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/*
* FB driver for the SH1106 OLED Controller
* Based on the SSD1306 driver by Noralf Tronnes
*
* Copyright (C) 2017 Heiner Kallweit
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include "fbtft.h"
#define DRVNAME "fb_sh1106"
#define WIDTH 128
#define HEIGHT 64
/*
* write_reg() caveat:
*
* This doesn't work because D/C has to be LOW for both values:
* write_reg(par, val1, val2);
*
* Do it like this:
* write_reg(par, val1);
* write_reg(par, val2);
*/
/* Init sequence based on the Adafruit SSD1306 Arduino library */
static int init_display(struct fbtft_par *par)
{
if (!par->info->var.xres || par->info->var.xres > WIDTH ||
!par->info->var.yres || par->info->var.yres > HEIGHT ||
par->info->var.yres % 8) {
dev_err(par->info->device, "Invalid screen size\n");
return -EINVAL;
}
if (par->info->var.rotate) {
dev_err(par->info->device, "Display rotation not supported\n");
return -EINVAL;
}
par->fbtftops.reset(par);
/* Set Display OFF */
write_reg(par, 0xAE);
/* Set Display Clock Divide Ratio/ Oscillator Frequency */
write_reg(par, 0xD5);
write_reg(par, 0x80);
/* Set Multiplex Ratio */
write_reg(par, 0xA8);
write_reg(par, par->info->var.yres - 1);
/* Set Display Offset */
write_reg(par, 0xD3);
write_reg(par, 0x0);
/* Set Display Start Line */
write_reg(par, 0x40 | 0x0);
/* Set Segment Re-map */
/* column address 127 is mapped to SEG0 */
write_reg(par, 0xA0 | 0x1);
/* Set COM Output Scan Direction */
/* remapped mode. Scan from COM[N-1] to COM0 */
write_reg(par, 0xC8);
/* Set COM Pins Hardware Configuration */
write_reg(par, 0xDA);
if (par->info->var.yres == 64)
/* A[4]=1b, Alternative COM pin configuration */
write_reg(par, 0x12);
else if (par->info->var.yres == 48)
/* A[4]=1b, Alternative COM pin configuration */
write_reg(par, 0x12);
else
/* A[4]=0b, Sequential COM pin configuration */
write_reg(par, 0x02);
/* Set Pre-charge Period */
write_reg(par, 0xD9);
write_reg(par, 0xF1);
/* Set VCOMH Deselect Level */
write_reg(par, 0xDB);
write_reg(par, 0x40);
/* Set Display ON */
write_reg(par, 0xAF);
msleep(150);
return 0;
}
static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
}
static int blank(struct fbtft_par *par, bool on)
{
fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n",
__func__, on ? "true" : "false");
write_reg(par, on ? 0xAE : 0xAF);
return 0;
}
/* Gamma is used to control Contrast */
static int set_gamma(struct fbtft_par *par, u32 *curves)
{
/* apply mask */
curves[0] &= 0xFF;
/* Set Contrast Control for BANK0 */
write_reg(par, 0x81);
write_reg(par, curves[0]);
return 0;
}
static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
{
u16 *vmem16 = (u16 *)par->info->screen_buffer;
u32 xres = par->info->var.xres;
int page, page_start, page_end, x, i, ret;
u8 *buf = par->txbuf.buf;
/* offset refers to vmem with 2 bytes element size */
page_start = offset / (8 * 2 * xres);
page_end = DIV_ROUND_UP(offset + len, 8 * 2 * xres);
for (page = page_start; page < page_end; page++) {
/* set page */
write_reg(par, 0xb0 | page);
/* set column to 2 to compensate for vidmem width 132 */
write_reg(par, 0x00 | 2);
write_reg(par, 0x10 | 0);
memset(buf, 0, xres);
for (x = 0; x < xres; x++)
for (i = 0; i < 8; i++)
if (vmem16[(page * 8 + i) * xres + x])
buf[x] |= BIT(i);
/* Write data */
gpio_set_value(par->gpio.dc, 1);
ret = par->fbtftops.write(par, buf, xres);
if (ret < 0) {
dev_err(par->info->device,
"write failed and returned: %d\n", ret);
return ret;
}
}
return 0;
}
static struct fbtft_display display = {
.regwidth = 8,
.width = WIDTH,
.height = HEIGHT,
.txbuflen = WIDTH,
.gamma_num = 1,
.gamma_len = 1,
/* set default contrast to 0xcd = 80% */
.gamma = "cd",
.fbtftops = {
.write_vmem = write_vmem,
.init_display = init_display,
.set_addr_win = set_addr_win,
.blank = blank,
.set_gamma = set_gamma,
},
};
FBTFT_REGISTER_DRIVER(DRVNAME, "sinowealth,sh1106", &display);
MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("platform:" DRVNAME);
MODULE_ALIAS("spi:sh1106");
MODULE_ALIAS("platform:sh1106");
MODULE_DESCRIPTION("SH1106 OLED Driver");
MODULE_AUTHOR("Heiner Kallweit");
MODULE_LICENSE("GPL");
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