1/*
2 * FB driver for the UltraChip UC1611 LCD controller
3 *
4 * The display is 4-bit grayscale (16 shades) 240x160.
5 *
6 * Copyright (C) 2015 Henri Chain
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 */
18
19#include <linux/module.h>
20#include <linux/kernel.h>
21#include <linux/init.h>
22#include <linux/gpio.h>
23#include <linux/spi/spi.h>
24#include <linux/delay.h>
25
26#include "fbtft.h"
27
28#define DRVNAME		"fb_uc1611"
29#define WIDTH		240
30#define HEIGHT		160
31#define BPP		8
32#define FPS		40
33
34/*
35 * LCD voltage is a combination of ratio, gain, pot and temp
36 *
37 * V_LCD = V_BIAS * ratio
38 * V_LCD = (C_V0 + C_PM �� pot) * (1 + (T - 25) * temp)
39 * C_V0 and C_PM depend on ratio and gain
40 * T is ambient temperature
41 */
42
43/* BR -> actual ratio: 0-3 -> 5, 10, 11, 13 */
44static unsigned ratio = 2;
45module_param(ratio, uint, 0);
46MODULE_PARM_DESC(ratio, "BR[1:0] Bias voltage ratio: 0-3 (default: 2)");
47
48static unsigned gain = 3;
49module_param(gain, uint, 0);
50MODULE_PARM_DESC(gain, "GN[1:0] Bias voltage gain: 0-3 (default: 3)");
51
52static unsigned pot = 16;
53module_param(pot, uint, 0);
54MODULE_PARM_DESC(pot, "PM[6:0] Bias voltage pot.: 0-63 (default: 16)");
55
56/* TC -> % compensation per deg C: 0-3 -> -.05, -.10, -.015, -.20 */
57static unsigned temp;
58module_param(temp, uint, 0);
59MODULE_PARM_DESC(temp, "TC[1:0] Temperature compensation: 0-3 (default: 0)");
60
61/* PC[1:0] -> LCD capacitance: 0-3 -> <20nF, 20-28 nF, 29-40 nF, 40-56 nF */
62static unsigned load = 1;
63module_param(load, uint, 0);
64MODULE_PARM_DESC(load, "PC[1:0] Panel Loading: 0-3 (default: 1)");
65
66/* PC[3:2] -> V_LCD: 0, 1, 3 -> ext., int. with ratio = 5, int. standard */
67static unsigned pump = 3;
68module_param(pump, uint, 0);
69MODULE_PARM_DESC(pump, "PC[3:2] Pump control: 0,1,3 (default: 3)");
70
71static int init_display(struct fbtft_par *par)
72{
73	int ret;
74
75	/* Set CS active high */
76	par->spi->mode |= SPI_CS_HIGH;
77	ret = spi_setup(par->spi);
78	if (ret) {
79		dev_err(par->info->device, "Could not set SPI_CS_HIGH\n");
80		return ret;
81	}
82
83	/* Reset controller */
84	write_reg(par, 0xE2);
85
86	/* Set bias ratio */
87	write_reg(par, 0xE8 | (ratio & 0x03));
88
89	/* Set bias gain and potentiometer */
90	write_reg(par, 0x81);
91	write_reg(par, (gain & 0x03) << 6 | (pot & 0x3F));
92
93	/* Set temperature compensation */
94	write_reg(par, 0x24 | (temp & 0x03));
95
96	/* Set panel loading */
97	write_reg(par, 0x28 | (load & 0x03));
98
99	/* Set pump control */
100	write_reg(par, 0x2C | (pump & 0x03));
101
102	/* Set inverse display */
103	write_reg(par, 0xA6 | (0x01 & 0x01));
104
105	/* Set 4-bit grayscale mode */
106	write_reg(par, 0xD0 | (0x02 & 0x03));
107
108	/* Set Display enable */
109	write_reg(par, 0xA8 | 0x07);
110
111	return 0;
112}
113
114static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
115{
116	switch (par->info->var.rotate) {
117	case 90:
118	case 270:
119		/* Set column address */
120		write_reg(par, ys & 0x0F);
121		write_reg(par, 0x10 | (ys >> 4));
