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
45/* diffusing error (�Floyd-Steinberg�) */
46#define DIFFUSING_MATRIX_WIDTH	2
47#define DIFFUSING_MATRIX_HEIGHT	2
48
49static const signed char
50diffusing_matrix[DIFFUSING_MATRIX_WIDTH][DIFFUSING_MATRIX_HEIGHT] = {
51	{-1, 3},
52	{3, 2},
53};
54
55static const unsigned char gamma_correction_table[] = {
560, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1,
571, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6,
586, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 11, 11, 12, 12, 13,
5913, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21,
6022, 22, 23, 23, 24, 25, 25, 26, 26, 27, 28, 28, 29, 30, 30, 31, 32,
6133, 33, 34, 35, 35, 36, 37, 38, 39, 39, 40, 41, 42, 43, 43, 44, 45,
6246, 47, 48, 49, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
6362, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81,
6482, 83, 84, 85, 87, 88, 89, 90, 91, 93, 94, 95, 97, 98, 99, 100, 102,
65103, 105, 106, 107, 109, 110, 111, 113, 114, 116, 117, 119, 120, 121,
66123, 124, 126, 127, 129, 130, 132, 133, 135, 137, 138, 140, 141, 143,
67145, 146, 148, 149, 151, 153, 154, 156, 158, 159, 161, 163, 165, 166,
68168, 170, 172, 173, 175, 177, 179, 181, 182, 184, 186, 188, 190, 192,
69194, 196, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219,
70221, 223, 225, 227, 229, 231, 234, 236, 238, 240, 242, 244, 246, 248,
71251, 253, 255
72};
73
74static int init_display(struct fbtft_par *par)
75{
76	u8 i;
77
78	fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
79
80	par->fbtftops.reset(par);
81
82	for (i = 0; i < 2; ++i) {
83		write_reg(par, i, 0x3f); /* display on */
84		write_reg(par, i, 0x40); /* set x to 0 */
85		write_reg(par, i, 0xb0); /* set page to 0 */
86		write_reg(par, i, 0xc0); /* set start line to 0 */
87	}
88
89	return 0;
90}
91
92static void reset(struct fbtft_par *par)
93{
94	if (par->gpio.reset == -1)
95		return;
96
97	fbtft_dev_dbg(DEBUG_RESET, par, par->info->device, "%s()\n", __func__);
98
99	gpio_set_value(par->gpio.reset, 0);
100	udelay(20);
101	gpio_set_value(par->gpio.reset, 1);
102	mdelay(120);
103}
104
105/* Check if all necessary GPIOS defined */
106static int verify_gpios(struct fbtft_par *par)
107{
108	int i;
109
110	fbtft_dev_dbg(DEBUG_VERIFY_GPIOS, par, par->info->device,
111		"%s()\n", __func__);
112
113	if (par->EPIN < 0) {
114		dev_err(par->info->device,
115			"Missing info about 'wr' (aka E) gpio. Aborting.\n");
116		return -EINVAL;
117	}
118	for (i = 0; i < 8; ++i) {
119		if (par->gpio.db[i] < 0) {
120			dev_err(par->info->device,
121				"Missing info about 'db[%i]' gpio. Aborting.\n",
122				i);
123			return -EINVAL;
124		}
125	}
126	if (par->CS0 < 0) {
127		dev_err(par->info->device,
128			"Missing info about 'cs0' gpio. Aborting.\n");
129		return -EINVAL;
130	}
131	if (par->CS1 < 0) {
132		dev_err(par->info->device,
133			"Missing info about 'cs1' gpio. Aborting.\n");
134		return -EINVAL;
135	}
136	if (par->RW < 0) {
137		dev_err(par->info->device,
138			"Missing info about 'rw' gpio. Aborting.\n");
139		return -EINVAL;
140	}
141
142	return 0;
143}
144
145static unsigned long
146request_gpios_match(struct fbtft_par *par, const struct fbtft_gpio *gpio)
147{
148	fbtft_dev_dbg(DEBUG_REQUEST_GPIOS_MATCH, par, par->info->device,
149		"%s('%s')\n", __func__, gpio->name);
150
151	if (strcasecmp(gpio->name, "wr") == 0) {
152		/* left ks0108 E pin */
153		par->EPIN = gpio->gpio;
154		return GPIOF_OUT_INIT_LOW;
155	} else if (strcasecmp(gpio->name, "cs0") == 0) {
156		/* left ks0108 controller pin */
157		par->CS0 = gpio->gpio;
158		return GPIOF_OUT_INIT_HIGH;
159	} else if (strcasecmp(gpio->name, "cs1") == 0) {
160		/* right ks0108 controller pin */
161		par->CS1 = gpio->gpio;
162		return GPIOF_OUT_INIT_HIGH;
163	}
164
165	/* if write (rw = 0) e(1->0) perform write */
166	/* if read (rw = 1) e(0->1) set data on D0-7*/
