1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Filename: cfag12864b.c |
4 | * Version: 0.1.0 |
5 | * Description: cfag12864b LCD driver |
6 | * Depends: ks0108 |
7 | * |
8 | * Author: Copyright (C) Miguel Ojeda <ojeda@kernel.org> |
9 | * Date: 2006-10-31 |
10 | */ |
11 | |
12 | #include <linux/init.h> |
13 | #include <linux/module.h> |
14 | #include <linux/kernel.h> |
15 | #include <linux/fs.h> |
16 | #include <linux/slab.h> |
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, 0444); |
37 | MODULE_PARM_DESC(cfag12864b_rate, |
38 | "Refresh rate (hertz)" ); |
39 | |
40 | unsigned int cfag12864b_getrate(void) |
41 | { |
42 | return cfag12864b_rate; |
43 | } |
44 | |
45 | /* |
46 | * cfag12864b Commands |
47 | * |
48 | * E = Enable signal |
49 | * Every time E switch from low to high, |
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(byte: 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(state: 0); |
112 | else |
113 | cfag12864b_cs1(state: 1); |
114 | |
115 | if (second) |
116 | cfag12864b_cs2(state: 0); |
117 | else |
118 | cfag12864b_cs2(state: 1); |
119 | } |
120 | |
121 | static void cfag12864b_controller(unsigned char which) |
122 | { |
123 | if (which == 0) |
124 | cfag12864b_setcontrollers(first: 1, second: 0); |
125 | else if (which == 1) |
126 | cfag12864b_setcontrollers(first: 0, second: 1); |
127 | } |
128 | |
129 | static void cfag12864b_displaystate(unsigned char state) |
130 | { |
131 | cfag12864b_di(state: 0); |
132 | cfag12864b_e(state: 1); |
133 | ks0108_displaystate(state); |
134 | cfag12864b_e(state: 0); |
135 | } |
136 | |
137 | static void cfag12864b_address(unsigned char address) |
138 | { |
139 | cfag12864b_di(state: 0); |
140 | cfag12864b_e(state: 1); |
141 | ks0108_address(address); |
142 | cfag12864b_e(state: 0); |
143 | } |
144 | |
145 | static void cfag12864b_page(unsigned char page) |
146 | { |
147 | cfag12864b_di(state: 0); |
148 | cfag12864b_e(state: 1); |
149 | ks0108_page(page); |
150 | cfag12864b_e(state: 0); |
151 | } |
152 | |
153 | static void cfag12864b_startline(unsigned char startline) |
154 | { |
155 | cfag12864b_di(state: 0); |
156 | cfag12864b_e(state: 1); |
157 | ks0108_startline(startline); |
158 | cfag12864b_e(state: 0); |
159 | } |
160 | |
161 | static void cfag12864b_writebyte(unsigned char byte) |
162 | { |
163 | cfag12864b_di(state: 1); |
164 | cfag12864b_e(state: 1); |
165 | ks0108_writedata(byte); |
166 | cfag12864b_e(state: 0); |
167 | } |
168 | |
169 | static void cfag12864b_nop(void) |
170 | { |
171 | cfag12864b_startline(startline: 0); |
172 | } |
173 | |
174 | /* |
175 | * cfag12864b Internal Commands |
176 | */ |
177 | |
178 | static void cfag12864b_on(void) |
179 | { |
180 | cfag12864b_setcontrollers(first: 1, second: 1); |
181 | cfag12864b_displaystate(state: 1); |
182 | } |
183 | |
184 | static void cfag12864b_off(void) |
185 | { |
186 | cfag12864b_setcontrollers(first: 1, second: 1); |
187 | cfag12864b_displaystate(state: 0); |
188 | } |
189 | |
190 | static void cfag12864b_clear(void) |
191 | { |
192 | unsigned char i, j; |
193 | |
194 | cfag12864b_setcontrollers(first: 1, second: 1); |
195 | for (i = 0; i < CFAG12864B_PAGES; i++) { |
196 | cfag12864b_page(page: i); |
197 | cfag12864b_address(address: 0); |
198 | for (j = 0; j < CFAG12864B_ADDRESSES; j++) |
199 | cfag12864b_writebyte(byte: 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(wq: cfag12864b_workqueue, dwork: &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(lock: &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(dwork: &cfag12864b_work); |
246 | flush_workqueue(cfag12864b_workqueue); |
247 | } |
248 | |
249 | mutex_unlock(lock: &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(p: cfag12864b_cache, q: cfag12864b_buffer, CFAG12864B_SIZE)) { |
263 | for (i = 0; i < CFAG12864B_CONTROLLERS; i++) { |
264 | cfag12864b_controller(which: i); |
265 | cfag12864b_nop(); |
266 | for (j = 0; j < CFAG12864B_PAGES; j++) { |
267 | cfag12864b_page(page: j); |
268 | cfag12864b_nop(); |
269 | cfag12864b_address(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(byte: 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 | |
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 | |
312 | /* |
313 | * Module Init & Exit |
314 | */ |
315 | |
316 | static int __init cfag12864b_init(void) |
317 | { |
318 | int ret = -EINVAL; |
319 | |
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 | } |
326 | BUILD_BUG_ON(PAGE_SIZE < CFAG12864B_SIZE); |
327 | |
328 | cfag12864b_buffer = (unsigned char *) get_zeroed_page(GFP_KERNEL); |
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 | |
336 | cfag12864b_cache = kmalloc(CFAG12864B_SIZE, |
337 | GFP_KERNEL); |
338 | if (cfag12864b_cache == NULL) { |
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 | |
350 | cfag12864b_clear(); |
351 | cfag12864b_on(); |
352 | |
353 | cfag12864b_inited = 1; |
354 | return 0; |
355 | |
356 | cachealloced: |
357 | kfree(objp: 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(wq: cfag12864b_workqueue); |
371 | kfree(objp: 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" ); |
379 | MODULE_AUTHOR("Miguel Ojeda <ojeda@kernel.org>" ); |
380 | MODULE_DESCRIPTION("cfag12864b LCD driver" ); |
381 | |