Added documentation for SN74HC165 (#2504)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

components/sn74hc165.rst

@@ -0,0 +1,66 @@
+SN74HC165 I/O Expander (shift register)
+=======================================
+
+.. seo::
+    :description: Instructions for setting up SN74HC165 shift registers as digital port expanders in ESPHome.
+
+The SN74HC165 component allows you to use SN74HC165 shift registers as I/O expanders (Input only, use SN74HC595 for outputs)
+(`datasheet <https://www.ti.com/lit/ds/symlink/sn74hc165.pdf>`__) in ESPHome. It uses 3 wires (optionally 4) for communication.
+
+Once configured, you can use any of the 8 pins for your projects. Up-to 256 shift registers can be daisy-chained
+to provide more pins, without using more GPIO pins on the controller. They are linked by connecting pin Q of the closer
+shift register to the pin QH of the next shift register.
+
+
+.. code-block:: yaml
+
+    # Example configuration entry
+    sn74hc165:
+      - id: sn74hc165_hub
+        clock_pin: GPIO16
+        data_pin: GPIO17
+        load_pin: GPIO4
+        clock_inhibit_pin: GPIO18
+        sr_count: 2
+
+    # Individual inputs
+    binary_sensor:
+      - platform: gpio
+        name: "SN74HC165 Pin #0"
+        pin:
+          sn74hc595: sn74hc165_hub
+          # Use pin number 0
+          number: 0
+          inverted: false
+
+
+Configuration variables:
+************************
+
+- **id** (**Required**, :ref:`config-id`): The id to use for this SN74HC165 component.
+- **data_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC165 Serial Output (QH) input.
+- **clock_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC165 Clock (CLK) pin
+- **load_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC165 Load input (SH/LD) pin
+- **clock_inhibit_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): Pin connected to SN74HC165 Clock Inhibit (CLK INH) pin
+- **sr_count** (*Optional*, int): Number of daisy-chained shift registers, up-to 256. Defaults to ``1``.
+
+
+Pin configuration variables:
+****************************
+
+- **SN74HC165** (**Required**, :ref:`config-id`): The id of the SN74HC165 component of the pin.
+- **number** (**Required**, int): The pin number.
+- **inverted** (*Optional*, boolean): If received value should be treated as inverted.
+  Defaults to ``false``.
+
+.. note::
+
+    Pin number 0 is Pin A on the SN74HC165 that is furthest away from the microcontroller.
+
+See Also
+--------
+
+
+- :doc:`binary_sensor/gpio`
+- :apiref:`SN74HC165/SN74HC165.h`
+- :ghedit:`Edit`

index.rst

@@ -680,6 +680,7 @@ Misc Components
     TCA9548A I²C Multiplexer, components/tca9548a, tca9548a.jpg
     MCP23SXX I/O Expander - SPI Bus, components/mcp23Sxx, mcp230xx.svg
     SX1509 I/O Expander, components/sx1509, sx1509.jpg
+    SN74HC165 I/O Expander, components/sn74hc165, sn74hc595.jpg
     SN74HC595 I/O Expander, components/sn74hc595, sn74hc595.jpg
     SIM800L, components/sim800l, sim800l.jpg
     DFPlayer, components/dfplayer, dfplayer.svg