122
123		/* Set page address (divide xs by 2) (not used by driver) */
124		write_reg(par, 0x60 | ((xs >> 1) & 0x0F));
125		write_reg(par, 0x70 | (xs >> 5));
126		break;
127	default:
128		/* Set column address (not used by driver) */
129		write_reg(par, xs & 0x0F);
130		write_reg(par, 0x10 | (xs >> 4));
131
132		/* Set page address (divide ys by 2) */
133		write_reg(par, 0x60 | ((ys >> 1) & 0x0F));
134		write_reg(par, 0x70 | (ys >> 5));
135		break;
136	}
137}
138
139static int blank(struct fbtft_par *par, bool on)
140{
141	fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n",
142		      __func__, on ? "true" : "false");
143
144	if (on)
145		write_reg(par, 0xA8 | 0x00);
146	else
147		write_reg(par, 0xA8 | 0x07);
148	return 0;
149}
150
151static int set_var(struct fbtft_par *par)
152{
153	/* par->info->fix.visual = FB_VISUAL_PSEUDOCOLOR; */
154	par->info->var.grayscale = 1;
155	par->info->var.red.offset    = 0;
156	par->info->var.red.length    = 8;
157	par->info->var.green.offset  = 0;
158	par->info->var.green.length  = 8;
159	par->info->var.blue.offset   = 0;
160	par->info->var.blue.length   = 8;
161	par->info->var.transp.offset = 0;
162	par->info->var.transp.length = 0;
163
164	switch (par->info->var.rotate) {
165	case 90:
166		/* Set RAM address control */
167		write_reg(par, 0x88
168			| (0x0 & 0x1) << 2 /* Increment positively */
169			| (0x1 & 0x1) << 1 /* Increment page first */
170			| (0x1 & 0x1));    /* Wrap around (default) */
171
172		/* Set LCD mapping */
173		write_reg(par, 0xC0
174			| (0x0 & 0x1) << 2 /* Mirror Y OFF */
175			| (0x0 & 0x1) << 1 /* Mirror X OFF */
176			| (0x0 & 0x1));    /* MS nibble last (default) */
177		break;
178	case 180:
179		/* Set RAM address control */
180		write_reg(par, 0x88
181			| (0x0 & 0x1) << 2 /* Increment positively */
182			| (0x0 & 0x1) << 1 /* Increment column first */
183			| (0x1 & 0x1));    /* Wrap around (default) */
184
185		/* Set LCD mapping */
186		write_reg(par, 0xC0
187			| (0x1 & 0x1) << 2 /* Mirror Y ON */
188			| (0x0 & 0x1) << 1 /* Mirror X OFF */
189			| (0x0 & 0x1));    /* MS nibble last (default) */
190		break;
191	case 270:
192		/* Set RAM address control */
193		write_reg(par, 0x88
194			| (0x0 & 0x1) << 2 /* Increment positively */
195			| (0x1 & 0x1) << 1 /* Increment page first */
196			| (0x1 & 0x1));    /* Wrap around (default) */
197
198		/* Set LCD mapping */
199		write_reg(par, 0xC0
200			| (0x1 & 0x1) << 2 /* Mirror Y ON */
201			| (0x1 & 0x1) << 1 /* Mirror X ON */
202			| (0x0 & 0x1));    /* MS nibble last (default) */
203		break;
204	default:
205		/* Set RAM address control */
206		write_reg(par, 0x88
207			| (0x0 & 0x1) << 2 /* Increment positively */
208			| (0x0 & 0x1) << 1 /* Increment column first */
209			| (0x1 & 0x1));    /* Wrap around (default) */
210
211		/* Set LCD mapping */
212		write_reg(par, 0xC0
213			| (0x0 & 0x1) << 2 /* Mirror Y OFF */
214			| (0x1 & 0x1) << 1 /* Mirror X ON */
215			| (0x0 & 0x1));    /* MS nibble last (default) */
216		break;
217	}
218
219	return 0;
220}
221
