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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 | /* 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/config.h> #include <linux/fs.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/init.h> #include <asm/uaccess.h> #include <asm/io.h> #include <linux/scx200_gpio.h> #define NAME "scx200_gpio" MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); MODULE_DESCRIPTION("NatSemi 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"); static ssize_t scx200_gpio_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { unsigned m = iminor(file->f_dentry->d_inode); size_t i; for (i = 0; i < len; ++i) { char c; if (get_user(c, data+i)) return -EFAULT; switch (c) { case '0': scx200_gpio_set(m, 0); break; case '1': scx200_gpio_set(m, 1); break; case 'O': printk(KERN_INFO NAME ": GPIO%d output enabled\n", m); scx200_gpio_configure(m, ~1, 1); break; case 'o': printk(KERN_INFO NAME ": GPIO%d output disabled\n", m); scx200_gpio_configure(m, ~1, 0); break; case 'T': printk(KERN_INFO NAME ": GPIO%d output is push pull\n", m); scx200_gpio_configure(m, ~2, 2); break; case 't': printk(KERN_INFO NAME ": GPIO%d output is open drain\n", m); scx200_gpio_configure(m, ~2, 0); break; case 'P': printk(KERN_INFO NAME ": GPIO%d pull up enabled\n", m); scx200_gpio_configure(m, ~4, 4); break; case 'p': printk(KERN_INFO NAME ": GPIO%d pull up disabled\n", m); scx200_gpio_configure(m, ~4, 0); break; } } return len; } static ssize_t scx200_gpio_read(struct file *file, char __user *buf, size_t len, loff_t *ppos) { unsigned m = iminor(file->f_dentry->d_inode); int value; value = scx200_gpio_get(m); if (put_user(value ? '1' : '0', buf)) return -EFAULT; return 1; } static int scx200_gpio_open(struct inode *inode, struct file *file) { unsigned m = iminor(inode); if (m > 63) return -EINVAL; return nonseekable_open(inode, file); } static int scx200_gpio_release(struct inode *inode, struct file *file) { return 0; } static struct file_operations scx200_gpio_fops = { .owner = THIS_MODULE, .write = scx200_gpio_write, .read = scx200_gpio_read, .open = scx200_gpio_open, .release = scx200_gpio_release, }; static int __init scx200_gpio_init(void) { int r; printk(KERN_DEBUG NAME ": NatSemi SCx200 GPIO Driver\n"); if (!scx200_gpio_present()) { printk(KERN_ERR NAME ": no SCx200 gpio pins available\n"); return -ENODEV; } r = register_chrdev(major, NAME, &scx200_gpio_fops); if (r < 0) { printk(KERN_ERR NAME ": unable to register character device\n"); return r; } if (!major) { major = r; printk(KERN_DEBUG NAME ": got dynamic major %d\n", major); } return 0; } static void __exit scx200_gpio_cleanup(void) { unregister_chrdev(major, NAME); } module_init(scx200_gpio_init); module_exit(scx200_gpio_cleanup); /* Local variables: compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules" c-basic-offset: 8 End: */ |