1 /* 2 * Filename: cfag12864b.c 3 * Version: 0.1.0 4 * Description: cfag12864b LCD driver 5 * License: GPLv2 6 * Depends: ks0108 7 * 8 * Author: Copyright (C) Miguel Ojeda Sandonis <maxextreme@gmail.com> 9 * Date: 2006-10-31 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 23 * 24 */ 25 26 #include <linux/init.h> 27 #include <linux/module.h> 28 #include <linux/kernel.h> 29 #include <linux/fs.h> 30 #include <linux/cdev.h> 31 #include <linux/delay.h> 32 #include <linux/device.h> 33 #include <linux/jiffies.h> 34 #include <linux/mutex.h> 35 #include <linux/uaccess.h> 36 #include <linux/vmalloc.h> 37 #include <linux/workqueue.h> 38 #include <linux/ks0108.h> 39 #include <linux/cfag12864b.h> 40 41 42 #define CFAG12864B_NAME "cfag12864b" 43 44 /* 45 * Module Parameters 46 */ 47 48 static unsigned int cfag12864b_rate = CONFIG_CFAG12864B_RATE; 49 module_param(cfag12864b_rate, uint, S_IRUGO); 50 MODULE_PARM_DESC(cfag12864b_rate, 51 "Refresh rate (hertzs)"); 52 53 unsigned int cfag12864b_getrate(void) 54 { 55 return cfag12864b_rate; 56 } 57 58 /* 59 * cfag12864b Commands 60 * 61 * E = Enable signal 62 * Everytime E switch from low to high, 63 * cfag12864b/ks0108 reads the command/data. 64 * 65 * CS1 = First ks0108controller. 66 * If high, the first ks0108 controller receives commands/data. 67 * 68 * CS2 = Second ks0108 controller 69 * If high, the second ks0108 controller receives commands/data. 70 * 71 * DI = Data/Instruction 72 * If low, cfag12864b will expect commands. 73 * If high, cfag12864b will expect data. 74 * 75 */ 76 77 #define bit(n) (((unsigned char)1)<<(n)) 78 79 #define CFAG12864B_BIT_E (0) 80 #define CFAG12864B_BIT_CS1 (2) 81 #define CFAG12864B_BIT_CS2 (1) 82 #define CFAG12864B_BIT_DI (3) 83 84 static unsigned char cfag12864b_state; 85 86 static void cfag12864b_set(void) 87 { 88 ks0108_writecontrol(cfag12864b_state); 89 } 90 91 static void cfag12864b_setbit(unsigned char state, unsigned char n) 92 { 93 if (state) 94 cfag12864b_state |= bit(n); 95 else 96 cfag12864b_state &= ~bit(n); 97 } 98 99 static void cfag12864b_e(unsigned char state) 100 { 101 cfag12864b_setbit(state, CFAG12864B_BIT_E); 102 cfag12864b_set(); 103 } 104 105 static void cfag12864b_cs1(unsigned char state) 106 { 107 cfag12864b_setbit(state, CFAG12864B_BIT_CS1); 108 } 109 110 static void cfag12864b_cs2(unsigned char state) 111 { 112 cfag12864b_setbit(state, CFAG12864B_BIT_CS2); 113 } 114 115 static void cfag12864b_di(unsigned char state) 116 { 117 cfag12864b_setbit(state, CFAG12864B_BIT_DI); 118 } 119 120 static void cfag12864b_setcontrollers(unsigned char first, 121 unsigned char second) 122 { 123 if (first) 124 cfag12864b_cs1(0); 125 else 126 cfag12864b_cs1(1); 127 128 if (second) 129 cfag12864b_cs2(0); 130 else 131 cfag12864b_cs2(1); 132 } 133 134 static void cfag12864b_controller(unsigned char which) 135 { 136 if (which == 0) 137 cfag12864b_setcontrollers(1, 0); 138 else if (which == 1) 139 cfag12864b_setcontrollers(0, 1); 140 } 141 142 static void cfag12864b_displaystate(unsigned char