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 <linux/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 26 static struct platform_device *pdev; 27 28 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); 29 MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver"); 30 MODULE_LICENSE("GPL"); 31 32 static int major = 0; /* default to dynamic major */ 33 module_param(major, int, 0); 34 MODULE_PARM_DESC(major, "Major device number"); 35 36 #define MAX_PINS 32 /* 64 later, when known ok */ 37 38 struct 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 }; 47 EXPORT_SYMBOL_GPL(scx200_gpio_ops); 48 49 static 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 59 static int scx200_gpio_release(struct inode *inode, struct file *file) 60 { 61 return 0; 62 } 63 64 static 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 .llseek = no_llseek, 71 }; 72 73 static struct cdev scx200_gpio_cdev; /* use 1 cdev for all pins */ 74 75 static int __init scx200_gpio_init(void) 76 { 77 int rc; 78 dev_t devid; 79 80 if (!scx200_gpio_present()) { 81 printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n"); 82 return -ENODEV; 83 } 84 85 /* support dev_dbg() with pdev->dev */ 86 pdev = platform_device_alloc(DRVNAME, 0); 87 if (!pdev) 88 return -ENOMEM; 89 90 rc = platform_device_add(pdev); 91 if (rc) 92 goto undo_malloc; 93 94 /* nsc_gpio uses dev_dbg(), so needs this */ 95 scx200_gpio_ops.dev = &pdev->dev; 96 97 if (major) { 98 devid = MKDEV(major, 0); 99 rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio"); 100 } else { 101 rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio"); 102 major = MAJOR(devid); 103 } 104 if (rc < 0) { 105 dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc); 106 goto undo_platform_device_add; 107 } 108 109 cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops); 110 cdev_add(&scx200_gpio_cdev, devid, MAX_PINS); 111 112 return 0; /* succeed */ 113 114 undo_platform_device_add: 115 platform_device_del(pdev); 116 undo_malloc: 117 platform_device_put(pdev); 118 119 return rc; 120 } 121 122 static void __exit scx200_gpio_cleanup(void) 123 { 124 cdev_del(&scx200_gpio_cdev); 125 /* cdev_put(&scx200_gpio_cdev); */ 126 127 unregister_chrdev_region(MKDEV(major, 0), MAX_PINS); 128 platform_device_unregister(pdev); 129 } 130 131 module_init(scx200_gpio_init); 132 module_exit(scx200_gpio_cleanup); 133