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1// SPDX-License-Identifier: GPL-2.02/*3 * Filename: cfag12864b.c4 * Version: 0.1.05 * Description: cfag12864b LCD driver6 * Depends: ks01087 *8 * Author: Copyright (C) Miguel Ojeda <ojeda@kernel.org>9 * Date: 2006-10-3110 */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 Parameters33 */34 35static unsigned int cfag12864b_rate = CONFIG_CFAG12864B_RATE;36module_param(cfag12864b_rate, uint, 0444);37MODULE_PARM_DESC(cfag12864b_rate,38 "Refresh rate (hertz)");39 40unsigned int cfag12864b_getrate(void)41{42 return cfag12864b_rate;43}44 45/*46 * cfag12864b Commands47 *48 * E = Enable signal49 * 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 controller56 * If high, the second ks0108 controller receives commands/data.57 *58 * DI = Data/Instruction59 * 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 71static unsigned char cfag12864b_state;72 73static void cfag12864b_set(void)74{75 ks0108_writecontrol(cfag12864b_state);76}77 78static void cfag12864b_setbit(unsigned char state, unsigned char n)79{80 if (state)81 cfag12864b_state |= bit(n);82 else83 cfag12864b_state &= ~bit(n);84}85 86static void cfag12864b_e(unsigned char state)87{88 cfag12864b_setbit(state, CFAG12864B_BIT_E);89 cfag12864b_set();90}91 92static void cfag12864b_cs1(unsigned char state)93{94 cfag12864b_setbit(state, CFAG12864B_BIT_CS1);95}96 97static void cfag12864b_cs2(unsigned char state)98{99 cfag12864b_setbit(state, CFAG12864B_BIT_CS2);100}101 102static void cfag12864b_di(unsigned char state)103{104 cfag12864b_setbit(state, CFAG12864B_BIT_DI);105}106 107static void cfag12864b_setcontrollers(unsigned char first,108 unsigned char second)109{110 if (first)111 cfag12864b_cs1(0);112 else113 cfag12864b_cs1(1);114 115 if (second)116 cfag12864b_cs2(0);117 else118 cfag12864b_cs2(1);119}120 121static 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 129static 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 137static 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 145static 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 153static 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 161static 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 169static void cfag12864b_nop(void)170{171 cfag12864b_startline(0);172}173 174/*175 * cfag12864b Internal Commands176 */177 178static void cfag12864b_on(void)179{180 cfag12864b_setcontrollers(1, 1);181 cfag12864b_displaystate(1);182}183 184static void cfag12864b_off(void)185{186 cfag12864b_setcontrollers(1, 1);187 cfag12864b_displaystate(0);188}189 190static 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 work205 */206 207unsigned char *cfag12864b_buffer;208static unsigned char *cfag12864b_cache;209static DEFINE_MUTEX(cfag12864b_mutex);210static unsigned char cfag12864b_updating;211static void cfag12864b_update(struct work_struct *delayed_work);212static struct workqueue_struct *cfag12864b_workqueue;213static DECLARE_DELAYED_WORK(cfag12864b_work, cfag12864b_update);214 215static void cfag12864b_queue(void)216{217 queue_delayed_work(cfag12864b_workqueue, &cfag12864b_work,218 HZ / cfag12864b_rate);219}220 221unsigned 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 } else232 ret = 1;233 234 mutex_unlock(&cfag12864b_mutex);235 236 return ret;237}238 239void 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 252unsigned char cfag12864b_isenabled(void)253{254 return cfag12864b_updating;255}256 257static 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_buffer274 [i * CFAG12864B_ADDRESSES / 8275 + 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 Symbols293 */294 295EXPORT_SYMBOL_GPL(cfag12864b_buffer);296EXPORT_SYMBOL_GPL(cfag12864b_getrate);297EXPORT_SYMBOL_GPL(cfag12864b_enable);298EXPORT_SYMBOL_GPL(cfag12864b_disable);299EXPORT_SYMBOL_GPL(cfag12864b_isenabled);300 301/*302 * Is the module inited?303 */304 305static unsigned char cfag12864b_inited;306unsigned char cfag12864b_isinited(void)307{308 return cfag12864b_inited;309}310EXPORT_SYMBOL_GPL(cfag12864b_isinited);311 312/*313 * Module Init & Exit314 */315 316static 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 356cachealloced:357 kfree(cfag12864b_cache);358 359bufferalloced:360 free_page((unsigned long) cfag12864b_buffer);361 362none:363 return ret;364}365 366static 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 375module_init(cfag12864b_init);376module_exit(cfag12864b_exit);377 378MODULE_LICENSE("GPL v2");379MODULE_AUTHOR("Miguel Ojeda <ojeda@kernel.org>");380MODULE_DESCRIPTION("cfag12864b LCD driver");381