root/drivers/staging/fbtft/fb_uc1701.c

DEFINITIONS

1. init_display
2. set_addr_win
3. write_vmem

   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 
  63 static 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 
 110 static 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 
 118 static 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 
 151 static 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 
 163 FBTFT_REGISTER_DRIVER(DRVNAME, "UltraChip,uc1701", &display);
 164 
 165 MODULE_ALIAS("spi:" DRVNAME);
 166 MODULE_ALIAS("spi:uc1701");
 167 
 168 MODULE_DESCRIPTION("FB driver for the UC1701 LCD Controller");
 169 MODULE_AUTHOR("Juergen Holzmann");
 170 MODULE_LICENSE("GPL");