add support for SN74HC595 shift register (#1083)

* add support for SN74HC595 shift register

* fix linter errors

* more linter reported issues fixed

* hopefully last linter error cleanup

* one more linter fix

* looks like the linter is always keeping stuff for later, is this the final fix?

* add test

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

esphome/components/sn74hc595/__init__.py

@@ -0,0 +1,54 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome import pins
+from esphome.const import CONF_ID, CONF_NUMBER, CONF_INVERTED, CONF_DATA_PIN, CONF_CLOCK_PIN
+
+DEPENDENCIES = []
+MULTI_CONF = True
+
+sn74hc595_ns = cg.esphome_ns.namespace('sn74hc595')
+
+SN74HC595Component = sn74hc595_ns.class_('SN74HC595Component', cg.Component)
+SN74HC595GPIOPin = sn74hc595_ns.class_('SN74HC595GPIOPin', cg.GPIOPin)
+
+CONF_SN74HC595 = 'sn74hc595'
+CONF_LATCH_PIN = 'latch_pin'
+CONF_OE_PIN = 'oe_pin'
+CONF_SR_COUNT = 'sr_count'
+CONFIG_SCHEMA = cv.Schema({
+    cv.Required(CONF_ID): cv.declare_id(SN74HC595Component),
+    cv.Required(CONF_DATA_PIN): pins.gpio_output_pin_schema,
+    cv.Required(CONF_CLOCK_PIN): pins.gpio_output_pin_schema,
+    cv.Required(CONF_LATCH_PIN): pins.gpio_output_pin_schema,
+    cv.Optional(CONF_OE_PIN): pins.gpio_output_pin_schema,
+    cv.Optional(CONF_SR_COUNT, default=1): cv.int_range(1, 4)
+}).extend(cv.COMPONENT_SCHEMA)
+
+
+def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    yield cg.register_component(var, config)
+    data_pin = yield cg.gpio_pin_expression(config[CONF_DATA_PIN])
+    cg.add(var.set_data_pin(data_pin))
+    clock_pin = yield cg.gpio_pin_expression(config[CONF_CLOCK_PIN])
+    cg.add(var.set_clock_pin(clock_pin))
+    latch_pin = yield cg.gpio_pin_expression(config[CONF_LATCH_PIN])
+    cg.add(var.set_latch_pin(latch_pin))
+    oe_pin = yield cg.gpio_pin_expression(config[CONF_OE_PIN])
+    cg.add(var.set_oe_pin(oe_pin))
+    cg.add(var.set_sr_count(config[CONF_SR_COUNT]))
+
+
+SN74HC595_OUTPUT_PIN_SCHEMA = cv.Schema({
+    cv.Required(CONF_SN74HC595): cv.use_id(SN74HC595Component),
+    cv.Required(CONF_NUMBER): cv.int_,
+    cv.Optional(CONF_INVERTED, default=False): cv.boolean,
+})
+SN74HC595_INPUT_PIN_SCHEMA = cv.Schema({})
+
+
+@pins.PIN_SCHEMA_REGISTRY.register(CONF_SN74HC595,
+                                   (SN74HC595_OUTPUT_PIN_SCHEMA, SN74HC595_INPUT_PIN_SCHEMA))
+def sn74hc595_pin_to_code(config):
+    parent = yield cg.get_variable(config[CONF_SN74HC595])
+    yield SN74HC595GPIOPin.new(parent, config[CONF_NUMBER], config[CONF_INVERTED])

