drivers/input/keyboard/matrix_keypad.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  GPIO driven matrix keyboard driver
  *
  *  Copyright (c) 2008 Marek Vasut <marek.vasut@gmail.com>
  *
  *  Based on corgikbd.c
  */

 #include <linux/types.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/input.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/jiffies.h>
 #include <linux/module.h>
 #include <linux/gpio.h>
 #include <linux/input/matrix_keypad.h>
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
 #include <linux/of_platform.h>

 struct matrix_keypad {
 	const struct matrix_keypad_platform_data *pdata;
 	struct input_dev *input_dev;
 	unsigned int row_shift;

 	unsigned int row_irqs[MATRIX_MAX_ROWS];
 	unsigned int num_row_irqs;
 	DECLARE_BITMAP(wakeup_enabled_irqs, MATRIX_MAX_ROWS);

 	uint32_t last_key_state[MATRIX_MAX_COLS];
 	struct delayed_work work;
 	spinlock_t lock;
 	bool scan_pending;
 	bool stopped;
 	bool gpio_all_disabled;
 };

 /*
  * NOTE: If drive_inactive_cols is false, then the GPIO has to be put into
  * HiZ when de-activated to cause minmal side effect when scanning other
  * columns. In that case it is configured here to be input, otherwise it is
  * driven with the inactive value.
  */
 static void __activate_col(const struct matrix_keypad_platform_data *pdata,
 			   int col, bool on)
 {
 	bool level_on = !pdata->active_low;

 	if (on) {
 		gpio_direction_output(pdata->col_gpios[col], level_on);
 	} else {
 		gpio_set_value_cansleep(pdata->col_gpios[col], !level_on);
 		if (!pdata->drive_inactive_cols)
 			gpio_direction_input(pdata->col_gpios[col]);
 	}
 }

 static void activate_col(const struct matrix_keypad_platform_data *pdata,
 			 int col, bool on)
 {
 	__activate_col(pdata, col, on);

 	if (on && pdata->col_scan_delay_us)
 		udelay(pdata->col_scan_delay_us);
 }

 static void activate_all_cols(const struct matrix_keypad_platform_data *pdata,
 			      bool on)
 {
 	int col;

 	for (col = 0; col < pdata->num_col_gpios; col++)
 		__activate_col(pdata, col, on);
 }

 static bool row_asserted(const struct matrix_keypad_platform_data *pdata,
 			 int row)
 {
 	return gpio_get_value_cansleep(pdata->row_gpios[row]) ?
 			!pdata->active_low : pdata->active_low;
 }

 static void enable_row_irqs(struct matrix_keypad *keypad)
 {
 	int i;

 	for (i = 0; i < keypad->num_row_irqs; i++)
 		enable_irq(keypad->row_irqs[i]);
 }

 static void disable_row_irqs(struct matrix_keypad *keypad)
 {
 	int i;

 	for (i = 0; i < keypad->num_row_irqs; i++)
 		disable_irq_nosync(keypad->row_irqs[i]);
 }

 /*
  * This gets the keys from keyboard and reports it to input subsystem
  */
 static void matrix_keypad_scan(struct work_struct *work)
 {
 	struct matrix_keypad *keypad =
 		container_of(work, struct matrix_keypad, work.work);
 	struct input_dev *input_dev = keypad->input_dev;
 	const unsigned short *keycodes = input_dev->keycode;
 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
 	uint32_t new_state[MATRIX_MAX_COLS];
 	int row, col, code;

 	/* de-activate all columns for scanning */
 	activate_all_cols(pdata, false);

 	memset(new_state, 0, sizeof(new_state));

 	for (row = 0; row < pdata->num_row_gpios; row++)
 		gpio_direction_input(pdata->row_gpios[row]);

