drivers/input/keyboard/twl4030_keypad.c - kernel/msm-4.9 - Gitiles

 /*
  * twl4030_keypad.c - driver for 8x8 keypad controller in twl4030 chips
  *
  * Copyright (C) 2007 Texas Instruments, Inc.
  * Copyright (C) 2008 Nokia Corporation
  *
  * Code re-written for 2430SDP by:
  * Syed Mohammed Khasim <x0khasim@ti.com>
  *
  * Initial Code:
  * Manjunatha G K <manjugk@ti.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * 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.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/input.h>
 #include <linux/platform_device.h>
 #include <linux/i2c/twl.h>
 #include <linux/slab.h>

 /*
  * The TWL4030 family chips include a keypad controller that supports
  * up to an 8x8 switch matrix.  The controller can issue system wakeup
  * events, since it uses only the always-on 32KiHz oscillator, and has
  * an internal state machine that decodes pressed keys, including
  * multi-key combinations.
  *
  * This driver lets boards define what keycodes they wish to report for
  * which scancodes, as part of the "struct twl4030_keypad_data" used in
  * the probe() routine.
  *
  * See the TPS65950 documentation; that's the general availability
  * version of the TWL5030 second generation part.
  */
 #define TWL4030_MAX_ROWS	8	/* TWL4030 hard limit */
 #define TWL4030_MAX_COLS	8
 /*
  * Note that we add space for an extra column so that we can handle
  * row lines connected to the gnd (see twl4030_col_xlate()).
  */
 #define TWL4030_ROW_SHIFT	4
 #define TWL4030_KEYMAP_SIZE	(TWL4030_MAX_ROWS << TWL4030_ROW_SHIFT)

 struct twl4030_keypad {
 	unsigned short	keymap[TWL4030_KEYMAP_SIZE];
 	u16		kp_state[TWL4030_MAX_ROWS];
 	unsigned	n_rows;
 	unsigned	n_cols;
 	unsigned	irq;

 	struct device *dbg_dev;
 	struct input_dev *input;
 };

 /*----------------------------------------------------------------------*/

 /* arbitrary prescaler value 0..7 */
 #define PTV_PRESCALER			4

 /* Register Offsets */
 #define KEYP_CTRL			0x00
 #define KEYP_DEB			0x01
 #define KEYP_LONG_KEY			0x02
 #define KEYP_LK_PTV			0x03
 #define KEYP_TIMEOUT_L			0x04
 #define KEYP_TIMEOUT_H			0x05
 #define KEYP_KBC			0x06
 #define KEYP_KBR			0x07
 #define KEYP_SMS			0x08
 #define KEYP_FULL_CODE_7_0		0x09	/* row 0 column status */
 #define KEYP_FULL_CODE_15_8		0x0a	/* ... row 1 ... */
 #define KEYP_FULL_CODE_23_16		0x0b
 #define KEYP_FULL_CODE_31_24		0x0c
 #define KEYP_FULL_CODE_39_32		0x0d
 #define KEYP_FULL_CODE_47_40		0x0e
 #define KEYP_FULL_CODE_55_48		0x0f
 #define KEYP_FULL_CODE_63_56		0x10
 #define KEYP_ISR1			0x11
 #define KEYP_IMR1			0x12
 #define KEYP_ISR2			0x13
 #define KEYP_IMR2			0x14
 #define KEYP_SIR			0x15
 #define KEYP_EDR			0x16	/* edge triggers */
 #define KEYP_SIH_CTRL			0x17

 /* KEYP_CTRL_REG Fields */
 #define KEYP_CTRL_SOFT_NRST		BIT(0)
 #define KEYP_CTRL_SOFTMODEN		BIT(1)
 #define KEYP_CTRL_LK_EN			BIT(2)
 #define KEYP_CTRL_TOE_EN		BIT(3)
 #define KEYP_CTRL_TOLE_EN		BIT(4)
 #define KEYP_CTRL_RP_EN			BIT(5)
 #define KEYP_CTRL_KBD_ON		BIT(6)

