From 6da275f5b4373089cd02a2a6c2c76a1edb06237a Mon Sep 17 00:00:00 2001
From: Karan Misra <kidoman@gmail.com>
Date: Thu, 9 Jan 2014 15:48:35 +0530
Subject: [PATCH] pca9685: add SetAnalog method

---
 controller/pca9685/pca9685.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/controller/pca9685/pca9685.go b/controller/pca9685/pca9685.go
index 5dfeea3..7b4b92d 100644
--- a/controller/pca9685/pca9685.go
+++ b/controller/pca9685/pca9685.go
@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/kid0m4n/go-rpi/i2c"
+	"github.com/kid0m4n/go-rpi/util"
 )
 
 const (
@@ -18,6 +19,9 @@ const (
 	preScaleRegAddr = 0xFE
 
 	pwm0OnLowReg = 0x6
+
+	minAnalogValue = 0
+	maxAnalogValue = 255
 )
 
 // PCA9685 represents a PCA9685 PWM generator.
@@ -154,6 +158,11 @@ func (d *PCA9685) SetMicroseconds(channel, us int) (err error) {
 	return d.SetPwm(channel, 0, offTime)
 }
 
+func (d *PCA9685) SetAnalog(channel int, value byte) (err error) {
+	offTime := util.Map(int64(value), minAnalogValue, maxAnalogValue, 0, pwmControlPoints-1)
+	return d.SetPwm(channel, 0, int(offTime))
+}
+
 // Close stops the controller and resets mode and pwm controller registers.
 func (d *PCA9685) Close() (err error) {
 	if err = d.setup(); err != nil {