/*
 * Driver for the IMX keypad port.
 * Copyright (C) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * <<Power management needs to be implemented>>.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/input/matrix_keypad.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/timer.h>

/*
 * Keypad Controller registers (halfword)
 */
#define KPCR		0x00 /* Keypad Control Register */

#define KPSR		0x02 /* Keypad Status Register */
#define KBD_STAT_KPKD	(0x1 << 0) /* Key Press Interrupt Status bit (w1c) */
#define KBD_STAT_KPKR	(0x1 << 1) /* Key Release Interrupt Status bit (w1c) */
#define KBD_STAT_KDSC	(0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/
#define KBD_STAT_KRSS	(0x1 << 3) /* Key Release Synch Status bit (w1c)*/
#define KBD_STAT_KDIE	(0x1 << 8) /* Key Depress Interrupt Enable Status bit */
#define KBD_STAT_KRIE	(0x1 << 9) /* Key Release Interrupt Enable */
#define KBD_STAT_KPPEN	(0x1 << 10) /* Keypad Clock Enable */

#define KDDR		0x04 /* Keypad Data Direction Register */
#define KPDR		0x06 /* Keypad Data Register */

#define MAX_MATRIX_KEY_ROWS	8
#define MAX_MATRIX_KEY_COLS	8
#define MATRIX_ROW_SHIFT	3

#define MAX_MATRIX_KEY_NUM	(MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS)

struct imx_keypad {

	struct clk *clk;
	struct input_dev *input_dev;
	void __iomem *mmio_base;

	int			irq;
	struct timer_list	check_matrix_timer;

	/*
	 * The matrix is stable only if no changes are detected after
	 * IMX_KEYPAD_SCANS_FOR_STABILITY scans
	 */
#define IMX_KEYPAD_SCANS_FOR_STABILITY 3
	int			stable_count;

	bool			enabled;

	/* Masks for enabled rows/cols */
	unsigned short		rows_en_mask;
	unsigned short		cols_en_mask;

	unsigned short		keycodes[MAX_MATRIX_KEY_NUM];

	/*
	 * Matrix states:
	 * -stable: achieved after a complete debounce process.
	 * -unstable: used in the debouncing process.
	 */
	unsigned short		matrix_stable_state[MAX_MATRIX_KEY_COLS];
	unsigned short		matrix_unstable_state[MAX_MATRIX_KEY_COLS];
};

/* Scan the matrix and return the new state in *matrix_volatile_state. */
static void imx_keypad_scan_matrix(struct imx_keypad *keypad,
				  unsigned short *matrix_volatile_state)
{
	int col;
	unsigned short reg_val;

	for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
		if ((keypad->cols_en_mask & (1 << col)) == 0)
			continue;
		/*
		 * Discharge keypad capacitance:
		 * 2. write 1s on column data.
		 * 3. configure columns as totem-pole to discharge capacitance.
		 * 4. configure columns as open-drain.
		 */
		reg_val = readw(keypad->mmio_base + KPDR);
		reg_val |= 0xff00;
		writew(reg_val, keypad->mmio_base + KPDR);

		reg_val = readw(keypad->mmio_base + KPCR);
		reg_val &= ~((keypad->cols_en_mask & 0xff) << 8);
		writew(reg_val, keypad->mmio_base + KPCR);

		udelay(2);

		reg_val = readw(keypad->mmio_base + KPCR);
		reg_val |= (keypad->cols_en_mask & 0xff) << 8;
		writew(reg_val, keypad->mmio_base + KPCR);

		/*
		 * 5. Write a single column to 0, others to 1.
		 * 6. Sample row inputs and save data.
		 * 7. Repeat steps 2 - 6 for remaining columns.
		 */
		reg_val = readw(keypad->mmio_base + KPDR);
		reg_val &= ~(1 << (8 + col));
		writew(reg_val, keypad->mmio_base + KPDR);

		/*
		 * Delay added to avoid propagating the 0 from column to row
		 * when scanning.
		 */
		udelay(5);