 /* KEYP_DEB, KEYP_LONG_KEY, KEYP_TIMEOUT_x*/
 #define KEYP_PERIOD_US(t, prescale)	((t) / (31 << (prescale + 1)) - 1)

 /* KEYP_LK_PTV_REG Fields */
 #define KEYP_LK_PTV_PTV_SHIFT		5

 /* KEYP_{IMR,ISR,SIR} Fields */
 #define KEYP_IMR1_MIS			BIT(3)
 #define KEYP_IMR1_TO			BIT(2)
 #define KEYP_IMR1_LK			BIT(1)
 #define KEYP_IMR1_KP			BIT(0)

 /* KEYP_EDR Fields */
 #define KEYP_EDR_KP_FALLING		0x01
 #define KEYP_EDR_KP_RISING		0x02
 #define KEYP_EDR_KP_BOTH		0x03
 #define KEYP_EDR_LK_FALLING		0x04
 #define KEYP_EDR_LK_RISING		0x08
 #define KEYP_EDR_TO_FALLING		0x10
 #define KEYP_EDR_TO_RISING		0x20
 #define KEYP_EDR_MIS_FALLING		0x40
 #define KEYP_EDR_MIS_RISING		0x80


 /*----------------------------------------------------------------------*/

 static int twl4030_kpread(struct twl4030_keypad *kp,
 		u8 *data, u32 reg, u8 num_bytes)
 {
 	int ret = twl_i2c_read(TWL4030_MODULE_KEYPAD, data, reg, num_bytes);

 	if (ret < 0)
 		dev_warn(kp->dbg_dev,
 			"Couldn't read TWL4030: %X - ret %d[%x]\n",
 			 reg, ret, ret);

 	return ret;
 }

 static int twl4030_kpwrite_u8(struct twl4030_keypad *kp, u8 data, u32 reg)
 {
 	int ret = twl_i2c_write_u8(TWL4030_MODULE_KEYPAD, data, reg);

 	if (ret < 0)
 		dev_warn(kp->dbg_dev,
 			"Could not write TWL4030: %X - ret %d[%x]\n",
 			 reg, ret, ret);

 	return ret;
 }

 static inline u16 twl4030_col_xlate(struct twl4030_keypad *kp, u8 col)
 {
 	/* If all bits in a row are active for all coloumns then
 	 * we have that row line connected to gnd. Mark this
 	 * key on as if it was on matrix position n_cols (ie
 	 * one higher than the size of the matrix).
 	 */
 	if (col == 0xFF)
 		return 1 << kp->n_cols;
 	else
 		return col & ((1 << kp->n_cols) - 1);
 }

 static int twl4030_read_kp_matrix_state(struct twl4030_keypad *kp, u16 *state)
 {
 	u8 new_state[TWL4030_MAX_ROWS];
 	int row;
 	int ret = twl4030_kpread(kp, new_state,
 				 KEYP_FULL_CODE_7_0, kp->n_rows);
 	if (ret >= 0)
 		for (row = 0; row < kp->n_rows; row++)
 			state[row] = twl4030_col_xlate(kp, new_state[row]);

 	return ret;
 }

 static bool twl4030_is_in_ghost_state(struct twl4030_keypad *kp, u16 *key_state)
 {
 	int i;
 	u16 check = 0;

 	for (i = 0; i < kp->n_rows; i++) {
 		u16 col = key_state[i];

 		if ((col & check) && hweight16(col) > 1)
 			return true;

 		check |= col;
 	}

 	return false;
 }

 static void twl4030_kp_scan(struct twl4030_keypad *kp, bool release_all)
 {
 	struct input_dev *input = kp->input;
 	u16 new_state[TWL4030_MAX_ROWS];
 	int col, row;

 	if (release_all)
 		memset(new_state, 0, sizeof(new_state));
 	else {
 		/* check for any changes */
 		int ret = twl4030_read_kp_matrix_state(kp, new_state);

 		if (ret < 0)	/* panic ... */
 			return;

 		if (twl4030_is_in_ghost_state(kp, new_state))
 			return;
 	}

 	/* check for changes and print those */
 	for (row = 0; row < kp->n_rows; row++) {
 		int changed = new_state[row] ^ kp->kp_state[row];

 		if (!changed)
 			continue;

