1 // SPDX-License-Identifier: GPL-2.0+
3 * FB driver for the SH1106 OLED Controller
4 * Based on the SSD1306 driver by Noralf Tronnes
6 * Copyright (C) 2017 Heiner Kallweit
9 #include <linux/module.h>
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/delay.h>
16 #define DRVNAME "fb_sh1106"
20 /* Init sequence based on the Adafruit SSD1306 Arduino library */
21 static int init_display(struct fbtft_par *par)
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");
30 if (par->info->var.rotate) {
31 dev_err(par->info->device, "Display rotation not supported\n");
35 par->fbtftops.reset(par);
40 /* Set Display Clock Divide Ratio/ Oscillator Frequency */
41 write_reg(par, 0xD5, 0x80);
43 /* Set Multiplex Ratio */
44 write_reg(par, 0xA8, par->info->var.yres - 1);
46 /* Set Display Offset */
47 write_reg(par, 0xD3, 0x00);
49 /* Set Display Start Line */
50 write_reg(par, 0x40 | 0x0);
52 /* Set Segment Re-map */
53 /* column address 127 is mapped to SEG0 */
54 write_reg(par, 0xA0 | 0x1);
56 /* Set COM Output Scan Direction */
57 /* remapped mode. Scan from COM[N-1] to COM0 */
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);
68 /* A[4]=0b, Sequential COM pin configuration */
69 write_reg(par, 0xDA, 0x02);
71 /* Set Pre-charge Period */
72 write_reg(par, 0xD9, 0xF1);
74 /* Set VCOMH Deselect Level */
75 write_reg(par, 0xDB, 0x40);
85 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
89 static int blank(struct fbtft_par *par, bool on)
91 fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
92 __func__, on ? "true" : "false");
94 write_reg(par, on ? 0xAE : 0xAF);
99 /* Gamma is used to control Contrast */
100 static int set_gamma(struct fbtft_par *par, u32 *curves)
105 /* Set Contrast Control for BANK0 */
106 write_reg(par, 0x81, curves[0]);
111 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
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;
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);
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);
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])
133 ret = fbtft_write_buf_dc(par, buf, xres, 1);
141 static void write_register(struct fbtft_par *par, int len, ...)
148 for (i = 0; i < len; i++)
149 par->buf[i] = va_arg(args, unsigned int);
151 /* keep DC low for all command bytes to transfer */
152 fbtft_write_buf_dc(par, par->buf, len, 0);
157 static struct fbtft_display display = {
164 /* set default contrast to 0xcd = 80% */
167 .write_vmem = write_vmem,
168 .write_register = write_register,
169 .init_display = init_display,
170 .set_addr_win = set_addr_win,
172 .set_gamma = set_gamma,
176 FBTFT_REGISTER_DRIVER(DRVNAME, "sinowealth,sh1106", &display);
178 MODULE_ALIAS("spi:" DRVNAME);
179 MODULE_ALIAS("platform:" DRVNAME);
180 MODULE_ALIAS("spi:sh1106");
181 MODULE_ALIAS("platform:sh1106");
183 MODULE_DESCRIPTION("SH1106 OLED Driver");
184 MODULE_AUTHOR("Heiner Kallweit");
185 MODULE_LICENSE("GPL");