 	/* assert each column and read the row status out */
 	for (col = 0; col < pdata->num_col_gpios; col++) {

 		activate_col(pdata, col, true);

 		for (row = 0; row < pdata->num_row_gpios; row++)
 			new_state[col] |=
 				row_asserted(pdata, row) ? (1 << row) : 0;

 		activate_col(pdata, col, false);
 	}

 	for (col = 0; col < pdata->num_col_gpios; col++) {
 		uint32_t bits_changed;

 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
 		if (bits_changed == 0)
 			continue;

 		for (row = 0; row < pdata->num_row_gpios; row++) {
 			if ((bits_changed & (1 << row)) == 0)
 				continue;

 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
 			input_event(input_dev, EV_MSC, MSC_SCAN, code);
 			input_report_key(input_dev,
 					 keycodes[code],
 					 new_state[col] & (1 << row));
 		}
 	}
 	input_sync(input_dev);

 	memcpy(keypad->last_key_state, new_state, sizeof(new_state));

 	activate_all_cols(pdata, true);

 	/* Enable IRQs again */
 	spin_lock_irq(&keypad->lock);
 	keypad->scan_pending = false;
 	enable_row_irqs(keypad);
 	spin_unlock_irq(&keypad->lock);
 }

 static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
 {
 	struct matrix_keypad *keypad = id;
 	unsigned long flags;

 	spin_lock_irqsave(&keypad->lock, flags);

 	/*
 	 * See if another IRQ beaten us to it and scheduled the
 	 * scan already. In that case we should not try to
 	 * disable IRQs again.
 	 */
 	if (unlikely(keypad->scan_pending || keypad->stopped))
 		goto out;

 	disable_row_irqs(keypad);
 	keypad->scan_pending = true;
 	schedule_delayed_work(&keypad->work,
 		msecs_to_jiffies(keypad->pdata->debounce_ms));

 out:
 	spin_unlock_irqrestore(&keypad->lock, flags);
 	return IRQ_HANDLED;
 }

 static int matrix_keypad_start(struct input_dev *dev)
 {
 	struct matrix_keypad *keypad = input_get_drvdata(dev);

 	keypad->stopped = false;
 	mb();

 	/*
 	 * Schedule an immediate key scan to capture current key state;
 	 * columns will be activated and IRQs be enabled after the scan.
 	 */
 	schedule_delayed_work(&keypad->work, 0);

 	return 0;
 }

 static void matrix_keypad_stop(struct input_dev *dev)
 {
 	struct matrix_keypad *keypad = input_get_drvdata(dev);

 	spin_lock_irq(&keypad->lock);
 	keypad->stopped = true;
 	spin_unlock_irq(&keypad->lock);

 	flush_delayed_work(&keypad->work);
 	/*
 	 * matrix_keypad_scan() will leave IRQs enabled;
 	 * we should disable them now.
 	 */
 	disable_row_irqs(keypad);
 }

 static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
 {
 	int i;

 	for_each_clear_bit(i, keypad->wakeup_enabled_irqs, keypad->num_row_irqs)
 		if (enable_irq_wake(keypad->row_irqs[i]) == 0)
 			__set_bit(i, keypad->wakeup_enabled_irqs);
 }

 static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
 {
 	int i;

 	for_each_set_bit(i, keypad->wakeup_enabled_irqs, keypad->num_row_irqs) {
 		disable_irq_wake(keypad->row_irqs[i]);
 		__clear_bit(i, keypad->wakeup_enabled_irqs);
 	}
 }

 static int matrix_keypad_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);

 	matrix_keypad_stop(keypad->input_dev);

 	if (device_may_wakeup(&pdev->dev))
 		matrix_keypad_enable_wakeup(keypad);

 	return 0;
 }

 static int matrix_keypad_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);

 	if (device_may_wakeup(&pdev->dev))
 		matrix_keypad_disable_wakeup(keypad);

 	matrix_keypad_start(keypad->input_dev);

 	return 0;
 }

 static DEFINE_SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
 				matrix_keypad_suspend, matrix_keypad_resume);

 static int matrix_keypad_init_gpio(struct platform_device *pdev,
 				   struct matrix_keypad *keypad)
 {
 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
 	int i, irq, err;

