1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Filename: cfag12864b.c 4 * Version: 0.1.0 5 * Description: cfag12864b LCD driver 6 * Depends: ks0108 7 * 8 * Author: Copyright (C) Miguel Ojeda <ojeda@kernel.org> 9 * Date: 2006-10-31 10 */ 11 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/kernel.h> 15 #include <linux/fs.h> 16 #include <linux/slab.h> 17 #include <linux/cdev.h> 18 #include <linux/delay.h> 19 #include <linux/device.h> 20 #include <linux/jiffies.h> 21 #include <linux/mutex.h> 22 #include <linux/uaccess.h> 23 #include <linux/vmalloc.h> 24 #include <linux/workqueue.h> 25 #include <linux/ks0108.h> 26 #include <linux/cfag12864b.h> 27 28 29 #define CFAG12864B_NAME "cfag12864b" 30 31 /* 32 * Module Parameters 33 */ 34 35 static unsigned int cfag12864b_rate = CONFIG_CFAG12864B_RATE; 36 module_param(cfag12864b_rate, uint, 0444); 37 MODULE_PARM_DESC(cfag12864b_rate, 38 "Refresh rate (hertz)"); 39 40 unsigned int cfag12864b_getrate(void) 41 { 42 return cfag12864b_rate; 43 } 44 45 /* 46 * cfag12864b Commands 47 * 48 * E = Enable signal 49 * Every time E switch from low to high, 50 * cfag12864b/ks0108 reads the command/data. 51 * 52 * CS1 = First ks0108controller. 53 * If high, the first ks0108 controller receives commands/data. 54 * 55 * CS2 = Second ks0108 controller 56 * If high, the second ks0108 controller receives commands/data. 57 * 58 * DI = Data/Instruction 59 * If low, cfag12864b will expect commands. 60 * If high, cfag12864b will expect data. 61 * 62 */ 63 64 #define bit(n) (((unsigned char)1)<<(n)) 65 66 #define CFAG12864B_BIT_E (0) 67 #define CFAG12864B_BIT_CS1 (2) 68 #define CFAG12864B_BIT_CS2 (1) 69 #define CFAG12864B_BIT_DI (3) 70 71 static unsigned char cfag12864b_state; 72 73 static void cfag12864b_set(void) 74 { 75 ks0108_writecontrol(cfag12864b_state); 76 } 77 78 static void cfag12864b_setbit(unsigned char state, unsigned char n) 79 { 80 if (state) 81 cfag12864b_state |= bit(n); 82 else 83 cfag12864b_state &= ~bit(n); 84 } 85 86 static void cfag12864b_e(unsigned char state) 87 { 88 cfag12864b_setbit(state, CFAG12864B_BIT_E); 89 cfag12864b_set(); 90 } 91 92 static void cfag12864b_cs1(unsigned char state) 93 { 94 cfag12864b_setbit(state, CFAG12864B_BIT_CS1); 95 } 96 97 static void cfag12864b_cs2(unsigned char state) 98 { 99 cfag12864b_setbit(state, CFAG12864B_BIT_CS2); 100 } 101 102 static void cfag12864b_di(unsigned char state) 103 { 104 cfag12864b_setbit(state, CFAG12864B_BIT_DI); 105 } 106 107 static void cfag12864b_setcontrollers(unsigned char first, 108 unsigned char second) 109 { 110 if (first) 111 cfag12864b_cs1(0); 112 else 113 cfag12864b_cs1(1); 114 115 if (second) 116 cfag12864b_cs2(0); 117 else 118 cfag12864b_cs2(1); 119 } 120 121 static void cfag12864b_controller(unsigned char which) 122 { 123 if (which == 0) 124 cfag12864b_setcontrollers(1, 0); 125 else if (which == 1) 126 cfag12864b_setcontrollers(0, 1); 127 } 