esphome/components/sn74hc595/sn74hc595.cpp

@@ -0,0 +1,70 @@
+#include "sn74hc595.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace sn74hc595 {
+
+static const char *TAG = "sn74hc595";
+
+void SN74HC595Component::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up SN74HC595...");
+
+  if (this->have_oe_pin_) {  // disable output
+    pinMode(this->oe_pin_->get_pin(), OUTPUT);
+    digitalWrite(this->oe_pin_->get_pin(), HIGH);
+  }
+
+  // initialize output pins
+  pinMode(this->clock_pin_->get_pin(), OUTPUT);
+  pinMode(this->data_pin_->get_pin(), OUTPUT);
+  pinMode(this->latch_pin_->get_pin(), OUTPUT);
+  digitalWrite(this->clock_pin_->get_pin(), LOW);
+  digitalWrite(this->data_pin_->get_pin(), LOW);
+  digitalWrite(this->latch_pin_->get_pin(), LOW);
+
+  // send state to shift register
+  this->write_gpio_();
+}
+
+void SN74HC595Component::dump_config() { ESP_LOGCONFIG(TAG, "SN74HC595:"); }
+
+bool SN74HC595Component::digital_read_(uint8_t pin) { return bitRead(this->output_bits_, pin); }
+
+void SN74HC595Component::digital_write_(uint8_t pin, bool value) {
+  bitWrite(this->output_bits_, pin, value);
+  this->write_gpio_();
+}
+
+bool SN74HC595Component::write_gpio_() {
+  for (int i = this->sr_count_ - 1; i >= 0; i--) {
+    uint8_t data = (uint8_t)(this->output_bits_ >> (8 * i) & 0xff);
+    shiftOut(this->data_pin_->get_pin(), this->clock_pin_->get_pin(), MSBFIRST, data);
+  }
+
+  // pulse latch to activate new values
+  digitalWrite(this->latch_pin_->get_pin(), HIGH);
+  digitalWrite(this->latch_pin_->get_pin(), LOW);
+
+  // enable output if configured
+  if (this->have_oe_pin_) {
+    digitalWrite(this->oe_pin_->get_pin(), LOW);
+  }
+
+  return true;
+}
+
+float SN74HC595Component::get_setup_priority() const { return setup_priority::IO; }
+
+void SN74HC595GPIOPin::setup() {}
+
+bool SN74HC595GPIOPin::digital_read() { return this->parent_->digital_read_(this->pin_) != this->inverted_; }
+
+void SN74HC595GPIOPin::digital_write(bool value) {
+  this->parent_->digital_write_(this->pin_, value != this->inverted_);
+}
+
+SN74HC595GPIOPin::SN74HC595GPIOPin(SN74HC595Component *parent, uint8_t pin, bool inverted)
+    : GPIOPin(pin, OUTPUT, inverted), parent_(parent) {}
+
+}  // namespace sn74hc595
+}  // namespace esphome

esphome/components/sn74hc595/sn74hc595.h

@@ -0,0 +1,55 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/core/esphal.h"
+
+namespace esphome {
+namespace sn74hc595 {
+
+class SN74HC595Component : public Component {
+ public:
+  SN74HC595Component() = default;
+
+  void setup() override;
+  float get_setup_priority() const override;
+  void dump_config() override;
+
+  void set_data_pin(GPIOPin *pin) { data_pin_ = pin; }
+  void set_clock_pin(GPIOPin *pin) { clock_pin_ = pin; }
+  void set_latch_pin(GPIOPin *pin) { latch_pin_ = pin; }
+  void set_oe_pin(GPIOPin *pin) {
+    oe_pin_ = pin;
+    have_oe_pin_ = true;
+  }
+  void set_sr_count(uint8_t count) { sr_count_ = count; }
+
+ protected:
+  friend class SN74HC595GPIOPin;
+  bool digital_read_(uint8_t pin);
+  void digital_write_(uint8_t pin, bool value);
+  bool write_gpio_();
+
+  GPIOPin *data_pin_;
+  GPIOPin *clock_pin_;
+  GPIOPin *latch_pin_;
+  GPIOPin *oe_pin_;
+  uint8_t sr_count_;
+  bool have_oe_pin_{false};
+  uint32_t output_bits_{0x00};
+};
+
+/// Helper class to expose a SC74HC595 pin as an internal output GPIO pin.
+class SN74HC595GPIOPin : public GPIOPin {
+ public:
+  SN74HC595GPIOPin(SN74HC595Component *parent, uint8_t pin, bool inverted = false);
+
+  void setup() override;
+  bool digital_read() override;
+  void digital_write(bool value) override;
+
+ protected:
+  SN74HC595Component *parent_;
+};
+
+}  // namespace sn74hc595
+}  // namespace esphome

tests/test1.yaml

@@ -1465,6 +1465,14 @@ switch:
         id: my_stepper
         position: 0
 
+  - platform: gpio
+    name: "SN74HC595 Pin #0"
+    pin:
+      sn74hc595: sn74hc595_hub
+      # Use pin number 0
+      number: 0
+      inverted: False
+
 fan:
   - platform: binary
     output: gpio_26
@@ -1715,3 +1723,11 @@ text_sensor:
     name: "BSSID"
   mac_address:
     name: "Mac Address"
+
+sn74hc595:
+  - id: 'sn74hc595_hub'
+    data_pin: GPIO21
+    clock_pin: GPIO23
+    latch_pin: GPIO22
+    oe_pin: GPIO32
+    sr_count: 2