/*
   * SuperH KEYSC Keypad Driver
   *
   * Copyright (C) 2008 Magnus Damm
   *
   * Based on gpio_keys.c, Copyright 2005 Phil Blundell
   *
   * 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.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/interrupt.h>
  #include <linux/irq.h>
  #include <linux/delay.h>
  #include <linux/platform_device.h>
  #include <linux/input.h>
  #include <linux/input/sh_keysc.h>
  #include <linux/bitmap.h>
  #include <linux/pm_runtime.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  
  static const struct {
  	unsigned char kymd, keyout, keyin;
  } sh_keysc_mode[] = {
  	[SH_KEYSC_MODE_1] = { 0, 6, 5 },
  	[SH_KEYSC_MODE_2] = { 1, 5, 6 },
  	[SH_KEYSC_MODE_3] = { 2, 4, 7 },
  	[SH_KEYSC_MODE_4] = { 3, 6, 6 },
  	[SH_KEYSC_MODE_5] = { 4, 6, 7 },
  	[SH_KEYSC_MODE_6] = { 5, 8, 8 },
  };
  
  struct sh_keysc_priv {
  	void __iomem *iomem_base;
  	DECLARE_BITMAP(last_keys, SH_KEYSC_MAXKEYS);
  	struct input_dev *input;
  	struct sh_keysc_info pdata;
  };
  
  #define KYCR1 0
  #define KYCR2 1
  #define KYINDR 2
  #define KYOUTDR 3
  
  #define KYCR2_IRQ_LEVEL    0x10
  #define KYCR2_IRQ_DISABLED 0x00
  
  static unsigned long sh_keysc_read(struct sh_keysc_priv *p, int reg_nr)
  {
  	return ioread16(p->iomem_base + (reg_nr << 2));
  }
  
  static void sh_keysc_write(struct sh_keysc_priv *p, int reg_nr,
  			   unsigned long value)
  {
  	iowrite16(value, p->iomem_base + (reg_nr << 2));
  }
  
  static void sh_keysc_level_mode(struct sh_keysc_priv *p,
  				unsigned long keys_set)
  {
  	struct sh_keysc_info *pdata = &p->pdata;
  
  	sh_keysc_write(p, KYOUTDR, 0);
  	sh_keysc_write(p, KYCR2, KYCR2_IRQ_LEVEL | (keys_set << 8));
  
  	if (pdata->kycr2_delay)
  		udelay(pdata->kycr2_delay);
  }
  
  static void sh_keysc_map_dbg(struct device *dev, unsigned long *map,
  			     const char *str)
  {
  	int k;
  
  	for (k = 0; k < BITS_TO_LONGS(SH_KEYSC_MAXKEYS); k++)
  		dev_dbg(dev, "%s[%d] 0x%lx
  ", str, k, map[k]);
  }
  
  static irqreturn_t sh_keysc_isr(int irq, void *dev_id)
  {
  	struct platform_device *pdev = dev_id;
  	struct sh_keysc_priv *priv = platform_get_drvdata(pdev);
  	struct sh_keysc_info *pdata = &priv->pdata;
  	int keyout_nr = sh_keysc_mode[pdata->mode].keyout;
  	int keyin_nr = sh_keysc_mode[pdata->mode].keyin;
  	DECLARE_BITMAP(keys, SH_KEYSC_MAXKEYS);
  	DECLARE_BITMAP(keys0, SH_KEYSC_MAXKEYS);
  	DECLARE_BITMAP(keys1, SH_KEYSC_MAXKEYS);
  	unsigned char keyin_set, tmp;
  	int i, k, n;
  
  	dev_dbg(&pdev->dev, "isr!
  ");
  
  	bitmap_fill(keys1, SH_KEYSC_MAXKEYS);
  	bitmap_zero(keys0, SH_KEYSC_MAXKEYS);
  
  	do {
  		bitmap_zero(keys, SH_KEYSC_MAXKEYS);
  		keyin_set = 0;
  
  		sh_keysc_write(priv, KYCR2, KYCR2_IRQ_DISABLED);
  
  		for (i = 0; i < keyout_nr; i++) {
  			n = keyin_nr * i;
  