 	/* initialized strobe lines as outputs, activated */
 	for (i = 0; i < pdata->num_col_gpios; i++) {
 		err = devm_gpio_request(&pdev->dev,
 					pdata->col_gpios[i], "matrix_kbd_col");
 		if (err) {
 			dev_err(&pdev->dev,
 				"failed to request GPIO%d for COL%d\n",
 				pdata->col_gpios[i], i);
 			return err;
 		}

 		gpio_direction_output(pdata->col_gpios[i], !pdata->active_low);
 	}

 	for (i = 0; i < pdata->num_row_gpios; i++) {
 		err = devm_gpio_request(&pdev->dev,
 					pdata->row_gpios[i], "matrix_kbd_row");
 		if (err) {
 			dev_err(&pdev->dev,
 				"failed to request GPIO%d for ROW%d\n",
 				pdata->row_gpios[i], i);
 			return err;
 		}

 		gpio_direction_input(pdata->row_gpios[i]);
 	}

 	if (pdata->clustered_irq > 0) {
 		err = devm_request_any_context_irq(&pdev->dev,
 				pdata->clustered_irq,
 				matrix_keypad_interrupt,
 				pdata->clustered_irq_flags,
 				"matrix-keypad", keypad);
 		if (err < 0) {
 			dev_err(&pdev->dev,
 				"Unable to acquire clustered interrupt\n");
 			return err;
 		}

 		keypad->row_irqs[0] = pdata->clustered_irq;
 		keypad->num_row_irqs = 1;
 	} else {
 		for (i = 0; i < pdata->num_row_gpios; i++) {
 			irq = gpio_to_irq(pdata->row_gpios[i]);
 			if (irq < 0) {
 				err = irq;
 				dev_err(&pdev->dev,
 					"Unable to convert GPIO line %i to irq: %d\n",
 					pdata->row_gpios[i], err);
 				return err;
 			}

 			err = devm_request_any_context_irq(&pdev->dev,
 					irq,
 					matrix_keypad_interrupt,
 					IRQF_TRIGGER_RISING |
 						IRQF_TRIGGER_FALLING,
 					"matrix-keypad", keypad);
 			if (err < 0) {
 				dev_err(&pdev->dev,
 					"Unable to acquire interrupt for GPIO line %i\n",
 					pdata->row_gpios[i]);
 				return err;
 			}

 			keypad->row_irqs[i] = irq;
 		}

 		keypad->num_row_irqs = pdata->num_row_gpios;
 	}

 	/* initialized as disabled - enabled by input->open */
 	disable_row_irqs(keypad);

 	return 0;
 }

 #ifdef CONFIG_OF
 static struct matrix_keypad_platform_data *
 matrix_keypad_parse_dt(struct device *dev)
 {
 	struct matrix_keypad_platform_data *pdata;
 	struct device_node *np = dev->of_node;
 	unsigned int *gpios;
 	int ret, i, nrow, ncol;

 	if (!np) {
 		dev_err(dev, "device lacks DT data\n");
 		return ERR_PTR(-ENODEV);
 	}

 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata) {
 		dev_err(dev, "could not allocate memory for platform data\n");
 		return ERR_PTR(-ENOMEM);
 	}

 	pdata->num_row_gpios = nrow = gpiod_count(dev, "row");
 	pdata->num_col_gpios = ncol = gpiod_count(dev, "col");
 	if (nrow < 0 || ncol < 0) {
 		dev_err(dev, "number of keypad rows/columns not specified\n");
 		return ERR_PTR(-EINVAL);
 	}

 	pdata->no_autorepeat = of_property_read_bool(np, "linux,no-autorepeat");

 	pdata->wakeup = of_property_read_bool(np, "wakeup-source") ||
 			of_property_read_bool(np, "linux,wakeup"); /* legacy */

 	pdata->active_low = of_property_read_bool(np, "gpio-activelow");

