1 /*
2 * FB driver for Two KS0108 LCD controllers in AGM1264K-FL display
3 *
4 * Copyright (C) 2014 ololoshka2871
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17 #include <linux/module.h>
18 #include <linux/kernel.h>
19 #include <linux/init.h>
20 #include <linux/gpio.h>
21 #include <linux/delay.h>
22 #include <linux/slab.h>
23
24 #include "fbtft.h"
25
26 /* Uncomment text line to use negative image on display */
27 /*#define NEGATIVE*/
28
29 #define WHITE 0xff
30 #define BLACK 0
31
32 #define DRVNAME "fb_agm1264k-fl"
33 #define WIDTH 64
34 #define HEIGHT 64
35 #define TOTALWIDTH (WIDTH * 2) /* because 2 x ks0108 in one display */
36 #define FPS 20
37
38 #define EPIN gpio.wr
39 #define RS gpio.dc
40 #define RW gpio.aux[2]
41 #define CS0 gpio.aux[0]
42 #define CS1 gpio.aux[1]
43
44 /* diffusing error (Floyd-Steinberg) */
45 #define DIFFUSING_MATRIX_WIDTH 2
46 #define DIFFUSING_MATRIX_HEIGHT 2
47
48 static const signed char
49 diffusing_matrix[DIFFUSING_MATRIX_WIDTH][DIFFUSING_MATRIX_HEIGHT] = {
50 {-1, 3},
51 {3, 2},
52 };
53
54 static const unsigned char gamma_correction_table[] = {
55 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1,
56 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6,
57 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 11, 11, 12, 12, 13,
58 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21,
59 22, 22, 23, 23, 24, 25, 25, 26, 26, 27, 28, 28, 29, 30, 30, 31, 32,
60 33, 33, 34, 35, 35, 36, 37, 38, 39, 39, 40, 41, 42, 43, 43, 44, 45,
61 46, 47, 48, 49, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
62 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81,
63 82, 83, 84, 85, 87, 88, 89, 90, 91, 93, 94, 95, 97, 98, 99, 100, 102,
64 103, 105, 106, 107, 109, 110, 111, 113, 114, 116, 117, 119, 120, 121,
65 123, 124, 126, 127, 129, 130, 132, 133, 135, 137, 138, 140, 141, 143,
66 145, 146, 148, 149, 151, 153, 154, 156, 158, 159, 161, 163, 165, 166,
67 168, 170, 172, 173, 175, 177, 179, 181, 182, 184, 186, 188, 190, 192,
68 194, 196, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219,
69 221, 223, 225, 227, 229, 231, 234, 236, 238, 240, 242, 244, 246, 248,
70 251, 253, 255
71 };
72
init_display(struct fbtft_par * par)73 static int init_display(struct fbtft_par *par)
74 {
75 u8 i;
76
77 par->fbtftops.reset(par);
78
79 for (i = 0; i < 2; ++i) {
80 write_reg(par, i, 0x3f); /* display on */
81 write_reg(par, i, 0x40); /* set x to 0 */
82 write_reg(par, i, 0xb0); /* set page to 0 */
83 write_reg(par, i, 0xc0); /* set start line to 0 */
84 }
85
86 return 0;
87 }
88
reset(struct fbtft_par * par)89 static void reset(struct fbtft_par *par)
90 {
91 if (par->gpio.reset == -1)
92 return;
93
94 dev_dbg(par->info->device, "%s()\n", __func__);
95
96 gpio_set_value(par->gpio.reset, 0);
97 udelay(20);
98 gpio_set_value(par->gpio.reset, 1);
99 mdelay(120);
100 }
101
102 /* Check if all necessary GPIOS defined */
verify_gpios(struct fbtft_par * par)103 static int verify_gpios(struct fbtft_par *par)
104 {
105 int i;
106
107 dev_dbg(par->info->device,
