MCP3204 4-channel 12-bit ADC component (#2895)

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

esphome/components/mcp3204/__init__.py

@@ -0,0 +1,27 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import spi
+from esphome.const import CONF_ID
+
+DEPENDENCIES = ["spi"]
+MULTI_CONF = True
+CODEOWNERS = ["@rsumner"]
+
+mcp3204_ns = cg.esphome_ns.namespace("mcp3204")
+MCP3204 = mcp3204_ns.class_("MCP3204", cg.Component, spi.SPIDevice)
+
+CONF_REFERENCE_VOLTAGE = "reference_voltage"
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.GenerateID(): cv.declare_id(MCP3204),
+        cv.Optional(CONF_REFERENCE_VOLTAGE, default="3.3V"): cv.voltage,
+    }
+).extend(spi.spi_device_schema(cs_pin_required=True))
+
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    cg.add(var.set_reference_voltage(config[CONF_REFERENCE_VOLTAGE]))
+    await cg.register_component(var, config)
+    await spi.register_spi_device(var, config)