 	pdata->drive_inactive_cols =
 		of_property_read_bool(np, "drive-inactive-cols");

 	of_property_read_u32(np, "debounce-delay-ms", &pdata->debounce_ms);
 	of_property_read_u32(np, "col-scan-delay-us",
 						&pdata->col_scan_delay_us);

 	gpios = devm_kcalloc(dev,
 			     pdata->num_row_gpios + pdata->num_col_gpios,
 			     sizeof(unsigned int),
 			     GFP_KERNEL);
 	if (!gpios) {
 		dev_err(dev, "could not allocate memory for gpios\n");
 		return ERR_PTR(-ENOMEM);
 	}

 	for (i = 0; i < nrow; i++) {
 		ret = of_get_named_gpio(np, "row-gpios", i);
 		if (ret < 0)
 			return ERR_PTR(ret);
 		gpios[i] = ret;
 	}

 	for (i = 0; i < ncol; i++) {
 		ret = of_get_named_gpio(np, "col-gpios", i);
 		if (ret < 0)
 			return ERR_PTR(ret);
 		gpios[nrow + i] = ret;
 	}

 	pdata->row_gpios = gpios;
 	pdata->col_gpios = &gpios[pdata->num_row_gpios];

 	return pdata;
 }
 #else
 static inline struct matrix_keypad_platform_data *
 matrix_keypad_parse_dt(struct device *dev)
 {
 	dev_err(dev, "no platform data defined\n");

 	return ERR_PTR(-EINVAL);
 }
 #endif

 static int matrix_keypad_probe(struct platform_device *pdev)
 {
 	const struct matrix_keypad_platform_data *pdata;
 	struct matrix_keypad *keypad;
 	struct input_dev *input_dev;
 	int err;

 	pdata = dev_get_platdata(&pdev->dev);
 	if (!pdata) {
 		pdata = matrix_keypad_parse_dt(&pdev->dev);
 		if (IS_ERR(pdata))
 			return PTR_ERR(pdata);
 	} else if (!pdata->keymap_data) {
 		dev_err(&pdev->dev, "no keymap data defined\n");
 		return -EINVAL;
 	}

 	keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
 	if (!keypad)
 		return -ENOMEM;

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

 	keypad->input_dev = input_dev;
 	keypad->pdata = pdata;
 	keypad->row_shift = get_count_order(pdata->num_col_gpios);
 	keypad->stopped = true;
 	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
 	spin_lock_init(&keypad->lock);

 	input_dev->name		= pdev->name;
 	input_dev->id.bustype	= BUS_HOST;
 	input_dev->open		= matrix_keypad_start;
 	input_dev->close	= matrix_keypad_stop;

 	err = matrix_keypad_build_keymap(pdata->keymap_data, NULL,
 					 pdata->num_row_gpios,
 					 pdata->num_col_gpios,
 					 NULL, input_dev);
 	if (err) {
 		dev_err(&pdev->dev, "failed to build keymap\n");
 		return -ENOMEM;
 	}

 	if (!pdata->no_autorepeat)
 		__set_bit(EV_REP, input_dev->evbit);
 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
 	input_set_drvdata(input_dev, keypad);

 	err = matrix_keypad_init_gpio(pdev, keypad);
 	if (err)
 		return err;

 	err = input_register_device(keypad->input_dev);
 	if (err)
 		return err;

 	device_init_wakeup(&pdev->dev, pdata->wakeup);
 	platform_set_drvdata(pdev, keypad);

 	return 0;
 }

 #ifdef CONFIG_OF
 static const struct of_device_id matrix_keypad_dt_match[] = {
 	{ .compatible = "gpio-matrix-keypad" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
 #endif

 static struct platform_driver matrix_keypad_driver = {
 	.probe		= matrix_keypad_probe,
 	.driver		= {
 		.name	= "matrix-keypad",
 		.pm	= pm_sleep_ptr(&matrix_keypad_pm_ops),
 		.of_match_table = of_match_ptr(matrix_keypad_dt_match),
 	},
 };
 module_platform_driver(matrix_keypad_driver);