 		/* Extra column handles "all gnd" rows */
 		for (col = 0; col < kp->n_cols + 1; col++) {
 			int code;

 			if (!(changed & (1 << col)))
 				continue;

 			dev_dbg(kp->dbg_dev, "key [%d:%d] %s\n", row, col,
 				(new_state[row] & (1 << col)) ?
 				"press" : "release");

 			code = MATRIX_SCAN_CODE(row, col, TWL4030_ROW_SHIFT);
 			input_event(input, EV_MSC, MSC_SCAN, code);
 			input_report_key(input, kp->keymap[code],
 					 new_state[row] & (1 << col));
 		}
 		kp->kp_state[row] = new_state[row];
 	}
 	input_sync(input);
 }

 /*
  * Keypad interrupt handler
  */
 static irqreturn_t do_kp_irq(int irq, void *_kp)
 {
 	struct twl4030_keypad *kp = _kp;
 	u8 reg;
 	int ret;

 	/* Read & Clear TWL4030 pending interrupt */
 	ret = twl4030_kpread(kp, &reg, KEYP_ISR1, 1);

 	/* Release all keys if I2C has gone bad or
 	 * the KEYP has gone to idle state */
 	if (ret >= 0 && (reg & KEYP_IMR1_KP))
 		twl4030_kp_scan(kp, false);
 	else
 		twl4030_kp_scan(kp, true);

 	return IRQ_HANDLED;
 }

 static int twl4030_kp_program(struct twl4030_keypad *kp)
 {
 	u8 reg;
 	int i;

 	/* Enable controller, with hardware decoding but not autorepeat */
 	reg = KEYP_CTRL_SOFT_NRST | KEYP_CTRL_SOFTMODEN
 		| KEYP_CTRL_TOE_EN | KEYP_CTRL_KBD_ON;
 	if (twl4030_kpwrite_u8(kp, reg, KEYP_CTRL) < 0)
 		return -EIO;

 	/* NOTE:  we could use sih_setup() here to package keypad
 	 * event sources as four different IRQs ... but we don't.
 	 */

 	/* Enable TO rising and KP rising and falling edge detection */
 	reg = KEYP_EDR_KP_BOTH | KEYP_EDR_TO_RISING;
 	if (twl4030_kpwrite_u8(kp, reg, KEYP_EDR) < 0)
 		return -EIO;

 	/* Set PTV prescaler Field */
 	reg = (PTV_PRESCALER << KEYP_LK_PTV_PTV_SHIFT);
 	if (twl4030_kpwrite_u8(kp, reg, KEYP_LK_PTV) < 0)
 		return -EIO;

 	/* Set key debounce time to 20 ms */
 	i = KEYP_PERIOD_US(20000, PTV_PRESCALER);
 	if (twl4030_kpwrite_u8(kp, i, KEYP_DEB) < 0)
 		return -EIO;

 	/* Set timeout period to 200 ms */
 	i = KEYP_PERIOD_US(200000, PTV_PRESCALER);
 	if (twl4030_kpwrite_u8(kp, (i & 0xFF), KEYP_TIMEOUT_L) < 0)
 		return -EIO;

 	if (twl4030_kpwrite_u8(kp, (i >> 8), KEYP_TIMEOUT_H) < 0)
 		return -EIO;

 	/*
 	 * Enable Clear-on-Read; disable remembering events that fire
 	 * after the IRQ but before our handler acks (reads) them,
 	 */
 	reg = TWL4030_SIH_CTRL_COR_MASK | TWL4030_SIH_CTRL_PENDDIS_MASK;
 	if (twl4030_kpwrite_u8(kp, reg, KEYP_SIH_CTRL) < 0)
 		return -EIO;