167	else if (strcasecmp(gpio->name, "rw") == 0) {
168		par->RW = gpio->gpio;
169		return GPIOF_OUT_INIT_LOW;
170	}
171
172	return FBTFT_GPIO_NO_MATCH;
173}
174
175/* This function oses to enter commands
176 * first byte - destination controller 0 or 1
177 * following - commands
178 */
179static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
180{
181	va_list args;
182	int i, ret;
183	u8 *buf = (u8 *)par->buf;
184
185	if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
186		va_start(args, len);
187		for (i = 0; i < len; i++)
188			buf[i] = (u8)va_arg(args, unsigned int);
189
190		va_end(args);
191		fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par,
192			par->info->device, u8, buf, len, "%s: ", __func__);
193	}
194
195	va_start(args, len);
196
197	*buf = (u8)va_arg(args, unsigned int);
198
199	if (*buf > 1) {
200		va_end(args);
201		dev_err(par->info->device,
202			"Incorrect chip select request (%d)\n", *buf);
203		return;
204	}
205
206	/* select chip */
207	if (*buf) {
208		/* cs1 */
209		gpio_set_value(par->CS0, 1);
210		gpio_set_value(par->CS1, 0);
211	} else {
212		/* cs0 */
213		gpio_set_value(par->CS0, 0);
214		gpio_set_value(par->CS1, 1);
215	}
216
217	gpio_set_value(par->RS, 0); /* RS->0 (command mode) */
218	len--;
219
220	if (len) {
221		i = len;
222		while (i--)
223			*buf++ = (u8)va_arg(args, unsigned int);
224		ret = par->fbtftops.write(par, par->buf, len * (sizeof(u8)));
225		if (ret < 0) {
226			va_end(args);
227			dev_err(par->info->device,
228				"write() failed and returned %d\n", ret);
229			return;
230		}
231	}
232
233	va_end(args);
234}
235
236static struct
237{
238	int xs, ys_page, xe, ye_page;
239} addr_win;
240
241/* save display writing zone */
242static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
243{
244	addr_win.xs = xs;
245	addr_win.ys_page = ys / 8;
246	addr_win.xe = xe;
247	addr_win.ye_page = ye / 8;
248
249	fbtft_par_dbg(DEBUG_SET_ADDR_WIN, par,
250		"%s(xs=%d, ys_page=%d, xe=%d, ye_page=%d)\n", __func__,
251		addr_win.xs, addr_win.ys_page, addr_win.xe, addr_win.ye_page);
252}
253
254static void
255construct_line_bitmap(struct fbtft_par *par, u8 *dest, signed short *src,
256						int xs, int xe, int y)
257{
258	int x, i;
259
260	for (x = xs; x < xe; ++x) {
261		u8 res = 0;
262
263		for (i = 0; i < 8; i++)
264			if (src[(y * 8 + i) * par->info->var.xres + x])
265				res |= 1 << i;
266#ifdef NEGATIVE
267		*dest++ = res;
268#else
269		*dest++ = ~res;
270#endif
271	}
272}
273
274static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
275{
276	u16 *vmem16 = (u16 *)par->info->screen_base;
277	u8 *buf = par->txbuf.buf;
278	int x, y;
279	int ret = 0;
280
281	/* buffer to convert RGB565 -> grayscale16 -> Dithered image 1bpp */
282	signed short *convert_buf = kmalloc(par->info->var.xres *
283		par->info->var.yres * sizeof(signed short), GFP_NOIO);
284
285	if (!convert_buf)
286		return -ENOMEM;
287
288	fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s()\n", __func__);
289
290	/* converting to grayscale16 */
291	for (x = 0; x < par->info->var.xres; ++x)
292		for (y = 0; y < par->info->var.yres; ++y) {
293			u16 pixel = vmem16[y *  par->info->var.xres + x];
294			u16 b = pixel & 0x1f;
295			u16 g = (pixel & (0x3f << 5)) >> 5;
296			u16 r = (pixel & (0x1f << (5 + 6))) >> (5 + 6);
297
298			pixel = (299 * r + 587 * g + 114 * b) / 200;
299			if (pixel > 255)
300				pixel = 255;
301
302			/* gamma-correction by table */
303			convert_buf[y *  par->info->var.xres + x] =
304				(signed short)gamma_correction_table[pixel];
305		}
306
307	/* Image Dithering */
308	for (x = 0; x < par->info->var.xres; ++x)
309		for (y = 0; y < par->info->var.yres; ++y) {
310			signed short pixel =
311				convert_buf[y *  par->info->var.xres + x];
312			signed short error_b = pixel - BLACK;
313			signed short error_w = pixel - WHITE;
314			signed short error;
315			u16 i, j;
316
