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/gpio/consumer.h>
13 #include <linux/delay.h>
14
15 #include "fbtft.h"
16
17 #define DRVNAME "fb_sh1106"
18 #define WIDTH 128
19 #define HEIGHT 64
20
21 /* Init sequence based on the Adafruit SSD1306 Arduino library */
init_display(struct fbtft_par * par)22 static int init_display(struct fbtft_par *par)
23 {
24 if (!par->info->var.xres || par->info->var.xres > WIDTH ||
25 !par->info->var.yres || par->info->var.yres > HEIGHT ||
26 par->info->var.yres % 8) {
27 dev_err(par->info->device, "Invalid screen size\n");
28 return -EINVAL;
29 }
30
31 if (par->info->var.rotate) {
32 dev_err(par->info->device, "Display rotation not supported\n");
33 return -EINVAL;
34 }
35
36 par->fbtftops.reset(par);
37
38 /* Set Display OFF */
39 write_reg(par, 0xAE);
40
41 /* Set Display Clock Divide Ratio/ Oscillator Frequency */
42 write_reg(par, 0xD5, 0x80);
43
44 /* Set Multiplex Ratio */
45 write_reg(par, 0xA8, par->info->var.yres - 1);
46
47 /* Set Display Offset */
48 write_reg(par, 0xD3, 0x00);
49
50 /* Set Display Start Line */
51 write_reg(par, 0x40 | 0x0);
52
53 /* Set Segment Re-map */
54 /* column address 127 is mapped to SEG0 */
55 write_reg(par, 0xA0 | 0x1);
56
57 /* Set COM Output Scan Direction */
58 /* remapped mode. Scan from COM[N-1] to COM0 */
59 write_reg(par, 0xC8);
60
61 /* Set COM Pins Hardware Configuration */
62 if (par->info->var.yres == 64)
63 /* A[4]=1b, Alternative COM pin configuration */
64 write_reg(par, 0xDA, 0x12);
65 else if (par->info->var.yres == 48)
66 /* A[4]=1b, Alternative COM pin configuration */
67 write_reg(par, 0xDA, 0x12);
68 else
69 /* A[4]=0b, Sequential COM pin configuration */
70 write_reg(par, 0xDA, 0x02);
71
72 /* Set Pre-charge Period */
73 write_reg(par, 0xD9, 0xF1);
74
75 /* Set VCOMH Deselect Level */
76 write_reg(par, 0xDB, 0x40);
77
78 /* Set Display ON */
79 write_reg(par, 0xAF);
80
81 msleep(150);
82
83 return 0;
84 }
85
set_addr_win(struct fbtft_par * par,int xs,int ys,int xe,int ye)86 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
87 {
88 }
89
blank(struct fbtft_par * par,bool on)90 static int blank(struct fbtft_par *par, bool on)
91 {
92 fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
93 __func__, on ? "true" : "false");
94
95 write_reg(par, on ? 0xAE : 0xAF);
96
97 return 0;
98 }
99
100 /* Gamma is used to control Contrast */
set_gamma(struct fbtft_par * par,u32 * curves)101 static int set_gamma(struct fbtft_par *par, u32 *curves)
102 {
103 /* apply mask */
104 curves[0] &= 0xFF;
105
106 /* Set Contrast Control for BANK0 */
107 write_reg(par, 0x81, curves[0]);
108
109 return 0;
110 }
111
write_vmem(struct fbtft_par * par,size_t offset,size_t len)112 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
113 {
114 u16 *vmem16 = (u16 *)par->info->screen_buffer;
115 u32 xres = par->info->var.xres;
116 int page, page_start, page_end, x, i, ret;
117 u8 *buf = par->txbuf.buf;
118
119 /* offset refers to vmem with 2 bytes element size */
120 page_start = offset / (8 * 2 * xres);
121 page_end = DIV_ROUND_UP(offset + len, 8 * 2 * xres);
122
123 for (page = page_start; page < page_end; page++) {
124 /* set page and set column to 2 because of vidmem width 132 */
125 write_reg(par, 0xb0 | page, 0x00 | 2, 0x10 | 0);
126
127 memset(buf, 0, xres);
128 for (x = 0; x < xres; x++)
129 for (i = 0; i < 8; i++)
130 if (vmem16[(page * 8 + i) * xres + x])
131 buf[x] |= BIT(i);
132
133 /* Write data */
134 ret = fbtft_write_buf_dc(par, buf, xres, 1);
135 if (ret < 0)
136 return ret;
137 }
138
139 return 0;
140 }
141
write_register(struct fbtft_par * par,int len,...)142 static void write_register(struct fbtft_par *par, int len, ...)
143 {
144 va_list args;
145 int i;
146
147 va_start(args, len);
148
149 for (i = 0; i < len; i++)
150 par->buf[i] = va_arg(args, unsigned int);
151
152 /* keep DC low for all command bytes to transfer */
153 fbtft_write_buf_dc(par, par->buf, len, 0);
154
155 va_end(args);
156 }
157
158 static struct fbtft_display display = {
159 .regwidth = 8,
160 .width = WIDTH,
161 .height = HEIGHT,
162 .txbuflen = WIDTH,
163 .gamma_num = 1,
164 .gamma_len = 1,
165 /* set default contrast to 0xcd = 80% */
166 .gamma = "cd",
167 .fbtftops = {
168 .write_vmem = write_vmem,
169 .write_register = write_register,
170 .init_display = init_display,
171 .set_addr_win = set_addr_win,
172 .blank = blank,
173 .set_gamma = set_gamma,
174 },
175 };
176
177 FBTFT_REGISTER_DRIVER(DRVNAME, "sinowealth,sh1106", &display);
178
179 MODULE_ALIAS("spi:" DRVNAME);
180 MODULE_ALIAS("platform:" DRVNAME);
181 MODULE_ALIAS("spi:sh1106");
182 MODULE_ALIAS("platform:sh1106");
183
184 MODULE_DESCRIPTION("SH1106 OLED Driver");
185 MODULE_AUTHOR("Heiner Kallweit");
186 MODULE_LICENSE("GPL");
187