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351f683b | 1 | // SPDX-License-Identifier: GPL-2.0 |
70e84049 MOS |
2 | /* |
3 | * Filename: cfag12864b.c | |
4 | * Version: 0.1.0 | |
5 | * Description: cfag12864b LCD driver | |
70e84049 MOS |
6 | * Depends: ks0108 |
7 | * | |
c131bd0b | 8 | * Author: Copyright (C) Miguel Ojeda <ojeda@kernel.org> |
70e84049 | 9 | * Date: 2006-10-31 |
70e84049 MOS |
10 | */ |
11 | ||
12 | #include <linux/init.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/fs.h> | |
5a0e3ad6 | 16 | #include <linux/slab.h> |
70e84049 MOS |
17 | #include <linux/cdev.h> |
18 | #include <linux/delay.h> | |
19 | #include <linux/device.h> | |
20 | #include <linux/jiffies.h> | |
21 | #include <linux/mutex.h> | |
22 | #include <linux/uaccess.h> | |
23 | #include <linux/vmalloc.h> | |
24 | #include <linux/workqueue.h> | |
25 | #include <linux/ks0108.h> | |
26 | #include <linux/cfag12864b.h> | |
27 | ||
28 | ||
29 | #define CFAG12864B_NAME "cfag12864b" | |
30 | ||
31 | /* | |
32 | * Module Parameters | |
33 | */ | |
34 | ||
35 | static unsigned int cfag12864b_rate = CONFIG_CFAG12864B_RATE; | |
36 | module_param(cfag12864b_rate, uint, S_IRUGO); | |
37 | MODULE_PARM_DESC(cfag12864b_rate, | |
25985edc | 38 | "Refresh rate (hertz)"); |
70e84049 MOS |
39 | |
40 | unsigned int cfag12864b_getrate(void) | |
41 | { | |
42 | return cfag12864b_rate; | |
43 | } | |
44 | ||
45 | /* | |
46 | * cfag12864b Commands | |
47 | * | |
48 | * E = Enable signal | |
25985edc | 49 | * Every time E switch from low to high, |
70e84049 MOS |
50 | * cfag12864b/ks0108 reads the command/data. |
51 | * | |
52 | * CS1 = First ks0108controller. | |
53 | * If high, the first ks0108 controller receives commands/data. | |
54 | * | |
55 | * CS2 = Second ks0108 controller | |
56 | * If high, the second ks0108 controller receives commands/data. | |
57 | * | |
58 | * DI = Data/Instruction | |
59 | * If low, cfag12864b will expect commands. | |
60 | * If high, cfag12864b will expect data. | |
61 | * | |
62 | */ | |
63 | ||
64 | #define bit(n) (((unsigned char)1)<<(n)) | |
65 | ||
66 | #define CFAG12864B_BIT_E (0) | |
67 | #define CFAG12864B_BIT_CS1 (2) | |
68 | #define CFAG12864B_BIT_CS2 (1) | |
69 | #define CFAG12864B_BIT_DI (3) | |
70 | ||
71 | static unsigned char cfag12864b_state; | |
72 | ||
73 | static void cfag12864b_set(void) | |
74 | { | |
75 | ks0108_writecontrol(cfag12864b_state); | |
76 | } | |
77 | ||
78 | static void cfag12864b_setbit(unsigned char state, unsigned char n) | |
79 | { | |
80 | if (state) | |
81 | cfag12864b_state |= bit(n); | |
82 | else | |
83 | cfag12864b_state &= ~bit(n); | |
84 | } | |
85 | ||
86 | static void cfag12864b_e(unsigned char state) | |
87 | { | |
88 | cfag12864b_setbit(state, CFAG12864B_BIT_E); | |
89 | cfag12864b_set(); | |
90 | } | |
91 | ||
92 | static void cfag12864b_cs1(unsigned char state) | |
93 | { | |
94 | cfag12864b_setbit(state, CFAG12864B_BIT_CS1); | |
95 | } | |
96 | ||
97 | static void cfag12864b_cs2(unsigned char state) | |
98 | { | |
99 | cfag12864b_setbit(state, CFAG12864B_BIT_CS2); | |
100 | } | |
101 | ||
102 | static void cfag12864b_di(unsigned char state) | |
103 | { | |
104 | cfag12864b_setbit(state, CFAG12864B_BIT_DI); | |
105 | } | |
106 | ||
107 | static void cfag12864b_setcontrollers(unsigned char first, | |
108 | unsigned char second) | |
109 | { | |
110 | if (first) | |
111 | cfag12864b_cs1(0); | |
112 | else | |
113 | cfag12864b_cs1(1); | |
114 | ||
115 | if (second) | |
116 | cfag12864b_cs2(0); | |
117 | else | |
118 | cfag12864b_cs2(1); | |
119 | } | |
120 | ||
121 | static void cfag12864b_controller(unsigned char which) | |
122 | { | |
123 | if (which == 0) | |
124 | cfag12864b_setcontrollers(1, 0); | |
125 | else if (which == 1) | |
