1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * FB driver for the SH1106 OLED Controller
4 * Based on the SSD1306 driver by Noralf Tronnes
5 *
6 * Copyright (C) 2017 Heiner Kallweit
7 */
8
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/init.h>
12#include <linux/delay.h>
13
14#include "fbtft.h"
15
16#define DRVNAME "fb_sh1106"
17#define WIDTH 128
18#define HEIGHT 64
19
20/* Init sequence based on the Adafruit SSD1306 Arduino library */
21static int init_display(struct fbtft_par *par)
22{
23 if (!par->info->var.xres || par->info->var.xres > WIDTH ||
24 !par->info->var.yres || par->info->var.yres > HEIGHT ||
25 par->info->var.yres % 8) {
26 dev_err(par->info->device, "Invalid screen size\n");
27 return -EINVAL;
28 }
29
30 if (par->info->var.rotate) {
31 dev_err(par->info->device, "Display rotation not supported\n");
32 return -EINVAL;
33 }
34
35 par->fbtftops.reset(par);
36
37 /* Set Display OFF */
38 write_reg(par, 0xAE);
39
40 /* Set Display Clock Divide Ratio/ Oscillator Frequency */
41 write_reg(par, 0xD5, 0x80);
42
43 /* Set Multiplex Ratio */
44 write_reg(par, 0xA8, par->info->var.yres - 1);
45
46 /* Set Display Offset */
47 write_reg(par, 0xD3, 0x00);
48
49 /* Set Display Start Line */
50 write_reg(par, 0x40 | 0x0);
51
52 /* Set Segment Re-map */
53 /* column address 127 is mapped to SEG0 */
54 write_reg(par, 0xA0 | 0x1);
55
56 /* Set COM Output Scan Direction */
57 /* remapped mode. Scan from COM[N-1] to COM0 */
58 write_reg(par, 0xC8);
59
60 /* Set COM Pins Hardware Configuration */
61 if (par->info->var.yres == 64)
62 /* A[4]=1b, Alternative COM pin configuration */
63 write_reg(par, 0xDA, 0x12);
64 else if (par->info->var.yres == 48)
65 /* A[4]=1b, Alternative COM pin configuration */
66 write_reg(par, 0xDA, 0x12);
67 else
68 /* A[4]=0b, Sequential COM pin configuration */
69 write_reg(par, 0xDA, 0x02);
70
71 /* Set Pre-charge Period */
72 write_reg(par, 0xD9, 0xF1);
73
74 /* Set VCOMH Deselect Level */
75 write_reg(par, 0xDB, 0x40);
76
77 /* Set Display ON */
78 write_reg(par, 0xAF);
79
80 msleep(msecs: 150);
81
82 return 0;
83}
84
85static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
86{
87}
88
89static int blank(struct fbtft_par *par, bool on)
90{
91 fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
92 __func__, on ? "true" : "false");
93
94 write_reg(par, on ? 0xAE : 0xAF);
95
96 return 0;
97}
98
99/* Gamma is used to control Contrast */
100static int set_gamma(struct fbtft_par *par, u32 *curves)
101{
102 /* apply mask */
103 curves[0] &= 0xFF;
104
105 /* Set Contrast Control for BANK0 */
106 write_reg(par, 0x81, curves[0]);
107
108 return 0;
109}
110
111static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
112{
113 u16 *vmem16 = (u16 *)par->info->screen_buffer;
114 u32 xres = par->info->var.xres;
115 int page, page_start, page_end, x, i, ret;
116 u8 *buf = par->txbuf.buf;
117
118 /* offset refers to vmem with 2 bytes element size */
119 page_start = offset / (8 * 2 * xres);
120 page_end = DIV_ROUND_UP(offset + len, 8 * 2 * xres);
121
122 for (page = page_start; page < page_end; page++) {
123 /* set page and set column to 2 because of vidmem width 132 */
124 write_reg(par, 0xb0 | page, 0x00 | 2, 0x10 | 0);
125
126 memset(buf, 0, xres);
127 for (x = 0; x < xres; x++)
128 for (i = 0; i < 8; i++)
129 if (vmem16[(page * 8 + i) * xres + x])
130 buf[x] |= BIT(i);
131
132 /* Write data */
133 ret = fbtft_write_buf_dc(par, buf, len: xres, dc: 1);
134 if (ret < 0)
135 return ret;
136 }
137
138 return 0;
139}
140
141static void write_register(struct fbtft_par *par, int len, ...)
142{
143 va_list args;
144 int i;
145
146 va_start(args, len);
147
148 for (i = 0; i < len; i++)
149 par->buf[i] = va_arg(args, unsigned int);
150
151 /* keep DC low for all command bytes to transfer */
152 fbtft_write_buf_dc(par, buf: par->buf, len, dc: 0);
153
154 va_end(args);
155}
156
157static struct fbtft_display display = {
158 .regwidth = 8,
159 .width = WIDTH,
160 .height = HEIGHT,
161 .txbuflen = WIDTH,
162 .gamma_num = 1,
163 .gamma_len = 1,
164 /* set default contrast to 0xcd = 80% */
165 .gamma = "cd",
166 .fbtftops = {
167 .write_vmem = write_vmem,
168 .write_register = write_register,
169 .init_display = init_display,
170 .set_addr_win = set_addr_win,
171 .blank = blank,
172 .set_gamma = set_gamma,
173 },
174};
175
176FBTFT_REGISTER_SPI_DRIVER(DRVNAME, "sinowealth", "sh1106", &display);
177
178MODULE_DESCRIPTION("SH1106 OLED Driver");
179MODULE_AUTHOR("Heiner Kallweit");
180MODULE_LICENSE("GPL");
181

source code of linux/drivers/staging/fbtft/fb_sh1106.c