drivers/input/keyboard/cros_ec_keyb.c - kernel/msm-4.9 - Gitiles

 /*
  * 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)
 {
 	int ret = 0;
 	struct cros_ec_command *msg;

 	msg = kmalloc(sizeof(*msg) + ckdev->cols, GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;

 	msg->version = 0;
 	msg->command = EC_CMD_MKBP_STATE;
 	msg->insize = ckdev->cols;
 	msg->outsize = 0;

 	ret = cros_ec_cmd_xfer(ckdev->ec, msg);
 	if (ret < 0) {
 		dev_err(ckdev->dev, "Error transferring EC message %d\n", ret);
 		goto exit;
 	}

 	memcpy(kb_state, msg->data, ckdev->cols);
 exit:
 	kfree(msg);
 	return ret;
 }

 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 = CROS_EC_DEV_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");
	/*
	* 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)
	{
	int ret = 0;
	struct cros_ec_command *msg;

	msg = kmalloc(sizeof(*msg) + ckdev->cols, GFP_KERNEL);
	if (!msg)
	return -ENOMEM;

	msg->version = 0;
	msg->command = EC_CMD_MKBP_STATE;
	msg->insize = ckdev->cols;
	msg->outsize = 0;

	ret = cros_ec_cmd_xfer(ckdev->ec, msg);
	if (ret < 0) {
	dev_err(ckdev->dev, "Error transferring EC message %d\n", ret);
	goto exit;
	}

	memcpy(kb_state, msg->data, ckdev->cols);
	exit:
	kfree(msg);
	return ret;
	}

	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 = CROS_EC_DEV_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");