/*
 *  Copyright (c) 2005 John Lenz
 *
 * Based on from xtkbd.c
 */

/*
 * LoCoMo keyboard driver for Linux/ARM
 */

/*
 * 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/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>

#include <asm/hardware/locomo.h>
#include <asm/irq.h>

MODULE_AUTHOR("John Lenz <lenz@cs.wisc.edu>");
MODULE_DESCRIPTION("LoCoMo keyboard driver");
MODULE_LICENSE("GPL");

#define LOCOMOKBD_NUMKEYS	128

#define KEY_ACTIVITY		KEY_F16
#define KEY_CONTACT		KEY_F18
#define KEY_CENTER		KEY_F15

static unsigned char locomokbd_keycode[LOCOMOKBD_NUMKEYS] = {
	0, KEY_ESC, KEY_ACTIVITY, 0, 0, 0, 0, 0, 0, 0,				/* 0 - 9 */
	0, 0, 0, 0, 0, 0, 0, KEY_MENU, KEY_HOME, KEY_CONTACT,			/* 10 - 19 */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0,						/* 20 - 29 */
	0, 0, 0, KEY_CENTER, 0, KEY_MAIL, 0, 0, 0, 0,				/* 30 - 39 */
	0, 0, 0, 0, 0, 0, 0, 0, 0, KEY_RIGHT,					/* 40 - 49 */
	KEY_UP, KEY_LEFT, 0, 0, KEY_P, 0, KEY_O, KEY_I, KEY_Y, KEY_T,		/* 50 - 59 */
	KEY_E, KEY_W, 0, 0, 0, 0, KEY_DOWN, KEY_ENTER, 0, 0,			/* 60 - 69 */
	KEY_BACKSPACE, 0, KEY_L, KEY_U, KEY_H, KEY_R, KEY_D, KEY_Q, 0, 0,	/* 70 - 79 */
	0, 0, 0, 0, 0, 0, KEY_ENTER, KEY_RIGHTSHIFT, KEY_K, KEY_J,		/* 80 - 89 */
	KEY_G, KEY_F, KEY_X, KEY_S, 0, 0, 0, 0, 0, 0,				/* 90 - 99 */
	0, 0, KEY_DOT, 0, KEY_COMMA, KEY_N, KEY_B, KEY_C, KEY_Z, KEY_A,		/* 100 - 109 */
	KEY_LEFTSHIFT, KEY_TAB, KEY_LEFTCTRL, 0, 0, 0, 0, 0, 0, 0,		/* 110 - 119 */
	KEY_M, KEY_SPACE, KEY_V, KEY_APOSTROPHE, KEY_SLASH, 0, 0, 0		/* 120 - 128 */
};

#define KB_ROWS			16
#define KB_COLS			8
#define KB_ROWMASK(r)		(1 << (r))
#define SCANCODE(c,r)		( ((c)<<4) + (r) + 1 )
#define	NR_SCANCODES		128

#define KB_DELAY		8
#define SCAN_INTERVAL		(HZ/10)
#define LOCOMOKBD_PRESSED	1

struct locomokbd {
	unsigned char keycode[LOCOMOKBD_NUMKEYS];
	struct input_dev *input;
	char phys[32];

	struct locomo_dev *ldev;
	unsigned long base;
	spinlock_t lock;

	struct timer_list timer;
};

/* helper functions for reading the keyboard matrix */
static inline void locomokbd_charge_all(unsigned long membase)
{
	locomo_writel(0x00FF, membase + LOCOMO_KSC);
}

static inline void locomokbd_activate_all(unsigned long membase)
{
	unsigned long r;

	locomo_writel(0, membase + LOCOMO_KSC);
	r = locomo_readl(membase + LOCOMO_KIC);
	r &= 0xFEFF;
	locomo_writel(r, membase + LOCOMO_KIC);
}

static inline void locomokbd_activate_col(unsigned long membase, int col)
{
	unsigned short nset;
	unsigned short nbset;

	nset = 0xFF & ~(1 << col);
	nbset = (nset << 8) + nset;
	locomo_writel(nbset, membase + LOCOMO_KSC);
}

static inline void locomokbd_reset_col(unsigned long membase, int col)
{
	unsigned short nbset;

	nbset = ((0xFF & ~(1 << col)) << 8) + 0xFF;
	locomo_writel(nbset, membase + LOCOMO_KSC);
}

/*
 * The LoCoMo keyboard only generates interrupts when a key is pressed.
 * So when a key is pressed, we enable a timer.  This timer scans the
 * keyboard, and this is how we detect when the key is released.
 */