		/*
		 * 1s in matrix_volatile_state[col] means key pressures
		 * throw data from non enabled rows.
		 */
		reg_val = readw(keypad->mmio_base + KPDR);
		matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask;
	}

	/*
	 * Return in standby mode:
	 * 9. write 0s to columns
	 */
	reg_val = readw(keypad->mmio_base + KPDR);
	reg_val &= 0x00ff;
	writew(reg_val, keypad->mmio_base + KPDR);
}

/*
 * Compare the new matrix state (volatile) with the stable one stored in
 * keypad->matrix_stable_state and fire events if changes are detected.
 */
static void imx_keypad_fire_events(struct imx_keypad *keypad,
				   unsigned short *matrix_volatile_state)
{
	struct input_dev *input_dev = keypad->input_dev;
	int row, col;

	for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
		unsigned short bits_changed;
		int code;

		if ((keypad->cols_en_mask & (1 << col)) == 0)
			continue; /* Column is not enabled */

		bits_changed = keypad->matrix_stable_state[col] ^
						matrix_volatile_state[col];

		if (bits_changed == 0)
			continue; /* Column does not contain changes */

		for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) {
			if ((keypad->rows_en_mask & (1 << row)) == 0)
				continue; /* Row is not enabled */
			if ((bits_changed & (1 << row)) == 0)
				continue; /* Row does not contain changes */

			code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT);
			/* value should be 1 when key pressed, 0 for released */
			input_report_key(input_dev, keypad->keycodes[code],
				     (matrix_volatile_state[col] >> row) & 0x1);
			dev_dbg(&input_dev->dev, "Event code: %d, val: %d",
				keypad->keycodes[code],
				matrix_volatile_state[col] & (1 << row));
		}
	}
	input_sync(input_dev);
}

/*
 * imx_keypad_check_for_events is the timer handler.
 */
static void imx_keypad_check_for_events(unsigned long data)
{
	struct imx_keypad *keypad = (struct imx_keypad *) data;
	unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS];
	unsigned short reg_val;
	bool state_changed, is_zero_matrix;
	int i;

	memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state));

	imx_keypad_scan_matrix(keypad, matrix_volatile_state);

	state_changed = false;
	for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
		if ((keypad->cols_en_mask & (1 << i)) == 0)
			continue;

		if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) {
			state_changed = true;
			break;
		}
	}

	/*
	 * If the matrix state is changed from the previous scan
	 *   (Re)Begin the debouncing process, saving the new state in
	 *    keypad->matrix_unstable_state.
	 * else
	 *   Increase the count of number of scans with a stable state.
	 */
	if (state_changed) {
		memcpy(keypad->matrix_unstable_state, matrix_volatile_state,
			sizeof(matrix_volatile_state));
		keypad->stable_count = 0;
	} else
		keypad->stable_count++;

	/*
	 * If the matrix is not as stable as we want reschedule scan
	 * in the near future.
	 */
	if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) {
		mod_timer(&keypad->check_matrix_timer,
			  jiffies + msecs_to_jiffies(10));
		return;
	}

	/*
	 * If the matrix state is stable, fire the events and save the new
	 * stable state. Note, if the matrix is kept stable for longer
	 * (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all
	 * events have already been generated.
	 */
	if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) {
		imx_keypad_fire_events(keypad, matrix_volatile_state);

		memcpy(keypad->matrix_stable_state, matrix_volatile_state,
			sizeof(matrix_volatile_state));
	}

	is_zero_matrix = true;
	for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
		if (matrix_volatile_state[i] != 0) {
			is_zero_matrix = false;
			break;
		}
	}


	if (is_zero_matrix) {
		/*
		 * All keys have been released. Enable only the KDI
		 * interrupt for future key presses (clear the KDI
		 * status bit and its sync chain before that).
		 */
		reg_val = readw(keypad->mmio_base + KPSR);
		reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC;
		writew(reg_val, keypad->mmio_base + KPSR);

