From acc1af0f51a518dfb4ceadb3c72cbbb7fbb86b88 Mon Sep 17 00:00:00 2001
From: Samuel Sieb <samuel-github@sieb.net>
Date: Wed, 17 Feb 2021 11:26:22 -0800
Subject: [PATCH] Add reverse_enable for max7219 (#1489)

---
 esphome/components/max7219/display.py  | 4 ++++
 esphome/components/max7219/max7219.cpp | 8 +++++---
 esphome/components/max7219/max7219.h   | 2 ++
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/esphome/components/max7219/display.py b/esphome/components/max7219/display.py
index 0657f3f042..05b383004d 100644
--- a/esphome/components/max7219/display.py
+++ b/esphome/components/max7219/display.py
@@ -9,11 +9,14 @@ max7219_ns = cg.esphome_ns.namespace('max7219')
 MAX7219Component = max7219_ns.class_('MAX7219Component', cg.PollingComponent, spi.SPIDevice)
 MAX7219ComponentRef = MAX7219Component.operator('ref')
 
+CONF_REVERSE_ENABLE = 'reverse_enable'
+
 CONFIG_SCHEMA = display.BASIC_DISPLAY_SCHEMA.extend({
     cv.GenerateID(): cv.declare_id(MAX7219Component),
 
     cv.Optional(CONF_NUM_CHIPS, default=1): cv.int_range(min=1, max=255),
     cv.Optional(CONF_INTENSITY, default=15): cv.int_range(min=0, max=15),
+    cv.Optional(CONF_REVERSE_ENABLE, default=False): cv.boolean,
 }).extend(cv.polling_component_schema('1s')).extend(spi.spi_device_schema())
 
 
@@ -25,6 +28,7 @@ def to_code(config):
 
     cg.add(var.set_num_chips(config[CONF_NUM_CHIPS]))
     cg.add(var.set_intensity(config[CONF_INTENSITY]))
+    cg.add(var.set_reverse(config[CONF_REVERSE_ENABLE]))
 
     if CONF_LAMBDA in config:
         lambda_ = yield cg.process_lambda(config[CONF_LAMBDA], [(MAX7219ComponentRef, 'it')],
diff --git a/esphome/components/max7219/max7219.cpp b/esphome/components/max7219/max7219.cpp
index 99eca6c14f..f58f203442 100644
--- a/esphome/components/max7219/max7219.cpp
+++ b/esphome/components/max7219/max7219.cpp
@@ -142,9 +142,11 @@ void MAX7219Component::dump_config() {
 void MAX7219Component::display() {
   for (uint8_t i = 0; i < 8; i++) {
     this->enable();
-    for (uint8_t j = 0; j < this->num_chips_; j++) {
-      this->send_byte_(8 - i, this->buffer_[j * 8 + i]);
-    }
+    for (uint8_t j = 0; j < this->num_chips_; j++)
+      if (reverse_)
+        this->send_byte_(8 - i, buffer_[(num_chips_ - j - 1) * 8 + i]);
+      else
+        this->send_byte_(8 - i, buffer_[j * 8 + i]);
     this->disable();
   }
 }
diff --git a/esphome/components/max7219/max7219.h b/esphome/components/max7219/max7219.h
index 1920268ba4..47b54a4c50 100644
--- a/esphome/components/max7219/max7219.h
+++ b/esphome/components/max7219/max7219.h
@@ -34,6 +34,7 @@ class MAX7219Component : public PollingComponent,
 
   void set_intensity(uint8_t intensity);
   void set_num_chips(uint8_t num_chips);
+  void set_reverse(bool reverse) { this->reverse_ = reverse; };
 
   /// Evaluate the printf-format and print the result at the given position.
   uint8_t printf(uint8_t pos, const char *format, ...) __attribute__((format(printf, 3, 4)));
@@ -60,6 +61,7 @@ class MAX7219Component : public PollingComponent,
   uint8_t intensity_{15};  /// Intensity of the display from 0 to 15 (most)
   uint8_t num_chips_{1};
   uint8_t *buffer_;
+  bool reverse_{false};
   optional<max7219_writer_t> writer_{};
 };