128 129 static void cfag12864b_displaystate(unsigned char state) 130 { 131 cfag12864b_di(0); 132 cfag12864b_e(1); 133 ks0108_displaystate(state); 134 cfag12864b_e(0); 135 } 136 137 static void cfag12864b_address(unsigned char address) 138 { 139 cfag12864b_di(0); 140 cfag12864b_e(1); 141 ks0108_address(address); 142 cfag12864b_e(0); 143 } 144 145 static void cfag12864b_page(unsigned char page) 146 { 147 cfag12864b_di(0); 148 cfag12864b_e(1); 149 ks0108_page(page); 150 cfag12864b_e(0); 151 } 152 153 static void cfag12864b_startline(unsigned char startline) 154 { 155 cfag12864b_di(0); 156 cfag12864b_e(1); 157 ks0108_startline(startline); 158 cfag12864b_e(0); 159 } 160 161 static void cfag12864b_writebyte(unsigned char byte) 162 { 163 cfag12864b_di(1); 164 cfag12864b_e(1); 165 ks0108_writedata(byte); 166 cfag12864b_e(0); 167 } 168 169 static void cfag12864b_nop(void) 170 { 171 cfag12864b_startline(0); 172 } 173 174 /* 175 * cfag12864b Internal Commands 176 */ 177 178 static void cfag12864b_on(void) 179 { 180 cfag12864b_setcontrollers(1, 1); 181 cfag12864b_displaystate(1); 182 } 183 184 static void cfag12864b_off(void) 185 { 186 cfag12864b_setcontrollers(1, 1); 187 cfag12864b_displaystate(0); 188 } 189 190 static void cfag12864b_clear(void) 191 { 192 unsigned char i, j; 193 194 cfag12864b_setcontrollers(1, 1); 195 for (i = 0; i < CFAG12864B_PAGES; i++) { 196 cfag12864b_page(i); 197 cfag12864b_address(0); 198 for (j = 0; j < CFAG12864B_ADDRESSES; j++) 199 cfag12864b_writebyte(0); 200 } 201 } 202 203 /* 204 * Update work 205 */ 206 207 unsigned char *cfag12864b_buffer; 208 static unsigned char *cfag12864b_cache; 209 static DEFINE_MUTEX(cfag12864b_mutex); 210 static unsigned char cfag12864b_updating; 211 static void cfag12864b_update(struct work_struct *delayed_work); 212 static struct workqueue_struct *cfag12864b_workqueue; 213 static DECLARE_DELAYED_WORK(cfag12864b_work, cfag12864b_update); 214 215 static void cfag12864b_queue(void) 216 { 217 queue_delayed_work(cfag12864b_workqueue, &cfag12864b_work, 218 HZ / cfag12864b_rate); 219 } 220 221 unsigned char cfag12864b_enable(void) 222 { 223 unsigned char ret; 224 225 mutex_lock(&cfag12864b_mutex); 226 227 if (!cfag12864b_updating) { 228 cfag12864b_updating = 1; 229 cfag12864b_queue(); 230 ret = 0; 231 } else 232 ret = 1; 233 234 mutex_unlock(&cfag12864b_mutex); 235 236 return ret; 237 } 238 239 void cfag12864b_disable(void) 240 { 241 mutex_lock(&cfag12864b_mutex); 242 243 if (cfag12864b_updating) { 244 cfag12864b_updating = 0; 245 cancel_delayed_work(&cfag12864b_work); 246 flush_workqueue(cfag12864b_workqueue); 247 } 248 249 mutex_unlock(&cfag12864b_mutex); 250 } 251 252 unsigned char cfag12864b_isenabled(void) 253 { 254 return cfag12864b_updating; 255 } 256 257 static void cfag12864b_update(struct work_struct *work) 258 { 259 unsigned char c; 260 unsigned short i, j, k, b; 261 262 if (memcmp(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE)) { 263 for (i = 0; i < CFAG12864B_CONTROLLERS; i++) { 264 cfag12864b_controller(i); 265 cfag12864b_nop(); 266 for (j = 0; j < CFAG12864B_PAGES; j++) { 267 cfag12864b_page(j); 268 cfag12864b_nop(); 269 cfag12864b_address(0); 270 cfag12864b_nop(); 271 for (k = 0; k < CFAG12864B_ADDRESSES; k++) { 272 for (c = 0, b = 0; b < 8; b++) 273 if (cfag12864b_buffer 274 [i * CFAG12864B_ADDRESSES / 8 275 + k / 8 + (j * 8 + b) * 276 CFAG12864B_WIDTH / 8] 277 & bit(k % 8)) 278 c |= bit(b); 279 cfag12864b_writebyte(c); 280 } 281 } 282 } 283 284 memcpy(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE); 285 } 286 287 if (cfag12864b_updating) 288 cfag12864b_queue(); 289 } 290 291 /* 292 * cfag12864b Exported Symbols 293 */ 294 295 EXPORT_SYMBOL_GPL(cfag12864b_buffer); 296 EXPORT_SYMBOL_GPL(cfag12864b_getrate); 297 EXPORT_SYMBOL_GPL(cfag12864b_enable); 298 EXPORT_SYMBOL_GPL(cfag12864b_disable); 299 EXPORT_SYMBOL_GPL(cfag12864b_isenabled); 300 301 /* 302 * Is the module inited? 303 */ 304 305 static unsigned char cfag12864b_inited; 306 unsigned char cfag12864b_isinited(void) 307 { 308 return cfag12864b_inited; 309 } 310 EXPORT_SYMBOL_GPL(cfag12864b_isinited); 311 312 /* 313 * Module Init & Exit 314 */ 315 316 static int __init cfag12864b_init(void) 317 { 318 int ret = -EINVAL; 319 320 /* ks0108_init() must be called first */ 321 if (!ks0108_isinited()) { 322 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 323 "ks0108 is not initialized\n"); 324 goto none; 325 } 326 BUILD_BUG_ON(PAGE_SIZE < CFAG12864B_SIZE); 327 328 cfag12864b_buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL); 329 if (cfag12864b_buffer == NULL) { 330 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 331 "can't get a free page\n"); 332 ret = -ENOMEM; 333 goto none; 334 } 335 336 cfag12864b_cache = kmalloc(CFAG12864B_SIZE, 337 GFP_KERNEL); 338 if (cfag12864b_cache == NULL) { 339 printk(KERN_ERR CFAG12864B_NAME ": ERROR: " 340 "can't alloc cache buffer (%i bytes)\n", 341 CFAG12864B_SIZE); 342 ret = -ENOMEM; 343 goto bufferalloced; 344 } 345 346 cfag12864b_workqueue = create_singlethread_workqueue(CFAG12864B_NAME); 347 if (cfag12864b_workqueue == NULL) 348 goto cachealloced; 349 350 cfag12864b_clear(); 351 cfag12864b_on(); 352 353 cfag12864b_inited = 1; 354 return 0; 355 356 cachealloced: 357 kfree(cfag12864b_cache); 358 359 bufferalloced: 360 free_page((unsigned long) cfag12864b_buffer); 361 362 none: 363 return ret; 364 } 365 366 static void __exit cfag12864b_exit(void) 367 { 368 cfag12864b_disable(); 369 cfag12864b_off(); 370 destroy_workqueue(cfag12864b_workqueue); 371 kfree(cfag12864b_cache); 372 free_page((unsigned long) cfag12864b_buffer); 373 } 374 375 module_init(cfag12864b_init); 376 module_exit(cfag12864b_exit); 377 378 MODULE_LICENSE("GPL v2"); 379 MODULE_AUTHOR("Miguel Ojeda <ojeda@kernel.org>"); 380 MODULE_DESCRIPTION("cfag12864b LCD driver"); 381