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   1 /*
   2  * Copyright © 2023 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #include <ao.h>
  20 #include <ao_st7565.h>
  21
  22 static void
  23 ao_st7565_reset(void)
  24 {
  25         ao_gpio_set(AO_ST7565_RESET_PORT, AO_ST7565_RESET_PIN, 0);
  26         ao_delay(AO_MS_TO_TICKS(100));
  27         ao_gpio_set(AO_ST7565_RESET_PORT, AO_ST7565_RESET_PIN, 1);
  28         ao_delay(AO_MS_TO_TICKS(100));
  29 }
  30
  31
  32 static void
  33 ao_st7565_start(uint8_t a0)
  34 {
  35         ao_gpio_set(AO_ST7565_A0_PORT, AO_ST7565_A0_PIN, a0);
  36         ao_spi_get_bit(AO_ST7565_CS_PORT,
  37                        AO_ST7565_CS_PIN,
  38                        AO_ST7565_SPI_BUS,
  39                        AO_ST7565_SPI_SPEED);
  40 }
  41
  42 static void
  43 ao_st7565_stop(void)
  44 {
  45         ao_spi_put_bit(AO_ST7565_CS_PORT,
  46                        AO_ST7565_CS_PIN,
  47                        AO_ST7565_SPI_BUS);
  48         ao_gpio_set(AO_ST7565_A0_PORT, AO_ST7565_A0_PIN, 1);
  49 }
  50
  51
  52 static void
  53 ao_st7565_instruction(uint8_t cmd)
  54 {
  55         ao_st7565_start(0);
  56         ao_spi_send(&cmd, 1, AO_ST7565_SPI_BUS);
  57         ao_st7565_stop();
  58 }
  59
  60 static void
  61 ao_st7565_instruction_param(uint8_t cmd, uint8_t param)
  62 {
  63         uint8_t b[2] = { cmd, param };
  64         ao_st7565_start(0);
  65         ao_spi_send(b, 2, AO_ST7565_SPI_BUS);
  66         ao_st7565_stop();
  67 }
  68
  69 static void
  70 ao_st7565_instructions(const uint8_t *cmd, uint16_t len)
  71 {
  72         ao_st7565_start(0);
  73         ao_spi_send(cmd, len, AO_ST7565_SPI_BUS);
  74         ao_st7565_stop();
  75 }
  76
  77 static void
  78 ao_st7565_data(const void *base, uint16_t len)
  79 {
  80         ao_st7565_start(1);
  81         ao_spi_send(base, len, AO_ST7565_SPI_BUS);
  82         ao_st7565_stop();
  83 }
  84
  85 static uint8_t brightness;
  86
  87 void
  88 ao_st7565_set_brightness(uint8_t val)
  89 {
  90         if (val > 63)
  91                 val = 63;
  92         brightness = val;
  93         ao_st7565_instruction_param(ST7565_ELECTRONIC_VOLUME_SET, val);
  94 }
  95
  96 uint8_t
  97 ao_st7565_get_brightness(void)
  98 {
  99         return brightness;
 100 }
 101
 102 static bool setup_done;
 103
 104 static void
 105 ao_st7565_setup(void)
 106 {
 107         static const uint8_t init[] = {
 108                 /*
 109                  * Should be set to one of ST7565_LCD_BIAS_1_9 or
 110                  * ST7565_LCD_BIAS_1_7
 111                  */
 112                 AO_ST7565_BIAS,
 113                 ST7565_ADC_SELECT_NORMAL,
 114                 ST7565_COMMON_MODE_NORMAL,
 115                 ST7565_DISPLAY_START_LINE_SET(0),
 116                 ST7565_POWER_CONTROL_SET(0x4),
 117         };
 118
 119         if (setup_done)
 120                 return;
 121         setup_done = true;
 122         ao_st7565_reset();
 123         ao_st7565_instructions(init, sizeof(init));
 124         ao_delay(AO_MS_TO_TICKS(50));
 125         ao_st7565_instruction(ST7565_POWER_CONTROL_SET(0x6));
 126         ao_delay(AO_MS_TO_TICKS(50));
 127         ao_st7565_instruction(ST7565_POWER_CONTROL_SET(0x7));
 128         ao_delay(AO_MS_TO_TICKS(10));
 129         ao_st7565_instruction(ST7565_RESISTOR_RATIO_SET(5));
 130         ao_st7565_instruction(ST7565_DISPLAY_ON);
 131         ao_st7565_set_brightness(13);
 132 }
