From 37fba09021fe094ea4daf0813626b1b6a201c8c0 Mon Sep 17 00:00:00 2001
From: Ryan <fauxpark@gmail.com>
Date: Sat, 19 Jun 2021 18:51:35 +1000
Subject: [PATCH] ST7565 invert (#13237)

---
 docs/feature_st7565.md |  4 ++++
 drivers/lcd/st7565.c   | 16 ++++++++++++++++
 drivers/lcd/st7565.h   |  4 ++++
 3 files changed, 24 insertions(+)

diff --git a/docs/feature_st7565.md b/docs/feature_st7565.md
index 7db0f9ac4..de3e44d8e 100644
--- a/docs/feature_st7565.md
+++ b/docs/feature_st7565.md
@@ -262,6 +262,10 @@ void st7565_task(void);
 // Called at the start of st7565_task, weak function overridable by the user
 void st7565_task_user(void);
 
+// Inverts the display
+// Returns true if the screen was or is inverted
+bool st7565_invert(bool invert);
+
 // Returns the maximum number of characters that will fit on a line
 uint8_t st7565_max_chars(void);
 
diff --git a/drivers/lcd/st7565.c b/drivers/lcd/st7565.c
index ee2661a5e..49b13c00f 100644
--- a/drivers/lcd/st7565.c
+++ b/drivers/lcd/st7565.c
@@ -31,6 +31,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define DISPLAY_ALL_ON 0xA5
 #define DISPLAY_ALL_ON_RESUME 0xA4
 #define NORMAL_DISPLAY 0xA6
+#define INVERT_DISPLAY 0xA7
 #define DISPLAY_ON 0xAF
 #define DISPLAY_OFF 0xAE
 #define NOP 0xE3
@@ -72,6 +73,7 @@ uint8_t *          st7565_cursor;
 ST7565_BLOCK_TYPE  st7565_dirty       = 0;
 bool               st7565_initialized = false;
 bool               st7565_active      = false;
+bool               st7565_inverted    = false;
 display_rotation_t st7565_rotation    = DISPLAY_ROTATION_0;
 #if ST7565_TIMEOUT > 0
 uint32_t st7565_timeout;
@@ -429,6 +431,20 @@ __attribute__((weak)) void st7565_off_user(void) {}
 
 bool st7565_is_on(void) { return st7565_active; }
 
+bool st7565_invert(bool invert) {
+    if (!st7565_initialized) {
+        return st7565_inverted;
+    }
+
+    if (invert != st7565_inverted) {
+        spi_start(ST7565_SS_PIN, false, 0, ST7565_SPI_CLK_DIVISOR);
+        st7565_send_cmd(invert ? INVERT_DISPLAY : NORMAL_DISPLAY);
+        spi_stop();
+        st7565_inverted = invert;
+    }
+    return st7565_inverted;
+}
+
 uint8_t st7565_max_chars(void) { return ST7565_DISPLAY_WIDTH / ST7565_FONT_WIDTH; }
 
 uint8_t st7565_max_lines(void) { return ST7565_DISPLAY_HEIGHT / ST7565_FONT_HEIGHT; }
diff --git a/drivers/lcd/st7565.h b/drivers/lcd/st7565.h
index 53cfc9a81..d453dbe6d 100644
--- a/drivers/lcd/st7565.h
+++ b/drivers/lcd/st7565.h
@@ -202,6 +202,10 @@ void st7565_task(void);
 // Called at the start of st7565_task, weak function overridable by the user
 void st7565_task_user(void);
 
+// Inverts the display
+// Returns true if the screen was or is inverted
+bool st7565_invert(bool invert);
+
 // Returns the maximum number of characters that will fit on a line
 uint8_t st7565_max_chars(void);