text: /*
   * DaVinci Key Scan Driver for TI platforms
   *
   * Copyright (C) 2009 Texas Instruments, Inc
   *
   * Author: Miguel Aguilar <miguel.aguilar@ridgerun.com>
   *
   * Initial Code: Sandeep Paulraj <s-paulraj@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/module.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/types.h>
  #include <linux/input.h>
  #include <linux/kernel.h>
  #include <linux/delay.h>
  #include <linux/platform_device.h>
  #include <linux/errno.h>
  #include <linux/slab.h>
  
  #include <asm/irq.h>
  
  #include <mach/hardware.h>
  #include <mach/irqs.h>
  #include <mach/keyscan.h>
  
  /* Key scan registers */
  #define DAVINCI_KEYSCAN_KEYCTRL		0x0000
  #define DAVINCI_KEYSCAN_INTENA		0x0004
  #define DAVINCI_KEYSCAN_INTFLAG		0x0008
  #define DAVINCI_KEYSCAN_INTCLR		0x000c
  #define DAVINCI_KEYSCAN_STRBWIDTH	0x0010
  #define DAVINCI_KEYSCAN_INTERVAL	0x0014
  #define DAVINCI_KEYSCAN_CONTTIME	0x0018
  #define DAVINCI_KEYSCAN_CURRENTST	0x001c
  #define DAVINCI_KEYSCAN_PREVSTATE	0x0020
  #define DAVINCI_KEYSCAN_EMUCTRL		0x0024
  #define DAVINCI_KEYSCAN_IODFTCTRL	0x002c
  
  /* Key Control Register (KEYCTRL) */
  #define DAVINCI_KEYSCAN_KEYEN		0x00000001
  #define DAVINCI_KEYSCAN_PREVMODE	0x00000002
  #define DAVINCI_KEYSCAN_CHATOFF		0x00000004
  #define DAVINCI_KEYSCAN_AUTODET		0x00000008
  #define DAVINCI_KEYSCAN_SCANMODE	0x00000010
  #define DAVINCI_KEYSCAN_OUTTYPE		0x00000020
  
  /* Masks for the interrupts */
  #define DAVINCI_KEYSCAN_INT_CONT	0x00000008
  #define DAVINCI_KEYSCAN_INT_OFF		0x00000004
  #define DAVINCI_KEYSCAN_INT_ON		0x00000002
  #define DAVINCI_KEYSCAN_INT_CHANGE	0x00000001
  #define DAVINCI_KEYSCAN_INT_ALL		0x0000000f
  
  struct davinci_ks {
  	struct input_dev		*input;
  	struct davinci_ks_platform_data	*pdata;
  	int				irq;
  	void __iomem			*base;
  	resource_size_t			pbase;
  	size_t				base_size;
  	unsigned short			keymap[];
  };
  
  /* Initializing the kp Module */
  static int __init davinci_ks_initialize(struct davinci_ks *davinci_ks)
  {
  	struct device *dev = &davinci_ks->input->dev;
  	struct davinci_ks_platform_data *pdata = davinci_ks->pdata;
  	u32 matrix_ctrl;
  
  	/* Enable all interrupts */
  	__raw_writel(DAVINCI_KEYSCAN_INT_ALL,
  		     davinci_ks->base + DAVINCI_KEYSCAN_INTENA);
  
  	/* Clear interrupts if any */
  	__raw_writel(DAVINCI_KEYSCAN_INT_ALL,
  		     davinci_ks->base + DAVINCI_KEYSCAN_INTCLR);
  
  	/* Setup the scan period = strobe + interval */
  	__raw_writel(pdata->strobe,
  		     davinci_ks->base + DAVINCI_KEYSCAN_STRBWIDTH);
  	__raw_writel(pdata->interval,
  		     davinci_ks->base + DAVINCI_KEYSCAN_INTERVAL);
  	__raw_writel(0x01,
  		     davinci_ks->base + DAVINCI_KEYSCAN_CONTTIME);
  
  	/* Define matrix type */
  	switch (pdata->matrix_type) {
  	case DAVINCI_KEYSCAN_MATRIX_4X4:
  		matrix_ctrl = 0;
  		break;
  	case DAVINCI_KEYSCAN_MATRIX_5X3:
  		matrix_ctrl = (1 << 6);
  		break;
  	default:
  		dev_err(dev->parent, "wrong matrix type\n");
  		return -EINVAL;
  	}
  
