/* linux/drivers/char/nsc_gpio.c
  
     National Semiconductor common GPIO device-file/VFS methods.
     Allows a user space process to control the GPIO pins.
  
     Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
     Copyright (c) 2005      Jim Cromie <jim.cromie@gmail.com>
  */

  #include <linux/fs.h>
  #include <linux/module.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/nsc_gpio.h>

  #include <linux/platform_device.h>

  #include <asm/uaccess.h>
  #include <asm/io.h>
  
  #define NAME "nsc_gpio"

  void nsc_gpio_dump(struct nsc_gpio_ops *amp, unsigned index)

  {

  	/* retrieve current config w/o changing it */
  	u32 config = amp->gpio_config(index, ~0, 0);
  
  	/* user requested via 'v' command, so its INFO */

  	dev_info(amp->dev, "io%02u: 0x%04x %s %s %s %s %s %s %s\tio:%d/%d
  ",

  		 index, config,
  		 (config & 1) ? "OE" : "TS",      /* output-enabled/tristate */
  		 (config & 2) ? "PP" : "OD",      /* push pull / open drain */
  		 (config & 4) ? "PUE" : "PUD",    /* pull up enabled/disabled */
  		 (config & 8) ? "LOCKED" : "",    /* locked / unlocked */
  		 (config & 16) ? "LEVEL" : "EDGE",/* level/edge input */
  		 (config & 32) ? "HI" : "LO",     /* trigger on rise/fall edge */

  		 (config & 64) ? "DEBOUNCE" : "", /* debounce */
  
  		 amp->gpio_get(index), amp->gpio_current(index));

  }

  ssize_t nsc_gpio_write(struct file *file, const char __user *data,
  		       size_t len, loff_t *ppos)
  {

  	unsigned m = iminor(file->f_path.dentry->d_inode);

  	struct nsc_gpio_ops *amp = file->private_data;

  	struct device *dev = amp->dev;

  	size_t i;
  	int err = 0;
  
  	for (i = 0; i < len; ++i) {
  		char c;
  		if (get_user(c, data + i))
  			return -EFAULT;
  		switch (c) {
  		case '0':
  			amp->gpio_set(m, 0);
  			break;
  		case '1':
  			amp->gpio_set(m, 1);
  			break;
  		case 'O':

  			dev_dbg(dev, "GPIO%d output enabled
  ", m);

  			amp->gpio_config(m, ~1, 1);
  			break;
  		case 'o':

  			dev_dbg(dev, "GPIO%d output disabled
  ", m);

  			amp->gpio_config(m, ~1, 0);
  			break;
  		case 'T':

  			dev_dbg(dev, "GPIO%d output is push pull
  ", m);

  			amp->gpio_config(m, ~2, 2);
  			break;
  		case 't':

  			dev_dbg(dev, "GPIO%d output is open drain
  ", m);

  			amp->gpio_config(m, ~2, 0);
  			break;
  		case 'P':

  			dev_dbg(dev, "GPIO%d pull up enabled
  ", m);

  			amp->gpio_config(m, ~4, 4);
  			break;
  		case 'p':

  			dev_dbg(dev, "GPIO%d pull up disabled
  ", m);

  			amp->gpio_config(m, ~4, 0);
  			break;

  		case 'v':
  			/* View Current pin settings */

  			amp->gpio_dump(amp, m);

  			break;
  		case '
  ':
  			/* end of settings string, do nothing */
  			break;
  		default:

  			dev_err(dev, "io%2d bad setting: chr<0x%2x>
  ",
  				m, (int)c);

  			err++;
  		}
  	}
  	if (err)
  		return -EINVAL;	/* full string handled, report error */
  
  	return len;
  }
  
  ssize_t nsc_gpio_read(struct file *file, char __user * buf,
  		      size_t len, loff_t * ppos)
  {

  	unsigned m = iminor(file->f_path.dentry->d_inode);

  	int value;
  	struct nsc_gpio_ops *amp = file->private_data;
  
  	value = amp->gpio_get(m);
  	if (put_user(value ? '1' : '0', buf))
  		return -EFAULT;
  
  	return 1;
  }

  /* common file-ops routines for both scx200_gpio and pc87360_gpio */

  EXPORT_SYMBOL(nsc_gpio_write);
  EXPORT_SYMBOL(nsc_gpio_read);

  EXPORT_SYMBOL(nsc_gpio_dump);

  
  static int __init nsc_gpio_init(void)
  {
  	printk(KERN_DEBUG NAME " initializing
  ");
  	return 0;
  }
  
  static void __exit nsc_gpio_cleanup(void)
  {
  	printk(KERN_DEBUG NAME " cleanup
  ");
  }

  module_init(nsc_gpio_init);
  module_exit(nsc_gpio_cleanup);

  
  MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
  MODULE_DESCRIPTION("NatSemi GPIO Common Methods");
  MODULE_LICENSE("GPL");