linux/Documentation/auxdisplay/cfag12864b-example.c
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   1/*
   2 *    Filename: cfag12864b-example.c
   3 *     Version: 0.1.0
   4 * Description: cfag12864b LCD userspace example program
   5 *     License: GPLv2
   6 *
   7 *      Author: Copyright (C) Miguel Ojeda Sandonis
   8 *        Date: 2006-10-31
   9 *
  10 *  This program is free software; you can redistribute it and/or modify
  11 *  it under the terms of the GNU General Public License version 2 as
  12 *  published by the Free Software Foundation.
  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 *  You should have received a copy of the GNU General Public License
  20 *  along with this program; if not, write to the Free Software
  21 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22 *
  23 */
  24
  25/*
  26 * ------------------------
  27 * start of cfag12864b code
  28 * ------------------------
  29 */
  30
  31#include <string.h>
  32#include <fcntl.h>
  33#include <unistd.h>
  34#include <sys/types.h>
  35#include <sys/stat.h>
  36#include <sys/mman.h>
  37
  38#define CFAG12864B_WIDTH                (128)
  39#define CFAG12864B_HEIGHT               (64)
  40#define CFAG12864B_SIZE                 (128 * 64 / 8)
  41#define CFAG12864B_BPB                  (8)
  42#define CFAG12864B_ADDRESS(x, y)        ((y) * CFAG12864B_WIDTH / \
  43                                        CFAG12864B_BPB + (x) / CFAG12864B_BPB)
  44#define CFAG12864B_BIT(n)               (((unsigned char) 1) << (n))
  45
  46#undef CFAG12864B_DOCHECK
  47#ifdef CFAG12864B_DOCHECK
  48        #define CFAG12864B_CHECK(x, y)          ((x) < CFAG12864B_WIDTH && \
  49                                                (y) < CFAG12864B_HEIGHT)
  50#else
  51        #define CFAG12864B_CHECK(x, y)          (1)
  52#endif
  53
  54int cfag12864b_fd;
  55unsigned char * cfag12864b_mem;
  56unsigned char cfag12864b_buffer[CFAG12864B_SIZE];
  57
  58/*
  59 * init a cfag12864b framebuffer device
  60 *
  61 * No error:       return = 0
  62 * Unable to open: return = -1
  63 * Unable to mmap: return = -2
  64 */
  65static int cfag12864b_init(char *path)
  66{
  67        cfag12864b_fd = open(path, O_RDWR);
  68        if (cfag12864b_fd == -1)
  69                return -1;
  70
  71        cfag12864b_mem = mmap(0, CFAG12864B_SIZE, PROT_READ | PROT_WRITE,
  72                MAP_SHARED, cfag12864b_fd, 0);
  73        if (cfag12864b_mem == MAP_FAILED) {
  74                close(cfag12864b_fd);
  75                return -2;
  76        }
  77
  78        return 0;
  79}
  80
  81/*
  82 * exit a cfag12864b framebuffer device
  83 */
  84static void cfag12864b_exit(void)
  85{
  86        munmap(cfag12864b_mem, CFAG12864B_SIZE);
  87        close(cfag12864b_fd);
  88}
  89
  90/*
  91 * set (x, y) pixel
  92 */
  93static void cfag12864b_set(unsigned char x, unsigned char y)
  94{
  95        if (CFAG12864B_CHECK(x, y))
  96                cfag12864b_buffer[CFAG12864B_ADDRESS(x, y)] |=
  97                        CFAG12864B_BIT(x % CFAG12864B_BPB);
  98}
  99
 100/*
 101 * unset (x, y) pixel
 102 */
 103static void cfag12864b_unset(unsigned char x, unsigned char y)
 104{
 105        if (CFAG12864B_CHECK(x, y))
 106                cfag12864b_buffer[CFAG12864B_ADDRESS(x, y)] &=
 107                        ~CFAG12864B_BIT(x % CFAG12864B_BPB);
 108}
 109
 110/*
 111 * is set (x, y) pixel?