317			/* what color close? */
318			if (abs(error_b) >= abs(error_w)) {
319				/* white */
320				error = error_w;
321				pixel = 0xff;
322			} else {
323				/* black */
324				error = error_b;
325				pixel = 0;
326			}
327
328			error /= 8;
329
330			/* diffusion matrix row */
331			for (i = 0; i < DIFFUSING_MATRIX_WIDTH; ++i)
332				/* diffusion matrix column */
333				for (j = 0; j < DIFFUSING_MATRIX_HEIGHT; ++j) {
334					signed short *write_pos;
335					signed char coeff;
336
337					/* skip pixels out of zone */
338					if (x + i < 0 ||
339						x + i >= par->info->var.xres
340						|| y + j >= par->info->var.yres)
341						continue;
342					write_pos = &convert_buf[
343						(y + j) * par->info->var.xres +
344						x + i];
345					coeff = diffusing_matrix[i][j];
346					if (coeff == -1)
347						/* pixel itself */
348						*write_pos = pixel;
349					else {
350						signed short p = *write_pos +
351							error * coeff;
352
353						if (p > WHITE)
354							p = WHITE;
355						if (p < BLACK)
356							p = BLACK;
357						*write_pos = p;
358					}
359				}
360		}
361
362	 /* 1 string = 2 pages */
363	 for (y = addr_win.ys_page; y <= addr_win.ye_page; ++y) {
364		/* left half of display */
365		if (addr_win.xs < par->info->var.xres / 2) {
366			construct_line_bitmap(par, buf, convert_buf,
367				addr_win.xs, par->info->var.xres / 2, y);
368
369			len = par->info->var.xres / 2 - addr_win.xs;
370
371			/* select left side (sc0)
372			 * set addr
373			 */
374			write_reg(par, 0x00, (1 << 6) | (u8)addr_win.xs);
375			write_reg(par, 0x00, (0x17 << 3) | (u8)y);
376
377			/* write bitmap */
378			gpio_set_value(par->RS, 1); /* RS->1 (data mode) */
379			ret = par->fbtftops.write(par, buf, len);
380			if (ret < 0)
381				dev_err(par->info->device,
382					"write failed and returned: %d\n",
383					ret);
384		}
385		/* right half of display */
386		if (addr_win.xe >= par->info->var.xres / 2) {
387			construct_line_bitmap(par, buf,
388				convert_buf, par->info->var.xres / 2,
389				addr_win.xe + 1, y);
390
391			len = addr_win.xe + 1 - par->info->var.xres / 2;
392
393			/* select right side (sc1)
394			 * set addr
395			 */
396			write_reg(par, 0x01, 1 << 6);
397			write_reg(par, 0x01, (0x17 << 3) | (u8)y);
398
399			/* write bitmap */
400			gpio_set_value(par->RS, 1); /* RS->1 (data mode) */
401			par->fbtftops.write(par, buf, len);
402			if (ret < 0)
403				dev_err(par->info->device,
404					"write failed and returned: %d\n",
405					ret);
406		}
407	}
408	kfree(convert_buf);
409
410	gpio_set_value(par->CS0, 1);
411	gpio_set_value(par->CS1, 1);
412
413	return ret;
414}
415
416static int write(struct fbtft_par *par, void *buf, size_t len)
417{
418	fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
419		"%s(len=%d): ", __func__, len);
420
421	gpio_set_value(par->RW, 0); /* set write mode */
422
423
424	while (len--) {
425		u8 i, data;
426
427		data = *(u8 *) buf++;
428
429		/* set data bus */
430		for (i = 0; i < 8; ++i)
431			gpio_set_value(par->gpio.db[i], data & (1 << i));
432		/* set E */
433		gpio_set_value(par->EPIN, 1);
434		udelay(5);
435		/* unset E - write */
436		gpio_set_value(par->EPIN, 0);
437		udelay(1);
438	}
439
440	return 0;
441}
442
443static struct fbtft_display display = {
444	.regwidth = 8,
445	.width = TOTALWIDTH,
446	.height = HEIGHT,
447	.fps = FPS,
448	.fbtftops = {
449		.init_display = init_display,
450		.set_addr_win = set_addr_win,
451		.verify_gpios = verify_gpios,
452		.request_gpios_match = request_gpios_match,
453		.reset = reset,
454		.write = write,
455		.write_register = write_reg8_bus8,
456		.write_vmem = write_vmem,
457	},
458};
459FBTFT_REGISTER_DRIVER(DRVNAME, "displaytronic,fb_agm1264k-fl", &display);
460
461MODULE_ALIAS("platform:" DRVNAME);
462
463MODULE_DESCRIPTION("Two KS0108 LCD controllers in AGM1264K-FL display");
464MODULE_AUTHOR("ololoshka2871");
465MODULE_LICENSE("GPL");
466