108 "%s()\n", __func__);
109
110 if (par->EPIN < 0) {
111 dev_err(par->info->device,
112 "Missing info about 'wr' (aka E) gpio. Aborting.\n");
113 return -EINVAL;
114 }
115 for (i = 0; i < 8; ++i) {
116 if (par->gpio.db[i] < 0) {
117 dev_err(par->info->device,
118 "Missing info about 'db[%i]' gpio. Aborting.\n",
119 i);
120 return -EINVAL;
121 }
122 }
123 if (par->CS0 < 0) {
124 dev_err(par->info->device,
125 "Missing info about 'cs0' gpio. Aborting.\n");
126 return -EINVAL;
127 }
128 if (par->CS1 < 0) {
129 dev_err(par->info->device,
130 "Missing info about 'cs1' gpio. Aborting.\n");
131 return -EINVAL;
132 }
133 if (par->RW < 0) {
134 dev_err(par->info->device,
135 "Missing info about 'rw' gpio. Aborting.\n");
136 return -EINVAL;
137 }
138
139 return 0;
140 }
141
142 static unsigned long
request_gpios_match(struct fbtft_par * par,const struct fbtft_gpio * gpio)143 request_gpios_match(struct fbtft_par *par, const struct fbtft_gpio *gpio)
144 {
145 dev_dbg(par->info->device,
146 "%s('%s')\n", __func__, gpio->name);
147
148 if (strcasecmp(gpio->name, "wr") == 0) {
149 /* left ks0108 E pin */
150 par->EPIN = gpio->gpio;
151 return GPIOF_OUT_INIT_LOW;
152 } else if (strcasecmp(gpio->name, "cs0") == 0) {
153 /* left ks0108 controller pin */
154 par->CS0 = gpio->gpio;
155 return GPIOF_OUT_INIT_HIGH;
156 } else if (strcasecmp(gpio->name, "cs1") == 0) {
157 /* right ks0108 controller pin */
158 par->CS1 = gpio->gpio;
159 return GPIOF_OUT_INIT_HIGH;
160 }
161
162 /* if write (rw = 0) e(1->0) perform write */
163 /* if read (rw = 1) e(0->1) set data on D0-7*/
164 else if (strcasecmp(gpio->name, "rw") == 0) {
165 par->RW = gpio->gpio;
166 return GPIOF_OUT_INIT_LOW;
167 }
168
169 return FBTFT_GPIO_NO_MATCH;
170 }
171
172 /* This function oses to enter commands
173 * first byte - destination controller 0 or 1
174 * following - commands
175 */
write_reg8_bus8(struct fbtft_par * par,int len,...)176 static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
177 {
178 va_list args;
179 int i, ret;
180 u8 *buf = par->buf;
181
182 if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
183 va_start(args, len);
184 for (i = 0; i < len; i++)
185 buf[i] = (u8)va_arg(args, unsigned int);
186
187 va_end(args);
188 fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par,
189 par->info->device, u8, buf, len, "%s: ", __func__);
190 }
191
192 va_start(args, len);
193
194 *buf = (u8)va_arg(args, unsigned int);
195
196 if (*buf > 1) {
197 va_end(args);
198 dev_err(par->info->device,
199 "Incorrect chip select request (%d)\n", *buf);
200 return;
201 }
202
203 /* select chip */
204 if (*buf) {
205 /* cs1 */
206 gpio_set_value(par->CS0, 1);
207 gpio_set_value(par->CS1, 0);
208 } else {
209 /* cs0 */
210 gpio_set_value(par->CS0, 0);
211 gpio_set_value(par->CS1, 1);
212 }
213
214 gpio_set_value(par->RS, 0); /* RS->0 (command mode) */
215 len--;
216
217 if (len) {
218 i = len;
219 while (i--)
220 *buf++ = (u8)va_arg(args, unsigned int);
221 ret = par->fbtftops.write(par, par->buf, len * (sizeof(u8)));