  	/* Enable key scan module and set matrix type */
  	__raw_writel(DAVINCI_KEYSCAN_AUTODET | DAVINCI_KEYSCAN_KEYEN |
  		     matrix_ctrl, davinci_ks->base + DAVINCI_KEYSCAN_KEYCTRL);
  
  	return 0;
  }
  
  static irqreturn_t davinci_ks_interrupt(int irq, void *dev_id)
  {
  	struct davinci_ks *davinci_ks = dev_id;
  	struct device *dev = &davinci_ks->input->dev;
  	unsigned short *keymap = davinci_ks->keymap;
  	int keymapsize = davinci_ks->pdata->keymapsize;
  	u32 prev_status, new_status, changed;
  	bool release;
  	int keycode = KEY_UNKNOWN;
  	int i;
  
  	/* Disable interrupt */
  	__raw_writel(0x0, davinci_ks->base + DAVINCI_KEYSCAN_INTENA);
  
  	/* Reading previous and new status of the key scan */
  	prev_status = __raw_readl(davinci_ks->base + DAVINCI_KEYSCAN_PREVSTATE);
  	new_status = __raw_readl(davinci_ks->base + DAVINCI_KEYSCAN_CURRENTST);
  
  	changed = prev_status ^ new_status;
  
  	if (changed) {
  		/*
  		 * It goes through all bits in 'changed' to ensure
  		 * that no key changes are being missed
  		 */
  		for (i = 0 ; i < keymapsize; i++) {
  			if ((changed>>i) & 0x1) {
  				keycode = keymap[i];
  				release = (new_status >> i) & 0x1;
  				dev_dbg(dev->parent, "key %d %s\n", keycode,
  					release ? "released" : "pressed");
  				input_report_key(davinci_ks->input, keycode,
  						 !release);
  				input_sync(davinci_ks->input);
  			}
  		}
  		/* Clearing interrupt */
  		__raw_writel(DAVINCI_KEYSCAN_INT_ALL,
  			     davinci_ks->base + DAVINCI_KEYSCAN_INTCLR);
  	}
  
  	/* Enable interrupts */
  	__raw_writel(0x1, davinci_ks->base + DAVINCI_KEYSCAN_INTENA);
  
  	return IRQ_HANDLED;
  }
  
  static int __init davinci_ks_probe(struct platform_device *pdev)
  {
  	struct davinci_ks *davinci_ks;
  	struct input_dev *key_dev;
  	struct resource *res, *mem;
  	struct device *dev = &pdev->dev;
  	struct davinci_ks_platform_data *pdata = pdev->dev.platform_data;
  	int error, i;
  
  	if (pdata->device_enable) {
  		error = pdata->device_enable(dev);
  		if (error < 0) {
  			dev_dbg(dev, "device enable function failed\n");
  			return error;
  		}
  	}
  
  	if (!pdata->keymap) {
  		dev_dbg(dev, "no keymap from pdata\n");
  		return -EINVAL;
  	}
  
  	davinci_ks = kzalloc(sizeof(struct davinci_ks) +
  		sizeof(unsigned short) * pdata->keymapsize, GFP_KERNEL);
  	if (!davinci_ks) {
  		dev_dbg(dev, "could not allocate memory for private data\n");
  		return -ENOMEM;
  	}
  
  	memcpy(davinci_ks->keymap, pdata->keymap,
  		sizeof(unsigned short) * pdata->keymapsize);
  
  	key_dev = input_allocate_device();
  	if (!key_dev) {
  		dev_dbg(dev, "could not allocate input device\n");
  		error = -ENOMEM;
  		goto fail1;
  	}
  
  	davinci_ks->input = key_dev;
  
  	davinci_ks->irq = platform_get_irq(pdev, 0);
  	if (davinci_ks->irq < 0) {
  		dev_err(dev, "no key scan irq\n");
  		error = davinci_ks->irq;
  		goto fail2;
  	}
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!res) {
  		dev_err(dev, "no mem resource\n");
  		error = -EINVAL;
  		goto fail2;
  	}
  
  	davinci_ks->pbase = res->start;
  	davinci_ks->base_size = resource_size(res);
  
  	mem = request_mem_region(davinci_ks->pbase, davinci_ks->base_size,
  				 pdev->name);
  	if (!mem) {
  		dev_err(dev, "key scan registers at %08x are not free\n",
  			davinci_ks->pbase);
  		error = -EBUSY;
  		goto fail2;
  	}
  
  	davinci_ks->base = ioremap(davinci_ks->pbase, davinci_ks->base_size);
  	if (!davinci_ks->base) {
  		dev_err(dev, "can't ioremap MEM resource.\n");
  		error = -ENOMEM;
  		goto fail3;
  	}
  