 112 *
 113 * Pixel off: return = 0
 114 * Pixel on:  return = 1
 115 */
 116static unsigned char cfag12864b_isset(unsigned char x, unsigned char y)
 117{
 118        if (CFAG12864B_CHECK(x, y))
 119                if (cfag12864b_buffer[CFAG12864B_ADDRESS(x, y)] &
 120                        CFAG12864B_BIT(x % CFAG12864B_BPB))
 121                        return 1;
 122
 123        return 0;
 124}
 125
 126/*
 127 * not (x, y) pixel
 128 */
 129static void cfag12864b_not(unsigned char x, unsigned char y)
 130{
 131        if (cfag12864b_isset(x, y))
 132                cfag12864b_unset(x, y);
 133        else
 134                cfag12864b_set(x, y);
 135}
 136
 137/*
 138 * fill (set all pixels)
 139 */
 140static void cfag12864b_fill(void)
 141{
 142        unsigned short i;
 143
 144        for (i = 0; i < CFAG12864B_SIZE; i++)
 145                cfag12864b_buffer[i] = 0xFF;
 146}
 147
 148/*
 149 * clear (unset all pixels)
 150 */
 151static void cfag12864b_clear(void)
 152{
 153        unsigned short i;
 154
 155        for (i = 0; i < CFAG12864B_SIZE; i++)
 156                cfag12864b_buffer[i] = 0;
 157}
 158
 159/*
 160 * format a [128*64] matrix
 161 *
 162 * Pixel off: src[i] = 0
 163 * Pixel on:  src[i] > 0
 164 */
 165static void cfag12864b_format(unsigned char * matrix)
 166{
 167        unsigned char i, j, n;
 168
 169        for (i = 0; i < CFAG12864B_HEIGHT; i++)
 170        for (j = 0; j < CFAG12864B_WIDTH / CFAG12864B_BPB; j++) {
 171                cfag12864b_buffer[i * CFAG12864B_WIDTH / CFAG12864B_BPB +
 172                        j] = 0;
 173                for (n = 0; n < CFAG12864B_BPB; n++)
 174                        if (matrix[i * CFAG12864B_WIDTH +
 175                                j * CFAG12864B_BPB + n])
 176                                cfag12864b_buffer[i * CFAG12864B_WIDTH /
 177                                        CFAG12864B_BPB + j] |=
 178                                        CFAG12864B_BIT(n);
 179        }
 180}
 181
 182/*
 183 * blit buffer to lcd
 184 */
 185static void cfag12864b_blit(void)
 186{
 187        memcpy(cfag12864b_mem, cfag12864b_buffer, CFAG12864B_SIZE);
 188}
 189
 190/*
 191 * ----------------------
 192 * end of cfag12864b code
 193 * ----------------------
 194 */
 195
 196#include <stdio.h>
 197
 198#define EXAMPLES        6
 199
 200static void example(unsigned char n)
 201{
 202        unsigned short i, j;
 203        unsigned char matrix[CFAG12864B_WIDTH * CFAG12864B_HEIGHT];
 204
 205        if (n > EXAMPLES)
 206                return;
 207
 208        printf("Example %i/%i - ", n, EXAMPLES);
 209
 210        switch (n) {
 211        case 1:
 212                printf("Draw points setting bits");
 213                cfag12864b_clear();
 214                for (i = 0; i < CFAG12864B_WIDTH; i += 2)
 215                        for (j = 0; j < CFAG12864B_HEIGHT; j += 2)
 216                                cfag12864b_set(i, j);
 217                break;
 218
 219        case 2:
 220                printf("Clear the LCD");
 221                cfag12864b_clear();
 222                break;
 223
 224        case 3:
 225                printf("Draw rows formatting a [128*64] matrix");
 226                memset(matrix, 0, CFAG12864B_WIDTH * CFAG12864B_HEIGHT);
 227                for (i = 0; i < CFAG12864B_WIDTH; i++)
 228                        for (j = 0; j < CFAG12864B_HEIGHT; j += 2)
 229                                matrix[j * CFAG12864B_WIDTH + i] = 1;
 230                cfag12864b_format(matrix);
 231                break;
 232
 233        case 4:
 234                printf("Fill the lcd");
 235                cfag12864b_fill();
 236                break;
 237
 238        case 5:
 239                printf("Draw columns unsetting bits");
 240                for (i = 0; i < CFAG12864B_WIDTH; i += 2)
 241                        for (j = 0; j < CFAG12864B_HEIGHT; j++)
 242                                cfag12864b_unset(i, j);
 243                break;
 244
 245        case 6:
 246                printf("Do negative not-ing all bits");
 247                for (i = 0; i < CFAG12864B_WIDTH; i++)
 248                        for (j = 0; j < CFAG12864B_HEIGHT; j ++)
 249                                cfag12864b_not(i, j);
 250                break;
 251        }
 252
 253        puts(" - [Press Enter]");
 254}
 255
 256int main(int argc, char *argv[])
 257{
 258        unsigned char n;
 259
 260        if (argc != 2) {
 261                printf(
 262                        "Sintax:  %s fbdev\n"
 263                        "Usually: /dev/fb0, /dev/fb1...\n", argv[0]);
 264                return -1;
 265        }
 266
 267        if (cfag12864b_init(argv[1])) {
 268                printf("Can't init %s fbdev\n", argv[1]);
 269                return -2;
 270        }
 271
 272        for (n = 1; n <= EXAMPLES; n++) {
 273                example(n);
 274                cfag12864b_blit();
 275                while (getchar() != '\n');
 276        }
 277
 278        cfag12864b_exit();
 279
 280        return 0;
 281}
 282
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