222 if (ret < 0) {
223 va_end(args);
224 dev_err(par->info->device,
225 "write() failed and returned %d\n", ret);
226 return;
227 }
228 }
229
230 va_end(args);
231 }
232
233 static struct
234 {
235 int xs, ys_page, xe, ye_page;
236 } addr_win;
237
238 /* save display writing zone */
set_addr_win(struct fbtft_par * par,int xs,int ys,int xe,int ye)239 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
240 {
241 addr_win.xs = xs;
242 addr_win.ys_page = ys / 8;
243 addr_win.xe = xe;
244 addr_win.ye_page = ye / 8;
245 }
246
247 static void
construct_line_bitmap(struct fbtft_par * par,u8 * dest,signed short * src,int xs,int xe,int y)248 construct_line_bitmap(struct fbtft_par *par, u8 *dest, signed short *src,
249 int xs, int xe, int y)
250 {
251 int x, i;
252
253 for (x = xs; x < xe; ++x) {
254 u8 res = 0;
255
256 for (i = 0; i < 8; i++)
257 if (src[(y * 8 + i) * par->info->var.xres + x])
258 res |= 1 << i;
259 #ifdef NEGATIVE
260 *dest++ = res;
261 #else
262 *dest++ = ~res;
263 #endif
264 }
265 }
266
write_vmem(struct fbtft_par * par,size_t offset,size_t len)267 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
268 {
269 u16 *vmem16 = (u16 *)par->info->screen_buffer;
270 u8 *buf = par->txbuf.buf;
271 int x, y;
272 int ret = 0;
273
274 /* buffer to convert RGB565 -> grayscale16 -> Dithered image 1bpp */
275 signed short *convert_buf = kmalloc(par->info->var.xres *
276 par->info->var.yres * sizeof(signed short), GFP_NOIO);
277
278 if (!convert_buf)
279 return -ENOMEM;
280
281 /* converting to grayscale16 */
282 for (x = 0; x < par->info->var.xres; ++x)
283 for (y = 0; y < par->info->var.yres; ++y) {
284 u16 pixel = vmem16[y * par->info->var.xres + x];
285 u16 b = pixel & 0x1f;
286 u16 g = (pixel & (0x3f << 5)) >> 5;
287 u16 r = (pixel & (0x1f << (5 + 6))) >> (5 + 6);
288
289 pixel = (299 * r + 587 * g + 114 * b) / 200;
290 if (pixel > 255)
291 pixel = 255;
292
293 /* gamma-correction by table */
294 convert_buf[y * par->info->var.xres + x] =
295 (signed short)gamma_correction_table[pixel];
296 }
297
298 /* Image Dithering */
299 for (x = 0; x < par->info->var.xres; ++x)
300 for (y = 0; y < par->info->var.yres; ++y) {
301 signed short pixel =
302 convert_buf[y * par->info->var.xres + x];
303 signed short error_b = pixel - BLACK;
304 signed short error_w = pixel - WHITE;
305 signed short error;
306 u16 i, j;
307
308 /* what color close? */
309 if (abs(error_b) >= abs(error_w)) {
310 /* white */
311 error = error_w;
312 pixel = 0xff;
313 } else {
314 /* black */
315 error = error_b;
316 pixel = 0;
317 }
318
319 error /= 8;
320
321 /* diffusion matrix row */
322 for (i = 0; i < DIFFUSING_MATRIX_WIDTH; ++i)
323 /* diffusion matrix column */
324 for (j = 0; j < DIFFUSING_MATRIX_HEIGHT; ++j) {
325 signed short *write_pos;
326 signed char coeff;
327
328 /* skip pixels out of zone */
329 if (x + i < 0 ||
330 x + i >= par->info->var.xres
331 || y + j >= par->info->var.yres)
332 continue;
333 write_pos = &convert_buf[
334 (y + j) * par->info->var.xres +
335 x + i];
