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 */
init_display(struct fbtft_par * par)21 static 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(150);
81
82 return 0;
83 }
84
set_addr_win(struct fbtft_par * par,int xs,int ys,int xe,int ye)85 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
86 {
87 }
88
blank(struct fbtft_par * par,bool on)89 static int blank(struct fbtft_par *par, bool on)
90 {
91 write_reg(par, on ? 0xAE : 0xAF);
92
93 return 0;
94 }
95
96 /* Gamma is used to control Contrast */
set_gamma(struct fbtft_par * par,u32 * curves)97 static int set_gamma(struct fbtft_par *par, u32 *curves)
98 {
99 /* apply mask */
100 curves[0] &= 0xFF;
101
102 /* Set Contrast Control for BANK0 */
103 write_reg(par, 0x81, curves[0]);
104
105 return 0;
106 }
107
write_vmem(struct fbtft_par * par,size_t offset,size_t len)108 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
109 {
110 u16 *vmem16 = (u16 *)par->info->screen_buffer;
111 u32 xres = par->info->var.xres;
112 int page, page_start, page_end, x, i, ret;
113 u8 *buf = par->txbuf.buf;
114
115 /* offset refers to vmem with 2 bytes element size */
116 page_start = offset / (8 * 2 * xres);
117 page_end = DIV_ROUND_UP(offset + len, 8 * 2 * xres);
118
119 for (page = page_start; page < page_end; page++) {
120 /* set page and set column to 2 because of vidmem width 132 */
121 write_reg(par, 0xb0 | page, 0x00 | 2, 0x10 | 0);
122
123 memset(buf, 0, xres);
124 for (x = 0; x < xres; x++)
125 for (i = 0; i < 8; i++)
126 if (vmem16[(page * 8 + i) * xres + x])
127 buf[x] |= BIT(i);
128
129 /* Write data */
130 ret = fbtft_write_buf_dc(par, buf, xres, 1);
131 if (ret < 0)
132 return ret;
133 }
134
135 return 0;
136 }
137
write_register(struct fbtft_par * par,int len,...)138 static void write_register(struct fbtft_par *par, int len, ...)
139 {
140 va_list args;
141 int i;
142
143 va_start(args, len);
144
145 for (i = 0; i < len; i++)
146 par->buf[i] = va_arg(args, unsigned int);
147
148 /* keep DC low for all command bytes to transfer */
149 fbtft_write_buf_dc(par, par->buf, len, 0);
150
151 va_end(args);
152 }
153
154 static struct fbtft_display display = {
155 .regwidth = 8,
156 .width = WIDTH,
157 .height = HEIGHT,
158 .txbuflen = WIDTH,
159 .gamma_num = 1,
160 .gamma_len = 1,
161 /* set default contrast to 0xcd = 80% */
162 .gamma = "cd",
163 .fbtftops = {
164 .write_vmem = write_vmem,
165 .write_register = write_register,
166 .init_display = init_display,
167 .set_addr_win = set_addr_win,
168 .blank = blank,
169 .set_gamma = set_gamma,
170 },
171 };
172
173 FBTFT_REGISTER_SPI_DRIVER(DRVNAME, "sinowealth", "sh1106", &display);
174
175 MODULE_DESCRIPTION("SH1106 OLED Driver");
176 MODULE_AUTHOR("Heiner Kallweit");
177 MODULE_LICENSE("GPL");
178