1 /* 2 * FB driver for the SH1106 OLED Controller 3 * Based on the SSD1306 driver by Noralf Tronnes 4 * 5 * Copyright (C) 2017 Heiner Kallweit 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 */ 17 18 #include <linux/module.h> 19 #include <linux/kernel.h> 20 #include <linux/init.h> 21 #include <linux/gpio.h> 22 #include <linux/delay.h> 23 24 #include "fbtft.h" 25 26 #define DRVNAME "fb_sh1106" 27 #define WIDTH 128 28 #define HEIGHT 64 29 30 /* Init sequence based on the Adafruit SSD1306 Arduino library */ 31 static int init_display(struct fbtft_par *par) 32 { 33 if (!par->info->var.xres || par->info->var.xres > WIDTH || 34 !par->info->var.yres || par->info->var.yres > HEIGHT || 35 par->info->var.yres % 8) { 36 dev_err(par->info->device, "Invalid screen size\n"); 37 return -EINVAL; 38 } 39 40 if (par->info->var.rotate) { 41 dev_err(par->info->device, "Display rotation not supported\n"); 42 return -EINVAL; 43 } 44 45 par->fbtftops.reset(par); 46 47 /* Set Display OFF */ 48 write_reg(par, 0xAE); 49 50 /* Set Display Clock Divide Ratio/ Oscillator Frequency */ 51 write_reg(par, 0xD5, 0x80); 52 53 /* Set Multiplex Ratio */ 54 write_reg(par, 0xA8, par->info->var.yres - 1); 55 56 /* Set Display Offset */ 57 write_reg(par, 0xD3, 0x00); 58 59 /* Set Display Start Line */ 60 write_reg(par, 0x40 | 0x0); 61 62 /* Set Segment Re-map */ 63 /* column address 127 is mapped to SEG0 */ 64 write_reg(par, 0xA0 | 0x1); 65 66 /* Set COM Output Scan Direction */ 67 /* remapped mode. Scan from COM[N-1] to COM0 */ 68 write_reg(par, 0xC8); 69 70 /* Set COM Pins Hardware Configuration */ 71 if (par->info->var.yres == 64) 72 /* A[4]=1b, Alternative COM pin configuration */ 73 write_reg(par, 0xDA, 0x12); 74 else if (par->info->var.yres == 48) 75 /* A[4]=1b, Alternative COM pin configuration */ 76 write_reg(par, 0xDA, 0x12); 77 else 78 /* A[4]=0b, Sequential COM pin configuration */ 79 write_reg(par, 0xDA, 0x02); 80 81 /* Set Pre-charge Period */ 82 write_reg(par, 0xD9, 0xF1); 83 84 /* Set VCOMH Deselect Level */ 85 write_reg(par, 0xDB, 0x40); 86 87 /* Set Display ON */ 88 write_reg(par, 0xAF); 89 90 msleep(150); 91 92 return 0; 93 } 94 95 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye) 96 { 97 } 98 99 static int blank(struct fbtft_par *par, bool on) 100 { 101 fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n", 102 __func__, on ? "true" : "false"); 103 104 write_reg(par, on ? 0xAE : 0xAF); 105 106 return 0; 107 } 108 109 /* Gamma is used to control Contrast */ 110 static int set_gamma(struct fbtft_par *par, u32 *curves) 111 { 112 /* apply mask */ 113 curves[0] &= 0xFF; 114 115 /* Set Contrast Control for BANK0 */ 116 write_reg(par, 0x81, curves[0]); 117 118 return 0; 119 } 120 121 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len) 122 { 123 u16 *vmem16 = (u16 *)par->info->screen_buffer; 124 u32 xres = par->info->var.xres; 125 int page, page_start, page_end, x, i, ret; 126 u8 *buf = par->txbuf.buf; 127 128 /* offset refers to vmem with 2 bytes element size */ 129 page_start = offset / (8 * 2 * xres); 130 page_end = DIV_ROUND_UP(offset + len, 8 * 2 * xres); 131 132 for (page = page_start; page < page_end; page++) { 133 /* set page and set column to 2 because of vidmem width 132 */ 134 write_reg(par, 0xb0 | page, 0x00 | 2, 0x10 | 0); 135 136 memset(buf, 0, xres); 137 for (x = 0; x < xres; x++) 138 for (i = 0; i < 8; i++) 139 if (vmem16[(page * 8 + i) * xres + x]) 140 buf[x] |= BIT(i); 141 142 /* Write data */ 143 ret = fbtft_write_buf_dc(par, buf, xres, 1); 144 if (ret < 0) 145 return ret; 146 } 147 148 return 0; 149 } 150 151 static void write_register(struct fbtft_par *par, int len, ...) 152 { 153 va_list args; 154 int i; 155 156 va_start(args, len); 157 158 for (i = 0; i < len; i++) 159 par->buf[i] = va_arg(args, unsigned int); 160 161 /* keep DC low for all command bytes to transfer */ 162 fbtft_write_buf_dc(par, par->buf, len, 0); 163 164 va_end(args); 165 } 166 167 static struct fbtft_display display = { 168 .regwidth = 8, 169 .width = WIDTH, 170 .height = HEIGHT, 171 .txbuflen = WIDTH, 172 .gamma_num = 1, 173 .gamma_len = 1, 174 /* set default contrast to 0xcd = 80% */ 175 .gamma = "cd", 176 .fbtftops = { 177 .write_vmem = write_vmem, 178 .write_register = write_register, 179 .init_display = init_display, 180 .set_addr_win = set_addr_win, 181 .blank = blank, 182 .set_gamma = set_gamma, 183 }, 184 }; 185 186 FBTFT_REGISTER_DRIVER(DRVNAME, "sinowealth,sh1106", &display); 187 188 MODULE_ALIAS("spi:" DRVNAME); 189 MODULE_ALIAS("platform:" DRVNAME); 190 MODULE_ALIAS("spi:sh1106"); 191 MODULE_ALIAS("platform:sh1106"); 192 193 MODULE_DESCRIPTION("SH1106 OLED Driver"); 194 MODULE_AUTHOR("Heiner Kallweit"); 195 MODULE_LICENSE("GPL"); 196