		reg_val = readw(keypad->mmio_base + KPSR);
		reg_val |= KBD_STAT_KDIE;
		reg_val &= ~KBD_STAT_KRIE;
		writew(reg_val, keypad->mmio_base + KPSR);
	} else {
		/*
		 * Some keys are still pressed. Schedule a rescan in
		 * attempt to detect multiple key presses and enable
		 * the KRI interrupt to react quickly to key release
		 * event.
		 */
		mod_timer(&keypad->check_matrix_timer,
			  jiffies + msecs_to_jiffies(60));

		reg_val = readw(keypad->mmio_base + KPSR);
		reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS;
		writew(reg_val, keypad->mmio_base + KPSR);

		reg_val = readw(keypad->mmio_base + KPSR);
		reg_val |= KBD_STAT_KRIE;
		reg_val &= ~KBD_STAT_KDIE;
		writew(reg_val, keypad->mmio_base + KPSR);
	}
}

static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id)
{
	struct imx_keypad *keypad = dev_id;
	unsigned short reg_val;

	reg_val = readw(keypad->mmio_base + KPSR);

	/* Disable both interrupt types */
	reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
	/* Clear interrupts status bits */
	reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD;
	writew(reg_val, keypad->mmio_base + KPSR);

	if (keypad->enabled) {
		/* The matrix is supposed to be changed */
		keypad->stable_count = 0;

		/* Schedule the scanning procedure near in the future */
		mod_timer(&keypad->check_matrix_timer,
			  jiffies + msecs_to_jiffies(2));
	}

	return IRQ_HANDLED;
}

static void imx_keypad_config(struct imx_keypad *keypad)
{
	unsigned short reg_val;

	/*
	 * Include enabled rows in interrupt generation (KPCR[7:0])
	 * Configure keypad columns as open-drain (KPCR[15:8])
	 */
	reg_val = readw(keypad->mmio_base + KPCR);
	reg_val |= keypad->rows_en_mask & 0xff;		/* rows */
	reg_val |= (keypad->cols_en_mask & 0xff) << 8;	/* cols */
	writew(reg_val, keypad->mmio_base + KPCR);

	/* Write 0's to KPDR[15:8] (Colums) */
	reg_val = readw(keypad->mmio_base + KPDR);
	reg_val &= 0x00ff;
	writew(reg_val, keypad->mmio_base + KPDR);

	/* Configure columns as output, rows as input (KDDR[15:0]) */
	writew(0xff00, keypad->mmio_base + KDDR);

	/*
	 * Clear Key Depress and Key Release status bit.
	 * Clear both synchronizer chain.
	 */
	reg_val = readw(keypad->mmio_base + KPSR);
	reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD |
		   KBD_STAT_KDSC | KBD_STAT_KRSS;
	writew(reg_val, keypad->mmio_base + KPSR);

	/* Enable KDI and disable KRI (avoid false release events). */
	reg_val |= KBD_STAT_KDIE;
	reg_val &= ~KBD_STAT_KRIE;
	writew(reg_val, keypad->mmio_base + KPSR);
}

static void imx_keypad_inhibit(struct imx_keypad *keypad)
{
	unsigned short reg_val;

	/* Inhibit KDI and KRI interrupts. */
	reg_val = readw(keypad->mmio_base + KPSR);
	reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
	writew(reg_val, keypad->mmio_base + KPSR);

	/* Colums as open drain and disable all rows */
	writew(0xff00, keypad->mmio_base + KPCR);
}

static void imx_keypad_close(struct input_dev *dev)
{
	struct imx_keypad *keypad = input_get_drvdata(dev);

	dev_dbg(&dev->dev, ">%s\n", __func__);

	/* Mark keypad as being inactive */
	keypad->enabled = false;
	synchronize_irq(keypad->irq);
	del_timer_sync(&keypad->check_matrix_timer);

	imx_keypad_inhibit(keypad);

	/* Disable clock unit */
	clk_disable(keypad->clk);
}

static int imx_keypad_open(struct input_dev *dev)
{
	struct imx_keypad *keypad = input_get_drvdata(dev);

	dev_dbg(&dev->dev, ">%s\n", __func__);

	/* We became active from now */
	keypad->enabled = true;

	/* Enable the kpp clock */
	clk_enable(keypad->clk);
	imx_keypad_config(keypad);

