From 3fc843c21a6aa78e195e8e4ebab24e0c861b4860 Mon Sep 17 00:00:00 2001
From: John Ott <john.ott@johnott.us>
Date: Mon, 15 Jul 2019 20:22:47 -0700
Subject: [PATCH] Add IMU consumer template

This should *in theory* work to read and write registers on the I2C
bus. It's totally untested code, but it does appear to compile.
---
 consumer/imu.go | 142 ++++++++++++++++++++++++++++++++++++++++++++++++
 go.mod          |   1 +
 go.sum          |   2 +
 3 files changed, 145 insertions(+)
 create mode 100644 consumer/imu.go

diff --git a/consumer/imu.go b/consumer/imu.go
new file mode 100644
index 00000000..c003abd7
--- /dev/null
+++ b/consumer/imu.go
@@ -0,0 +1,142 @@
+// Copyright 2019 John Ott
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package consumer
+
+import (
+	"fmt"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/trivago/gollum/core"
+
+	"periph.io/x/periph/conn/i2c"
+	"periph.io/x/periph/conn/i2c/i2creg"
+	"periph.io/x/periph/host"
+)
+
+// IMU I2C Consumer
+//
+// This consumer read IMU values for the LSM9DS1 9DOF IMU over an I2C bus.
+//
+// Parameters
+//
+// - Bus: Defines the I2C Bus to connect to.
+//
+// - AccelerometerAddress: The accelerometer/gyroscope address on the I2C bus.
+//
+// - MagnetometerAddress: The magnetometer address on the I2C bus.
+//
+// Examples
+//
+// This config reads data from I2C2 on default addresses
+//
+//  IMUIn:
+//    Type: consumer.Imu
+//    Streams: imu
+//	  Bus: I2C2
+type Imu struct {
+	core.SimpleConsumer `gollumdoc:"embed_type"`
+	busName             string `config:"Bus"`
+	accelAddr           string `config:"AccelerometerAddress" default:"0x6A"`
+	magnetoAddr         string `config:"MagnetometerAddress" default:"0x1C"`
+	bus                 i2c.BusCloser
+	accel               *i2c.Dev
+	magneto             *i2c.Dev
+}
+
+func init() {
+	core.TypeRegistry.Register(Imu{})
+}
+
+func readReg(dev *i2c.Dev, reg byte, length byte) ([]byte, error) {
+	tx := []byte{reg}
+	r := make([]byte, length)
+	err := dev.Tx(tx, r)
+	return r, err
+}
+
+func writeReg(dev *i2c.Dev, reg byte, value []byte) error {
+	tx := []byte{reg}
+	tx = append(tx, value...)
+	err := dev.Tx(tx, nil)
+	return err
+}
+
+func (cons *Imu) Configure(conf core.PluginConfigReader) {
+	var err error
+
+	// Initialize periph
+	if _, err := host.Init(); err != nil {
+		cons.Logger.Error(err)
+	}
+
+	// Open I2C Bus
+	if cons.bus, err = i2creg.Open(cons.busName); err != nil {
+		cons.Logger.Error(err)
+	}
+
+	// Parse out the accelerometer address
+	accelAddrInt, err := strconv.ParseUint(cons.accelAddr, 0, 16)
+	if err != nil {
+		cons.Logger.Error(err)
+	}
+	cons.accel = &i2c.Dev{Bus: cons.bus, Addr: uint16(accelAddrInt)}
+
+	// Parse out the magnetometer address
+	magnetoAddrInt, err := strconv.ParseUint(cons.magnetoAddr, 0, 16)
+	if err != nil {
+		cons.Logger.Error(err)
+	}
+	cons.magneto = &i2c.Dev{Bus: cons.bus, Addr: uint16(magnetoAddrInt)}
+
+	// Do some configuration for the accelerometer and magnetometer here!
+
+	// For example:
+	err = writeReg(cons.accel, 0x10, []byte{0x20})
+	if err != nil {
+		cons.Logger.Error(err)
+	}
+}
+
+func (cons *Imu) pollAccel() {
+	for cons.IsActive() {
+		// Poll the accelerometer status register for data and call cons.Enqueue()
+
+		// For example:
+		r, err := readReg(cons.accel, 0x20, 2)
+		if err != nil {
+			cons.Logger.Error(err)
+		}
+
+		value := (r[1] << 8) | r[0]
+
+		// Enqueue new value
+		str := fmt.Sprintf("{\"value\":%d}\n", value)
+		cons.Enqueue([]byte(str))
+
+		// Don't spam
+		time.Sleep(100 * time.Millisecond)
+	}
+}
+
+func (cons *Imu) Consume(workers *sync.WaitGroup) {
+	// Close I2C bus on exit
+	defer cons.bus.Close()
+
+	go cons.pollAccel()
+
+	cons.ControlLoop()
+}
diff --git a/go.mod b/go.mod
index 400ec67d..ba4234d9 100644
--- a/go.mod
+++ b/go.mod
@@ -51,4 +51,5 @@ require (
 	gopkg.in/olivere/elastic.v5 v5.0.74
 	gopkg.in/oschwald/geoip2-golang.v1 v1.2.1
 	gopkg.in/yaml.v2 v2.2.1
+	periph.io/x/periph v3.4.0+incompatible
 )
diff --git a/go.sum b/go.sum
index 5b802e3f..a1bf0012 100644
--- a/go.sum
+++ b/go.sum
@@ -107,3 +107,5 @@ gopkg.in/oschwald/geoip2-golang.v1 v1.2.1 h1:j+YFlqD+OjnYkIzz0+XOqlKfB1j+LNHmEhx
 gopkg.in/oschwald/geoip2-golang.v1 v1.2.1/go.mod h1:5XB6J0gyVcbPdgVd3M73mvo/19VTkVUrPjnmGSiO2E0=
 gopkg.in/yaml.v2 v2.2.1 h1:mUhvW9EsL+naU5Q3cakzfE91YhliOondGd6ZrsDBHQE=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+periph.io/x/periph v3.4.0+incompatible h1:5gzxE4ryPq52cdqSw0mErR6pyJK8cBF2qdUAcOWh0bo=
+periph.io/x/periph v3.4.0+incompatible/go.mod h1:EWr+FCIU2dBWz5/wSWeiIUJTriYv9v2j2ENBmgYyy7Y=