  	/* Enable auto repeat feature of Linux input subsystem */
  	if (pdata->rep)
  		__set_bit(EV_REP, key_dev->evbit);
  
  	/* Setup input device */
  	__set_bit(EV_KEY, key_dev->evbit);
  
  	/* Setup the platform data */
  	davinci_ks->pdata = pdata;
  
  	for (i = 0; i < davinci_ks->pdata->keymapsize; i++)
  		__set_bit(davinci_ks->pdata->keymap[i], key_dev->keybit);
  
  	key_dev->name = "davinci_keyscan";
  	key_dev->phys = "davinci_keyscan/input0";
  	key_dev->dev.parent = &pdev->dev;
  	key_dev->id.bustype = BUS_HOST;
  	key_dev->id.vendor = 0x0001;
  	key_dev->id.product = 0x0001;
  	key_dev->id.version = 0x0001;
  	key_dev->keycode = davinci_ks->keymap;
  	key_dev->keycodesize = sizeof(davinci_ks->keymap[0]);
  	key_dev->keycodemax = davinci_ks->pdata->keymapsize;
  
  	error = input_register_device(davinci_ks->input);
  	if (error < 0) {
  		dev_err(dev, "unable to register davinci key scan device\n");
  		goto fail4;
  	}
  
  	error = request_irq(davinci_ks->irq, davinci_ks_interrupt,
  			  IRQF_DISABLED, pdev->name, davinci_ks);
  	if (error < 0) {
  		dev_err(dev, "unable to register davinci key scan interrupt\n");
  		goto fail5;
  	}
  
  	error = davinci_ks_initialize(davinci_ks);
  	if (error < 0) {
  		dev_err(dev, "unable to initialize davinci key scan device\n");
  		goto fail6;
  	}
  
  	platform_set_drvdata(pdev, davinci_ks);
  	return 0;
  
  fail6:
  	free_irq(davinci_ks->irq, davinci_ks);
  fail5:
  	input_unregister_device(davinci_ks->input);
  	key_dev = NULL;
  fail4:
  	iounmap(davinci_ks->base);
  fail3:
  	release_mem_region(davinci_ks->pbase, davinci_ks->base_size);
  fail2:
  	input_free_device(key_dev);
  fail1:
  	kfree(davinci_ks);
  
  	return error;
  }
  
  static int __devexit davinci_ks_remove(struct platform_device *pdev)
  {
  	struct davinci_ks *davinci_ks = platform_get_drvdata(pdev);
  
  	free_irq(davinci_ks->irq, davinci_ks);
  
  	input_unregister_device(davinci_ks->input);
  
  	iounmap(davinci_ks->base);
  	release_mem_region(davinci_ks->pbase, davinci_ks->base_size);
  
  	platform_set_drvdata(pdev, NULL);
  
  	kfree(davinci_ks);
  
  	return 0;
  }
  
  static struct platform_driver davinci_ks_driver = {
  	.driver	= {
  		.name = "davinci_keyscan",
  		.owner = THIS_MODULE,
  	},
  	.remove	= __devexit_p(davinci_ks_remove),
  };
  
  static int __init davinci_ks_init(void)
  {
  	return platform_driver_probe(&davinci_ks_driver, davinci_ks_probe);
  }
  module_init(davinci_ks_init);
  
  static void __exit davinci_ks_exit(void)
  {
  	platform_driver_unregister(&davinci_ks_driver);
  }
  module_exit(davinci_ks_exit);
  
  MODULE_AUTHOR("Miguel Aguilar");
  MODULE_DESCRIPTION("Texas Instruments DaVinci Key Scan Driver");
  MODULE_LICENSE("GPL");
  