126 | cfag12864b_setcontrollers(0, 1); | |
127 | } | |
128 | ||
129 | static void cfag12864b_displaystate(unsigned char state) | |
130 | { | |
131 | cfag12864b_di(0); | |
132 | cfag12864b_e(1); | |
133 | ks0108_displaystate(state); | |
134 | cfag12864b_e(0); | |
135 | } | |
136 | ||
137 | static void cfag12864b_address(unsigned char address) | |
138 | { | |
139 | cfag12864b_di(0); | |
140 | cfag12864b_e(1); | |
141 | ks0108_address(address); | |
142 | cfag12864b_e(0); | |
143 | } | |
144 | ||
145 | static void cfag12864b_page(unsigned char page) | |
146 | { | |
147 | cfag12864b_di(0); | |
148 | cfag12864b_e(1); | |
149 | ks0108_page(page); | |
150 | cfag12864b_e(0); | |
151 | } | |
152 | ||
153 | static void cfag12864b_startline(unsigned char startline) | |
154 | { | |
155 | cfag12864b_di(0); | |
156 | cfag12864b_e(1); | |
157 | ks0108_startline(startline); | |
158 | cfag12864b_e(0); | |
159 | } | |
160 | ||
161 | static void cfag12864b_writebyte(unsigned char byte) | |
162 | { | |
163 | cfag12864b_di(1); | |
164 | cfag12864b_e(1); | |
165 | ks0108_writedata(byte); | |
166 | cfag12864b_e(0); | |
167 | } | |
168 | ||
169 | static void cfag12864b_nop(void) | |
170 | { | |
171 | cfag12864b_startline(0); | |
172 | } | |
173 | ||
174 | /* | |
175 | * cfag12864b Internal Commands | |
176 | */ | |
177 | ||
178 | static void cfag12864b_on(void) | |
179 | { | |
180 | cfag12864b_setcontrollers(1, 1); | |
181 | cfag12864b_displaystate(1); | |
182 | } | |
183 | ||
184 | static void cfag12864b_off(void) | |
185 | { | |
186 | cfag12864b_setcontrollers(1, 1); | |
187 | cfag12864b_displaystate(0); | |
188 | } | |
189 | ||
190 | static void cfag12864b_clear(void) | |
191 | { | |
192 | unsigned char i, j; | |
193 | ||
194 | cfag12864b_setcontrollers(1, 1); | |
195 | for (i = 0; i < CFAG12864B_PAGES; i++) { | |
196 | cfag12864b_page(i); | |
197 | cfag12864b_address(0); | |
198 | for (j = 0; j < CFAG12864B_ADDRESSES; j++) | |
199 | cfag12864b_writebyte(0); | |
200 | } | |
201 | } | |
202 | ||
203 | /* | |
204 | * Update work | |
205 | */ | |
206 | ||
207 | unsigned char *cfag12864b_buffer; | |
208 | static unsigned char *cfag12864b_cache; | |
209 | static DEFINE_MUTEX(cfag12864b_mutex); | |
210 | static unsigned char cfag12864b_updating; | |
211 | static void cfag12864b_update(struct work_struct *delayed_work); | |
212 | static struct workqueue_struct *cfag12864b_workqueue; | |
213 | static DECLARE_DELAYED_WORK(cfag12864b_work, cfag12864b_update); | |
214 | ||
215 | static void cfag12864b_queue(void) | |
216 | { | |
217 | queue_delayed_work(cfag12864b_workqueue, &cfag12864b_work, | |
218 | HZ / cfag12864b_rate); | |
219 | } | |
220 | ||
221 | unsigned char cfag12864b_enable(void) | |
222 | { | |
223 | unsigned char ret; | |
224 | ||
225 | mutex_lock(&cfag12864b_mutex); | |
226 | ||
227 | if (!cfag12864b_updating) { | |
228 | cfag12864b_updating = 1; | |
229 | cfag12864b_queue(); | |
230 | ret = 0; | |
231 | } else | |
232 | ret = 1; | |
233 | ||
234 | mutex_unlock(&cfag12864b_mutex); | |
235 | ||
236 | return ret; | |
237 | } | |
238 | ||
239 | void cfag12864b_disable(void) | |
240 | { | |
241 | mutex_lock(&cfag12864b_mutex); | |
242 | ||
243 | if (cfag12864b_updating) { | |
244 | cfag12864b_updating = 0; | |
245 | cancel_delayed_work(&cfag12864b_work); | |
246 | flush_workqueue(cfag12864b_workqueue); | |
247 | } | |
248 | ||
249 | mutex_unlock(&cfag12864b_mutex); | |
250 | } | |
251 | ||
252 | unsigned char cfag12864b_isenabled(void) | |
253 | { | |
254 | return cfag12864b_updating; | |
255 | } | |
256 | ||
257 | static void cfag12864b_update(struct work_struct *work) | |
258 | { | |
259 | unsigned char c; | |
260 | unsigned short i, j, k, b; | |
261 | ||
