/*
   * LoCoMo keyboard driver for Linux-based ARM PDAs:
   * 	- SHARP Zaurus Collie (SL-5500)
   * 	- SHARP Zaurus Poodle (SL-5600)
   *
   * Copyright (c) 2005 John Lenz
   * Based on from xtkbd.c
   *
   *
   * 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 const 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 KB_DELAY		8
  #define SCAN_INTERVAL		(HZ/10)
  
  struct locomokbd {
  	unsigned char keycode[LOCOMOKBD_NUMKEYS];
  	struct input_dev *input;
  	char phys[32];
  
  	unsigned long base;
  	spinlock_t lock;
  
  	struct timer_list timer;
  	unsigned long suspend_jiffies;
  	unsigned int count_cancel;
  };
  
  /* 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)
  {
  	unsigned int row, col, rowd;
  	unsigned long flags;
  	unsigned int num_pressed;
  	unsigned long membase = locomokbd->base;
  
  	spin_lock_irqsave(&locomokbd->lock, flags);
  
  	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++) {
  			unsigned int scancode, pressed, key;
  
  			scancode = SCANCODE(col, row);
  			pressed = rowd & KB_ROWMASK(row);
  			key = locomokbd->keycode[scancode];
  
  			input_report_key(locomokbd->input, key, pressed);
  			if (likely(!pressed))
  				continue;
  
  			num_pressed++;
  
  			/* The "Cancel/ESC" key is labeled "On/Off" on
  			 * Collie and Poodle and should suspend the device
  			 * if it was pressed for more than a second. */
  			if (unlikely(key == KEY_ESC)) {
  				if (!time_after(jiffies,
  					locomokbd->suspend_jiffies + HZ))
  					continue;
  				if (locomokbd->count_cancel++
  					!= (HZ/SCAN_INTERVAL + 1))
  					continue;
  				input_event(locomokbd->input, EV_PWR,
  					KEY_SUSPEND, 1);
  				locomokbd->suspend_jiffies = jiffies;
  			} else
  				locomokbd->count_cancel = 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);
  	else
  		locomokbd->count_cancel = 0;
  
  	spin_unlock_irqrestore(&locomokbd->lock, flags);
  }
  
  /*
   * LoCoMo keyboard interrupt handler.
   */
  static irqreturn_t locomokbd_interrupt(int irq, void *dev_id)
  {
  	struct locomokbd *locomokbd = dev_id;
  	u16 r;
  
  	r = locomo_readl(locomokbd->base + LOCOMO_KIC);
  	if ((r & 0x0001) == 0)
  		return IRQ_HANDLED;
  
  	locomo_writel(r & ~0x0100, locomokbd->base + LOCOMO_KIC); /* Ack */
  
  	/** wait chattering delay **/
  	udelay(100);
  
  	locomokbd_scankeyboard(locomokbd);
  	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);
  }
  
  static int locomokbd_open(struct input_dev *dev)
  {
  	struct locomokbd *locomokbd = input_get_drvdata(dev);
  	u16 r;
  	
  	r = locomo_readl(locomokbd->base + LOCOMO_KIC) | 0x0010;
  	locomo_writel(r, locomokbd->base + LOCOMO_KIC);
  	return 0;
  }
  
  static void locomokbd_close(struct input_dev *dev)
  {
  	struct locomokbd *locomokbd = input_get_drvdata(dev);
  	u16 r;
  	
  	r = locomo_readl(locomokbd->base + LOCOMO_KIC) & ~0x0010;
  	locomo_writel(r, locomokbd->base + LOCOMO_KIC);
  }
  
  static int locomokbd_probe(struct locomo_dev *dev)
  {
  	struct locomokbd *locomokbd;
  	struct input_dev *input_dev;
  	int i, err;
  
  	locomokbd = kzalloc(sizeof(struct locomokbd), GFP_KERNEL);
  	input_dev = input_allocate_device();
  	if (!locomokbd || !input_dev) {
  		err = -ENOMEM;
  		goto err_free_mem;
  	}
  
  	/* try and claim memory region */
  	if (!request_mem_region((unsigned long) dev->mapbase,
  				dev->length,
  				LOCOMO_DRIVER_NAME(dev))) {
  		err = -EBUSY;
  		printk(KERN_ERR "locomokbd: Can't acquire access to io memory for keyboard
  ");
  		goto err_free_mem;
  	}
  
  	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->suspend_jiffies = jiffies;
  
  	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->open = locomokbd_open;
  	input_dev->close = locomokbd_close;
  	input_dev->dev.parent = &dev->dev;
  
  	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP) |
  				BIT_MASK(EV_PWR);
  	input_dev->keycode = locomokbd->keycode;
  	input_dev->keycodesize = sizeof(locomokbd_keycode[0]);
  	input_dev->keycodemax = ARRAY_SIZE(locomokbd_keycode);
  
  	input_set_drvdata(input_dev, locomokbd);
  
  	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 */
  	err = request_irq(dev->irq[0], locomokbd_interrupt, 0, "locomokbd", locomokbd);
  	if (err) {
  		printk(KERN_ERR "locomokbd: Can't get irq for keyboard
  ");
  		goto err_release_region;
  	}
  
  	err = input_register_device(locomokbd->input);
  	if (err)
  		goto err_free_irq;
  
  	return 0;
  
   err_free_irq:
  	free_irq(dev->irq[0], locomokbd);
   err_release_region:
  	release_mem_region((unsigned long) dev->mapbase, dev->length);
  	locomo_set_drvdata(dev, NULL);
   err_free_mem:
  	input_free_device(input_dev);
  	kfree(locomokbd);
  
  	return err;
  }
  
  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);