 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
 MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:matrix-keypad");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* GPIO driven matrix keyboard driver
	*
	* Copyright (c) 2008 Marek Vasut <marek.vasut@gmail.com>
	*
	* Based on corgikbd.c
	*/

	#include <linux/types.h>
	#include <linux/delay.h>
	#include <linux/gpio/consumer.h>
	#include <linux/platform_device.h>
	#include <linux/input.h>
	#include <linux/irq.h>
	#include <linux/interrupt.h>
	#include <linux/jiffies.h>
	#include <linux/module.h>
	#include <linux/gpio.h>
	#include <linux/input/matrix_keypad.h>
	#include <linux/slab.h>
	#include <linux/of.h>
	#include <linux/of_gpio.h>
	#include <linux/of_platform.h>

	struct matrix_keypad {
	const struct matrix_keypad_platform_data *pdata;
	struct input_dev *input_dev;
	unsigned int row_shift;

	unsigned int row_irqs[MATRIX_MAX_ROWS];
	unsigned int num_row_irqs;
	DECLARE_BITMAP(wakeup_enabled_irqs, MATRIX_MAX_ROWS);

	uint32_t last_key_state[MATRIX_MAX_COLS];
	struct delayed_work work;
	spinlock_t lock;
	bool scan_pending;
	bool stopped;
	bool gpio_all_disabled;
	};

	/*
	* NOTE: If drive_inactive_cols is false, then the GPIO has to be put into
	* HiZ when de-activated to cause minmal side effect when scanning other
	* columns. In that case it is configured here to be input, otherwise it is
	* driven with the inactive value.
	*/
	static void __activate_col(const struct matrix_keypad_platform_data *pdata,
	int col, bool on)
	{
	bool level_on = !pdata->active_low;

	if (on) {
	gpio_direction_output(pdata->col_gpios[col], level_on);
	} else {
	gpio_set_value_cansleep(pdata->col_gpios[col], !level_on);
	if (!pdata->drive_inactive_cols)
	gpio_direction_input(pdata->col_gpios[col]);
	}
	}

	static void activate_col(const struct matrix_keypad_platform_data *pdata,
	int col, bool on)
	{
	__activate_col(pdata, col, on);

	if (on && pdata->col_scan_delay_us)
	udelay(pdata->col_scan_delay_us);
	}

	static void activate_all_cols(const struct matrix_keypad_platform_data *pdata,
	bool on)
	{
	int col;

	for (col = 0; col < pdata->num_col_gpios; col++)
	__activate_col(pdata, col, on);
	}

	static bool row_asserted(const struct matrix_keypad_platform_data *pdata,
	int row)
	{
	return gpio_get_value_cansleep(pdata->row_gpios[row]) ?
	!pdata->active_low : pdata->active_low;
	}

	static void enable_row_irqs(struct matrix_keypad *keypad)
	{
	int i;

	for (i = 0; i < keypad->num_row_irqs; i++)
	enable_irq(keypad->row_irqs[i]);
	}

	static void disable_row_irqs(struct matrix_keypad *keypad)
	{
	int i;

	for (i = 0; i < keypad->num_row_irqs; i++)
	disable_irq_nosync(keypad->row_irqs[i]);
	}

	/*
	* This gets the keys from keyboard and reports it to input subsystem
	*/
	static void matrix_keypad_scan(struct work_struct *work)
	{
	struct matrix_keypad *keypad =
	container_of(work, struct matrix_keypad, work.work);
	struct input_dev *input_dev = keypad->input_dev;
	const unsigned short *keycodes = input_dev->keycode;
	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
	uint32_t new_state[MATRIX_MAX_COLS];
	int row, col, code;

	/* de-activate all columns for scanning */
	activate_all_cols(pdata, false);

	memset(new_state, 0, sizeof(new_state));

	for (row = 0; row < pdata->num_row_gpios; row++)
	gpio_direction_input(pdata->row_gpios[row]);

