drivers/char/tb0219.c

   1 /*
   2  *  Driver for TANBAC TB0219 base board.
   3  *
   4  *  Copyright (C) 2005  Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <linux/device.h>
  21 #include <linux/fs.h>
  22 #include <linux/init.h>
  23 #include <linux/module.h>
  24
  25 #include <asm/io.h>
  26 #include <asm/reboot.h>
  27
  28 MODULE_AUTHOR("Yoichi Yuasa <yuasa@hh.iij4u.or.jp>");
  29 MODULE_DESCRIPTION("TANBAC TB0219 base board driver");
  30 MODULE_LICENSE("GPL");
  31
  32 static int major;       /* default is dynamic major device number */
  33 module_param(major, int, 0);
  34 MODULE_PARM_DESC(major, "Major device number");
  35
  36 static void (*old_machine_restart)(char *command);
  37 static void __iomem *tb0219_base;
  38 static spinlock_t tb0219_lock;
  39
  40 #define tb0219_read(offset)             readw(tb0219_base + (offset))
  41 #define tb0219_write(offset, value)     writew((value), tb0219_base + (offset))
  42
  43 #define TB0219_START    0x0a000000UL
  44 #define TB0219_SIZE     0x20UL
  45
  46 #define TB0219_LED                      0x00
  47 #define TB0219_GPIO_INPUT               0x02
  48 #define TB0219_GPIO_OUTPUT              0x04
  49 #define TB0219_DIP_SWITCH               0x06
  50 #define TB0219_MISC                     0x08
  51 #define TB0219_RESET                    0x0e
  52 #define TB0219_PCI_SLOT1_IRQ_STATUS     0x10
  53 #define TB0219_PCI_SLOT2_IRQ_STATUS     0x12
  54 #define TB0219_PCI_SLOT3_IRQ_STATUS     0x14
  55
  56 typedef enum {
  57         TYPE_LED,
  58         TYPE_GPIO_OUTPUT,
  59 } tb0219_type_t;
  60
  61 /*
  62  * Minor device number
  63  *       0 = 7 segment LED
  64  *
  65  *      16 = GPIO IN 0
  66  *      17 = GPIO IN 1
  67  *      18 = GPIO IN 2
  68  *      19 = GPIO IN 3
  69  *      20 = GPIO IN 4
  70  *      21 = GPIO IN 5
  71  *      22 = GPIO IN 6
  72  *      23 = GPIO IN 7
  73  *
  74  *      32 = GPIO OUT 0
  75  *      33 = GPIO OUT 1
  76  *      34 = GPIO OUT 2
  77  *      35 = GPIO OUT 3
  78  *      36 = GPIO OUT 4
  79  *      37 = GPIO OUT 5
  80  *      38 = GPIO OUT 6
  81  *      39 = GPIO OUT 7
  82  *
  83  *      48 = DIP switch 1
  84  *      49 = DIP switch 2
  85  *      50 = DIP switch 3
  86  *      51 = DIP switch 4
  87  *      52 = DIP switch 5
  88  *      53 = DIP switch 6
  89  *      54 = DIP switch 7
  90  *      55 = DIP switch 8
  91  */
  92
  93 static inline char get_led(void)
  94 {
  95         return (char)tb0219_read(TB0219_LED);
  96 }
  97
  98 static inline char get_gpio_input_pin(unsigned int pin)
  99 {
 100         uint16_t values;
 101
 102         values = tb0219_read(TB0219_GPIO_INPUT);
 103         if (values & (1 << pin))
 104                 return '1';
 105
 106         return '0';
 107 }
 108
 109 static inline char get_gpio_output_pin(unsigned int pin)
 110 {
 111         uint16_t values;
 112
 113         values = tb0219_read(TB0219_GPIO_OUTPUT);
 114         if (values & (1 << pin))
 115                 return '1';
 116
 117         return '0';
 118 }
 119
 120 static inline char get_dip_switch(unsigned int pin)
 121 {
 122         uint16_t values;
 123
 124         values = tb0219_read(TB0219_DIP_SWITCH);
 125         if (values & (1 << pin))
 126                 return '1';
 127
 128         return '0';
 129 }
 130
 131 static inline int set_led(char command)
 132 {
 133         tb0219_write(TB0219_LED, command);
 134
 135         return 0;
 136 }
 137
 138 static inline int set_gpio_output_pin(unsigned int pin, char command)
 139 {
 140         unsigned long flags;
 141         uint16_t value;
 142
 143         if (command != '0' && command != '1')
 144                 return -EINVAL;
 145
 146         spin_lock_irqsave(&tb0219_lock, flags);
 147         value = tb0219_read(TB0219_GPIO_OUTPUT);
 148         if (command == '0')
 149                 value &= ~(1 << pin);
 150         else
 151                 value |= 1 << pin;
 152         tb0219_write(TB0219_GPIO_OUTPUT, value);
 153         spin_unlock_irqrestore(&tb0219_lock, flags);
 154
 155         return 0;
 156
 157 }
 158
 159 static ssize_t tanbac_tb0219_read(struct file *file, char __user *buf, size_t len,
 160                                   loff_t *ppos)
 161 {
 162         unsigned int minor;
 163         char value;
 164
 165         minor = iminor(file->f_dentry->d_inode);
 166         switch (minor) {
 167         case 0:
 168                 value = get_led();
 169                 break;
 170         case 16 ... 23:
 171                 value = get_gpio_input_pin(minor - 16);
 172                 break;
 173         case 32 ... 39:
 174                 value = get_gpio_output_pin(minor - 32);
 175                 break;
 176         case 48 ... 55:
 177                 value = get_dip_switch(minor - 48);
 178                 break;
 179         default:
 180                 return -EBADF;
 181         }
 182
