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