	/* Sanity control, not all the rows must be actived now. */
	if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) {
		dev_err(&dev->dev,
			"too many keys pressed, control pins initialisation\n");
		goto open_err;
	}

	return 0;

open_err:
	imx_keypad_close(dev);
	return -EIO;
}

static struct input_dev *mxckbd_dev;

void mxc_kpp_report_event(unsigned int type, unsigned int code, int value)
{
	if (mxckbd_dev) {
		input_event(mxckbd_dev, type, code, value);
		input_sync(mxckbd_dev);
	}
	else { 
		printk ("[%s-%d] error mxckbd_dev not assigned.\n",__func__,__LINE__);
	}

#if 0 // debug code .
	printk("%s():mxckbd_dev@%p,Keycode=0x%x,%s\n",\
			__FUNCTION__,mxckbd_dev,wKeyCode,isDown?"DOWN":"UP");
#endif
}


void mxc_kpp_report_key(int isDown,__u16 wKeyCode)
{
	mxc_kpp_report_event(EV_KEY,wKeyCode,isDown);
}

void mxc_kpp_report_power(int isDown)
{
	mxc_kpp_report_key(isDown,KEY_POWER);
}

static int __devinit imx_keypad_probe(struct platform_device *pdev)
{
	const struct matrix_keymap_data *keymap_data = pdev->dev.platform_data;
	struct imx_keypad *keypad;
	struct input_dev *input_dev;
	struct resource *res;
	int irq, error, i;

	if (keymap_data == NULL) {
		dev_err(&pdev->dev, "no keymap defined\n");
		return -EINVAL;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "no irq defined in platform data\n");
		return -EINVAL;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
		dev_err(&pdev->dev, "no I/O memory defined in platform data\n");
		return -EINVAL;
	}

	res = request_mem_region(res->start, resource_size(res), pdev->name);
	if (res == NULL) {
		dev_err(&pdev->dev, "failed to request I/O memory\n");
		return -EBUSY;
	}

	input_dev = input_allocate_device();
	if (!input_dev) {
		dev_err(&pdev->dev, "failed to allocate the input device\n");
		error = -ENOMEM;
		goto failed_rel_mem;
	}
	mxckbd_dev = input_dev;

	keypad = kzalloc(sizeof(struct imx_keypad), GFP_KERNEL);
	if (!keypad) {
		dev_err(&pdev->dev, "not enough memory for driver data\n");
		error = -ENOMEM;
		goto failed_free_input;
	}

	keypad->input_dev = input_dev;
	keypad->irq = irq;
	keypad->stable_count = 0;

	setup_timer(&keypad->check_matrix_timer,
		    imx_keypad_check_for_events, (unsigned long) keypad);

	keypad->mmio_base = ioremap(res->start, resource_size(res));
	if (keypad->mmio_base == NULL) {
		dev_err(&pdev->dev, "failed to remap I/O memory\n");
		error = -ENOMEM;
		goto failed_free_priv;
	}

	keypad->clk = clk_get(&pdev->dev, "kpp");
	if (IS_ERR(keypad->clk)) {
		dev_err(&pdev->dev, "failed to get keypad clock\n");
		error = PTR_ERR(keypad->clk);
		goto failed_unmap;
	}

	/* Search for rows and cols enabled */
	for (i = 0; i < keymap_data->keymap_size; i++) {
		keypad->rows_en_mask |= 1 << KEY_ROW(keymap_data->keymap[i]);
		keypad->cols_en_mask |= 1 << KEY_COL(keymap_data->keymap[i]);
	}

	if (keypad->rows_en_mask > ((1 << MAX_MATRIX_KEY_ROWS) - 1) ||
	   keypad->cols_en_mask > ((1 << MAX_MATRIX_KEY_COLS) - 1)) {
		dev_err(&pdev->dev,
			"invalid key data (too many rows or colums)\n");
		error = -EINVAL;
		goto failed_clock_put;
	}
	dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask);
	dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask);

