drivers/staging/fbtft/fb_uc1701.c

   1 /*
   2  * FB driver for the UC1701 LCD Controller
   3  *
   4  * The display is monochrome and the video memory is RGB565.
   5  * Any pixel value except 0 turns the pixel on.
   6  *
   7  * Copyright (C) 2014 Juergen Holzmann
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/kernel.h>
  22 #include <linux/init.h>
  23 #include <linux/gpio.h>
  24 #include <linux/spi/spi.h>
  25 #include <linux/delay.h>
  26
  27 #include "fbtft.h"
  28
  29 #define DRVNAME "fb_uc1701"
  30 #define WIDTH     102
  31 #define HEIGHT   64
  32 #define PAGES     (HEIGHT / 8)
  33
  34 /* 1: Display on/off */
  35 #define LCD_DISPLAY_ENABLE    0xAE
  36 /* 2: display start line set */
  37 #define LCD_START_LINE  0x40
  38 /* 3: Page address set (lower 4 bits select one of the pages) */
  39 #define LCD_PAGE_ADDRESS      0xB0
  40 /* 4: column address */
  41 #define LCD_COL_ADDRESS       0x10
  42 /* 8: select orientation */
  43 #define LCD_BOTTOMVIEW  0xA0
  44 /* 9: inverted display */
  45 #define LCD_DISPLAY_INVERT    0xA6
  46 /* 10: show memory content or switch all pixels on */
  47 #define LCD_ALL_PIXEL    0xA4
  48 /* 11: lcd bias set */
  49 #define LCD_BIAS              0xA2
  50 /* 14: Reset Controller */
  51 #define LCD_RESET_CMD    0xE2
  52 /* 15: output mode select (turns display upside-down) */
  53 #define LCD_SCAN_DIR      0xC0
  54 /* 16: power control set */
  55 #define LCD_POWER_CONTROL     0x28
  56 /* 17: voltage regulator resistor ratio set */
  57 #define LCD_VOLTAGE        0x20
  58 /* 18: Volume mode set */
  59 #define LCD_VOLUME_MODE       0x81
  60 /* 22: NOP command */
  61 #define LCD_NO_OP            0xE3
  62 /* 25: advanced program control */
  63 #define LCD_ADV_PROG_CTRL     0xFA
  64 /* 25: advanced program control2 */
  65 #define LCD_ADV_PROG_CTRL2    0x10
  66 #define LCD_TEMPCOMP_HIGH     0x80
  67 /* column offset for normal orientation */
  68 #define SHIFT_ADDR_NORMAL     0
  69 /* column offset for bottom view orientation */
  70 #define SHIFT_ADDR_TOPVIEW    30
  71
  72 static int init_display(struct fbtft_par *par)
  73 {
  74         par->fbtftops.reset(par);
  75
  76         /* softreset of LCD */
  77         write_reg(par, LCD_RESET_CMD);
  78         mdelay(10);
  79
  80         /* set startpoint */
  81         write_reg(par, LCD_START_LINE);
  82
  83         /* select orientation BOTTOMVIEW */
  84         write_reg(par, LCD_BOTTOMVIEW | 1);
  85
  86         /* output mode select (turns display upside-down) */
  87         write_reg(par, LCD_SCAN_DIR | 0x00);
  88
  89         /* Normal Pixel mode */
  90         write_reg(par, LCD_ALL_PIXEL | 0);
  91
  92         /* positive display */
  93         write_reg(par, LCD_DISPLAY_INVERT | 0);
  94
  95         /* bias 1/9 */
  96         write_reg(par, LCD_BIAS | 0);
  97
  98         /* power control mode: all features on */
  99         write_reg(par, LCD_POWER_CONTROL | 0x07);
 100
 101         /* set voltage regulator R/R */
 102         write_reg(par, LCD_VOLTAGE | 0x07);
 103
 104         /* volume mode set */
 105         write_reg(par, LCD_VOLUME_MODE);
 106         write_reg(par, 0x09);
 107         write_reg(par, LCD_NO_OP);
 108
 109         /* advanced program control */
 110         write_reg(par, LCD_ADV_PROG_CTRL);
 111         write_reg(par, LCD_ADV_PROG_CTRL2 | LCD_TEMPCOMP_HIGH);
 112
 113         /* enable display */
 114         write_reg(par, LCD_DISPLAY_ENABLE | 1);
 115
 116         return 0;
 117 }
 118
 119 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
 120 {
 121         /* goto address */
 122         write_reg(par, LCD_PAGE_ADDRESS);
 123         write_reg(par, 0x00);
 124         write_reg(par, LCD_COL_ADDRESS);
 125 }
 126
 127 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
 128 {
 129         u16 *vmem16 = (u16 *)par->info->screen_buffer;
 130         u8 *buf = par->txbuf.buf;
 131         int x, y, i;
 132         int ret = 0;
 133
 134         for (y = 0; y < PAGES; y++) {
 135                 buf = par->txbuf.buf;
 136                 for (x = 0; x < WIDTH; x++) {
 137                         *buf = 0x00;
 138                         for (i = 0; i < 8; i++)
 139                                 *buf |= (vmem16[((y * 8 * WIDTH) +
 140                                                  (i * WIDTH)) + x] ?
 141                                          1 : 0) << i;
 142                         buf++;
 143                 }
 144
 145                 write_reg(par, LCD_PAGE_ADDRESS | (u8)y);
 146                 write_reg(par, 0x00);
 147                 write_reg(par, LCD_COL_ADDRESS);
 148                 gpio_set_value(par->gpio.dc, 1);
 149                 ret = par->fbtftops.write(par, par->txbuf.buf, WIDTH);
 150                 gpio_set_value(par->gpio.dc, 0);
 151         }
 152
 153         if (ret < 0)
 154                 dev_err(par->info->device, "write failed and returned: %d\n",
 155                         ret);
 156
 157         return ret;
 158 }
 159
 160 static struct fbtft_display display = {
 161         .regwidth = 8,
 162         .width = WIDTH,
 163         .height = HEIGHT,
 164         .fbtftops = {
 165                 .init_display = init_display,
 166                 .set_addr_win = set_addr_win,
 167                 .write_vmem = write_vmem,
 168         },
 169         .backlight = 1,
 170 };
 171
 172 FBTFT_REGISTER_DRIVER(DRVNAME, "UltraChip,uc1701", &display);
 173
 174 MODULE_ALIAS("spi:" DRVNAME);
 175 MODULE_ALIAS("spi:uc1701");
 176
 177 MODULE_DESCRIPTION("FB driver for the UC1701 LCD Controller");
 178 MODULE_AUTHOR("Juergen Holzmann");
 179 MODULE_LICENSE("GPL");