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 */ 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 86 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye) 87 { 88 } 89 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 */ 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 } 111 112 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 } 141 142 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