	/* Init the Input device */
	input_dev->name = pdev->name;
	input_dev->id.bustype = BUS_HOST;
	input_dev->dev.parent = &pdev->dev;
	input_dev->open = imx_keypad_open;
	input_dev->close = imx_keypad_close;

	/* Should not set BIT_MASK(EV_REP) to evbit[0] when some keys(like
	   power key) in keypad don't require to repeat, otherwise it will
	   auto repeat the key event if long press those keys. The disadvantage
	   is all keys in keypad, will not auto repeat when long pressed, but it
	   should be acceptable to remove the EV_REP flag*/
	input_dev->evbit[0] = BIT_MASK(EV_KEY);
	input_dev->keycode = keypad->keycodes;
	input_dev->keycodesize = sizeof(keypad->keycodes[0]);
	input_dev->keycodemax = ARRAY_SIZE(keypad->keycodes);

	matrix_keypad_build_keymap(keymap_data, MATRIX_ROW_SHIFT,
				keypad->keycodes, input_dev->keybit);

	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
	input_set_capability(input_dev, EV_SW, SW_LID);
	input_set_drvdata(input_dev, keypad);

	/* Ensure that the keypad will stay dormant until opened */
	imx_keypad_inhibit(keypad);

	error = request_irq(irq, imx_keypad_irq_handler, IRQF_DISABLED,
			    pdev->name, keypad);
	if (error) {
		dev_err(&pdev->dev, "failed to request IRQ\n");
		goto failed_clock_put;
	}

	/* Register the input device */
	error = input_register_device(input_dev);
	if (error) {
		dev_err(&pdev->dev, "failed to register input device\n");
		goto failed_free_irq;
	}

	platform_set_drvdata(pdev, keypad);
	device_init_wakeup(&pdev->dev, 1);

	return 0;

failed_free_irq:
	free_irq(irq, pdev);
failed_clock_put:
	clk_put(keypad->clk);
failed_unmap:
	iounmap(keypad->mmio_base);
failed_free_priv:
	kfree(keypad);
failed_free_input:
	input_free_device(input_dev);
failed_rel_mem:
	release_mem_region(res->start, resource_size(res));
	return error;
}

static int __devexit imx_keypad_remove(struct platform_device *pdev)
{
	struct imx_keypad *keypad = platform_get_drvdata(pdev);
	struct resource *res;

	dev_dbg(&pdev->dev, ">%s\n", __func__);

	platform_set_drvdata(pdev, NULL);

	input_unregister_device(keypad->input_dev);

	free_irq(keypad->irq, keypad);
	clk_put(keypad->clk);

	iounmap(keypad->mmio_base);
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(res->start, resource_size(res));

	kfree(keypad);

	return 0;
}

#ifdef CONFIG_PM
extern int gSleep_Mode_Suspend;

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

	if (device_may_wakeup(&pdev->dev) && !gSleep_Mode_Suspend) {
		enable_irq_wake(keypad->irq);
	} else {
		disable_irq(keypad->irq);
	}

	return 0;
}

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

	if (device_may_wakeup(&pdev->dev) && !gSleep_Mode_Suspend) {
		disable_irq_wake(keypad->irq);
	} else {
		enable_irq(keypad->irq);
	}		

	return 0;
}

static const struct dev_pm_ops imx_keypad_pm_ops = {
	.suspend	= imx_keypad_suspend,
	.resume		= imx_keypad_resume,
};
#endif

static struct platform_driver imx_keypad_driver = {
	.driver		= {
		.name	= "imx-keypad",
		.owner	= THIS_MODULE,
#ifdef CONFIG_PM
		.pm	= &imx_keypad_pm_ops,
#endif
	},
	.probe		= imx_keypad_probe,
	.remove		= __devexit_p(imx_keypad_remove),
};

static int __init imx_keypad_init(void)
{
	return platform_driver_register(&imx_keypad_driver);
}

static void __exit imx_keypad_exit(void)
{
	platform_driver_unregister(&imx_keypad_driver);
}

module_init(imx_keypad_init);
module_exit(imx_keypad_exit);

MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>");
MODULE_DESCRIPTION("IMX Keypad Port Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:imx-keypad");