222static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
223{
224	u8 *vmem8 = (u8 *)(par->info->screen_buffer);
225	u8 *buf8 = (u8 *)(par->txbuf.buf);
226	u16 *buf16 = (u16 *)(par->txbuf.buf);
227	int line_length = par->info->fix.line_length;
228	int y_start = (offset / line_length);
229	int y_end = (offset + len - 1) / line_length;
230	int x, y, i;
231	int ret = 0;
232
233	switch (par->pdata->display.buswidth) {
234	case 8:
235		switch (par->info->var.rotate) {
236		case 90:
237		case 270:
238			i = y_start * line_length;
239			for (y = y_start; y <= y_end; y++) {
240				for (x = 0; x < line_length; x += 2) {
241					*buf8 = vmem8[i] >> 4;
242					*buf8 |= vmem8[i + 1] & 0xF0;
243					buf8++;
244					i += 2;
245				}
246			}
247			break;
248		default:
249			/* Must be even because pages are two lines */
250			y_start &= 0xFE;
251			i = y_start * line_length;
252			for (y = y_start; y <= y_end; y += 2) {
253				for (x = 0; x < line_length; x++) {
254					*buf8 = vmem8[i] >> 4;
255					*buf8 |= vmem8[i + line_length] & 0xF0;
256					buf8++;
257					i++;
258				}
259				i += line_length;
260			}
261			break;
262		}
263		gpio_set_value(par->gpio.dc, 1);
264
265		/* Write data */
266		ret = par->fbtftops.write(par, par->txbuf.buf, len / 2);
267		break;
268	case 9:
269		switch (par->info->var.rotate) {
270		case 90:
271		case 270:
272			i = y_start * line_length;
273			for (y = y_start; y <= y_end; y++) {
274				for (x = 0; x < line_length; x += 2) {
275					*buf16 = 0x100;
276					*buf16 |= vmem8[i] >> 4;
277					*buf16 |= vmem8[i + 1] & 0xF0;
278					buf16++;
279					i += 2;
280				}
281			}
282			break;
283		default:
284			/* Must be even because pages are two lines */
285			y_start &= 0xFE;
286			i = y_start * line_length;
287			for (y = y_start; y <= y_end; y += 2) {
288				for (x = 0; x < line_length; x++) {
289					*buf16 = 0x100;
290					*buf16 |= vmem8[i] >> 4;
291					*buf16 |= vmem8[i + line_length] & 0xF0;
292					buf16++;
293					i++;
294				}
295				i += line_length;
296			}
297			break;
298		}
299
300		/* Write data */
301		ret = par->fbtftops.write(par, par->txbuf.buf, len);
302		break;
303	default:
304		dev_err(par->info->device, "unsupported buswidth %d\n",
305			par->pdata->display.buswidth);
306	}
307
308	if (ret < 0)
309		dev_err(par->info->device, "write failed and returned: %d\n",
310			ret);
311
312	return ret;
313}
314
315static struct fbtft_display display = {
316	.txbuflen = -1,
317	.regwidth = 8,
318	.width = WIDTH,
319	.height = HEIGHT,
320	.bpp = BPP,
321	.fps = FPS,
322	.fbtftops = {
323		.write_vmem = write_vmem,
324		.init_display = init_display,
325		.set_addr_win = set_addr_win,
326		.set_var = set_var,
327		.blank = blank,
328	},
329};
330
331FBTFT_REGISTER_DRIVER(DRVNAME, "ultrachip,uc1611", &display);
332
333MODULE_ALIAS("spi:" DRVNAME);
334MODULE_ALIAS("platform:" DRVNAME);
335MODULE_ALIAS("spi:uc1611");
336MODULE_ALIAS("platform:uc1611");
337
338MODULE_DESCRIPTION("FB driver for the UC1611 LCD controller");
339MODULE_AUTHOR("Henri Chain");
340MODULE_LICENSE("GPL");
341