 	/* initialize key state; irqs update it from here on */
 	if (twl4030_read_kp_matrix_state(kp, kp->kp_state) < 0)
 		return -EIO;

 	return 0;
 }

 /*
  * Registers keypad device with input subsystem
  * and configures TWL4030 keypad registers
  */
 static int twl4030_kp_probe(struct platform_device *pdev)
 {
 	struct twl4030_keypad_data *pdata = pdev->dev.platform_data;
 	const struct matrix_keymap_data *keymap_data;
 	struct twl4030_keypad *kp;
 	struct input_dev *input;
 	u8 reg;
 	int error;

 	if (!pdata || !pdata->rows || !pdata->cols || !pdata->keymap_data ||
 	    pdata->rows > TWL4030_MAX_ROWS || pdata->cols > TWL4030_MAX_COLS) {
 		dev_err(&pdev->dev, "Invalid platform_data\n");
 		return -EINVAL;
 	}

 	keymap_data = pdata->keymap_data;

 	kp = kzalloc(sizeof(*kp), GFP_KERNEL);
 	input = input_allocate_device();
 	if (!kp || !input) {
 		error = -ENOMEM;
 		goto err1;
 	}

 	/* Get the debug Device */
 	kp->dbg_dev = &pdev->dev;
 	kp->input = input;

 	kp->n_rows = pdata->rows;
 	kp->n_cols = pdata->cols;
 	kp->irq = platform_get_irq(pdev, 0);

 	/* setup input device */
 	input->name		= "TWL4030 Keypad";
 	input->phys		= "twl4030_keypad/input0";
 	input->dev.parent	= &pdev->dev;

 	input->id.bustype	= BUS_HOST;
 	input->id.vendor	= 0x0001;
 	input->id.product	= 0x0001;
 	input->id.version	= 0x0003;

 	error = matrix_keypad_build_keymap(keymap_data, NULL,
 					   TWL4030_MAX_ROWS,
 					   1 << TWL4030_ROW_SHIFT,
 					   kp->keymap, input);
 	if (error) {
 		dev_err(kp->dbg_dev, "Failed to build keymap\n");
 		goto err1;
 	}

 	input_set_capability(input, EV_MSC, MSC_SCAN);
 	/* Enable auto repeat feature of Linux input subsystem */
 	if (pdata->rep)
 		__set_bit(EV_REP, input->evbit);

 	error = input_register_device(input);
 	if (error) {
 		dev_err(kp->dbg_dev,
 			"Unable to register twl4030 keypad device\n");
 		goto err1;
 	}

 	error = twl4030_kp_program(kp);
 	if (error)
 		goto err2;

 	/*
 	 * This ISR will always execute in kernel thread context because of
 	 * the need to access the TWL4030 over the I2C bus.
 	 *
 	 * NOTE:  we assume this host is wired to TWL4040 INT1, not INT2 ...
 	 */
 	error = request_threaded_irq(kp->irq, NULL, do_kp_irq,
 			0, pdev->name, kp);
 	if (error) {
 		dev_info(kp->dbg_dev, "request_irq failed for irq no=%d\n",
 			kp->irq);
 		goto err2;
 	}

 	/* Enable KP and TO interrupts now. */
 	reg = (u8) ~(KEYP_IMR1_KP | KEYP_IMR1_TO);
 	if (twl4030_kpwrite_u8(kp, reg, KEYP_IMR1)) {
 		error = -EIO;
 		goto err3;
 	}

 	platform_set_drvdata(pdev, kp);
 	return 0;

 err3:
 	/* mask all events - we don't care about the result */
 	(void) twl4030_kpwrite_u8(kp, 0xff, KEYP_IMR1);
 	free_irq(kp->irq, kp);
 err2:
 	input_unregister_device(input);
 	input = NULL;
 err1:
 	input_free_device(input);
 	kfree(kp);
 	return error;
 }

 static int twl4030_kp_remove(struct platform_device *pdev)
 {
 	struct twl4030_keypad *kp = platform_get_drvdata(pdev);

 	free_irq(kp->irq, kp);
 	input_unregister_device(kp->input);
 	kfree(kp);

 	return 0;
 }

 /*
  * NOTE: twl4030 are multi-function devices connected via I2C.
  * So this device is a child of an I2C parent, thus it needs to
  * support unplug/replug (which most platform devices don't).
  */

 static struct platform_driver twl4030_kp_driver = {
 	.probe		= twl4030_kp_probe,
 	.remove		= twl4030_kp_remove,
 	.driver		= {
 		.name	= "twl4030_keypad",
 		.owner	= THIS_MODULE,
 	},
 };
 module_platform_driver(twl4030_kp_driver);