 183         if (len <= 0)
 184                 return -EFAULT;
 185
 186         if (put_user(value, buf))
 187                 return -EFAULT;
 188
 189         return 1;
 190 }
 191
 192 static ssize_t tanbac_tb0219_write(struct file *file, const char __user *data,
 193                                    size_t len, loff_t *ppos)
 194 {
 195         unsigned int minor;
 196         tb0219_type_t type;
 197         size_t i;
 198         int retval = 0;
 199         char c;
 200
 201         minor = iminor(file->f_dentry->d_inode);
 202         switch (minor) {
 203         case 0:
 204                 type = TYPE_LED;
 205                 break;
 206         case 32 ... 39:
 207                 type = TYPE_GPIO_OUTPUT;
 208                 break;
 209         default:
 210                 return -EBADF;
 211         }
 212
 213         for (i = 0; i < len; i++) {
 214                 if (get_user(c, data + i))
 215                         return -EFAULT;
 216
 217                 switch (type) {
 218                 case TYPE_LED:
 219                         retval = set_led(c);
 220                         break;
 221                 case TYPE_GPIO_OUTPUT:
 222                         retval = set_gpio_output_pin(minor - 32, c);
 223                         break;
 224                 }
 225
 226                 if (retval < 0)
 227                         break;
 228         }
 229
 230         return i;
 231 }
 232
 233 static int tanbac_tb0219_open(struct inode *inode, struct file *file)
 234 {
 235         unsigned int minor;
 236
 237         minor = iminor(inode);
 238         switch (minor) {
 239         case 0:
 240         case 16 ... 23:
 241         case 32 ... 39:
 242         case 48 ... 55:
 243                 return nonseekable_open(inode, file);
 244         default:
 245                 break;
 246         }
 247
 248         return -EBADF;
 249 }
 250
 251 static int tanbac_tb0219_release(struct inode *inode, struct file *file)
 252 {
 253         return 0;
 254 }
 255
 256 static struct file_operations tb0219_fops = {
 257         .owner          = THIS_MODULE,
 258         .read           = tanbac_tb0219_read,
 259         .write          = tanbac_tb0219_write,
 260         .open           = tanbac_tb0219_open,
 261         .release        = tanbac_tb0219_release,
 262 };
 263
 264 static void tb0219_restart(char *command)
 265 {
 266         tb0219_write(TB0219_RESET, 0);
 267 }
 268
 269 static int tb0219_probe(struct device *dev)
 270 {
 271         int retval;
 272
 273         if (request_mem_region(TB0219_START, TB0219_SIZE, "TB0219") == NULL)
 274                 return -EBUSY;
 275
 276         tb0219_base = ioremap(TB0219_START, TB0219_SIZE);
 277         if (tb0219_base == NULL) {
 278                 release_mem_region(TB0219_START, TB0219_SIZE);
 279                 return -ENOMEM;
 280         }
 281
 282         retval = register_chrdev(major, "TB0219", &tb0219_fops);
 283         if (retval < 0) {
 284                 iounmap(tb0219_base);
 285                 tb0219_base = NULL;
 286                 release_mem_region(TB0219_START, TB0219_SIZE);
 287                 return retval;
 288         }
 289
 290         spin_lock_init(&tb0219_lock);
 291
 292         old_machine_restart = _machine_restart;
 293         _machine_restart = tb0219_restart;
 294
 295         if (major == 0) {
 296                 major = retval;
 297                 printk(KERN_INFO "TB0219: major number %d\n", major);
 298         }
 299
 300         return 0;
 301 }
 302
 303 static int tb0219_remove(struct device *dev)
 304 {
 305         _machine_restart = old_machine_restart;
 306
 307         iounmap(tb0219_base);
 308         tb0219_base = NULL;
 309
 310         release_mem_region(TB0219_START, TB0219_SIZE);
 311
 312         return 0;
 313 }
 314
 315 static struct platform_device *tb0219_platform_device;
 316
 317 static struct device_driver tb0219_device_driver = {
 318         .name           = "TB0219",
 319         .bus            = &platform_bus_type,
 320         .probe          = tb0219_probe,
 321         .remove         = tb0219_remove,
 322 };
 323
 324 static int __devinit tanbac_tb0219_init(void)
 325 {
 326         int retval;
 327
 328         tb0219_platform_device = platform_device_register_simple("TB0219", -1, NULL, 0);
 329         if (IS_ERR(tb0219_platform_device))
 330                 return PTR_ERR(tb0219_platform_device);
 331
 332         retval = driver_register(&tb0219_device_driver);
 333         if (retval < 0)
 334                 platform_device_unregister(tb0219_platform_device);
 335
 336         return retval;
 337 }
 338
 339 static void __devexit tanbac_tb0219_exit(void)
 340 {
 341         driver_unregister(&tb0219_device_driver);
 342
 343         platform_device_unregister(tb0219_platform_device);
 344 }
 345
 346 module_init(tanbac_tb0219_init);
 347 module_exit(tanbac_tb0219_exit);