/* Scan the hardware keyboard and push any changes up through the input layer */
static void locomokbd_scankeyboard(struct locomokbd *locomokbd, struct pt_regs *regs)
{
	unsigned int row, col, rowd, scancode;
	unsigned long flags;
	unsigned int num_pressed;
	unsigned long membase = locomokbd->base;

	spin_lock_irqsave(&locomokbd->lock, flags);

	input_regs(locomokbd->input, regs);

	locomokbd_charge_all(membase);

	num_pressed = 0;
	for (col = 0; col < KB_COLS; col++) {

		locomokbd_activate_col(membase, col);
		udelay(KB_DELAY);

		rowd = ~locomo_readl(membase + LOCOMO_KIB);
		for (row = 0; row < KB_ROWS; row++) {
			scancode = SCANCODE(col, row);
			if (rowd & KB_ROWMASK(row)) {
				num_pressed += 1;
				input_report_key(locomokbd->input, locomokbd->keycode[scancode], 1);
			} else {
				input_report_key(locomokbd->input, locomokbd->keycode[scancode], 0);
			}
		}
		locomokbd_reset_col(membase, col);
	}
	locomokbd_activate_all(membase);

	input_sync(locomokbd->input);

	/* if any keys are pressed, enable the timer */
	if (num_pressed)
		mod_timer(&locomokbd->timer, jiffies + SCAN_INTERVAL);

	spin_unlock_irqrestore(&locomokbd->lock, flags);
}

/*
 * LoCoMo keyboard interrupt handler.
 */
static irqreturn_t locomokbd_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	struct locomokbd *locomokbd = dev_id;
	/** wait chattering delay **/
	udelay(100);

	locomokbd_scankeyboard(locomokbd, regs);

	return IRQ_HANDLED;
}

/*
 * LoCoMo timer checking for released keys
 */
static void locomokbd_timer_callback(unsigned long data)
{
	struct locomokbd *locomokbd = (struct locomokbd *) data;
	locomokbd_scankeyboard(locomokbd, NULL);
}

static int locomokbd_probe(struct locomo_dev *dev)
{
	struct locomokbd *locomokbd;
	struct input_dev *input_dev;
	int i, ret;

	locomokbd = kzalloc(sizeof(struct locomokbd), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!locomokbd || !input_dev) {
		ret = -ENOMEM;
		goto free;
	}

	/* try and claim memory region */
	if (!request_mem_region((unsigned long) dev->mapbase,
				dev->length,
				LOCOMO_DRIVER_NAME(dev))) {
		ret = -EBUSY;
		printk(KERN_ERR "locomokbd: Can't acquire access to io memory for keyboard\n");
		goto free;
	}

	locomokbd->ldev = dev;
	locomo_set_drvdata(dev, locomokbd);

	locomokbd->base = (unsigned long) dev->mapbase;

	spin_lock_init(&locomokbd->lock);

	init_timer(&locomokbd->timer);
	locomokbd->timer.function = locomokbd_timer_callback;
	locomokbd->timer.data = (unsigned long) locomokbd;

	locomokbd->input = input_dev;
	strcpy(locomokbd->phys, "locomokbd/input0");

	input_dev->name = "LoCoMo keyboard";
	input_dev->phys = locomokbd->phys;
	input_dev->id.bustype = BUS_HOST;
	input_dev->id.vendor = 0x0001;
	input_dev->id.product = 0x0001;
	input_dev->id.version = 0x0100;
	input_dev->private = locomokbd;

	input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_REP);
	input_dev->keycode = locomokbd->keycode;
	input_dev->keycodesize = sizeof(unsigned char);
	input_dev->keycodemax = ARRAY_SIZE(locomokbd_keycode);

	memcpy(locomokbd->keycode, locomokbd_keycode, sizeof(locomokbd->keycode));
	for (i = 0; i < LOCOMOKBD_NUMKEYS; i++)
		set_bit(locomokbd->keycode[i], input_dev->keybit);
	clear_bit(0, input_dev->keybit);

	/* attempt to get the interrupt */
	ret = request_irq(dev->irq[0], locomokbd_interrupt, 0, "locomokbd", locomokbd);
	if (ret) {
		printk(KERN_ERR "locomokbd: Can't get irq for keyboard\n");
		goto out;
	}

	input_register_device(locomokbd->input);

	return 0;

out:
	release_mem_region((unsigned long) dev->mapbase, dev->length);
	locomo_set_drvdata(dev, NULL);
free:
	input_free_device(input_dev);
	kfree(locomokbd);

	return ret;
}

static int locomokbd_remove(struct locomo_dev *dev)
{
	struct locomokbd *locomokbd = locomo_get_drvdata(dev);

	free_irq(dev->irq[0], locomokbd);

	del_timer_sync(&locomokbd->timer);

	input_unregister_device(locomokbd->input);
	locomo_set_drvdata(dev, NULL);

	release_mem_region((unsigned long) dev->mapbase, dev->length);

	kfree(locomokbd);

	return 0;
}

static struct locomo_driver keyboard_driver = {
	.drv = {
		.name = "locomokbd"
	},
	.devid	= LOCOMO_DEVID_KEYBOARD,
	.probe	= locomokbd_probe,
	.remove	= locomokbd_remove,
};

static int __init locomokbd_init(void)
{
	return locomo_driver_register(&keyboard_driver);
}

static void __exit locomokbd_exit(void)
{
	locomo_driver_unregister(&keyboard_driver);
}

module_init(locomokbd_init);
module_exit(locomokbd_exit);