1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * FB driver for the UC1701 LCD Controller
4 *
5 * The display is monochrome and the video memory is RGB565.
6 * Any pixel value except 0 turns the pixel on.
7 *
8 * Copyright (C) 2014 Juergen Holzmann
9 */
10
11#include <linux/module.h>
12#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/gpio/consumer.h>
15#include <linux/spi/spi.h>
16#include <linux/delay.h>
17
18#include "fbtft.h"
19
20#define DRVNAME	"fb_uc1701"
21#define WIDTH	  102
22#define HEIGHT	 64
23#define PAGES	  (HEIGHT / 8)
24
25/* 1: Display on/off */
26#define LCD_DISPLAY_ENABLE    0xAE
27/* 2: display start line set */
28#define LCD_START_LINE	0x40
29/* 3: Page address set (lower 4 bits select one of the pages) */
30#define LCD_PAGE_ADDRESS      0xB0
31/* 4: column address */
32#define LCD_COL_ADDRESS       0x10
33/* 8: select orientation */
34#define LCD_BOTTOMVIEW	0xA0
35/* 9: inverted display */
36#define LCD_DISPLAY_INVERT    0xA6
37/* 10: show memory content or switch all pixels on */
38#define LCD_ALL_PIXEL	 0xA4
39/* 11: lcd bias set */
40#define LCD_BIAS	      0xA2
41/* 14: Reset Controller */
42#define LCD_RESET_CMD	 0xE2
43/* 15: output mode select (turns display upside-down) */
44#define LCD_SCAN_DIR	  0xC0
45/* 16: power control set */
46#define LCD_POWER_CONTROL     0x28
47/* 17: voltage regulator resistor ratio set */
48#define LCD_VOLTAGE	   0x20
49/* 18: Volume mode set */
50#define LCD_VOLUME_MODE       0x81
51/* 22: NOP command */
52#define LCD_NO_OP	     0xE3
53/* 25: advanced program control */
54#define LCD_ADV_PROG_CTRL     0xFA
55/* 25: advanced program control2 */
56#define LCD_ADV_PROG_CTRL2    0x10
57#define LCD_TEMPCOMP_HIGH     0x80
58/* column offset for normal orientation */
59#define SHIFT_ADDR_NORMAL     0
60/* column offset for bottom view orientation */
61#define SHIFT_ADDR_TOPVIEW    30
62
63static int init_display(struct fbtft_par *par)
64{
65	par->fbtftops.reset(par);
66
67	/* softreset of LCD */
68	write_reg(par, LCD_RESET_CMD);
69	mdelay(10);
70
71	/* set startpoint */
72	write_reg(par, LCD_START_LINE);
73
74	/* select orientation BOTTOMVIEW */
75	write_reg(par, LCD_BOTTOMVIEW | 1);
76
77	/* output mode select (turns display upside-down) */
78	write_reg(par, LCD_SCAN_DIR | 0x00);
79
80	/* Normal Pixel mode */
81	write_reg(par, LCD_ALL_PIXEL | 0);
82
83	/* positive display */
84	write_reg(par, LCD_DISPLAY_INVERT | 0);
85
86	/* bias 1/9 */
87	write_reg(par, LCD_BIAS | 0);
88
89	/* power control mode: all features on */
90	write_reg(par, LCD_POWER_CONTROL | 0x07);
91
92	/* set voltage regulator R/R */
93	write_reg(par, LCD_VOLTAGE | 0x07);
94
95	/* volume mode set */
96	write_reg(par, LCD_VOLUME_MODE);
97	write_reg(par, 0x09);
98	write_reg(par, LCD_NO_OP);
99
100	/* advanced program control */
101	write_reg(par, LCD_ADV_PROG_CTRL);
102	write_reg(par, LCD_ADV_PROG_CTRL2 | LCD_TEMPCOMP_HIGH);
103
104	/* enable display */
105	write_reg(par, LCD_DISPLAY_ENABLE | 1);
106
107	return 0;
108}
109
110static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
111{
112	/* goto address */
113	write_reg(par, LCD_PAGE_ADDRESS);
114	write_reg(par, 0x00);
115	write_reg(par, LCD_COL_ADDRESS);
116}
117
118static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
119{
120	u16 *vmem16 = (u16 *)par->info->screen_buffer;
121	u8 *buf;
122	int x, y, i;
123	int ret = 0;
124
125	for (y = 0; y < PAGES; y++) {
126		buf = par->txbuf.buf;
127		for (x = 0; x < WIDTH; x++) {
128			*buf = 0x00;
129			for (i = 0; i < 8; i++)
130				*buf |= (vmem16[((y * 8 * WIDTH) +
131						 (i * WIDTH)) + x] ?
132					 1 : 0) << i;
133			buf++;
134		}
135
136		write_reg(par, LCD_PAGE_ADDRESS | (u8)y);
137		write_reg(par, 0x00);
138		write_reg(par, LCD_COL_ADDRESS);
139		gpiod_set_value(par->gpio.dc, 1);
140		ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH);
141		gpiod_set_value(par->gpio.dc, 0);
142	}
143
144	if (ret < 0)
145		dev_err(par->info->device, "write failed and returned: %d\n",
146			ret);
147
148	return ret;
149}
150
151static struct fbtft_display display = {
152	.regwidth = 8,
153	.width = WIDTH,
154	.height = HEIGHT,
155	.fbtftops = {
156		.init_display = init_display,
157		.set_addr_win = set_addr_win,
158		.write_vmem = write_vmem,
159	},
160	.backlight = 1,
161};
162
163FBTFT_REGISTER_DRIVER(DRVNAME, "UltraChip,uc1701", &display);
164
165MODULE_ALIAS("spi:" DRVNAME);
166MODULE_ALIAS("spi:uc1701");
167
168MODULE_DESCRIPTION("FB driver for the UC1701 LCD Controller");
169MODULE_AUTHOR("Juergen Holzmann");
170MODULE_LICENSE("GPL");
171