Add support for blanking the screen

Makefile

@@ -7,7 +7,7 @@ LD=clang
 LDFLAGS=-lgpio -lfigpar -lpthread ${SQLITE3_LDFLAGS}
 SRCS=src/main.c src/util.c src/lcd.c src/ths.c src/button.c src/ui/screen.c\
      src/ui/datesel.c src/ui/statsby.c src/ui/datapoints.c src/ui/timesel.c\
-     src/ui/statrange.c src/config.c
+     src/ui/statrange.c src/config.c src/ui/blankscreen.c
 PROG=rpi4b-temp-humidity
 
 OBJS=${SRCS:C/^src/bin/:C/.c$/.o/}
@@ -38,6 +38,7 @@ bin/main.o bin/config.o: src/config.h
 bin/main.o bin/button.o bin/ui/screen.o: src/button.h
 bin/main.o bin/ui/statsby.o: src/ui/statsby.h
 bin/main.o bin/ui/datapoints.o: src/ui/datapoints.h
+bin/main.o bin/ui/blankscreen.o: src/ui/blankscreen.h
 bin/main.o bin/ui/statrange.o: src/ui/statrange.h
 
 .if "${DEFAULT_TEMP_UNIT}" != "F" && "${DEFAULT_TEMP_UNIT}" != "C" &&\

src/config.c

@@ -1,5 +1,5 @@
 /*
- * config.h - Config file parsing
+ * config.c - Config file parsing
  * Copyright (C) 2024  Alexander Rosenberg
  *
  * This program is free software: you can redistribute it and/or modify it under
@@ -29,17 +29,32 @@ static int unknown_key_callback(struct figpar_config *opt, uint32_t line,
     return 0;
 }
 
+static int parse_int_callback(struct figpar_config *opt, uint32_t line,
+                               char *directive, char *value) {
+    char last_char;
+    if (sscanf(value, "%" SCNi32 " %c", &opt->value.num, &last_char) < 1 ||
+        (last_char && !isdigit(last_char))) {
+        warnx("line %" PRIu32 ": not a valid number \"%s\"", line, value);
+        return 1;
+    }
+    LOG_VERBOSE("Loaded config int option: %s = %" PRIi32 "\n", directive,
+                opt->value.num);
+    opt->type = FIGPAR_TYPE_INT;
+    return 0;
+}
+
 static int parse_uint_callback(struct figpar_config *opt, uint32_t line,
                                char *directive, char *value) {
     char last_char;
     if (sscanf(value, "%" SCNu32 " %c", &opt->value.u_num, &last_char) < 1 ||
         (last_char && !isdigit(last_char))) {
-        warnx("line %" PRIu32 ": not a valid number \"%s\"", line, value);
+        warnx("line %" PRIu32 ": not a valid unsigned number \"%s\"", line,
+              value);
         return 1;
     }
     LOG_VERBOSE("Loaded config uint option: %s = %" PRIu32 "\n", directive,
                 opt->value.u_num);
-    opt->type = FIGPAR_TYPE_INT;
+    opt->type = FIGPAR_TYPE_UINT;
     return 0;
 }
 
@@ -183,6 +198,8 @@ static void set_options_from_entries(struct figpar_config *entries,
     GLOBAL_OPTS.back_pin = entries[14].value.u_num;
 
     GLOBAL_OPTS.temp_unit = entries[15].value.num;
+
+    GLOBAL_OPTS.bl_pin = entries[16].value.num;
 }
 
 static char *strdup_default_opt(const char *def) {
@@ -283,6 +300,12 @@ void parse_config_file(const char *path) {
             .action = parse_temp_unit_callback,
             .value = {.num = DEFAULT_TEMP_UNIT}
         },
+        {
+            .directive = "bl_pin",
+            .type = FIGPAR_TYPE_INT,
+            .action = parse_int_callback,
+            .value = {.num = -1}
+        },
         { .directive = NULL },
     };
     size_t entry_count = sizeof(entries) / sizeof(struct figpar_config);