  			/* drive one KEYOUT pin low, read KEYIN pins */
  			sh_keysc_write(priv, KYOUTDR, 0xffff ^ (3 << (i * 2)));
  			udelay(pdata->delay);
  			tmp = sh_keysc_read(priv, KYINDR);
  
  			/* set bit if key press has been detected */
  			for (k = 0; k < keyin_nr; k++) {
  				if (tmp & (1 << k))
  					__set_bit(n + k, keys);
  			}
  
  			/* keep track of which KEYIN bits that have been set */
  			keyin_set |= tmp ^ ((1 << keyin_nr) - 1);
  		}
  
  		sh_keysc_level_mode(priv, keyin_set);
  
  		bitmap_complement(keys, keys, SH_KEYSC_MAXKEYS);
  		bitmap_and(keys1, keys1, keys, SH_KEYSC_MAXKEYS);
  		bitmap_or(keys0, keys0, keys, SH_KEYSC_MAXKEYS);
  
  		sh_keysc_map_dbg(&pdev->dev, keys, "keys");
  
  	} while (sh_keysc_read(priv, KYCR2) & 0x01);
  
  	sh_keysc_map_dbg(&pdev->dev, priv->last_keys, "last_keys");
  	sh_keysc_map_dbg(&pdev->dev, keys0, "keys0");
  	sh_keysc_map_dbg(&pdev->dev, keys1, "keys1");
  
  	for (i = 0; i < SH_KEYSC_MAXKEYS; i++) {
  		k = pdata->keycodes[i];
  		if (!k)
  			continue;
  
  		if (test_bit(i, keys0) == test_bit(i, priv->last_keys))
  			continue;
  
  		if (test_bit(i, keys1) || test_bit(i, keys0)) {
  			input_event(priv->input, EV_KEY, k, 1);
  			__set_bit(i, priv->last_keys);
  		}
  
  		if (!test_bit(i, keys1)) {
  			input_event(priv->input, EV_KEY, k, 0);
  			__clear_bit(i, priv->last_keys);
  		}
  
  	}
  	input_sync(priv->input);
  
  	return IRQ_HANDLED;
  }
  
  static int sh_keysc_probe(struct platform_device *pdev)
  {
  	struct sh_keysc_priv *priv;
  	struct sh_keysc_info *pdata;
  	struct resource *res;
  	struct input_dev *input;
  	int i;
  	int irq, error;
  
  	if (!dev_get_platdata(&pdev->dev)) {
  		dev_err(&pdev->dev, "no platform data defined
  ");
  		error = -EINVAL;
  		goto err0;
  	}
  
  	error = -ENXIO;
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (res == NULL) {
  		dev_err(&pdev->dev, "failed to get I/O memory
  ");
  		goto err0;
  	}
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0) {
  		dev_err(&pdev->dev, "failed to get irq
  ");
  		goto err0;
  	}
  
  	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  	if (priv == NULL) {
  		dev_err(&pdev->dev, "failed to allocate driver data
  ");
  		error = -ENOMEM;
  		goto err0;
  	}
  
  	platform_set_drvdata(pdev, priv);
  	memcpy(&priv->pdata, dev_get_platdata(&pdev->dev), sizeof(priv->pdata));
  	pdata = &priv->pdata;
  
  	priv->iomem_base = ioremap_nocache(res->start, resource_size(res));
  	if (priv->iomem_base == NULL) {
  		dev_err(&pdev->dev, "failed to remap I/O memory
  ");
  		error = -ENXIO;
  		goto err1;
  	}
  
  	priv->input = input_allocate_device();
  	if (!priv->input) {
  		dev_err(&pdev->dev, "failed to allocate input device
  ");
  		error = -ENOMEM;
  		goto err2;
  	}
  
