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/config.h> 11 #include <linux/fs.h> 12 #include <linux/module.h> 13 #include <linux/errno.h> 14 #include <linux/kernel.h> 15 #include <linux/init.h> 16 #include <linux/nsc_gpio.h> 17 #include <linux/platform_device.h> 18 #include <asm/uaccess.h> 19 #include <asm/io.h> 20 21 #define NAME "nsc_gpio" 22 23 void nsc_gpio_dump(struct nsc_gpio_ops *amp, unsigned index) 24 { 25 /* retrieve current config w/o changing it */ 26 u32 config = amp->gpio_config(index, ~0, 0); 27 28 /* user requested via 'v' command, so its INFO */ 29 dev_info(amp->dev, "io%02u: 0x%04x %s %s %s %s %s %s %s\tio:%d/%d\n", 30 index, config, 31 (config & 1) ? "OE" : "TS", /* output-enabled/tristate */ 32 (config & 2) ? "PP" : "OD", /* push pull / open drain */ 33 (config & 4) ? "PUE" : "PUD", /* pull up enabled/disabled */ 34 (config & 8) ? "LOCKED" : "", /* locked / unlocked */ 35 (config & 16) ? "LEVEL" : "EDGE",/* level/edge input */ 36 (config & 32) ? "HI" : "LO", /* trigger on rise/fall edge */ 37 (config & 64) ? "DEBOUNCE" : "", /* debounce */ 38 39 amp->gpio_get(index), amp->gpio_current(index)); 40 } 41 42 ssize_t nsc_gpio_write(struct file *file, const char __user *data, 43 size_t len, loff_t *ppos) 44 { 45 unsigned m = iminor(file->f_dentry->d_inode); 46 struct nsc_gpio_ops *amp = file->private_data; 47 struct device *dev = amp->dev; 48 size_t i; 49 int err = 0; 50 51 for (i = 0; i < len; ++i) { 52 char c; 53 if (get_user(c, data + i)) 54 return -EFAULT; 55 switch (c) { 56 case '0': 57 amp->gpio_set(m, 0); 58 break; 59 case '1': 60 amp->gpio_set(m, 1); 61 break; 62 case 'O': 63 dev_dbg(dev, "GPIO%d output enabled\n", m); 64 amp->gpio_config(m, ~1, 1); 65 break; 66 case 'o': 67 dev_dbg(dev, "GPIO%d output disabled\n", m); 68 amp->gpio_config(m, ~1, 0); 69 break; 70 case 'T': 71 dev_dbg(dev, "GPIO%d output is push pull\n", 72 m); 73 amp->gpio_config(m, ~2, 2); 74 break; 75 case 't': 76 dev_dbg(dev, "GPIO%d output is open drain\n", 77 m); 78 amp->gpio_config(m, ~2, 0); 79 break; 80 case 'P': 81 dev_dbg(dev, "GPIO%d pull up enabled\n", m); 82 amp->gpio_config(m, ~4, 4); 83 break; 84 case 'p': 85 dev_dbg(dev, "GPIO%d pull up disabled\n", m); 86 amp->gpio_config(m, ~4, 0); 87 break; 88 case 'v': 89 /* View Current pin settings */ 90 amp->gpio_dump(amp, m); 91 break; 92 case '\n': 93 /* end of settings string, do nothing */ 94 break; 95 default: 96 dev_err(dev, "io%2d bad setting: chr<0x%2x>\n", 97 m, (int)c); 98 err++; 99 } 100 } 101 if (err) 102 return -EINVAL; /* full string handled, report error */ 103 104 return len; 105 } 106 107 ssize_t nsc_gpio_read(struct file *file, char __user * buf, 108 size_t len, loff_t * ppos) 109 { 110 unsigned m = iminor(file->f_dentry->d_inode); 111 int value; 112 struct nsc_gpio_ops *amp = file->private_data; 113 114 value = amp->gpio_get(m); 115 if (put_user(value ? '1' : '0', buf)) 116 return -EFAULT; 117 118 return 1; 119 } 120 121 /* common file-ops routines for both scx200_gpio and pc87360_gpio */ 122 EXPORT_SYMBOL(nsc_gpio_write); 123 EXPORT_SYMBOL(nsc_gpio_read); 124 EXPORT_SYMBOL(nsc_gpio_dump); 125 126 static int __init nsc_gpio_init(void) 127 { 128 printk(KERN_DEBUG NAME " initializing\n"); 129 return 0; 130 } 131 132 static void __exit nsc_gpio_cleanup(void) 133 { 134 printk(KERN_DEBUG NAME " cleanup\n"); 135 } 136 137 module_init(nsc_gpio_init); 138 module_exit(nsc_gpio_cleanup); 139 140 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>"); 141 MODULE_DESCRIPTION("NatSemi GPIO Common Methods"); 142 MODULE_LICENSE("GPL"); 143