Add MCP3008 I/O Expander (#1057)

* Add MCP3008

* Fixed Travis build issues

* Travis Build Fix

* Fix Travis foramt issues

* Travis fixes

* Code review changes

* Fix bit shift. off by one and selecting wrong pin

* general fixes

* lint

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

esphome/components/mcp3008/__init__.py

@@ -0,0 +1,23 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import spi
+from esphome.const import CONF_ID
+
+DEPENDENCIES = ['spi']
+AUTO_LOAD = ['sensor']
+MULTI_CONF = True
+
+CONF_MCP3008 = 'mcp3008'
+
+mcp3008_ns = cg.esphome_ns.namespace('mcp3008')
+MCP3008 = mcp3008_ns.class_('MCP3008', cg.Component, spi.SPIDevice)
+
+CONFIG_SCHEMA = cv.Schema({
+    cv.GenerateID(): cv.declare_id(MCP3008),
+}).extend(spi.spi_device_schema(CS_PIN_required=True))
+
+
+def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    yield cg.register_component(var, config)
+    yield spi.register_spi_device(var, config)

esphome/components/mcp3008/mcp3008.cpp

@@ -0,0 +1,52 @@
+#include "mcp3008.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace mcp3008 {
+
+static const char *TAG = "mcp3008";
+
+float MCP3008::get_setup_priority() const { return setup_priority::HARDWARE; }
+
+void MCP3008::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up mcp3008");
+  this->spi_setup();
+}
+
+void MCP3008::dump_config() {
+  ESP_LOGCONFIG(TAG, "MCP3008:");
+  LOG_PIN("  CS Pin: ", this->cs_);
+}
+
+float MCP3008::read_data_(uint8_t pin) {
+  byte data_msb = 0;
+  byte data_lsb = 0;
+
+  byte command = ((0x01 << 7) |          // start bit
+                  ((pin & 0x07) << 4));  // channel number
+
+  this->enable();
+
+  this->transfer_byte(0x01);
+  data_msb = this->transfer_byte(command) & 0x03;
+  data_lsb = this->transfer_byte(0x00);
+
+  this->disable();
+
+  int data = data_msb << 8 | data_lsb;
+
+  return data / 1024.0f;
+}
+
+MCP3008Sensor::MCP3008Sensor(MCP3008 *parent, std::string name, uint8_t pin)
+    : PollingComponent(1000), parent_(parent), pin_(pin) {
+  this->set_name(name);
+}
+void MCP3008Sensor::setup() { LOG_SENSOR("", "Setting up MCP3008 Sensor '%s'...", this); }
+void MCP3008Sensor::update() {
+  float value_v = this->parent_->read_data_(pin_);
+  this->publish_state(value_v);
+}
+
+}  // namespace mcp3008
+}  // namespace esphome

esphome/components/mcp3008/mcp3008.h

@@ -0,0 +1,42 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/core/esphal.h"
+#include "esphome/components/sensor/sensor.h"
+#include "esphome/components/spi/spi.h"
+
+namespace esphome {
+namespace mcp3008 {
+
+class MCP3008Sensor;
+
+class MCP3008 : public Component,
+                public spi::SPIDevice<spi::BIT_ORDER_MSB_FIRST, spi::CLOCK_POLARITY_LOW, spi::CLOCK_PHASE_LEADING,
+                                      spi::DATA_RATE_1MHZ> {  // At 3.3V 2MHz is too fast 1.35MHz is about right
+ public:
+  MCP3008() = default;
+
+  void setup() override;
+  void dump_config() override;
+  float get_setup_priority() const override;
+
+ protected:
+  float read_data_(uint8_t pin);
+
+  friend class MCP3008Sensor;
+};
+
+class MCP3008Sensor : public PollingComponent, public sensor::Sensor {
+ public:
+  MCP3008Sensor(MCP3008 *parent, std::string name, uint8_t pin);
+
+  void setup() override;
+  void update() override;
+
+ protected:
+  MCP3008 *parent_;
+  uint8_t pin_;
+};
+
+}  // namespace mcp3008
+}  // namespace esphome

esphome/components/mcp3008/sensor.py

@@ -0,0 +1,23 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import sensor
+from esphome.const import CONF_ID, CONF_NUMBER, CONF_NAME
+from . import mcp3008_ns, MCP3008
+
+DEPENDENCIES = ['mcp3008']
+
+MCP3008Sensor = mcp3008_ns.class_('MCP3008Sensor', sensor.Sensor, cg.PollingComponent)
+
+CONF_MCP3008_ID = 'mcp3008_id'
+
+CONFIG_SCHEMA = sensor.SENSOR_SCHEMA.extend({
+    cv.GenerateID(): cv.declare_id(MCP3008Sensor),
+    cv.GenerateID(CONF_MCP3008_ID): cv.use_id(MCP3008),
+    cv.Required(CONF_NUMBER): cv.int_,
+}).extend(cv.polling_component_schema('1s'))
+
+
+def to_code(config):
+    parent = yield cg.get_variable(config[CONF_MCP3008_ID])
+    var = cg.new_Pvariable(config[CONF_ID], parent, config[CONF_NAME], config[CONF_NUMBER])
+    yield cg.register_component(var, config)