Add X9C Potentiometer component (#4183)

fixes https://github.com/esphome/feature-requests/issues/1270

esphome/components/x9c/x9c.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/core/hal.h"
+#include "esphome/components/output/float_output.h"
+
+namespace esphome {
+namespace x9c {
+
+class X9cOutput : public output::FloatOutput, public Component {
+ public:
+  void set_cs_pin(InternalGPIOPin *pin) { cs_pin_ = pin; }
+  void set_inc_pin(InternalGPIOPin *pin) { inc_pin_ = pin; }
+  void set_ud_pin(InternalGPIOPin *pin) { ud_pin_ = pin; }
+  void set_initial_value(float initial_value) { initial_value_ = initial_value; }
+
+  void setup() override;
+  void dump_config() override;
+
+  void trim_value(int change_amount);
+
+ protected:
+  void write_state(float state) override;
+  InternalGPIOPin *cs_pin_;
+  InternalGPIOPin *inc_pin_;
+  InternalGPIOPin *ud_pin_;
+  float initial_value_;
+  float pot_value_;
+};
+
+}  // namespace x9c
+}  // namespace esphome