tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
48static unsigned int cfag12864b_rate = CONFIG_CFAG12864B_RATE;
49module_param(cfag12864b_rate, uint, S_IRUGO);
50MODULE_PARM_DESC(cfag12864b_rate,
51 "Refresh rate (hertzs)");
52
53unsigned 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
84static unsigned char cfag12864b_state;
85
86static void cfag12864b_set(void)
87{
88 ks0108_writecontrol(cfag12864b_state);
89}
90
91static 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
99static void cfag12864b_e(unsigned char state)
100{
101 cfag12864b_setbit(state, CFAG12864B_BIT_E);
102 cfag12864b_set();
103}
104
105static void cfag12864b_cs1(unsigned char state)
106{
107 cfag12864b_setbit(state, CFAG12864B_BIT_CS1);
108}
109
110static void cfag12864b_cs2(unsigned char state)
111{
112 cfag12864b_setbit(state, CFAG12864B_BIT_CS2);
113}
114
115static void cfag12864b_di(unsigned char state)
116{
117 cfag12864b_setbit(state, CFAG12864B_BIT_DI);
118}
119
120static 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
134static 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
142static 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
150static 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
158static 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
166static 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
174static 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
182static void cfag12864b_nop(void)
183{
184 cfag12864b_startline(0);
185}
186
187/*
188 * cfag12864b Internal Commands
189 */
190
191static void cfag12864b_on(void)
192{
193 cfag12864b_setcontrollers(1, 1);
194 cfag12864b_displaystate(1);
195}
196
197static void cfag12864b_off(void)
198{
199 cfag12864b_setcontrollers(1, 1);
200 cfag12864b_displaystate(0);
201}
202
203static 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
220unsigned char *cfag12864b_buffer;
221static unsigned char *cfag12864b_cache;
222static DEFINE_MUTEX(cfag12864b_mutex);
223static unsigned char cfag12864b_updating;
224static void cfag12864b_update(struct work_struct *delayed_work);
225static struct workqueue_struct *cfag12864b_workqueue;
226static DECLARE_DELAYED_WORK(cfag12864b_work, cfag12864b_update);
227
228static void cfag12864b_queue(void)
229{
230 queue_delayed_work(cfag12864b_workqueue, &cfag12864b_work,
231 HZ / cfag12864b_rate);
232}
233
234unsigned 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
252void 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
265unsigned char cfag12864b_isenabled(void)
266{
267 return cfag12864b_updating;
268}
269
270static 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
308EXPORT_SYMBOL_GPL(cfag12864b_buffer);
309EXPORT_SYMBOL_GPL(cfag12864b_getrate);
310EXPORT_SYMBOL_GPL(cfag12864b_enable);
311EXPORT_SYMBOL_GPL(cfag12864b_disable);
312EXPORT_SYMBOL_GPL(cfag12864b_isenabled);
313
314/*
315 * Is the module inited?
316 */
317
318static unsigned char cfag12864b_inited;
319unsigned char cfag12864b_isinited(void)
320{
321 return cfag12864b_inited;
322}
323EXPORT_SYMBOL_GPL(cfag12864b_isinited);
324
325/*
326 * Module Init & Exit
327 */
328
329static 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 BUILD_BUG_ON(PAGE_SIZE < CFAG12864B_SIZE);
340
341 cfag12864b_buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL);
342 if (cfag12864b_buffer == NULL) {
343 printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
344 "can't get a free page\n");
345 ret = -ENOMEM;
346 goto none;
347 }
348
349 cfag12864b_cache = kmalloc(sizeof(unsigned char) *
350 CFAG12864B_SIZE, GFP_KERNEL);
351 if (cfag12864b_cache == NULL) {
352 printk(KERN_ERR CFAG12864B_NAME ": ERROR: "
353 "can't alloc cache buffer (%i bytes)\n",
354 CFAG12864B_SIZE);
355 ret = -ENOMEM;
356 goto bufferalloced;
357 }
358
359 cfag12864b_workqueue = create_singlethread_workqueue(CFAG12864B_NAME);
360 if (cfag12864b_workqueue == NULL)
361 goto cachealloced;
362
363 cfag12864b_clear();
364 cfag12864b_on();
365
366 cfag12864b_inited = 1;
367 return 0;
368
369cachealloced:
370 kfree(cfag12864b_cache);
371
372bufferalloced:
373 free_page((unsigned long) cfag12864b_buffer);
374
375none:
376 return ret;
377}
378
379static void __exit cfag12864b_exit(void)
380{
381 cfag12864b_disable();
382 cfag12864b_off();
383 destroy_workqueue(cfag12864b_workqueue);
384 kfree(cfag12864b_cache);
385 free_page((unsigned long) cfag12864b_buffer);
386}
387
388module_init(cfag12864b_init);
389module_exit(cfag12864b_exit);
390
391MODULE_LICENSE("GPL v2");
392MODULE_AUTHOR("Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>");
393MODULE_DESCRIPTION("cfag12864b LCD driver");