/* linux/drivers/char/scx200_gpio.c National Semiconductor SCx200 GPIO driver. Allows a user space process to play with the GPIO pins. Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */ #include <linux/device.h> #include <linux/fs.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/platform_device.h> #include <linux/uaccess.h> #include <asm/io.h> #include <linux/types.h> #include <linux/cdev.h> #include <linux/scx200_gpio.h> #include <linux/nsc_gpio.h> #define DRVNAME "scx200_gpio" static struct platform_device *pdev; MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver"); MODULE_LICENSE("GPL"); static int major = 0; /* default to dynamic major */ module_param(major, int, 0); MODULE_PARM_DESC(major, "Major device number"); #define MAX_PINS 32 /* 64 later, when known ok */ struct nsc_gpio_ops scx200_gpio_ops = { .owner = THIS_MODULE, .gpio_config = scx200_gpio_configure, .gpio_dump = nsc_gpio_dump, .gpio_get = scx200_gpio_get, .gpio_set = scx200_gpio_set, .gpio_change = scx200_gpio_change, .gpio_current = scx200_gpio_current }; EXPORT_SYMBOL_GPL(scx200_gpio_ops); static int scx200_gpio_open(struct inode *inode, struct file *file) { unsigned m = iminor(inode); file->private_data = &scx200_gpio_ops; if (m >= MAX_PINS) return -EINVAL; return nonseekable_open(inode, file); } static int scx200_gpio_release(struct inode *inode, struct file *file) { return 0; } static const struct file_operations scx200_gpio_fileops = { .owner = THIS_MODULE, .write = nsc_gpio_write, .read = nsc_gpio_read, .open = scx200_gpio_open, .release = scx200_gpio_release, .llseek = no_llseek, }; static struct cdev scx200_gpio_cdev; /* use 1 cdev for all pins */ static int __init scx200_gpio_init(void) { int rc; dev_t devid; if (!scx200_gpio_present()) { printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n"); return -ENODEV; } /* support dev_dbg() with pdev->dev */ pdev = platform_device_alloc(DRVNAME, 0); if (!pdev) return -ENOMEM; rc = platform_device_add(pdev); if (rc) goto undo_malloc; /* nsc_gpio uses dev_dbg(), so needs this */ scx200_gpio_ops.dev = &pdev->dev; if (major) { devid = MKDEV(major, 0); rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio"); } else { rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio"); major = MAJOR(devid); } if (rc < 0) { dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc); goto undo_platform_device_add; } cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops); cdev_add(&scx200_gpio_cdev, devid, MAX_PINS); return 0; /* succeed */ undo_platform_device_add: platform_device_del(pdev); undo_malloc: platform_device_put(pdev); return rc; } static void __exit scx200_gpio_cleanup(void) { cdev_del(&scx200_gpio_cdev); /* cdev_put(&scx200_gpio_cdev); */ unregister_chrdev_region(MKDEV(major, 0), MAX_PINS); platform_device_unregister(pdev); } module_init(scx200_gpio_init); module_exit(scx200_gpio_cleanup);