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/i2c.h>
 #include <linux/input.h>
 #include <linux/kernel.h>
 #include <linux/notifier.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
  * @dev: Device pointer
  * @idev: Input device
  * @ec: Top level ChromeOS device to use to talk to EC
  * @event_notifier: interrupt event notifier for transport devices
  */
 struct cros_ec_keyb {
 	unsigned int rows;
 	unsigned int cols;
 	int row_shift;
 	const struct matrix_keymap_data *keymap_data;
 	bool ghost_filter;

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


 static bool cros_ec_keyb_row_has_ghosting(struct cros_ec_keyb *ckdev,
 					  uint8_t *buf, int row)
 {
 	int pressed_in_row = 0;
 	int row_has_teeth = 0;
 	int col, mask;

 	mask = 1 << row;
 	for (col = 0; col < ckdev->cols; col++) {
 		if (buf[col] & mask) {
 			pressed_in_row++;
 			row_has_teeth |= buf[col] & ~mask;
 			if (pressed_in_row > 1 && row_has_teeth) {
 				/* ghosting */
 				dev_dbg(ckdev->dev,
 					"ghost found at: r%d c%d, pressed %d, teeth 0x%x\n",
 					row, col, pressed_in_row,
 					row_has_teeth);
 				return true;
 			}
 		}
 	}

 	return false;
 }

 /*
  * 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 row;

 	/*
 	 * 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).
 	 *
 	 * We can detect ghosting in a single pass (*) over the keyboard state
 	 * by maintaining two arrays.  pressed_in_row counts how many pressed
 	 * keys we have found in a row.  row_has_teeth is true if any of the
 	 * pressed keys for this row has other pressed keys in its column.  If
 	 * at any point of the scan we find that a row has multiple pressed
 	 * keys, and at least one of them is at the intersection with a column
 	 * with multiple pressed keys, we're sure there is ghosting.
 	 * Conversely, if there is ghosting, we will detect such situation for
 	 * at least one key during the pass.
 	 *
 	 * (*) This looks linear in the number of keys, but it's not.  We can
 	 * cheat because the number of rows is small.
 	 */
 	for (row = 0; row < ckdev->rows; row++)
 		if (cros_ec_keyb_row_has_ghosting(ckdev, buf, row))
 			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 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;
 			int code;

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

 				input_report_key(idev, code, new_state);
 			}
 		}
 	}
 	input_sync(ckdev->idev);
 }

 static int cros_ec_keyb_open(struct input_dev *dev)
 {
 	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);

 	return blocking_notifier_chain_register(&ckdev->ec->event_notifier,
 						&ckdev->notifier);
 }

 static void cros_ec_keyb_close(struct input_dev *dev)
 {
 	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);

 	blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
 					   &ckdev->notifier);
 }

 static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state)
 {
 	return ckdev->ec->command_recv(ckdev->ec, EC_CMD_MKBP_STATE,
 					  kb_state, ckdev->cols);
 }

 static int cros_ec_keyb_work(struct notifier_block *nb,
 		     unsigned long state, void *_notify)
 {
 	int ret;
 	struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
 						    notifier);
 	uint8_t kb_state[ckdev->cols];

 	ret = cros_ec_keyb_get_state(ckdev, kb_state);
 	if (ret >= 0)
 		cros_ec_keyb_process(ckdev, kb_state, ret);

 	return NOTIFY_DONE;
 }

 /* 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_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;

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

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

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 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);

 static struct platform_driver cros_ec_keyb_driver = {
 	.probe = cros_ec_keyb_probe,
 	.driver = {
 		.name = "cros-ec-keyb",
 		.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/i2c.h>
	#include <linux/input.h>
	#include <linux/kernel.h>
	#include <linux/notifier.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
	* @dev: Device pointer
	* @idev: Input device
	* @ec: Top level ChromeOS device to use to talk to EC
	* @event_notifier: interrupt event notifier for transport devices
	*/
	struct cros_ec_keyb {
	unsigned int rows;
	unsigned int cols;
	int row_shift;
	const struct matrix_keymap_data *keymap_data;
	bool ghost_filter;

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


	static bool cros_ec_keyb_row_has_ghosting(struct cros_ec_keyb *ckdev,
	uint8_t *buf, int row)
	{
	int pressed_in_row = 0;
	int row_has_teeth = 0;
	int col, mask;

	mask = 1 << row;
	for (col = 0; col < ckdev->cols; col++) {
	if (buf[col] & mask) {
	pressed_in_row++;
	row_has_teeth \|= buf[col] & ~mask;
	if (pressed_in_row > 1 && row_has_teeth) {
	/* ghosting */
	dev_dbg(ckdev->dev,
	"ghost found at: r%d c%d, pressed %d, teeth 0x%x\n",
	row, col, pressed_in_row,
	row_has_teeth);
	return true;
	}
	}
	}

	return false;
	}

	/*
	* 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 row;

	/*
	* 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).
	*
	* We can detect ghosting in a single pass (*) over the keyboard state
	* by maintaining two arrays. pressed_in_row counts how many pressed
	* keys we have found in a row. row_has_teeth is true if any of the
	* pressed keys for this row has other pressed keys in its column. If
	* at any point of the scan we find that a row has multiple pressed
	* keys, and at least one of them is at the intersection with a column
	* with multiple pressed keys, we're sure there is ghosting.
	* Conversely, if there is ghosting, we will detect such situation for
	* at least one key during the pass.
	*
	* (*) This looks linear in the number of keys, but it's not. We can
	* cheat because the number of rows is small.
	*/
	for (row = 0; row < ckdev->rows; row++)
	if (cros_ec_keyb_row_has_ghosting(ckdev, buf, row))
	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 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;
	int code;

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

	input_report_key(idev, code, new_state);
	}
	}
	}
	input_sync(ckdev->idev);
	}

	static int cros_ec_keyb_open(struct input_dev *dev)
	{
	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);

	return blocking_notifier_chain_register(&ckdev->ec->event_notifier,
	&ckdev->notifier);
	}

	static void cros_ec_keyb_close(struct input_dev *dev)
	{
	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);

	blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
	&ckdev->notifier);
	}

	static int cros_ec_keyb_get_state(struct cros_ec_keyb ckdev, uint8_t kb_state)
	{
	return ckdev->ec->command_recv(ckdev->ec, EC_CMD_MKBP_STATE,
	kb_state, ckdev->cols);
	}

	static int cros_ec_keyb_work(struct notifier_block *nb,
	unsigned long state, void *_notify)
	{
	int ret;
	struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
	notifier);
	uint8_t kb_state[ckdev->cols];

	ret = cros_ec_keyb_get_state(ckdev, kb_state);
	if (ret >= 0)
	cros_ec_keyb_process(ckdev, kb_state, ret);

	return NOTIFY_DONE;
	}

	/* 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_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;

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

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

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	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);

	static struct platform_driver cros_ec_keyb_driver = {
	.probe = cros_ec_keyb_probe,
	.driver = {
	.name = "cros-ec-keyb",
	.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");