  	input = priv->input;
  	input->evbit[0] = BIT_MASK(EV_KEY);
  
  	input->name = pdev->name;
  	input->phys = "sh-keysc-keys/input0";
  	input->dev.parent = &pdev->dev;
  
  	input->id.bustype = BUS_HOST;
  	input->id.vendor = 0x0001;
  	input->id.product = 0x0001;
  	input->id.version = 0x0100;
  
  	input->keycode = pdata->keycodes;
  	input->keycodesize = sizeof(pdata->keycodes[0]);
  	input->keycodemax = ARRAY_SIZE(pdata->keycodes);
  
  	error = request_threaded_irq(irq, NULL, sh_keysc_isr, IRQF_ONESHOT,
  				     dev_name(&pdev->dev), pdev);
  	if (error) {
  		dev_err(&pdev->dev, "failed to request IRQ
  ");
  		goto err3;
  	}
  
  	for (i = 0; i < SH_KEYSC_MAXKEYS; i++)
  		__set_bit(pdata->keycodes[i], input->keybit);
  	__clear_bit(KEY_RESERVED, input->keybit);
  
  	error = input_register_device(input);
  	if (error) {
  		dev_err(&pdev->dev, "failed to register input device
  ");
  		goto err4;
  	}
  
  	pm_runtime_enable(&pdev->dev);
  	pm_runtime_get_sync(&pdev->dev);
  
  	sh_keysc_write(priv, KYCR1, (sh_keysc_mode[pdata->mode].kymd << 8) |
  		       pdata->scan_timing);
  	sh_keysc_level_mode(priv, 0);
  
  	device_init_wakeup(&pdev->dev, 1);
  
  	return 0;
  
   err4:
  	free_irq(irq, pdev);
   err3:
  	input_free_device(input);
   err2:
  	iounmap(priv->iomem_base);
   err1:
  	kfree(priv);
   err0:
  	return error;
  }
  
  static int sh_keysc_remove(struct platform_device *pdev)
  {
  	struct sh_keysc_priv *priv = platform_get_drvdata(pdev);
  
  	sh_keysc_write(priv, KYCR2, KYCR2_IRQ_DISABLED);
  
  	input_unregister_device(priv->input);
  	free_irq(platform_get_irq(pdev, 0), pdev);
  	iounmap(priv->iomem_base);
  
  	pm_runtime_put_sync(&pdev->dev);
  	pm_runtime_disable(&pdev->dev);
  
  	kfree(priv);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int sh_keysc_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct sh_keysc_priv *priv = platform_get_drvdata(pdev);
  	int irq = platform_get_irq(pdev, 0);
  	unsigned short value;
  
  	value = sh_keysc_read(priv, KYCR1);
  
  	if (device_may_wakeup(dev)) {
  		sh_keysc_write(priv, KYCR1, value | 0x80);
  		enable_irq_wake(irq);
  	} else {
  		sh_keysc_write(priv, KYCR1, value & ~0x80);
  		pm_runtime_put_sync(dev);
  	}
  
  	return 0;
  }
  
  static int sh_keysc_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	int irq = platform_get_irq(pdev, 0);
  
  	if (device_may_wakeup(dev))
  		disable_irq_wake(irq);
  	else
  		pm_runtime_get_sync(dev);
  
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(sh_keysc_dev_pm_ops,
  			 sh_keysc_suspend, sh_keysc_resume);
  
  static struct platform_driver sh_keysc_device_driver = {
  	.probe		= sh_keysc_probe,
  	.remove		= sh_keysc_remove,
  	.driver		= {
  		.name	= "sh_keysc",
  		.pm	= &sh_keysc_dev_pm_ops,
  	}
  };
  module_platform_driver(sh_keysc_device_driver);
  
  MODULE_AUTHOR("Magnus Damm");
  MODULE_DESCRIPTION("SuperH KEYSC Keypad Driver");
  MODULE_LICENSE("GPL");