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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 (hertz)");
53
54unsigned int cfag12864b_getrate(void)
55{
56 return cfag12864b_rate;
57}
58
59/*
60 * cfag12864b Commands
61 *
62 * E = Enable signal
63 * Every time 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");