1/* linux/drivers/char/scx200_gpio.c 2 3 National Semiconductor SCx200 GPIO driver. Allows a user space 4 process to play with the GPIO pins. 5 6 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */ 7 8#include <linux/device.h> 9#include <linux/fs.h> 10#include <linux/module.h> 11#include <linux/errno.h> 12#include <linux/kernel.h> 13#include <linux/init.h> 14#include <linux/platform_device.h> 15#include <asm/uaccess.h> 16#include <asm/io.h> 17 18#include <linux/types.h> 19#include <linux/cdev.h> 20 21#include <linux/scx200_gpio.h> 22#include <linux/nsc_gpio.h> 23 24#define DRVNAME "scx200_gpio" 25 26static struct platform_device *pdev; 27 28MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); 29MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver"); 30MODULE_LICENSE("GPL"); 31 32static int major = 0; /* default to dynamic major */ 33module_param(major, int, 0); 34MODULE_PARM_DESC(major, "Major device number"); 35 36#define MAX_PINS 32 /* 64 later, when known ok */ 37 38struct nsc_gpio_ops scx200_gpio_ops = { 39 .owner = THIS_MODULE, 40 .gpio_config = scx200_gpio_configure, 41 .gpio_dump = nsc_gpio_dump, 42 .gpio_get = scx200_gpio_get, 43 .gpio_set = scx200_gpio_set, 44 .gpio_change = scx200_gpio_change, 45 .gpio_current = scx200_gpio_current 46}; 47EXPORT_SYMBOL_GPL(scx200_gpio_ops); 48 49static int scx200_gpio_open(struct inode *inode, struct file *file) 50{ 51 unsigned m = iminor(inode); 52 file->private_data = &scx200_gpio_ops; 53 54 if (m >= MAX_PINS) 55 return -EINVAL; 56 return nonseekable_open(inode, file); 57} 58 59static int scx200_gpio_release(struct inode *inode, struct file *file) 60{ 61 return 0; 62} 63 64static const struct file_operations scx200_gpio_fileops = { 65 .owner = THIS_MODULE, 66 .write = nsc_gpio_write, 67 .read = nsc_gpio_read, 68 .open = scx200_gpio_open, 69 .release = scx200_gpio_release, 70}; 71 72static struct cdev scx200_gpio_cdev; /* use 1 cdev for all pins */ 73 74static int __init scx200_gpio_init(void) 75{ 76 int rc; 77 dev_t devid; 78 79 if (!scx200_gpio_present()) { 80 printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n"); 81 return -ENODEV; 82 } 83 84 /* support dev_dbg() with pdev->dev */ 85 pdev = platform_device_alloc(DRVNAME, 0); 86 if (!pdev) 87 return -ENOMEM; 88 89 rc = platform_device_add(pdev); 90 if (rc) 91 goto undo_malloc; 92 93 /* nsc_gpio uses dev_dbg(), so needs this */ 94 scx200_gpio_ops.dev = &pdev->dev; 95 96 if (major) { 97 devid = MKDEV(major, 0); 98 rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio"); 99 } else { 100 rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio"); 101 major = MAJOR(devid); 102 } 103 if (rc < 0) { 104 dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc); 105 goto undo_platform_device_add; 106 } 107 108 cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops); 109 cdev_add(&scx200_gpio_cdev, devid, MAX_PINS); 110 111 return 0; /* succeed */ 112 113undo_platform_device_add: 114 platform_device_del(pdev); 115undo_malloc: 116 platform_device_put(pdev); 117 118 return rc; 119} 120 121static void __exit scx200_gpio_cleanup(void) 122{ 123 cdev_del(&scx200_gpio_cdev); 124 /* cdev_put(&scx200_gpio_cdev); */ 125 126 unregister_chrdev_region(MKDEV(major, 0), MAX_PINS); 127 platform_device_unregister(pdev); 128} 129 130module_init(scx200_gpio_init); 131module_exit(scx200_gpio_cleanup); 132