// SPDX-License-Identifier: GPL-2.0+
/*
* FB driver for the UC1701 LCD Controller
*
* The display is monochrome and the video memory is RGB565.
* Any pixel value except 0 turns the pixel on.
*
* Copyright (C) 2014 Juergen Holzmann
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>
#include "fbtft.h"
#define DRVNAME "fb_uc1701"
#define WIDTH 102
#define HEIGHT 64
#define PAGES (HEIGHT / 8)
/* 1: Display on/off */
#define LCD_DISPLAY_ENABLE 0xAE
/* 2: display start line set */
#define LCD_START_LINE 0x40
/* 3: Page address set (lower 4 bits select one of the pages) */
#define LCD_PAGE_ADDRESS 0xB0
/* 4: column address */
#define LCD_COL_ADDRESS 0x10
/* 8: select orientation */
#define LCD_BOTTOMVIEW 0xA0
/* 9: inverted display */
#define LCD_DISPLAY_INVERT 0xA6
/* 10: show memory content or switch all pixels on */
#define LCD_ALL_PIXEL 0xA4
/* 11: lcd bias set */
#define LCD_BIAS 0xA2
/* 14: Reset Controller */
#define LCD_RESET_CMD 0xE2
/* 15: output mode select (turns display upside-down) */
#define LCD_SCAN_DIR 0xC0
/* 16: power control set */
#define LCD_POWER_CONTROL 0x28
/* 17: voltage regulator resistor ratio set */
#define LCD_VOLTAGE 0x20
/* 18: Volume mode set */
#define LCD_VOLUME_MODE 0x81
/* 22: NOP command */
#define LCD_NO_OP 0xE3
/* 25: advanced program control */
#define LCD_ADV_PROG_CTRL 0xFA
/* 25: advanced program control2 */
#define LCD_ADV_PROG_CTRL2 0x10
#define LCD_TEMPCOMP_HIGH 0x80
/* column offset for normal orientation */
#define SHIFT_ADDR_NORMAL 0
/* column offset for bottom view orientation */
#define SHIFT_ADDR_TOPVIEW 30
static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
/* softreset of LCD */
write_reg(par, LCD_RESET_CMD);
mdelay(10);
/* set startpoint */
write_reg(par, LCD_START_LINE);
/* select orientation BOTTOMVIEW */
write_reg(par, LCD_BOTTOMVIEW | 1);
/* output mode select (turns display upside-down) */
write_reg(par, LCD_SCAN_DIR | 0x00);
/* Normal Pixel mode */
write_reg(par, LCD_ALL_PIXEL | 0);
/* positive display */
write_reg(par, LCD_DISPLAY_INVERT | 0);
/* bias 1/9 */
write_reg(par, LCD_BIAS | 0);
/* power control mode: all features on */
write_reg(par, LCD_POWER_CONTROL | 0x07);
/* set voltage regulator R/R */
write_reg(par, LCD_VOLTAGE | 0x07);
/* volume mode set */
write_reg(par, LCD_VOLUME_MODE);
write_reg(par, 0x09);
write_reg(par, LCD_NO_OP);
/* advanced program control */
write_reg(par, LCD_ADV_PROG_CTRL);
write_reg(par, LCD_ADV_PROG_CTRL2 | LCD_TEMPCOMP_HIGH);
/* enable display */
write_reg(par, LCD_DISPLAY_ENABLE | 1);
return 0;
}
static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
/* goto address */
write_reg(par, LCD_PAGE_ADDRESS);
write_reg(par, 0x00);
write_reg(par, LCD_COL_ADDRESS);
}
static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
{
u16 *vmem16 = (u16 *)par->info->screen_buffer;
u8 *buf;
int x, y, i;
int ret = 0;
for (y = 0; y < PAGES; y++) {
buf = par->txbuf.buf;
for (x = 0; x < WIDTH; x++) {
*buf = 0x00;
for (i = 0; i < 8; i++)
*buf |= (vmem16[((y * 8 * WIDTH) +
(i * WIDTH)) + x] ?
1 : 0) << i;
buf++;
}
write_reg(par, LCD_PAGE_ADDRESS | (u8)y);
write_reg(par, 0x00);
write_reg(par, LCD_COL_ADDRESS);
gpiod_set_value(par->gpio.dc, 1);
ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH);
gpiod_set_value(par->gpio.dc, 0);
}
if (ret < 0)
dev_err(par->info->device, "write failed and returned: %d\n",
ret);
return ret;
}
static struct fbtft_display display = {
.regwidth = 8,
.width = WIDTH,
.height = HEIGHT,
.fbtftops = {
.init_display = init_display,
.set_addr_win = set_addr_win,
.write_vmem = write_vmem,
},
.backlight = 1,
};
FBTFT_REGISTER_DRIVER(DRVNAME, "UltraChip,uc1701", &display);
MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("spi:uc1701");
MODULE_DESCRIPTION("FB driver for the UC1701 LCD Controller");
MODULE_AUTHOR("Juergen Holzmann");
MODULE_LICENSE("GPL");
Codebase Browser
linux