	/* assert each column and read the row status out */
	for (col = 0; col < pdata->num_col_gpios; col++) {

	activate_col(pdata, col, true);

	for (row = 0; row < pdata->num_row_gpios; row++)
	new_state[col] \|=
	row_asserted(pdata, row) ? (1 << row) : 0;

	activate_col(pdata, col, false);
	}

	for (col = 0; col < pdata->num_col_gpios; col++) {
	uint32_t bits_changed;

	bits_changed = keypad->last_key_state[col] ^ new_state[col];
	if (bits_changed == 0)
	continue;

	for (row = 0; row < pdata->num_row_gpios; row++) {
	if ((bits_changed & (1 << row)) == 0)
	continue;

	code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
	input_event(input_dev, EV_MSC, MSC_SCAN, code);
	input_report_key(input_dev,
	keycodes[code],
	new_state[col] & (1 << row));
	}
	}
	input_sync(input_dev);

	memcpy(keypad->last_key_state, new_state, sizeof(new_state));

	activate_all_cols(pdata, true);

	/* Enable IRQs again */
	spin_lock_irq(&keypad->lock);
	keypad->scan_pending = false;
	enable_row_irqs(keypad);
	spin_unlock_irq(&keypad->lock);
	}

	static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
	{
	struct matrix_keypad *keypad = id;
	unsigned long flags;

	spin_lock_irqsave(&keypad->lock, flags);

	/*
	* See if another IRQ beaten us to it and scheduled the
	* scan already. In that case we should not try to
	* disable IRQs again.
	*/
	if (unlikely(keypad->scan_pending \|\| keypad->stopped))
	goto out;

	disable_row_irqs(keypad);
	keypad->scan_pending = true;
	schedule_delayed_work(&keypad->work,
	msecs_to_jiffies(keypad->pdata->debounce_ms));

	out:
	spin_unlock_irqrestore(&keypad->lock, flags);
	return IRQ_HANDLED;
	}

	static int matrix_keypad_start(struct input_dev *dev)
	{
	struct matrix_keypad *keypad = input_get_drvdata(dev);

	keypad->stopped = false;
	mb();

	/*
	* Schedule an immediate key scan to capture current key state;
	* columns will be activated and IRQs be enabled after the scan.
	*/
	schedule_delayed_work(&keypad->work, 0);

	return 0;
	}

	static void matrix_keypad_stop(struct input_dev *dev)
	{
	struct matrix_keypad *keypad = input_get_drvdata(dev);

	spin_lock_irq(&keypad->lock);
	keypad->stopped = true;
	spin_unlock_irq(&keypad->lock);

	flush_delayed_work(&keypad->work);
	/*
	* matrix_keypad_scan() will leave IRQs enabled;
	* we should disable them now.
	*/
	disable_row_irqs(keypad);
	}

	static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
	{
	int i;

	for_each_clear_bit(i, keypad->wakeup_enabled_irqs, keypad->num_row_irqs)
	if (enable_irq_wake(keypad->row_irqs[i]) == 0)
	__set_bit(i, keypad->wakeup_enabled_irqs);
	}

	static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
	{
	int i;

	for_each_set_bit(i, keypad->wakeup_enabled_irqs, keypad->num_row_irqs) {
	disable_irq_wake(keypad->row_irqs[i]);
	__clear_bit(i, keypad->wakeup_enabled_irqs);
	}
	}

	static int matrix_keypad_suspend(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct matrix_keypad *keypad = platform_get_drvdata(pdev);

	matrix_keypad_stop(keypad->input_dev);

	if (device_may_wakeup(&pdev->dev))
	matrix_keypad_enable_wakeup(keypad);

	return 0;
	}

	static int matrix_keypad_resume(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct matrix_keypad *keypad = platform_get_drvdata(pdev);

	if (device_may_wakeup(&pdev->dev))
	matrix_keypad_disable_wakeup(keypad);

	matrix_keypad_start(keypad->input_dev);

	return 0;
	}

	static DEFINE_SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
	matrix_keypad_suspend, matrix_keypad_resume);

	static int matrix_keypad_init_gpio(struct platform_device *pdev,
	struct matrix_keypad *keypad)
	{
	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
	int i, irq, err;