state) 143 { 144 cfag12864b_di(0); 145 cfag12864b_e(1); 146 ks0108_displaystate(state); 147 cfag12864b_e(0); 148 } 149 150 static void cfag12864b_address(unsigned char address) 151 { 152 cfag12864b_di(0); 153 cfag12864b_e(1); 154 ks0108_address(address); 155 cfag12864b_e(0); 156 } 157 158 static void cfag12864b_page(unsigned char page) 159 { 160 cfag12864b_di(0); 161 cfag12864b_e(1); 162 ks0108_page(page); 163 cfag12864b_e(0); 164 } 165 166 static void cfag12864b_startline(unsigned char startline) 167 { 168 cfag12864b_di(0); 169 cfag12864b_e(1); 170 ks0108_startline(startline); 171 cfag12864b_e(0); 172 } 173 174 static void cfag12864b_writebyte(unsigned char byte) 175 { 176 cfag12864b_di(1); 177 cfag12864b_e(1); 178 ks0108_writedata(byte); 179 cfag12864b_e(0); 180 } 181 182 static void cfag12864b_nop(void) 183 { 184 cfag12864b_startline(0); 185 } 186 187 /* 188 * cfag12864b Internal Commands 189 */ 190 191 static void cfag12864b_on(void) 192 { 193 cfag12864b_setcontrollers(1, 1); 194 cfag12864b_displaystate(1); 195 } 196 197 static void cfag12864b_off(void) 198 { 199 cfag12864b_setcontrollers(1, 1); 200 cfag12864b_displaystate(0); 201 } 202 203 static void cfag12864b_clear(void) 204 { 205 unsigned char i, j; 206 207 cfag12864b_setcontrollers(1, 1); 208 for (i = 0; i < CFAG12864B_PAGES; i++) { 209 cfag12864b_page(i); 210 cfag12864b_address(0); 211 for (j = 0; j < CFAG12864B_ADDRESSES; j++) 212 cfag12864b_writebyte(0); 213 } 214 } 215 216 /* 217 * Update work 218 */ 219 220 unsigned char *cfag12864b_buffer; 221 static unsigned char *cfag12864b_cache; 222 static DEFINE_MUTEX(cfag12864b_mutex); 223 static unsigned char cfag12864b_updating; 224 static void cfag12864b_update(struct work_struct *delayed_work); 225 static struct workqueue_struct *cfag12864b_workqueue; 226 static DECLARE_DELAYED_WORK(cfag12864b_work, cfag12864b_update); 227 228 static void cfag12864b_queue(void) 229 { 230 queue_delayed_work(cfag12864b_workqueue, &cfag12864b_work, 231 HZ / cfag12864b_rate); 232 } 233 234 unsigned char cfag12864b_enable(void) 235 { 236 unsigned char ret; 237 238 mutex_lock(&cfag12864b_mutex); 239 240 if (!cfag12864b_updating) { 241 cfag12864b_updating = 1; 242 cfag12864b_queue(); 243 ret = 0; 244 } else 245 ret = 1; 246 247 mutex_unlock(&cfag12864b_mutex); 248 249 return ret; 250 } 251 252 void cfag12864b_disable(void) 253 { 254 mutex_lock(&cfag12864b_mutex); 255 256 if (cfag12864b_updating) { 257 cfag12864b_updating = 0; 258 cancel_delayed_work(&cfag12864b_work); 259 flush_workqueue(cfag12864b_workqueue); 260 } 261 262 mutex_unlock(&cfag12864b_mutex); 263 } 264 265 unsigned char cfag12864b_isenabled(void) 266 { 267 return cfag12864b_updating; 268 } 269 270 static void cfag12864b_update(struct work_struct *work) 271 { 272 unsigned char c; 273 unsigned short i, j, k, b; 274 275 if (memcmp(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE)) { 276 for (i = 0; i < CFAG12864B_CONTROLLERS; i++) { 277 cfag12864b_controller(i); 278 cfag12864b_nop(); 279 for (j = 0; j < CFAG12864B_PAGES; j++) { 