Miguel Ojeda has moved
[linux-2.6.git] / drivers / auxdisplay / cfag12864b.c
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/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_cache == 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 <miguel.ojeda.sandonis@gmail.com>");
402 MODULE_DESCRIPTION("cfag12864b LCD driver");