RS485: fix inconsistencies in the meaning of some variables
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / auxdisplay / cfag12864b.c
blob41ce4bd96813eea5818f6774a45e1bc5a923db2a
1 /*
2 * Filename: cfag12864b.c
3 * Version: 0.1.0
4 * Description: cfag12864b LCD driver
5 * License: GPLv2
6 * Depends: ks0108
8 * Author: Copyright (C) Miguel Ojeda Sandonis
9 * Date: 2006-10-31
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.
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.
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
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>
43 #define CFAG12864B_NAME "cfag12864b"
46 * Module Parameters
49 static unsigned int cfag12864b_rate = CONFIG_CFAG12864B_RATE;
50 module_param(cfag12864b_rate, uint, S_IRUGO);
51 MODULE_PARM_DESC(cfag12864b_rate,
52 "Refresh rate (hertz)");
54 unsigned int cfag12864b_getrate(void)
56 return cfag12864b_rate;
60 * cfag12864b Commands
62 * E = Enable signal
63 * Every time E switch from low to high,
64 * cfag12864b/ks0108 reads the command/data.
66 * CS1 = First ks0108controller.
67 * If high, the first ks0108 controller receives commands/data.
69 * CS2 = Second ks0108 controller
70 * If high, the second ks0108 controller receives commands/data.
72 * DI = Data/Instruction
73 * If low, cfag12864b will expect commands.
74 * If high, cfag12864b will expect data.
78 #define bit(n) (((unsigned char)1)<<(n))
80 #define CFAG12864B_BIT_E (0)
81 #define CFAG12864B_BIT_CS1 (2)
82 #define CFAG12864B_BIT_CS2 (1)
83 #define CFAG12864B_BIT_DI (3)
85 static unsigned char cfag12864b_state;
87 static void cfag12864b_set(void)
89 ks0108_writecontrol(cfag12864b_state);
92 static void cfag12864b_setbit(unsigned char state, unsigned char n)
94 if (state)
95 cfag12864b_state |= bit(n);
96 else
97 cfag12864b_state &= ~bit(n);
100 static void cfag12864b_e(unsigned char state)
102 cfag12864b_setbit(state, CFAG12864B_BIT_E);
103 cfag12864b_set();
106 static void cfag12864b_cs1(unsigned char state)
108 cfag12864b_setbit(state, CFAG12864B_BIT_CS1);
111 static void cfag12864b_cs2(unsigned char state)
113 cfag12864b_setbit(state, CFAG12864B_BIT_CS2);
116 static void cfag12864b_di(unsigned char state)
118 cfag12864b_setbit(state, CFAG12864B_BIT_DI);
121 static void cfag12864b_setcontrollers(unsigned char first,
122 unsigned char second)
124 if (first)
125 cfag12864b_cs1(0);
126 else
127 cfag12864b_cs1(1);
129 if (second)
130 cfag12864b_cs2(0);
131 else
132 cfag12864b_cs2(1);
135 static void cfag12864b_controller(unsigned char which)
137 if (which == 0)
138 cfag12864b_setcontrollers(1, 0);
139 else if (which == 1)
140 cfag12864b_setcontrollers(0, 1);
143 static void cfag12864b_displaystate(unsigned char state)
145 cfag12864b_di(0);
146 cfag12864b_e(1);
147 ks0108_displaystate(state);
148 cfag12864b_e(0);
151 static void cfag12864b_address(unsigned char address)
153 cfag12864b_di(0);
154 cfag12864b_e(1);
155 ks0108_address(address);
156 cfag12864b_e(0);
159 static void cfag12864b_page(unsigned char page)
161 cfag12864b_di(0);
162 cfag12864b_e(1);
163 ks0108_page(page);
164 cfag12864b_e(0);
167 static void cfag12864b_startline(unsigned char startline)
169 cfag12864b_di(0);
170 cfag12864b_e(1);
171 ks0108_startline(startline);
172 cfag12864b_e(0);
175 static void cfag12864b_writebyte(unsigned char byte)
177 cfag12864b_di(1);
178 cfag12864b_e(1);
179 ks0108_writedata(byte);