src/lcd.c

@@ -47,9 +47,11 @@ static void lcd_pulse_enable(LCD *lcd) {
 
 LCD *lcd_open(gpio_handle_t handle, gpio_pin_t rs, gpio_pin_t rw, gpio_pin_t en,
               gpio_pin_t d0, gpio_pin_t d1, gpio_pin_t d2, gpio_pin_t d3,
-              gpio_pin_t d4, gpio_pin_t d5, gpio_pin_t d6, gpio_pin_t d7) {
+              gpio_pin_t d4, gpio_pin_t d5, gpio_pin_t d6, gpio_pin_t d7,
+              int32_t bl) {
     LOG_VERBOSE("Initializing LCD: rs=%d, rw=%d, en=%d, d={%d, %d, %d, %d, %d, "
-                "%d, %d, %d}\n", rs, rw, en, d0, d1, d2, d3, d4, d5, d6, d7);
+                "%d, %d, %d}, bl=%d\n", rs, rw, en, d0, d1, d2, d3, d4, d5, d6,
+                d7, bl);
     LCD *lcd = malloc_checked(sizeof(LCD));
     lcd->handle = handle;
     lcd->rs = rs;
@@ -63,13 +65,18 @@ LCD *lcd_open(gpio_handle_t handle, gpio_pin_t rs, gpio_pin_t rw, gpio_pin_t en,
     lcd->d5 = d5;
     lcd->d6 = d6;
     lcd->d7 = d7;
+    lcd->bl = bl;
     gpio_pin_output(lcd->handle, lcd->rw);
     gpio_pin_output(lcd->handle, lcd->en);
     gpio_pin_output(lcd->handle, lcd->rs);
+    if (lcd->bl >= 0) {
+        gpio_pin_output(lcd->handle, lcd->bl);
+    }
     lcd_clear(lcd);
     lcd_call(lcd, 0, 0, 0, 0, 1, 1, 1, 0, 0); // 5x8 font, 2 lines, 8bit
     lcd_entry_mode(lcd, LCD_INCREMENT, LCD_CURSOR_MOVE);
     lcd_display_control(lcd, LCD_CURSOR_NO_BLINK, LCD_CURSOR_OFF, LCD_DISPLAY_ON);
+    lcd_backlight_set_enabled(lcd, true);
     LOG_VERBOSE("LCD Initialization done\n");
     return lcd;
 }
@@ -145,3 +152,9 @@ bool lcd_is_busy(LCD *lcd) {
     usleep(1);
     return busy;
 }
+
+void lcd_backlight_set_enabled(LCD *lcd, bool enable) {
+    if (lcd->bl > 0) {
+        gpio_pin_set(lcd->handle, lcd->bl, enable);
+    }
+}

src/lcd.h

@@ -28,6 +28,7 @@ typedef struct {
     gpio_pin_t d5;
     gpio_pin_t d6;
     gpio_pin_t d7;
+    int32_t bl;
 
     // gpio_value_ternal use
     bool is_read;
@@ -37,12 +38,14 @@ typedef struct {
  * Allocate and initialize a new LCD object and return a pogpio_value_ter to it. HANDLE
  * is a gpio_handle_t, each of the other arguments corresponds to the GPIO pin
  * number that the given controller pin is connected to: "register select",
- * "read-write", "enable", and data pins 0-7.
+ * "read-write", "enable", and data pins 0-7. If BL is 0 or greater, it is a pin
+ *  that will enable the backlight when HIGH, and disable the backlight when LOW.
  * Return: the newly created object.
  */
 LCD *lcd_open(gpio_handle_t handle, gpio_pin_t rs, gpio_pin_t rw, gpio_pin_t en,
               gpio_pin_t d0, gpio_pin_t d1, gpio_pin_t d2, gpio_pin_t d3,
-              gpio_pin_t d4, gpio_pin_t d5, gpio_pin_t d6, gpio_pin_t d7);
+              gpio_pin_t d4, gpio_pin_t d5, gpio_pin_t d6, gpio_pin_t d7,
+              int32_t bl);
 /*
  * Close LCD by freeing any resources associated with it.
  */
@@ -106,4 +109,9 @@ void lcd_cursor_shift(LCD *lcd, gpio_value_t sc, gpio_value_t rl);
  */
 bool lcd_is_busy(LCD *lcd);
 
