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/* 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\n",

                 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\n", m);

                        amp->gpio_config(m, ~1, 1);

                        break;

                case 'o':

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

                        amp->gpio_config(m, ~1, 0);

                        break;

                case 'T':

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

                        amp->gpio_config(m, ~2, 2);

                        break;

                case 't':

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

                        amp->gpio_config(m, ~2, 0);

                        break;

                case 'P':

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

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

                        break;

                case 'p':

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

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

                        break;

                case 'v':

                        /* View Current pin settings */

                        amp->gpio_dump(amp, m);

                        break;

                case '\n':

                        /* end of settings string, do nothing */

                        break;

                default:

                        dev_err(dev, "io%2d bad setting: chr<0x%2x>\n",

                                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\n");

        return 0;

}

static void __exit nsc_gpio_cleanup(void)

{

        printk(KERN_DEBUG NAME " cleanup\n");

}

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");