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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(0x10);
 132 }
 133
 134 static uint8_t  rotbuf[AO_ST7565_WIDTH];
 135
 136 void
 137 ao_st7565_update(struct ao_bitmap *bitmap)
 138 {
 139         uint8_t         col, c, page;
 140         int             row;
 141         uint32_t        *line;
 142         uint8_t         *r;
 143
 144         ao_st7565_setup();
 145
 146         line = bitmap->base;
 147         for (page = 0; page < 8; page++) {
 148                 uint8_t         i[4] = {
 149                         ST7565_PAGE_ADDRESS_SET(7-page),
 150                         ST7565_COLUMN_ADDRESS_SET_MSN(0 >> 4),
 151                         ST7565_COLUMN_ADDRESS_SET_MSN(0 & 0xf),
 152                         ST7565_RMW
 153                 };
 154                 memset(rotbuf, 0, sizeof(rotbuf));
 155                 for (row = 7; row >= 0; row--) {
 156                         r = rotbuf;
 157                         for (col = 0; col < AO_BITMAP_STRIDE(AO_ST7565_WIDTH); col++) {
 158                                 uint32_t        bits = ~*line++;
 159                                 for (c = 0; c < 32; c++) {
 160                                         *r++ |= ((bits >> c) & 1) << row;
 161                                 }
 162                         }
 163                 }
 164                 ao_st7565_instructions(i, 4);
 165                 ao_st7565_data(rotbuf, AO_ST7565_WIDTH);
 166         }
 167 }
 168
 169 void
 170 ao_st7565_init(void)
 171 {
 172         ao_enable_output(AO_ST7565_RESET_PORT, AO_ST7565_RESET_PIN, 1);
 173         ao_enable_output(AO_ST7565_A0_PORT, AO_ST7565_A0_PIN, 1);
 174
 175         ao_enable_cs(AO_ST7565_CS_PORT, AO_ST7565_CS_PIN);
 176 }