	/* initialized strobe lines as outputs, activated */
	for (i = 0; i < pdata->num_col_gpios; i++) {
	err = devm_gpio_request(&pdev->dev,
	pdata->col_gpios[i], "matrix_kbd_col");
	if (err) {
	dev_err(&pdev->dev,
	"failed to request GPIO%d for COL%d\n",
	pdata->col_gpios[i], i);
	return err;
	}

	gpio_direction_output(pdata->col_gpios[i], !pdata->active_low);
	}

	for (i = 0; i < pdata->num_row_gpios; i++) {
	err = devm_gpio_request(&pdev->dev,
	pdata->row_gpios[i], "matrix_kbd_row");
	if (err) {
	dev_err(&pdev->dev,
	"failed to request GPIO%d for ROW%d\n",
	pdata->row_gpios[i], i);
	return err;
	}

	gpio_direction_input(pdata->row_gpios[i]);
	}

	if (pdata->clustered_irq > 0) {
	err = devm_request_any_context_irq(&pdev->dev,
	pdata->clustered_irq,
	matrix_keypad_interrupt,
	pdata->clustered_irq_flags,
	"matrix-keypad", keypad);
	if (err < 0) {
	dev_err(&pdev->dev,
	"Unable to acquire clustered interrupt\n");
	return err;
	}

	keypad->row_irqs[0] = pdata->clustered_irq;
	keypad->num_row_irqs = 1;
	} else {
	for (i = 0; i < pdata->num_row_gpios; i++) {
	irq = gpio_to_irq(pdata->row_gpios[i]);
	if (irq < 0) {
	err = irq;
	dev_err(&pdev->dev,
	"Unable to convert GPIO line %i to irq: %d\n",
	pdata->row_gpios[i], err);
	return err;
	}

	err = devm_request_any_context_irq(&pdev->dev,
	irq,
	matrix_keypad_interrupt,
	IRQF_TRIGGER_RISING \|
	IRQF_TRIGGER_FALLING,
	"matrix-keypad", keypad);
	if (err < 0) {
	dev_err(&pdev->dev,
	"Unable to acquire interrupt for GPIO line %i\n",
	pdata->row_gpios[i]);
	return err;
	}

	keypad->row_irqs[i] = irq;
	}

	keypad->num_row_irqs = pdata->num_row_gpios;
	}

	/* initialized as disabled - enabled by input->open */
	disable_row_irqs(keypad);

	return 0;
	}

	#ifdef CONFIG_OF
	static struct matrix_keypad_platform_data *
	matrix_keypad_parse_dt(struct device *dev)
	{
	struct matrix_keypad_platform_data *pdata;
	struct device_node *np = dev->of_node;
	unsigned int *gpios;
	int ret, i, nrow, ncol;

	if (!np) {
	dev_err(dev, "device lacks DT data\n");
	return ERR_PTR(-ENODEV);
	}

	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata) {
	dev_err(dev, "could not allocate memory for platform data\n");
	return ERR_PTR(-ENOMEM);
	}

	pdata->num_row_gpios = nrow = gpiod_count(dev, "row");
	pdata->num_col_gpios = ncol = gpiod_count(dev, "col");
	if (nrow < 0 \|\| ncol < 0) {
	dev_err(dev, "number of keypad rows/columns not specified\n");
	return ERR_PTR(-EINVAL);
	}

	pdata->no_autorepeat = of_property_read_bool(np, "linux,no-autorepeat");

	pdata->wakeup = of_property_read_bool(np, "wakeup-source") \|\|
	of_property_read_bool(np, "linux,wakeup"); /* legacy */

