From 53f58a31339c3d4785e670b2e14e67223fd35dd3 Mon Sep 17 00:00:00 2001
From: Mitchell Marino <mitchoah@gmail.com>
Date: Fri, 22 Aug 2025 11:38:21 -0500
Subject: [PATCH] fix mutex issue

---
 main/drivers/char_lcd.cpp      | 13 ++++++++++++-
 main/drivers/char_lcd.h        |  6 ++++--
 main/drivers/i2c_lcd_pcf8574.c |  6 ++----
 main/steps/setup_wires.cpp     |  3 ++-
 main/steps/step0.cpp           |  3 ++-
 5 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/main/drivers/char_lcd.cpp b/main/drivers/char_lcd.cpp
index 2d08276..32bb85b 100644
--- a/main/drivers/char_lcd.cpp
+++ b/main/drivers/char_lcd.cpp
@@ -92,11 +92,12 @@ void init_lcd() {
     ESP_LOGI(TAG, "Initializing LCD...");
 
     lcd_mutex = xSemaphoreCreateMutex();
+    assert(lcd_mutex != NULL);
 
     lcd_init(&lcd, LCD_ADDR, CHAR_LCD_I2C_NUM);
     lcd_begin(&lcd, LCD_COLS, LCD_ROWS);
 
-    lcd_set_backlight(&lcd, true);
+    lcd_set_backlight_to(&lcd, 1);
 
     register_replay_fn(replay_handler);
 
@@ -229,6 +230,8 @@ void lcd_set_backlight(bool backlight, bool no_lock) {
 }
 
 void lcd_create_char(uint8_t location, const uint8_t charmap[], bool no_lock) {
+    if (location == 8) location = 0;
+
     if (!no_lock) xSemaphoreTake(lcd_mutex, portMAX_DELAY);
     lcd_create_char(&lcd, location, charmap);
     if (!no_lock) xSemaphoreGive(lcd_mutex);
@@ -300,4 +303,12 @@ void lcd_do_splash() {
     lcd_print(6, 1, "\x01\x02Marino", true);
     lcd_print(5, 2, "\x03\x04\x05\x06""DEV", true);
     xSemaphoreGive(lcd_mutex);
+}
+
+bool lcd_lock(uint32_t ticks_to_wait) {
+    return xSemaphoreTake(lcd_mutex, ticks_to_wait);
+}
+
+void lcd_unlock() {
+    xSemaphoreGive(lcd_mutex);
 }
\ No newline at end of file
diff --git a/main/drivers/char_lcd.h b/main/drivers/char_lcd.h
index d881899..884f0e9 100644
--- a/main/drivers/char_lcd.h
+++ b/main/drivers/char_lcd.h
@@ -71,10 +71,12 @@ void lcd_do_splash();
 /// @brief Locks the LCD to allow chaining multiple commands without interuptions.
 ///
 /// Commands you call while you lock the LCD, you must call with the `no_lock` flag set to true.
-void lcd_lock();
+///
+/// Do not hold this lock for an extended period of time.
+/// @return `true` iff the lock was aquired.
+bool lcd_lock(uint32_t ticks_to_wait);
 
 /// @brief Unlocks the LCD to give away the mutex access to it.
 void lcd_unlock();
 
-
 #endif /* CHAR_LCD_H */
diff --git a/main/drivers/i2c_lcd_pcf8574.c b/main/drivers/i2c_lcd_pcf8574.c
index 581ef31..0bcd51c 100644
--- a/main/drivers/i2c_lcd_pcf8574.c
+++ b/main/drivers/i2c_lcd_pcf8574.c
@@ -260,7 +260,7 @@ void lcd_print(i2c_lcd_pcf8574_handle_t* lcd, const char* str) {
     while (*str) {
         if (*str == '\x08') {
             lcd_write(lcd, '\x00');
-            *str++;
+            str++;
         } else {
             lcd_write(lcd, *str++);
         }
@@ -305,10 +305,10 @@ static void lcd_send(i2c_lcd_pcf8574_handle_t* lcd, uint8_t value, bool is_data)
     i2c_cmd_handle_t cmd = i2c_cmd_link_create();
     i2c_master_start(cmd);
     i2c_master_write_byte(cmd, (lcd->i2c_addr << 1) | I2C_MASTER_WRITE, true);
+    xSemaphoreTake(main_i2c_mutex, portMAX_DELAY);
     lcd_write_nibble(lcd, (value >> 4 & 0x0F), is_data, cmd);
     lcd_write_nibble(lcd, (value & 0x0F), is_data, cmd);
     i2c_master_stop(cmd);
-    xSemaphoreTake(main_i2c_mutex, portMAX_DELAY);
     esp_err_t ret = i2c_master_cmd_begin(lcd->i2c_port, cmd, I2C_MASTER_TIMEOUT_MS / portTICK_PERIOD_MS);
     xSemaphoreGive(main_i2c_mutex);
     i2c_cmd_link_delete(cmd);
@@ -334,10 +334,8 @@ static void lcd_write_nibble(i2c_lcd_pcf8574_handle_t* lcd, uint8_t half_byte, b
     if (half_byte & 0x04) data |= lcd->data_mask[2];
     if (half_byte & 0x08) data |= lcd->data_mask[3];
 
-    xSemaphoreTake(main_i2c_mutex, portMAX_DELAY);
     i2c_master_write_byte(cmd, data | lcd->enable_mask, true);
     i2c_master_write_byte(cmd, data, true);
-    xSemaphoreGive(main_i2c_mutex);
 }  // lcd_write_nibble()
 
 // Private function to change the PCF8574 pins to the given value.
diff --git a/main/steps/setup_wires.cpp b/main/steps/setup_wires.cpp
index 732a43f..99f9bcb 100644
--- a/main/steps/setup_wires.cpp
+++ b/main/steps/setup_wires.cpp
@@ -23,7 +23,8 @@ void print_wires(WireColor* wires, int editing_idx) {
     }
     lcd_print(1, 3, string_buf);
 
-    lcd_set_cursor_pos(editing_idx+1, 1);
+    // TODO: find a way to indicate without a cursor.
+    // lcd_set_cursor_pos(editing_idx+1, 1);
 }
 
 void setup_wires(void) {
diff --git a/main/steps/step0.cpp b/main/steps/step0.cpp
index 44d4bb9..7205db1 100644
--- a/main/steps/step0.cpp
+++ b/main/steps/step0.cpp
@@ -214,7 +214,8 @@ static void _update_display(uint8_t* digits, uint8_t cursor_pos) {
     lcd_print(1, 1, str_buf);
     cursor_pos = MAX(0, MIN(4, cursor_pos));
     int mapped_cursor_pos = CURSOR_POS_MAP[cursor_pos];
-    lcd_set_cursor_pos(mapped_cursor_pos, 1);
+    // TODO: find some way to indicate without a cursor.
+    // lcd_set_cursor_pos(mapped_cursor_pos, 1);
 }
 
 static void set_game_time() {