180 cfag12864b_e(0);
183 static void cfag12864b_nop(void)
185 cfag12864b_startline(0);
189 * cfag12864b Internal Commands
192 static void cfag12864b_on(void)
194 cfag12864b_setcontrollers(1, 1);
195 cfag12864b_displaystate(1);
198 static void cfag12864b_off(void)
200 cfag12864b_setcontrollers(1, 1);
201 cfag12864b_displaystate(0);
204 static void cfag12864b_clear(void)
206 unsigned char i, j;
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);
218 * Update work
221 unsigned char *cfag12864b_buffer;
222 static unsigned char *cfag12864b_cache;
223 static DEFINE_MUTEX(cfag12864b_mutex);
224 static unsigned char cfag12864b_updating;
225 static void cfag12864b_update(struct work_struct *delayed_work);
226 static struct workqueue_struct *cfag12864b_workqueue;
227 static DECLARE_DELAYED_WORK(cfag12864b_work, cfag12864b_update);
229 static void cfag12864b_queue(void)
231 queue_delayed_work(cfag12864b_workqueue, &cfag12864b_work,
232 HZ / cfag12864b_rate);
235 unsigned char cfag12864b_enable(void)
237 unsigned char ret;
239 mutex_lock(&cfag12864b_mutex);
241 if (!cfag12864b_updating) {
242 cfag12864b_updating = 1;
243 cfag12864b_queue();
244 ret = 0;
245 } else
246 ret = 1;
248 mutex_unlock(&cfag12864b_mutex);
250 return ret;
253 void cfag12864b_disable(void)
255 mutex_lock(&cfag12864b_mutex);
257 if (cfag12864b_updating) {
258 cfag12864b_updating = 0;
259 cancel_delayed_work(&cfag12864b_work);
260 flush_workqueue(cfag12864b_workqueue);
263 mutex_unlock(&cfag12864b_mutex);
266 unsigned char cfag12864b_isenabled(void)
268 return cfag12864b_updating;
271 static void cfag12864b_update(struct work_struct *work)
273 unsigned char c;
274 unsigned short i, j, k, b;
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);
298 memcpy(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE);
301 if (cfag12864b_updating)
302 cfag12864b_queue();
306 * cfag12864b Exported Symbols
309 EXPORT_SYMBOL_GPL(cfag12864b_buffer);
310 EXPORT_SYMBOL_GPL(cfag12864b_getrate);
311 EXPORT_SYMBOL_GPL(cfag12864b_enable);
312 EXPORT_SYMBOL_GPL(cfag12864b_disable);
313 EXPORT_SYMBOL_GPL(cfag12864b_isenabled);
316 * Is the module inited?
319 static unsigned char cfag12864b_inited;
320 unsigned char cfag12864b_isinited(void)
322 return cfag12864b_inited;
324 EXPORT_SYMBOL_GPL(cfag12864b_isinited);
327 * Module Init & Exit
330 static int __init cfag12864b_init(void)
332 int ret = -EINVAL;
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;
340 BUILD_BUG_ON(PAGE_SIZE < CFAG12864B_SIZE);
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;
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;
360 cfag12864b_workqueue = create_singlethread_workqueue(CFAG12864B_NAME);
361 if (cfag12864b_workqueue == NULL)
362 goto cachealloced;
364 cfag12864b_clear();
365 cfag12864b_on();
367 cfag12864b_inited = 1;
368 return 0;
370 cachealloced:
371 kfree(cfag12864b_cache);
373 bufferalloced:
374 free_page((unsigned long) cfag12864b_buffer);
376 none:
377 return ret;
380 static void __exit cfag12864b_exit(void)
382 cfag12864b_disable();
383 cfag12864b_off();
384 destroy_workqueue(cfag12864b_workqueue);
385 kfree(cfag12864b_cache);
386 free_page((unsigned long) cfag12864b_buffer);
389 module_init(cfag12864b_init);
390 module_exit(cfag12864b_exit);
392 MODULE_LICENSE("GPL v2");
393 MODULE_AUTHOR("Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>");
394 MODULE_DESCRIPTION("cfag12864b LCD driver");