	pdata->active_low = of_property_read_bool(np, "gpio-activelow");

	pdata->drive_inactive_cols =
	of_property_read_bool(np, "drive-inactive-cols");

	of_property_read_u32(np, "debounce-delay-ms", &pdata->debounce_ms);
	of_property_read_u32(np, "col-scan-delay-us",
	&pdata->col_scan_delay_us);

	gpios = devm_kcalloc(dev,
	pdata->num_row_gpios + pdata->num_col_gpios,
	sizeof(unsigned int),
	GFP_KERNEL);
	if (!gpios) {
	dev_err(dev, "could not allocate memory for gpios\n");
	return ERR_PTR(-ENOMEM);
	}

	for (i = 0; i < nrow; i++) {
	ret = of_get_named_gpio(np, "row-gpios", i);
	if (ret < 0)
	return ERR_PTR(ret);
	gpios[i] = ret;
	}

	for (i = 0; i < ncol; i++) {
	ret = of_get_named_gpio(np, "col-gpios", i);
	if (ret < 0)
	return ERR_PTR(ret);
	gpios[nrow + i] = ret;
	}

	pdata->row_gpios = gpios;
	pdata->col_gpios = &gpios[pdata->num_row_gpios];

	return pdata;
	}
	#else
	static inline struct matrix_keypad_platform_data *
	matrix_keypad_parse_dt(struct device *dev)
	{
	dev_err(dev, "no platform data defined\n");

	return ERR_PTR(-EINVAL);
	}
	#endif

	static int matrix_keypad_probe(struct platform_device *pdev)
	{
	const struct matrix_keypad_platform_data *pdata;
	struct matrix_keypad *keypad;
	struct input_dev *input_dev;
	int err;

	pdata = dev_get_platdata(&pdev->dev);
	if (!pdata) {
	pdata = matrix_keypad_parse_dt(&pdev->dev);
	if (IS_ERR(pdata))
	return PTR_ERR(pdata);
	} else if (!pdata->keymap_data) {
	dev_err(&pdev->dev, "no keymap data defined\n");
	return -EINVAL;
	}

	keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
	if (!keypad)
	return -ENOMEM;

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

	keypad->input_dev = input_dev;
	keypad->pdata = pdata;
	keypad->row_shift = get_count_order(pdata->num_col_gpios);
	keypad->stopped = true;
	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
	spin_lock_init(&keypad->lock);

	input_dev->name = pdev->name;
	input_dev->id.bustype = BUS_HOST;
	input_dev->open = matrix_keypad_start;
	input_dev->close = matrix_keypad_stop;

	err = matrix_keypad_build_keymap(pdata->keymap_data, NULL,
	pdata->num_row_gpios,
	pdata->num_col_gpios,
	NULL, input_dev);
	if (err) {
	dev_err(&pdev->dev, "failed to build keymap\n");
	return -ENOMEM;
	}

	if (!pdata->no_autorepeat)
	__set_bit(EV_REP, input_dev->evbit);
	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
	input_set_drvdata(input_dev, keypad);

	err = matrix_keypad_init_gpio(pdev, keypad);
	if (err)
	return err;

	err = input_register_device(keypad->input_dev);
	if (err)
	return err;

	device_init_wakeup(&pdev->dev, pdata->wakeup);
	platform_set_drvdata(pdev, keypad);

	return 0;
	}

	#ifdef CONFIG_OF
	static const struct of_device_id matrix_keypad_dt_match[] = {
	{ .compatible = "gpio-matrix-keypad" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
	#endif

	static struct platform_driver matrix_keypad_driver = {
	.probe = matrix_keypad_probe,
	.driver = {
	.name = "matrix-keypad",
	.pm = pm_sleep_ptr(&matrix_keypad_pm_ops),
	.of_match_table = of_match_ptr(matrix_keypad_dt_match),
	},
	};
	module_platform_driver(matrix_keypad_driver);

	MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
	MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:matrix-keypad");