 133
 134 static uint8_t  rotbuf[AO_ST7565_WIDTH];
 135
 136 #define WIDTH   AO_ST7565_WIDTH
 137 #define HEIGHT  AO_ST7565_HEIGHT
 138 #define STRIDE  AO_BITMAP_STRIDE(WIDTH)
 139
 140 static uint32_t previous_image[STRIDE * HEIGHT];
 141
 142 void
 143 ao_st7565_update(struct ao_bitmap *bitmap)
 144 {
 145         int16_t         col, c, page;
 146         int16_t         row;
 147         uint32_t        *line, *prev, *l;
 148         uint32_t        bits;
 149         uint8_t         *r;
 150         int16_t         min_col, min_row, max_col, max_row;
 151         int16_t         min_page, max_page;
 152
 153         ao_st7565_setup();
 154
 155         min_col = STRIDE - 1;
 156         max_col = 0;
 157         min_row = HEIGHT - 1;
 158         max_row = 0;
 159         line = bitmap->base;
 160         prev = previous_image;
 161         for (row = 0; row < HEIGHT; row++) {
 162                 for (col = 0; col < STRIDE; col++) {
 163                         bits = *line++;
 164                         if (bits != *prev) {
 165                                 *prev = bits;
 166                                 if (row < min_row)
 167                                         min_row = row;
 168                                 if (row > max_row)
 169                                         max_row = row;
 170                                 if (col < min_col)
 171                                         min_col = col;
 172                                 if (col > max_col)
 173                                         max_col = col;
 174                         }
 175                         prev++;
 176                 }
 177         }
 178
 179         if (min_col > max_col || min_row > max_row)
 180                 return;
 181
 182         min_page = min_row >> 3;
 183         max_page = max_row >> 3;
 184         line = bitmap->base + min_page * 8 * STRIDE + min_col;
 185
 186         uint8_t first_col = (uint8_t) (min_col * 32);
 187         uint8_t num_col = (uint8_t) (max_col + 1 - min_col) * 32;
 188
 189         for (page = min_page; page <= max_page; page++) {
 190                 uint8_t         i[4] = {
 191                         ST7565_PAGE_ADDRESS_SET(7-(uint8_t) page),
 192                         ST7565_COLUMN_ADDRESS_SET_MSN(first_col >> 4),
 193                         ST7565_COLUMN_ADDRESS_SET_LSN(first_col & 0xf),
 194                         ST7565_RMW
 195                 };
 196                 memset(rotbuf, 0, num_col);
 197                 for (row = 7; row >= 0; row--) {
 198                         r = rotbuf;
 199                         l = line;
 200                         line += STRIDE;
 201                         for (col = min_col; col <= max_col; col++) {
 202                                 bits = ~*l++;
 203                                 for (c = 0; c < 32; c++) {
 204                                         *r++ |= ((bits >> c) & 1) << row;
 205                                 }
 206                         }
 207                 }
 208                 ao_st7565_instructions(i, 4);
 209                 ao_st7565_data(rotbuf, num_col);
 210         }
 211 }
 212
 213 void
 214 ao_st7565_init(void)
 215 {
 216         memset(previous_image, 0xff, sizeof(previous_image));
 217         ao_enable_output(AO_ST7565_RESET_PORT, AO_ST7565_RESET_PIN, 1);
 218         ao_enable_output(AO_ST7565_A0_PORT, AO_ST7565_A0_PIN, 1);
 219
 220         ao_enable_cs(AO_ST7565_CS_PORT, AO_ST7565_CS_PIN);
 221 }