keyscan(s) in %dus\n", i,
	328	jiffies_to_usecs(duration));
	329	}
	330
6af6dc2d SG	331	static int cros_ec_keyb_resume(struct device *dev)
	332	{
	333	struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
	334
	335	/*
	336	* When the EC is not a wake source, then it could not have caused the
	337	* resume, so we clear the EC's key scan buffer. If the EC was a
	338	* wake source (e.g. the lid is open and the user might press a key to
	339	* wake) then the key scan buffer should be preserved.
	340	*/
	341	if (ckdev->ec->was_wake_device)
	342	cros_ec_keyb_clear_keyboard(ckdev);
	343
	344	return 0;
	345	}
	346
	347	#endif
	348
	349	static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);
	350
3f1fe73b SS	351	#ifdef CONFIG_OF
	352	static const struct of_device_id cros_ec_keyb_of_match[] = {
	353	{ .compatible = "google,cros-ec-keyb" },
	354	{},
	355	};
	356	MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
	357	#endif
	358
6af6dc2d SG	359	static struct platform_driver cros_ec_keyb_driver = {
	360	.probe = cros_ec_keyb_probe,
	361	.driver = {
	362	.name = "cros-ec-keyb",
3f1fe73b	363	.of_match_table = of_match_ptr(cros_ec_keyb_of_match),
6af6dc2d SG	364	.pm = &cros_ec_keyb_pm_ops,
	365	},
	366	};
	367
	368	module_platform_driver(cros_ec_keyb_driver);
	369
	370	MODULE_LICENSE("GPL");
	371	MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
	372	MODULE_ALIAS("platform:cros-ec-keyb");