262 | if (memcmp(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE)) { | |
263 | for (i = 0; i < CFAG12864B_CONTROLLERS; i++) { | |
264 | cfag12864b_controller(i); | |
265 | cfag12864b_nop(); | |
266 | for (j = 0; j < CFAG12864B_PAGES; j++) { | |
267 | cfag12864b_page(j); | |
268 | cfag12864b_nop(); | |
269 | cfag12864b_address(0); | |
270 | cfag12864b_nop(); | |
271 | for (k = 0; k < CFAG12864B_ADDRESSES; k++) { | |
272 | for (c = 0, b = 0; b < 8; b++) | |
273 | if (cfag12864b_buffer | |
274 | [i * CFAG12864B_ADDRESSES / 8 | |
275 | + k / 8 + (j * 8 + b) * | |
276 | CFAG12864B_WIDTH / 8] | |
277 | & bit(k % 8)) | |
278 | c |= bit(b); | |
279 | cfag12864b_writebyte(c); | |
280 | } | |
281 | } | |
282 | } | |
283 | ||
284 | memcpy(cfag12864b_cache, cfag12864b_buffer, CFAG12864B_SIZE); | |
285 | } | |
286 | ||
287 | if (cfag12864b_updating) | |
288 | cfag12864b_queue(); | |
289 | } | |
290 | ||
291 | /* | |
292 | * cfag12864b Exported Symbols | |
293 | */ | |
294 | ||
295 | EXPORT_SYMBOL_GPL(cfag12864b_buffer); | |
296 | EXPORT_SYMBOL_GPL(cfag12864b_getrate); | |
297 | EXPORT_SYMBOL_GPL(cfag12864b_enable); | |
298 | EXPORT_SYMBOL_GPL(cfag12864b_disable); | |
299 | EXPORT_SYMBOL_GPL(cfag12864b_isenabled); | |
300 | ||
34173a4a MO |
301 | /* |
302 | * Is the module inited? | |
303 | */ | |
304 | ||
305 | static unsigned char cfag12864b_inited; | |
306 | unsigned char cfag12864b_isinited(void) | |
307 | { | |
308 | return cfag12864b_inited; | |
309 | } | |
310 | EXPORT_SYMBOL_GPL(cfag12864b_isinited); | |
311 | ||
70e84049 MOS |
312 | /* |
313 | * Module Init & Exit | |
314 | */ | |
315 | ||
316 | static int __init cfag12864b_init(void) | |
317 | { | |
318 | int ret = -EINVAL; | |
319 | ||
34173a4a MO |
320 | /* ks0108_init() must be called first */ |
321 | if (!ks0108_isinited()) { | |
322 | printk(KERN_ERR CFAG12864B_NAME ": ERROR: " | |
323 | "ks0108 is not initialized\n"); | |
324 | goto none; | |
325 | } | |
b340e8a5 | 326 | BUILD_BUG_ON(PAGE_SIZE < CFAG12864B_SIZE); |
34173a4a | 327 | |
b340e8a5 | 328 | cfag12864b_buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL); |
70e84049 MOS |
329 | if (cfag12864b_buffer == NULL) { |
330 | printk(KERN_ERR CFAG12864B_NAME ": ERROR: " | |
331 | "can't get a free page\n"); | |
332 | ret = -ENOMEM; | |
333 | goto none; | |
334 | } | |
335 | ||
6da2ec56 KC |
336 | cfag12864b_cache = kmalloc(CFAG12864B_SIZE, |
337 | GFP_KERNEL); | |
fe58103a | 338 | if (cfag12864b_cache == NULL) { |
70e84049 MOS |
339 | printk(KERN_ERR CFAG12864B_NAME ": ERROR: " |
340 | "can't alloc cache buffer (%i bytes)\n", | |
341 | CFAG12864B_SIZE); | |
342 | ret = -ENOMEM; | |
343 | goto bufferalloced; | |
344 | } | |
345 | ||
346 | cfag12864b_workqueue = create_singlethread_workqueue(CFAG12864B_NAME); | |
347 | if (cfag12864b_workqueue == NULL) | |
348 | goto cachealloced; | |
349 | ||
70e84049 MOS |
350 | cfag12864b_clear(); |
351 | cfag12864b_on(); | |
352 | ||
34173a4a | 353 | cfag12864b_inited = 1; |
70e84049 MOS |
354 | return 0; |
355 | ||
356 | cachealloced: | |
357 | kfree(cfag12864b_cache); | |
358 | ||
359 | bufferalloced: | |
360 | free_page((unsigned long) cfag12864b_buffer); | |
361 | ||
362 | none: | |
363 | return ret; | |
364 | } | |
365 | ||
366 | static void __exit cfag12864b_exit(void) | |
367 | { | |
368 | cfag12864b_disable(); | |
369 | cfag12864b_off(); | |
370 | destroy_workqueue(cfag12864b_workqueue); | |
371 | kfree(cfag12864b_cache); | |
372 | free_page((unsigned long) cfag12864b_buffer); | |
373 | } | |
374 | ||
375 | module_init(cfag12864b_init); | |
376 | module_exit(cfag12864b_exit); | |
377 | ||
378 | MODULE_LICENSE("GPL v2"); | |
c131bd0b | 379 | MODULE_AUTHOR("Miguel Ojeda <ojeda@kernel.org>"); |
70e84049 | 380 | MODULE_DESCRIPTION("cfag12864b LCD driver"); |