 MODULE_AUTHOR("Texas Instruments");
 MODULE_DESCRIPTION("TWL4030 Keypad Driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:twl4030_keypad");
	/*
	* twl4030_keypad.c - driver for 8x8 keypad controller in twl4030 chips
	*
	* Copyright (C) 2007 Texas Instruments, Inc.
	* Copyright (C) 2008 Nokia Corporation
	*
	* Code re-written for 2430SDP by:
	* Syed Mohammed Khasim <x0khasim@ti.com>
	*
	* Initial Code:
	* Manjunatha G K <manjugk@ti.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* 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.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/input.h>
	#include <linux/platform_device.h>
	#include <linux/i2c/twl.h>
	#include <linux/slab.h>

	/*
	* The TWL4030 family chips include a keypad controller that supports
	* up to an 8x8 switch matrix. The controller can issue system wakeup
	* events, since it uses only the always-on 32KiHz oscillator, and has
	* an internal state machine that decodes pressed keys, including
	* multi-key combinations.
	*
	* This driver lets boards define what keycodes they wish to report for
	* which scancodes, as part of the "struct twl4030_keypad_data" used in
	* the probe() routine.
	*
	* See the TPS65950 documentation; that's the general availability
	* version of the TWL5030 second generation part.
	*/
	#define TWL4030_MAX_ROWS 8 /* TWL4030 hard limit */
	#define TWL4030_MAX_COLS 8
	/*
	* Note that we add space for an extra column so that we can handle
	* row lines connected to the gnd (see twl4030_col_xlate()).
	*/
	#define TWL4030_ROW_SHIFT 4
	#define TWL4030_KEYMAP_SIZE (TWL4030_MAX_ROWS << TWL4030_ROW_SHIFT)

	struct twl4030_keypad {
	unsigned short keymap[TWL4030_KEYMAP_SIZE];
	u16 kp_state[TWL4030_MAX_ROWS];
	unsigned n_rows;
	unsigned n_cols;
	unsigned irq;

	struct device *dbg_dev;
	struct input_dev *input;
	};

	/----------------------------------------------------------------------/

	/* arbitrary prescaler value 0..7 */
	#define PTV_PRESCALER 4

	/* Register Offsets */
	#define KEYP_CTRL 0x00
	#define KEYP_DEB 0x01
	#define KEYP_LONG_KEY 0x02
	#define KEYP_LK_PTV 0x03
	#define KEYP_TIMEOUT_L 0x04
	#define KEYP_TIMEOUT_H 0x05
	#define KEYP_KBC 0x06
	#define KEYP_KBR 0x07
	#define KEYP_SMS 0x08
	#define KEYP_FULL_CODE_7_0 0x09 /* row 0 column status */
	#define KEYP_FULL_CODE_15_8 0x0a /* ... row 1 ... */
	#define KEYP_FULL_CODE_23_16 0x0b
	#define KEYP_FULL_CODE_31_24 0x0c
	#define KEYP_FULL_CODE_39_32 0x0d
	#define KEYP_FULL_CODE_47_40 0x0e
	#define KEYP_FULL_CODE_55_48 0x0f
	#define KEYP_FULL_CODE_63_56 0x10
	#define KEYP_ISR1 0x11
	#define KEYP_IMR1 0x12
	#define KEYP_ISR2 0x13
	#define KEYP_IMR2 0x14
	#define KEYP_SIR 0x15
	#define KEYP_EDR 0x16 /* edge triggers */
	#define KEYP_SIH_CTRL 0x17

	/* KEYP_CTRL_REG Fields */
	#define KEYP_CTRL_SOFT_NRST BIT(0)
	#define KEYP_CTRL_SOFTMODEN BIT(1)
	#define KEYP_CTRL_LK_EN BIT(2)
	#define KEYP_CTRL_TOE_EN BIT(3)
	#define KEYP_CTRL_TOLE_EN BIT(4)
	#define KEYP_CTRL_RP_EN BIT(5)
	#define KEYP_CTRL_KBD_ON BIT(6)

