root/drivers/staging/fbtft/fb_sh1106.c

DEFINITIONS

1. init_display
2. set_addr_win
3. blank
4. set_gamma
5. write_vmem
6. write_register

   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");