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 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/slab.h> 31#include <linux/cdev.h> 32#include <linux/delay.h> 33#include <linux/device.h> 34#include <linux/jiffies.h> 35#include <linux/mutex.h> 36#include <linux/uaccess.h> 37#include <linux/vmalloc.h> 38#include <linux/workqueue.h> 39#include <linux/ks0108.h> 40#include <linux/cfag12864b.h> 41 42 43#define CFAG12864B_NAME "cfag12864b" 44 45/* 46 * Module Parameters 47 */ 48 49static unsigned int cfag12864b_rate = CONFIG_CFAG12864B_RATE; 50module_param(cfag12864b_rate, uint, S_IRUGO); 51MODULE_PARM_DESC(cfag12864b_rate, 52 "Refresh rate (hertzs)"); 53 54unsigned int cfag12864b_getrate(void) 55{ 56 return cfag12864b_rate; 57} 58 59/* 60 * cfag12864b Commands 61 * 62 * E = Enable signal 63 * Everytime E switch from low to high, 64 * cfag12864b/ks0108 reads the command/data. 65 * 66 * CS1 = First ks0108controller. 67 * If high, the first ks0108 controller receives commands/data. 68 * 69 * CS2 = Second ks0108 controller 70 * If high, the second ks0108 controller receives commands/data. 71 * 72 * DI = Data/Instruction 73 * If low, cfag12864b will expect commands. 74 * If high, cfag12864b will expect data. 75 * 76 */ 77 78#define bit(n) (((unsigned char)1)<<(n)) 79 80#define CFAG12864B_BIT_E (0) 81#define CFAG12864B_BIT_CS1 (2) 82#define CFAG12864B_BIT_CS2 (1) 83#define CFAG12864B_BIT_DI (3) 84 85static unsigned char cfag12864b_state; 86 87static void cfag12864b_set(void) 88{ 89 ks0108_writecontrol(cfag12864b_state); 90} 91 92static void cfag12864b_setbit(unsigned char state, unsigned char n) 93{ 94 if (state) 95 cfag12864b_state |= bit(n); 96 else 97 cfag12864b_state &= ~bit(n); 98} 99 100static void cfag12864b_e(unsigned char state) 101{ 102 cfag12864b_setbit(state, CFAG12864B_BIT_E); 103 cfag12864b_set(); 104} 105 106static void cfag12864b_cs1(unsigned char state) 107{ 108 cfag12864b_setbit(state, CFAG12864B_BIT_CS1); 109} 110 111static void cfag12864b_cs2(unsigned char state) 112{ 113 cfag12864b_setbit(state, CFAG12864B_BIT_CS2); 114} 115 116static void cfag12864b_di(unsigned char state) 117{ 118 cfag12864b_setbit(state, CFAG12864B_BIT_DI); 119} 120 121static void cfag12864b_setcontrollers(unsigned char first, 122 unsigned char second) 123{ 124 if (first) 125 cfag12864b_cs1(0); 126 else 127 cfag12864b_cs1(1); 128 129 if (second) 130 cfag12864b_cs2(0); 131 else 132 cfag12864b_cs2(1); 133} 134 135static void cfag12864b_controller(unsigned char which) 136{ 137 if (which == 0) 138 cfag12864b_setcontrollers(1, 0); 139 else if (which == 1) 140 cfag12864b_setcontrollers(0, 1); 141} 142 143static void cfag12864b_displaystate(unsigned char state) 144{ 145 cfag12864b_di(0); 146 cfag12864b_e(1); 147 ks0108_displaystate(state); 148 cfag12864b_e(0); 149} 150 151static void cfag12864b_address(unsigned char address) 152{ 153 cfag12864b_di(0); 154 cfag12864b_e(1); 155 ks0108_address(address); 156 cfag12864b_e(0); 157} 158 159static void cfag12864b_page(unsigned char page) 160{ 161 cfag12864b_di(0); 162 cfag12864b_e(1); 163 ks0108_page(page); 164 cfag12864b_e(0); 165} 166 167static void cfag12864b_startline(unsigned char startline) 168{ 169 cfag12864b_di(0); 170 cfag12864b_e(1); 171 ks0108_startline(startline); 172 cfag12864b_e(0); 173} 174 175static void cfag12864b_writebyte(unsigned char byte) 176{ 177 cfag12864b_di(1); 178 cfag12864b_e(1); 179 ks0108_writedata(byte); 180 cfag12864b_e(0); 181} 182 183static void cfag12864b_nop(void) 184{ 185 cfag12864b_startline(0); 186} 187 188/* 189 * cfag12864b Internal Commands 190 */ 191 192static void cfag12864b_on(void) 193{ 194 cfag12864b_setcontrollers(1, 1); 195 cfag12864b_displaystate(1); 196} 197 198static void cfag12864b_off(void) 199{ 200 cfag12864b_setcontrollers(1, 1); 201 cfag12864b_displaystate(0); 202} 203 204static void cfag12864b_clear(void) 205{ 206 unsigned char i, j; 207 208 cfag12864b_setcontrollers(1, 1); 209 for (i = 0; i < CFAG12864B_PAGES; i++) { 210 cfag12864b_page(i); 211 cfag12864b_address(0); 212 for (j = 0; j < CFAG12864B_ADDRESSES; j++) 213 cfag12864b_writebyte(0); 214 } 215} 216 217/* 218 * Update work 219 */ 220 221unsigned char *cfag12864b_buffer; 222static unsigned char *cfag12864b_cache; 223static DEFINE_MUTEX(cfag12864b_mutex); 224static unsigned char cfag12864b_updating; 225static void cfag12864b_update(struct work_struct *delayed_work); 226static struct workqueue_struct *cfag12864b_workqueue; 227static DECLARE_DELAYED_WORK(cfag12864b_work, cfag12864b_update); 228 229static void cfag12864b_queue(void) 230{ 231 queue_delayed_work(cfag12864b_workqueue, &cfag12864b_work, 232 HZ / cfag12864b_rate); 233} 234 235unsigned char cfag12864b_enable(void) 236{ 237 unsigned char ret; 238 239 mutex_lock(&cfag12864b_mutex); 240 241 if (!cfag12864b_updating) { 242 cfag12864b_updating = 1; 243 cfag12864b_queue(); 244 ret = 0; 245 } else 246 ret = 1; 247 248 mutex_unlock(&cfag12864b_mutex); 249 250 return ret; 251} 252 253void cfag12864b_disable(void) 254{ 255 mutex_lock(&cfag12864b_mutex); 256 257 if (cfag12864b_updating) { 258 cfag12864b_updating = 0; 259 cancel_delayed_work(&cfag12864b_work); 260 flush_workqueue(cfag12864b_workqueue); 261 } 262 263 mutex_unlock(&cfag12864b_mutex); 264} 265 266unsigned char cfag12864b_isenabled(void) 267{ 268 return cfag12864b_updating; 269} 270 271static void cfag12864b_update(struct work_struct *work) 272{ 273 unsigned char c; 274 unsigned short i, j, k, b; 275 276 if (memcmp(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE)) { 277 for (i = 0; i < CFAG12864B_CONTROLLERS; i++) { 278 cfag12864b_controller(i); 279 cfag12864b_nop(); 280 for (j = 0; j < CFAG12864B_PAGES; j++) { 281 cfag12864b_page(j); 282 cfag12864b_nop(); 283 cfag12864b_address(0); 284 cfag12864b_nop(); 285 for (k = 0; k < CFAG12864B_ADDRESSES; k++) { 286 for (c = 0, b = 0; b < 8; b++) 287 if (cfag12864b_buffer 288 [i * CFAG12864B_ADDRESSES / 8 289 + k / 8 + (j * 8 + b) * 290 CFAG12864B_WIDTH / 8] 291 & bit(k % 8)) 292 c |= bit(b); 293 cfag12864b_writebyte(c); 294 } 295 } 296 } 297 298 memcpy(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE); 299 } 300 301 if (cfag12864b_updating) 302 cfag12864b_queue(); 303} 304 305/* 306 * cfag12864b Exported Symbols 307 */ 308 309EXPORT_SYMBOL_GPL(cfag12864b_buffer); 310EXPORT_SYMBOL_GPL(cfag12864b_getrate); 311EXPORT_SYMBOL_GPL(cfag12864b_enable); 312EXPORT_SYMBOL_GPL(cfag12864b_disable); 313EXPORT_SYMBOL_GPL(cfag12864b_isenabled); 314 315/* 316 * Is the module inited? 317 */ 318 319static unsigned char cfag12864b_inited; 320unsigned char cfag12864b_isinited(void) 321{ 322 return cfag12864b_inited; 323} 324EXPORT_SYMBOL_GPL(cfag12864b_isinited); 325 326/* 327 * Module Init & Exit 328 */ 329 330static int __init cfag12864b_init(void) 331{ 332 int ret = -EINVAL; 333 334 /* ks0108_init() must be called first */ 335 if (!ks0108_isinited()) { 336 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 337 "ks0108 is not initialized\n"); 338 goto none; 339 } 340 BUILD_BUG_ON(PAGE_SIZE < CFAG12864B_SIZE); 341 342 cfag12864b_buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL); 343 if (cfag12864b_buffer == NULL) { 344 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 345 "can't get a free page\n"); 346 ret = -ENOMEM; 347 goto none; 348 } 349 350 cfag12864b_cache = kmalloc(sizeof(unsigned char) * 351 CFAG12864B_SIZE, GFP_KERNEL); 352 if (cfag12864b_cache == NULL) { 353 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 354 "can't alloc cache buffer (%i bytes)\n", 355 CFAG12864B_SIZE); 356 ret = -ENOMEM; 357 goto bufferalloced; 358 } 359 360 cfag12864b_workqueue = create_singlethread_workqueue(CFAG12864B_NAME); 361 if (cfag12864b_workqueue == NULL) 362 goto cachealloced; 363 364 cfag12864b_clear(); 365 cfag12864b_on(); 366 367 cfag12864b_inited = 1; 368 return 0; 369 370cachealloced: 371 kfree(cfag12864b_cache); 372 373bufferalloced: 374 free_page((unsigned long) cfag12864b_buffer); 375 376none: 377 return ret; 378} 379 380static void __exit cfag12864b_exit(void) 381{ 382 cfag12864b_disable(); 383 cfag12864b_off(); 384 destroy_workqueue(cfag12864b_workqueue); 385 kfree(cfag12864b_cache); 386 free_page((unsigned long) cfag12864b_buffer); 387} 388 389module_init(cfag12864b_init); 390module_exit(cfag12864b_exit); 391 392MODULE_LICENSE("GPL v2"); 393MODULE_AUTHOR("Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>"); 394MODULE_DESCRIPTION("cfag12864b LCD driver"); 395