280 cfag12864b_page(j); 281 cfag12864b_nop(); 282 cfag12864b_address(0); 283 cfag12864b_nop(); 284 for (k = 0; k < CFAG12864B_ADDRESSES; k++) { 285 for (c = 0, b = 0; b < 8; b++) 286 if (cfag12864b_buffer 287 [i * CFAG12864B_ADDRESSES / 8 288 + k / 8 + (j * 8 + b) * 289 CFAG12864B_WIDTH / 8] 290 & bit(k % 8)) 291 c |= bit(b); 292 cfag12864b_writebyte(c); 293 } 294 } 295 } 296 297 memcpy(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE); 298 } 299 300 if (cfag12864b_updating) 301 cfag12864b_queue(); 302 } 303 304 /* 305 * cfag12864b Exported Symbols 306 */ 307 308 EXPORT_SYMBOL_GPL(cfag12864b_buffer); 309 EXPORT_SYMBOL_GPL(cfag12864b_getrate); 310 EXPORT_SYMBOL_GPL(cfag12864b_enable); 311 EXPORT_SYMBOL_GPL(cfag12864b_disable); 312 EXPORT_SYMBOL_GPL(cfag12864b_isenabled); 313 314 /* 315 * Is the module inited? 316 */ 317 318 static unsigned char cfag12864b_inited; 319 unsigned char cfag12864b_isinited(void) 320 { 321 return cfag12864b_inited; 322 } 323 EXPORT_SYMBOL_GPL(cfag12864b_isinited); 324 325 /* 326 * Module Init & Exit 327 */ 328 329 static int __init cfag12864b_init(void) 330 { 331 int ret = -EINVAL; 332 333 /* ks0108_init() must be called first */ 334 if (!ks0108_isinited()) { 335 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 336 "ks0108 is not initialized\n"); 337 goto none; 338 } 339 340 if (PAGE_SIZE < CFAG12864B_SIZE) { 341 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 342 "page size (%i) < cfag12864b size (%i)\n", 343 (unsigned int)PAGE_SIZE, CFAG12864B_SIZE); 344 ret = -ENOMEM; 345 goto none; 346 } 347 348 cfag12864b_buffer = (unsigned char *) __get_free_page(GFP_KERNEL); 349 if (cfag12864b_buffer == NULL) { 350 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 351 "can't get a free page\n"); 352 ret = -ENOMEM; 353 goto none; 354 } 355 356 cfag12864b_cache = kmalloc(sizeof(unsigned char) * 357 CFAG12864B_SIZE, GFP_KERNEL); 358 if (cfag12864b_buffer == NULL) { 359 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 360 "can't alloc cache buffer (%i bytes)\n", 361 CFAG12864B_SIZE); 362 ret = -ENOMEM; 363 goto bufferalloced; 364 } 365 366 cfag12864b_workqueue = create_singlethread_workqueue(CFAG12864B_NAME); 367 if (cfag12864b_workqueue == NULL) 368 goto cachealloced; 369 370 memset(cfag12864b_buffer, 0, CFAG12864B_SIZE); 371 372 cfag12864b_clear(); 373 cfag12864b_on(); 374 375 cfag12864b_inited = 1; 376 return 0; 377 378 cachealloced: 379 kfree(cfag12864b_cache); 380 381 bufferalloced: 382 free_page((unsigned long) cfag12864b_buffer); 383 384 none: 385 return ret; 386 } 387 388 static void __exit cfag12864b_exit(void) 389 { 390 cfag12864b_disable(); 391 cfag12864b_off(); 392 destroy_workqueue(cfag12864b_workqueue); 393 kfree(cfag12864b_cache); 394 free_page((unsigned long) cfag12864b_buffer); 395 } 396 397 module_init(cfag12864b_init); 398 module_exit(cfag12864b_exit); 399 400 MODULE_LICENSE("GPL v2"); 401 MODULE_AUTHOR("Miguel Ojeda Sandonis <maxextreme@gmail.com>"); 402 MODULE_DESCRIPTION("cfag12864b LCD driver"); 403