From d724d36d6a6b7e63a49010391170aee102700973 Mon Sep 17 00:00:00 2001
From: James Carr <lesamouraipourpre@gmail.com>
Date: Sun, 25 Apr 2021 21:05:18 +0100
Subject: [PATCH] Add a display_offset parameter to SH1107. The current
 init_sequence assumes it is connected to the Adafruit FeatherWing 128x64 OLED
 screen. This parameter provides a way to set value provided to the Display
 Offset (D3) command. The value of this cannot be calculated from the size of
 the screen (except in the maximum case) as a manufacturer can choose where in
 the 128x128 grid they wire up their screen to.

The default value has been kept to the FeatherWing value of 0x60 so this should not be a
breaking change.

Constants have been included for:
* Adafruit FeatherWing 128x64 OLED
* Pimoroni Mono 128x128 OLED
---
 adafruit_displayio_sh1107.py | 59 +++++++++++++++++++++++++++++++++---
 docs/conf.py                 |  2 +-
 2 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/adafruit_displayio_sh1107.py b/adafruit_displayio_sh1107.py
index 0b22b73..11593c3 100644
--- a/adafruit_displayio_sh1107.py
+++ b/adafruit_displayio_sh1107.py
@@ -1,5 +1,6 @@
 # SPDX-FileCopyrightText: 2017 Scott Shawcroft, written for Adafruit Industries
 # SPDX-FileCopyrightText: Copyright (c) 2020 Mark Roberts for Adafruit Industries
+# SPDX-FileCopyrightText: 2021 James Carr
 #
 # SPDX-License-Identifier: MIT
 """
@@ -9,7 +10,7 @@
 DisplayIO driver for SH1107 monochrome displays
 
 
-* Author(s): Scott Shawcroft, Mark Roberts (mdroberts1243)
+* Author(s): Scott Shawcroft, Mark Roberts (mdroberts1243), James Carr
 
 Implementation Notes
 --------------------
@@ -26,10 +27,43 @@
 """
 
 import displayio
+from micropython import const
 
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_DisplayIO_SH1107.git"
 
+
+DISPLAY_OFFSET_ADAFRUIT_FEATHERWING_OLED_4650 = const(0x60)
+"""
+The hardware display offset to use when configuring the SH1107 for the
+`Adafruit Featherwing 128x64 OLED <https://www.adafruit.com/product/4650>`_
+
+.. code-block::
+
+    from adafruit_displayio_sh1107 import SH1107, DISPLAY_OFFSET_ADAFRUIT_FEATHERWING_OLED_4650
+
+    # Simplest constructor, assumes it is an Adafruit FeatherWing 128x64 OLED
+    display = SH1107(bus, width=128, height=64,
+        display_offset=DISPLAY_OFFSET_ADAFRUIT_FEATHERWING_OLED_4650)
+    # Or as it's the default
+    display = SH1107(bus, width=128, height=64)
+"""
+
+DISPLAY_OFFSET_PIMORONI_MONO_OLED_PIM374 = const(0x00)
+"""
+The hardware display offset to use when configuring the SH1107 for the
+`Pimoroni Mono 128x128 OLED <https://shop.pimoroni.com/products/1-12-oled-breakout>`_
+
+.. code-block::
+
+    from adafruit_displayio_sh1107 import SH1107, DISPLAY_OFFSET_PIMORONI_MONO_OLED_PIM374
+
+    # Constructor for the Pimoroni Mono 128x128 OLED
+    display = SH1107(bus, width=128, height=128,
+        display_offset=DISPLAY_OFFSET_PIMORONI_MONO_OLED_PIM374)
+"""
+
+
 # Sequence from sh1107 framebuf driver formatted for displayio init
 _INIT_SEQUENCE = (
     b"\xae\x00"  # display off, sleep mode
@@ -51,10 +85,27 @@
 
 
 class SH1107(displayio.Display):
-    """SSD1107 driver"""
-
-    def __init__(self, bus, **kwargs):
+    """
+    SSD1107 driver for use with DisplayIO
+
+    :param bus: The bus that the display is connected to.
+    :param int width: The width of the display. Maximum of 128
+    :param int height: The height of the display. Maximum of 128
+    :param int rotation: The rotation of the display. 0, 90, 180 or 270.
+    :param int display_offset: The display offset that the first column is wired to.
+        This will be dependent on the OLED display and two displays with the
+        same dimensions could have different offsets. This defaults to
+        `DISPLAY_OFFSET_ADAFRUIT_FEATHERWING_OLED_4650`
+    """
+
+    def __init__(
+        self,
+        bus,
+        display_offset=DISPLAY_OFFSET_ADAFRUIT_FEATHERWING_OLED_4650,
+        **kwargs
+    ):
         init_sequence = bytearray(_INIT_SEQUENCE)
+        init_sequence[19] = display_offset
         super().__init__(
             bus,
             init_sequence,
diff --git a/docs/conf.py b/docs/conf.py
index 827e3ef..17664ce 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -25,7 +25,7 @@
 # Uncomment the below if you use native CircuitPython modules such as
 # digitalio, micropython and busio. List the modules you use. Without it, the
 # autodoc module docs will fail to generate with a warning.
-autodoc_mock_imports = ["displayio"]
+autodoc_mock_imports = ["displayio", "micropython"]
 
 
 intersphinx_mapping = {