	/* KEYP_DEB, KEYP_LONG_KEY, KEYP_TIMEOUT_x*/
	#define KEYP_PERIOD_US(t, prescale) ((t) / (31 << (prescale + 1)) - 1)

	/* KEYP_LK_PTV_REG Fields */
	#define KEYP_LK_PTV_PTV_SHIFT 5

	/* KEYP_{IMR,ISR,SIR} Fields */
	#define KEYP_IMR1_MIS BIT(3)
	#define KEYP_IMR1_TO BIT(2)
	#define KEYP_IMR1_LK BIT(1)
	#define KEYP_IMR1_KP BIT(0)

	/* KEYP_EDR Fields */
	#define KEYP_EDR_KP_FALLING 0x01
	#define KEYP_EDR_KP_RISING 0x02
	#define KEYP_EDR_KP_BOTH 0x03
	#define KEYP_EDR_LK_FALLING 0x04
	#define KEYP_EDR_LK_RISING 0x08
	#define KEYP_EDR_TO_FALLING 0x10
	#define KEYP_EDR_TO_RISING 0x20
	#define KEYP_EDR_MIS_FALLING 0x40
	#define KEYP_EDR_MIS_RISING 0x80


	/----------------------------------------------------------------------/

	static int twl4030_kpread(struct twl4030_keypad *kp,
	u8 *data, u32 reg, u8 num_bytes)
	{
	int ret = twl_i2c_read(TWL4030_MODULE_KEYPAD, data, reg, num_bytes);

	if (ret < 0)
	dev_warn(kp->dbg_dev,
	"Couldn't read TWL4030: %X - ret %d[%x]\n",
	reg, ret, ret);

	return ret;
	}

	static int twl4030_kpwrite_u8(struct twl4030_keypad *kp, u8 data, u32 reg)
	{
	int ret = twl_i2c_write_u8(TWL4030_MODULE_KEYPAD, data, reg);

	if (ret < 0)
	dev_warn(kp->dbg_dev,
	"Could not write TWL4030: %X - ret %d[%x]\n",
	reg, ret, ret);

	return ret;
	}

	static inline u16 twl4030_col_xlate(struct twl4030_keypad *kp, u8 col)
	{
	/* If all bits in a row are active for all coloumns then
	* we have that row line connected to gnd. Mark this
	* key on as if it was on matrix position n_cols (ie
	* one higher than the size of the matrix).
	*/
	if (col == 0xFF)
	return 1 << kp->n_cols;
	else
	return col & ((1 << kp->n_cols) - 1);
	}

	static int twl4030_read_kp_matrix_state(struct twl4030_keypad kp, u16 state)
	{
	u8 new_state[TWL4030_MAX_ROWS];
	int row;
	int ret = twl4030_kpread(kp, new_state,
	KEYP_FULL_CODE_7_0, kp->n_rows);
	if (ret >= 0)
	for (row = 0; row < kp->n_rows; row++)
	state[row] = twl4030_col_xlate(kp, new_state[row]);

	return ret;
	}

	static bool twl4030_is_in_ghost_state(struct twl4030_keypad kp, u16 key_state)
	{
	int i;
	u16 check = 0;

	for (i = 0; i < kp->n_rows; i++) {
	u16 col = key_state[i];

	if ((col & check) && hweight16(col) > 1)
	return true;

	check \|= col;
	}

	return false;
	}

	static void twl4030_kp_scan(struct twl4030_keypad *kp, bool release_all)
	{
	struct input_dev *input = kp->input;
	u16 new_state[TWL4030_MAX_ROWS];
	int col, row;

	if (release_all)
	memset(new_state, 0, sizeof(new_state));
	else {
	/* check for any changes */
	int ret = twl4030_read_kp_matrix_state(kp, new_state);

	if (ret < 0) /* panic ... */
	return;

	if (twl4030_is_in_ghost_state(kp, new_state))
	return;
	}

	/* check for changes and print those */
	for (row = 0; row < kp->n_rows; row++) {
	int changed = new_state[row] ^ kp->kp_state[row];

	if (!changed)
	continue;