+/*
+ * Set the backlight's power to ENABLE.
+ */
+void lcd_backlight_set_enabled(LCD *lcd, bool enable);
+
 #endif

src/main.c

@@ -17,6 +17,7 @@
 #include "ui/statsby.h"
 #include "ui/datapoints.h"
 #include "ui/statrange.h"
+#include "ui/blankscreen.h"
 
 #include <unistd.h>
 #include <err.h>
@@ -88,7 +89,7 @@ int main(int argc, char *const *argv) {
                         GLOBAL_OPTS.data_pins[1], GLOBAL_OPTS.data_pins[2],
                         GLOBAL_OPTS.data_pins[3], GLOBAL_OPTS.data_pins[4],
                         GLOBAL_OPTS.data_pins[5], GLOBAL_OPTS.data_pins[6],
-                        GLOBAL_OPTS.data_pins[7]);
+                        GLOBAL_OPTS.data_pins[7], GLOBAL_OPTS.bl_pin);
     setup_signals();
     open_database();
     initialize_util_queries(DATABASE);
@@ -104,6 +105,7 @@ int main(int argc, char *const *argv) {
     screen_manager_add(screen_manager, (Screen *) stats_by_screen_new());
     screen_manager_add(screen_manager, (Screen *) data_points_screen_new());
     screen_manager_add(screen_manager, (Screen *) stat_range_screen_new());
+    screen_manager_add(screen_manager, blank_screen_new());
     while (RUNNING) {
         lock_stat_globals();
         uint32_t temp = LAST_TEMP;

src/ui/blankscreen.c

@@ -0,0 +1,34 @@
+/*
+ * blankscreen.c - Screen that disables the display
+ * Copyright (C) 2024  Alexander Rosenberg
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version. See the LICENSE file for more information.
+ */
+#include "blankscreen.h"
+
+static bool blank_screen_dispatch(Screen *screen,
+                                  SensorState *state) {
+    if (state->back_down || state->sel_down || state->up_down ||
+        state->down_down) {
+        lcd_display_control(state->lcd, LCD_CURSOR_NO_BLINK, LCD_CURSOR_OFF,
+                            LCD_DISPLAY_ON);
+        lcd_backlight_set_enabled(state->lcd, true);
+        return true;
+    } else if (state->force_draw) {
+        lcd_display_control(state->lcd, LCD_CURSOR_NO_BLINK, LCD_CURSOR_OFF,
+                            LCD_DISPLAY_OFF);
+        lcd_backlight_set_enabled(state->lcd, false);
+    }
+    return false;
+}
+
+Screen *blank_screen_new() {
+    Screen *s = malloc_checked(sizeof(Screen));
+    screen_init(s, "Blank Display",
+                (ScreenDispatchFunc) blank_screen_dispatch,
+                (ScreenCleanupFunc) free);
+    return s;
+}

src/ui/blankscreen.h

@@ -0,0 +1,20 @@
+/*
+ * blankscreen.h - Screen that disables the display
+ * Copyright (C) 2024  Alexander Rosenberg
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version. See the LICENSE file for more information.
+ */
+#ifndef INCLUDED_BLANKSCREEN_H
+#define INCLUDED_BLANKSCREEN_H
+
+#include "screen.h"
+
+/*
+ * Create a new blank screen that will simply disable the display.
+ */
+Screen *blank_screen_new(void);
+
+#endif

src/util.h

@@ -34,6 +34,7 @@ typedef struct {
     gpio_pin_t rs_pin;
     gpio_pin_t rw_pin;
     gpio_pin_t data_pins[8];
+    gpio_pin_t bl_pin;
     char *database_location; // location of sqlite3 database
     char *temp_key; // sysctl key for temperature
     char *humid_key; // sysctl key for humidity