/* 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); 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_inode(file)); 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");