1 /* linux/drivers/char/nsc_gpio.c 2 3 National Semiconductor common GPIO device-file/VFS methods. 4 Allows a user space process to control the GPIO pins. 5 6 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> 7 Copyright (c) 2005 Jim Cromie <jim.cromie@gmail.com> 8 */ 9 10 #include <linux/fs.h> 11 #include <linux/module.h> 12 #include <linux/errno.h> 13 #include <linux/kernel.h> 14 #include <linux/init.h> 15 #include <linux/nsc_gpio.h> 16 #include <linux/platform_device.h> 17 #include <linux/uaccess.h> 18 #include <asm/io.h> 19 20 #define NAME "nsc_gpio" 21 22 void nsc_gpio_dump(struct nsc_gpio_ops *amp, unsigned index) 23 { 24 /* retrieve current config w/o changing it */ 25 u32 config = amp->gpio_config(index, ~0, 0); 26 27 /* user requested via 'v' command, so its INFO */ 28 dev_info(amp->dev, "io%02u: 0x%04x %s %s %s %s %s %s %s\tio:%d/%d\n", 29 index, config, 30 (config & 1) ? "OE" : "TS", /* output-enabled/tristate */ 31 (config & 2) ? "PP" : "OD", /* push pull / open drain */ 32 (config & 4) ? "PUE" : "PUD", /* pull up enabled/disabled */ 33 (config & 8) ? "LOCKED" : "", /* locked / unlocked */ 34 (config & 16) ? "LEVEL" : "EDGE",/* level/edge input */ 35 (config & 32) ? "HI" : "LO", /* trigger on rise/fall edge */ 36 (config & 64) ? "DEBOUNCE" : "", /* debounce */ 37 38 amp->gpio_get(index), amp->gpio_current(index)); 39 } 40 41 ssize_t nsc_gpio_write(struct file *file, const char __user *data, 42 size_t len, loff_t *ppos) 43 { 44 unsigned m = iminor(file_inode(file)); 45 struct nsc_gpio_ops *amp = file->private_data; 46 struct device *dev = amp->dev; 47 size_t i; 48 int err = 0; 49 50 for (i = 0; i < len; ++i) { 51 char c; 52 if (get_user(c, data + i)) 53 return -EFAULT; 54 switch (c) { 55 case '0': 56 amp->gpio_set(m, 0); 57 break; 58 case '1': 59 amp->gpio_set(m, 1); 60 break; 61 case 'O': 62 dev_dbg(dev, "GPIO%d output enabled\n", m); 63 amp->gpio_config(m, ~1, 1); 64 break; 65 case 'o': 66 dev_dbg(dev, "GPIO%d output disabled\n", m); 67 amp->gpio_config(m, ~1, 0); 68 break; 69 case 'T': 70 dev_dbg(dev, "GPIO%d output is push pull\n", m); 71 amp->gpio_config(m, ~2, 2); 72 break; 73 case 't': 74 dev_dbg(dev, "GPIO%d output is open drain\n", m); 75 amp->gpio_config(m, ~2, 0); 76 break; 77 case 'P': 78 dev_dbg(dev, "GPIO%d pull up enabled\n", m); 79 amp->gpio_config(m, ~4, 4); 80 break; 81 case 'p': 82 dev_dbg(dev, "GPIO%d pull up disabled\n", m); 83 amp->gpio_config(m, ~4, 0); 84 break; 85 case 'v': 86 /* View Current pin settings */ 87 amp->gpio_dump(amp, m); 88 break; 89 case '\n': 90 /* end of settings string, do nothing */ 91 break; 92 default: 93 dev_err(dev, "io%2d bad setting: chr<0x%2x>\n", 94 m, (int)c); 95 err++; 96 } 97 } 98 if (err) 99 return -EINVAL; /* full string handled, report error */ 100 101 return len; 102 } 103 104 ssize_t nsc_gpio_read(struct file *file, char __user * buf, 105 size_t len, loff_t * ppos) 106 { 107 unsigned m = iminor(file_inode(file)); 108 int value; 109 struct nsc_gpio_ops *amp = file->private_data; 110 111 value = amp->gpio_get(m); 112 if (put_user(value ? '1' : '0', buf)) 113 return -EFAULT; 114 115 return 1; 116 } 117 118 /* common file-ops routines for both scx200_gpio and pc87360_gpio */ 119 EXPORT_SYMBOL(nsc_gpio_write); 120 EXPORT_SYMBOL(nsc_gpio_read); 121 EXPORT_SYMBOL(nsc_gpio_dump); 122 123 static int __init nsc_gpio_init(void) 124 { 125 printk(KERN_DEBUG NAME " initializing\n"); 126 return 0; 127 } 128 129 static void __exit nsc_gpio_cleanup(void) 130 { 131 printk(KERN_DEBUG NAME " cleanup\n"); 132 } 133 134 module_init(nsc_gpio_init); 135 module_exit(nsc_gpio_cleanup); 136 137 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>"); 138 MODULE_DESCRIPTION("NatSemi GPIO Common Methods"); 139 MODULE_LICENSE("GPL"); 140