LXR linux/drivers/staging/fbtft/fb

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * FB driver for the UC1701 LCD Controller
   4 *
   5 * The display is monochrome and the video memory is RGB565.
   6 * Any pixel value except 0 turns the pixel on.
   7 *
   8 * Copyright (C) 2014 Juergen Holzmann
   9 */
  10
  11#include <linux/module.h>
  12#include <linux/kernel.h>
  13#include <linux/init.h>
  14#include <linux/gpio/consumer.h>
  15#include <linux/spi/spi.h>
  16#include <linux/delay.h>
  17
  18#include "fbtft.h"
  19
  20#define DRVNAME "fb_uc1701"
  21#define WIDTH     102
  22#define HEIGHT   64
  23#define PAGES     (HEIGHT / 8)
  24
  25/* 1: Display on/off */
  26#define LCD_DISPLAY_ENABLE    0xAE
  27/* 2: display start line set */
  28#define LCD_START_LINE  0x40
  29/* 3: Page address set (lower 4 bits select one of the pages) */
  30#define LCD_PAGE_ADDRESS      0xB0
  31/* 4: column address */
  32#define LCD_COL_ADDRESS       0x10
  33/* 8: select orientation */
  34#define LCD_BOTTOMVIEW  0xA0
  35/* 9: inverted display */
  36#define LCD_DISPLAY_INVERT    0xA6
  37/* 10: show memory content or switch all pixels on */
  38#define LCD_ALL_PIXEL    0xA4
  39/* 11: lcd bias set */
  40#define LCD_BIAS              0xA2
  41/* 14: Reset Controller */
  42#define LCD_RESET_CMD    0xE2
  43/* 15: output mode select (turns display upside-down) */
  44#define LCD_SCAN_DIR      0xC0
  45/* 16: power control set */
  46#define LCD_POWER_CONTROL     0x28
  47/* 17: voltage regulator resistor ratio set */
  48#define LCD_VOLTAGE        0x20
  49/* 18: Volume mode set */
  50#define LCD_VOLUME_MODE       0x81
  51/* 22: NOP command */
  52#define LCD_NO_OP            0xE3
  53/* 25: advanced program control */
  54#define LCD_ADV_PROG_CTRL     0xFA
  55/* 25: advanced program control2 */
  56#define LCD_ADV_PROG_CTRL2    0x10
  57#define LCD_TEMPCOMP_HIGH     0x80
  58/* column offset for normal orientation */
  59#define SHIFT_ADDR_NORMAL     0
  60/* column offset for bottom view orientation */
  61#define SHIFT_ADDR_TOPVIEW    30
  62
  63static int init_display(struct fbtft_par *par)
  64{
  65        par->fbtftops.reset(par);
  66
  67        /* softreset of LCD */
  68        write_reg(par, LCD_RESET_CMD);
  69        mdelay(10);
  70
  71        /* set startpoint */
  72        write_reg(par, LCD_START_LINE);
  73
  74        /* select orientation BOTTOMVIEW */
  75        write_reg(par, LCD_BOTTOMVIEW | 1);
  76
  77        /* output mode select (turns display upside-down) */
  78        write_reg(par, LCD_SCAN_DIR | 0x00);
  79
  80        /* Normal Pixel mode */
  81        write_reg(par, LCD_ALL_PIXEL | 0);
  82
  83        /* positive display */
  84        write_reg(par, LCD_DISPLAY_INVERT | 0);
  85
  86        /* bias 1/9 */
  87        write_reg(par, LCD_BIAS | 0);
  88
  89        /* power control mode: all features on */
  90        write_reg(par, LCD_POWER_CONTROL | 0x07);
  91
  92        /* set voltage regulator R/R */
  93        write_reg(par, LCD_VOLTAGE | 0x07);
  94
  95        /* volume mode set */
  96        write_reg(par, LCD_VOLUME_MODE);
  97        write_reg(par, 0x09);
  98        write_reg(par, LCD_NO_OP);
  99
 100        /* advanced program control */
 101        write_reg(par, LCD_ADV_PROG_CTRL);
 102        write_reg(par, LCD_ADV_PROG_CTRL2 | LCD_TEMPCOMP_HIGH);
 103
 104        /* enable display */
 105        write_reg(par, LCD_DISPLAY_ENABLE | 1);
 106
 107        return 0;
 108}
 109
 110static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
 111{
 112        /* goto address */
 113        write_reg(par, LCD_PAGE_ADDRESS);
 114        write_reg(par, 0x00);
 115        write_reg(par, LCD_COL_ADDRESS);
 116}
 117
 118static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
 119{
 120        u16 *vmem16 = (u16 *)par->info->screen_buffer;
 121        u8 *buf;
 122        int x, y, i;
 123        int ret = 0;
 124
 125        for (y = 0; y < PAGES; y++) {
 126                buf = par->txbuf.buf;
 127                for (x = 0; x < WIDTH; x++) {
 128                        *buf = 0x00;
 129                        for (i = 0; i < 8; i++)
 130                                *buf |= (vmem16[((y * 8 * WIDTH) +
 131                                                 (i * WIDTH)) + x] ?
 132                                         1 : 0) << i;
 133                        buf++;
 134                }
 135
 136                write_reg(par, LCD_PAGE_ADDRESS | (u8)y);
 137                write_reg(par, 0x00);
 138                write_reg(par, LCD_COL_ADDRESS);
 139                gpiod_set_value(par->gpio.dc, 1);
 140                ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH);
 141                gpiod_set_value(par->gpio.dc, 0);
 142        }
 143
 144        if (ret < 0)
 145                dev_err(par->info->device, "write failed and returned: %d\n",
 146                        ret);
 147
 148        return ret;
 149}
 150
 151static struct fbtft_display display = {
 152        .regwidth = 8,
 153        .width = WIDTH,
 154        .height = HEIGHT,
 155        .fbtftops = {
 156                .init_display = init_display,
 157                .set_addr_win = set_addr_win,
 158                .write_vmem = write_vmem,
 159        },
 160        .backlight = 1,
 161};
 162
 163FBTFT_REGISTER_DRIVER(DRVNAME, "UltraChip,uc1701", &display);
 164
 165MODULE_ALIAS("spi:" DRVNAME);
 166MODULE_ALIAS("spi:uc1701");
 167
 168MODULE_DESCRIPTION("FB driver for the UC1701 LCD Controller");
 169MODULE_AUTHOR("Juergen Holzmann");
 170MODULE_LICENSE("GPL");
 171