	/* Extra column handles "all gnd" rows */
	for (col = 0; col < kp->n_cols + 1; col++) {
	int code;

	if (!(changed & (1 << col)))
	continue;

	dev_dbg(kp->dbg_dev, "key [%d:%d] %s\n", row, col,
	(new_state[row] & (1 << col)) ?
	"press" : "release");

	code = MATRIX_SCAN_CODE(row, col, TWL4030_ROW_SHIFT);
	input_event(input, EV_MSC, MSC_SCAN, code);
	input_report_key(input, kp->keymap[code],
	new_state[row] & (1 << col));
	}
	kp->kp_state[row] = new_state[row];
	}
	input_sync(input);
	}

	/*
	* Keypad interrupt handler
	*/
	static irqreturn_t do_kp_irq(int irq, void *_kp)
	{
	struct twl4030_keypad *kp = _kp;
	u8 reg;
	int ret;

	/* Read & Clear TWL4030 pending interrupt */
	ret = twl4030_kpread(kp, &reg, KEYP_ISR1, 1);

	/* Release all keys if I2C has gone bad or
	* the KEYP has gone to idle state */
	if (ret >= 0 && (reg & KEYP_IMR1_KP))
	twl4030_kp_scan(kp, false);
	else
	twl4030_kp_scan(kp, true);

	return IRQ_HANDLED;
	}

	static int twl4030_kp_program(struct twl4030_keypad *kp)
	{
	u8 reg;
	int i;

	/* Enable controller, with hardware decoding but not autorepeat */
	reg = KEYP_CTRL_SOFT_NRST \| KEYP_CTRL_SOFTMODEN
	\| KEYP_CTRL_TOE_EN \| KEYP_CTRL_KBD_ON;
	if (twl4030_kpwrite_u8(kp, reg, KEYP_CTRL) < 0)
	return -EIO;

	/* NOTE: we could use sih_setup() here to package keypad
	* event sources as four different IRQs ... but we don't.
	*/

	/* Enable TO rising and KP rising and falling edge detection */
	reg = KEYP_EDR_KP_BOTH \| KEYP_EDR_TO_RISING;
	if (twl4030_kpwrite_u8(kp, reg, KEYP_EDR) < 0)
	return -EIO;

	/* Set PTV prescaler Field */
	reg = (PTV_PRESCALER << KEYP_LK_PTV_PTV_SHIFT);
	if (twl4030_kpwrite_u8(kp, reg, KEYP_LK_PTV) < 0)
	return -EIO;

	/* Set key debounce time to 20 ms */
	i = KEYP_PERIOD_US(20000, PTV_PRESCALER);
	if (twl4030_kpwrite_u8(kp, i, KEYP_DEB) < 0)
	return -EIO;

	/* Set timeout period to 200 ms */
	i = KEYP_PERIOD_US(200000, PTV_PRESCALER);
	if (twl4030_kpwrite_u8(kp, (i & 0xFF), KEYP_TIMEOUT_L) < 0)
	return -EIO;

	if (twl4030_kpwrite_u8(kp, (i >> 8), KEYP_TIMEOUT_H) < 0)
	return -EIO;

	/*
	* Enable Clear-on-Read; disable remembering events that fire
	* after the IRQ but before our handler acks (reads) them,
	*/
	reg = TWL4030_SIH_CTRL_COR_MASK \| TWL4030_SIH_CTRL_PENDDIS_MASK;
	if (twl4030_kpwrite_u8(kp, reg, KEYP_SIH_CTRL) < 0)
	return -EIO;

