linux-imx

/* 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 <linux/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_inode(file));

    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);