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 <maxextreme@gmail.com>
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 <maxextreme@gmail.com>");
402 MODULE_DESCRIPTION("cfag12864b LCD driver");
403