	/* initialize key state; irqs update it from here on */
	if (twl4030_read_kp_matrix_state(kp, kp->kp_state) < 0)
	return -EIO;

	return 0;
	}

	/*
	* Registers keypad device with input subsystem
	* and configures TWL4030 keypad registers
	*/
	static int twl4030_kp_probe(struct platform_device *pdev)
	{
	struct twl4030_keypad_data *pdata = pdev->dev.platform_data;
	const struct matrix_keymap_data *keymap_data;
	struct twl4030_keypad *kp;
	struct input_dev *input;
	u8 reg;
	int error;

	if (!pdata \|\| !pdata->rows \|\| !pdata->cols \|\| !pdata->keymap_data \|\|
	pdata->rows > TWL4030_MAX_ROWS \|\| pdata->cols > TWL4030_MAX_COLS) {
	dev_err(&pdev->dev, "Invalid platform_data\n");
	return -EINVAL;
	}

	keymap_data = pdata->keymap_data;

	kp = kzalloc(sizeof(*kp), GFP_KERNEL);
	input = input_allocate_device();
	if (!kp \|\| !input) {
	error = -ENOMEM;
	goto err1;
	}

	/* Get the debug Device */
	kp->dbg_dev = &pdev->dev;
	kp->input = input;

	kp->n_rows = pdata->rows;
	kp->n_cols = pdata->cols;
	kp->irq = platform_get_irq(pdev, 0);

	/* setup input device */
	input->name = "TWL4030 Keypad";
	input->phys = "twl4030_keypad/input0";
	input->dev.parent = &pdev->dev;

	input->id.bustype = BUS_HOST;
	input->id.vendor = 0x0001;
	input->id.product = 0x0001;
	input->id.version = 0x0003;

	error = matrix_keypad_build_keymap(keymap_data, NULL,
	TWL4030_MAX_ROWS,
	1 << TWL4030_ROW_SHIFT,
	kp->keymap, input);
	if (error) {
	dev_err(kp->dbg_dev, "Failed to build keymap\n");
	goto err1;
	}

	input_set_capability(input, EV_MSC, MSC_SCAN);
	/* Enable auto repeat feature of Linux input subsystem */
	if (pdata->rep)
	__set_bit(EV_REP, input->evbit);

	error = input_register_device(input);
	if (error) {
	dev_err(kp->dbg_dev,
	"Unable to register twl4030 keypad device\n");
	goto err1;
	}

	error = twl4030_kp_program(kp);
	if (error)
	goto err2;

	/*
	* This ISR will always execute in kernel thread context because of
	* the need to access the TWL4030 over the I2C bus.
	*
	* NOTE: we assume this host is wired to TWL4040 INT1, not INT2 ...
	*/
	error = request_threaded_irq(kp->irq, NULL, do_kp_irq,
	0, pdev->name, kp);
	if (error) {
	dev_info(kp->dbg_dev, "request_irq failed for irq no=%d\n",
	kp->irq);
	goto err2;
	}

	/* Enable KP and TO interrupts now. */
	reg = (u8) ~(KEYP_IMR1_KP \| KEYP_IMR1_TO);
	if (twl4030_kpwrite_u8(kp, reg, KEYP_IMR1)) {
	error = -EIO;
	goto err3;
	}

	platform_set_drvdata(pdev, kp);
	return 0;

	err3:
	/* mask all events - we don't care about the result */
	(void) twl4030_kpwrite_u8(kp, 0xff, KEYP_IMR1);
	free_irq(kp->irq, kp);
	err2:
	input_unregister_device(input);
	input = NULL;
	err1:
	input_free_device(input);
	kfree(kp);
	return error;
	}

	static int twl4030_kp_remove(struct platform_device *pdev)
	{
	struct twl4030_keypad *kp = platform_get_drvdata(pdev);

	free_irq(kp->irq, kp);
	input_unregister_device(kp->input);
	kfree(kp);

	return 0;
	}

	/*
	* NOTE: twl4030 are multi-function devices connected via I2C.
	* So this device is a child of an I2C parent, thus it needs to
	* support unplug/replug (which most platform devices don't).
	*/

	static struct platform_driver twl4030_kp_driver = {
	.probe = twl4030_kp_probe,
	.remove = twl4030_kp_remove,
	.driver = {
	.name = "twl4030_keypad",
	.owner = THIS_MODULE,
	},
	};
	module_platform_driver(twl4030_kp_driver);

	MODULE_AUTHOR("Texas Instruments");
	MODULE_DESCRIPTION("TWL4030 Keypad Driver");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:twl4030_keypad");