336 coeff = diffusing_matrix[i][j];
337 if (coeff == -1)
338 /* pixel itself */
339 *write_pos = pixel;
340 else {
341 signed short p = *write_pos +
342 error * coeff;
343
344 if (p > WHITE)
345 p = WHITE;
346 if (p < BLACK)
347 p = BLACK;
348 *write_pos = p;
349 }
350 }
351 }
352
353 /* 1 string = 2 pages */
354 for (y = addr_win.ys_page; y <= addr_win.ye_page; ++y) {
355 /* left half of display */
356 if (addr_win.xs < par->info->var.xres / 2) {
357 construct_line_bitmap(par, buf, convert_buf,
358 addr_win.xs, par->info->var.xres / 2, y);
359
360 len = par->info->var.xres / 2 - addr_win.xs;
361
362 /* select left side (sc0)
363 * set addr
364 */
365 write_reg(par, 0x00, (1 << 6) | (u8)addr_win.xs);
366 write_reg(par, 0x00, (0x17 << 3) | (u8)y);
367
368 /* write bitmap */
369 gpio_set_value(par->RS, 1); /* RS->1 (data mode) */
370 ret = par->fbtftops.write(par, buf, len);
371 if (ret < 0)
372 dev_err(par->info->device,
373 "write failed and returned: %d\n",
374 ret);
375 }
376 /* right half of display */
377 if (addr_win.xe >= par->info->var.xres / 2) {
378 construct_line_bitmap(par, buf,
379 convert_buf, par->info->var.xres / 2,
380 addr_win.xe + 1, y);
381
382 len = addr_win.xe + 1 - par->info->var.xres / 2;
383
384 /* select right side (sc1)
385 * set addr
386 */
387 write_reg(par, 0x01, 1 << 6);
388 write_reg(par, 0x01, (0x17 << 3) | (u8)y);
389
390 /* write bitmap */
391 gpio_set_value(par->RS, 1); /* RS->1 (data mode) */
392 par->fbtftops.write(par, buf, len);
393 if (ret < 0)
394 dev_err(par->info->device,
395 "write failed and returned: %d\n",
396 ret);
397 }
398 }
399 kfree(convert_buf);
400
401 gpio_set_value(par->CS0, 1);
402 gpio_set_value(par->CS1, 1);
403
404 return ret;
405 }
406
write(struct fbtft_par * par,void * buf,size_t len)407 static int write(struct fbtft_par *par, void *buf, size_t len)
408 {
409 fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
410 "%s(len=%d): ", __func__, len);
411
412 gpio_set_value(par->RW, 0); /* set write mode */
413
414 while (len--) {
415 u8 i, data;
416
417 data = *(u8 *) buf++;
418
419 /* set data bus */
420 for (i = 0; i < 8; ++i)
421 gpio_set_value(par->gpio.db[i], data & (1 << i));
422 /* set E */
423 gpio_set_value(par->EPIN, 1);
424 udelay(5);
425 /* unset E - write */
426 gpio_set_value(par->EPIN, 0);
427 udelay(1);
428 }
429
430 return 0;
431 }
432
433 static struct fbtft_display display = {
434 .regwidth = 8,
435 .width = TOTALWIDTH,
436 .height = HEIGHT,
437 .fps = FPS,
438 .fbtftops = {
439 .init_display = init_display,
440 .set_addr_win = set_addr_win,
441 .verify_gpios = verify_gpios,
442 .request_gpios_match = request_gpios_match,
443 .reset = reset,
444 .write = write,
445 .write_register = write_reg8_bus8,
446 .write_vmem = write_vmem,
447 },
448 };
449
450 FBTFT_REGISTER_DRIVER(DRVNAME, "displaytronic,fb_agm1264k-fl", &display);
451
452 MODULE_ALIAS("platform:" DRVNAME);
453
454 MODULE_DESCRIPTION("Two KS0108 LCD controllers in AGM1264K-FL display");
455 MODULE_AUTHOR("ololoshka2871");
456 MODULE_LICENSE("GPL");
457