ds1808lc: Initial Implementation Maxim DS1808 based LED lighting controller

DS1808 is a general purpose potentiometer but this implementation
is limited to controlling brightness of custom LED lighting hardware.
Ideally there should be a DS1808 module used by a seperate
lighting module.

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
Signed-off-by: Abhishek Malik <abhishek.malik@intel.com>

src/ds1808lc/CMakeLists.txt

@@ -0,0 +1,6 @@
+include_directories(..)
+set (libname "ds1808lc")
+set (libdescription “DS1808 lighting controller”)
+set (module_src ${libname}.cxx mraa-utils.cxx)
+set (module_h ${libname}.h)
+upm_module_init()

src/ds1808lc/ds1808lc.cxx

@@ -0,0 +1,139 @@
+#include <iostream>
+#include <unistd.h>
+#include <string.h>
+#include <cmath>
+#include "ds1808lc.h"
+#include "mraa-utils.h"
+
+#define DS1808_I2C_ADDR 0x28
+#define DS1808_POT2_OFFSET 0x40
+#define DS1808_MAX_POT_VALUE 0x20
+#define DS1808_LOW_VALUE 32 // Lowest pot value that the eye can differentiate from 0
+#define DS1808_HIGH_VALUE 51 // Highest pot value that the eye can differentiate from full
+
+
+namespace upm {
+DS1808LC::DS1808LC(int gpioPower, int i2cBus)
+{
+   mraa_set_log_level(7);
+   pinPower = gpioPower;
+   i2c = new mraa::I2c(i2cBus);
+   status = i2c->address(DS1808_I2C_ADDR);
+   getBrightness();
+}
+
+DS1808LC::~DS1808LC()
+{
+}
+
+
+bool DS1808LC::isConfigured()
+{
+   return status == mraa::SUCCESS;
+}
+
+bool DS1808LC::isPowered()
+{
+   return static_cast<bool>(MraaUtils::getGpio(pinPower));
+}
+
+void DS1808LC::setPowerOn()
+{
+   if (!isPowered())
+   {
+      MraaUtils::setGpio(pinPower, 1);
+      setBrightness(0);
+   }
+}
+
+void DS1808LC::setPowerOff()
+{
+   MraaUtils::setGpio(pinPower, 0);
+}
+
+
+int DS1808LC::getBrightness()
+{
+   uint8_t values[2];
+
+   if (i2c->read(values, 2) == 2) {
+      return getPercentBrightness(values[0], values[1]);
+   }
+   else
+      UPM_THROW("i2c read error");
+}
+   
+
+void DS1808LC::setBrightness(int dutyPercent)
+{
+   uint8_t values[2];
+   values[0] = getPot1Value(dutyPercent);
+   values[1] = getPot2Value(dutyPercent);
+   status = i2c->write(values, 2);
+   if (status != mraa::SUCCESS)
+       UPM_THROW("i2c write error");
+}
+
+//
+// Helper Function
+//
+
+uint8_t DS1808LC::getPot1Value(int dutyPercent) {
+   uint8_t result = 0;
+   int scaledResistance = getScaledResistance(dutyPercent);
+
+   if (scaledResistance > DS1808_MAX_POT_VALUE)
+      result = DS1808_MAX_POT_VALUE;
+   else {
+      result = scaledResistance;
+   }
+
+   return result;
+}
+
+uint8_t DS1808LC::getPot2Value(int dutyPercent) {
+   uint8_t result = 0;
+   int scaledResistance = getScaledResistance(dutyPercent);
+
+   if (scaledResistance <= DS1808_MAX_POT_VALUE)
+      result = 0;
+   else {
+      result = scaledResistance - DS1808_MAX_POT_VALUE;
+   }
+
+   if (result > DS1808_MAX_POT_VALUE)
+      result = DS1808_MAX_POT_VALUE;
+
+   return result | DS1808_POT2_OFFSET;
+}
+
+int DS1808LC::getPercentBrightness(uint8_t val1, uint8_t val2) {
+   val2 = val2 & (~DS1808_POT2_OFFSET);
+   int scaledResistance = val1 + val2;
+   int percent;
+
+   if (scaledResistance < DS1808_LOW_VALUE)
+      percent = 100;
+   else if (scaledResistance > DS1808_HIGH_VALUE)
+      percent = 0;
+   else
+      percent = 100 - (((scaledResistance - DS1808_LOW_VALUE) * 100) / (DS1808_HIGH_VALUE - DS1808_LOW_VALUE));
+   return percent;
+}
+
+int DS1808LC::getScaledResistance(int dutyPercent) {
+   int scaledResistance;
+
+   if (dutyPercent == 0)
+      scaledResistance = 2 * DS1808_MAX_POT_VALUE;
+   else if (dutyPercent == 100)
+      scaledResistance = 0;
+   else
+      scaledResistance = (((100 - dutyPercent) * (DS1808_HIGH_VALUE - DS1808_LOW_VALUE)) / 100) + DS1808_LOW_VALUE;
+   return scaledResistance;
+}
+
+}
+
+
+

src/ds1808lc/ds1808lc.h

@@ -0,0 +1,81 @@
+/*
+ * Author: Henry Bruce <henry.bruce@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "upm/iLightController.h"
+#include "mraa/i2c.hpp"
+
+namespace upm
+{
+/**
+ * @brief DS1808LC lighting controller library
+ * @defgroup DS1808LC libupm-ds1808lc
+ * @ingroup ds1808lc i2c maxim light ilightcontroller
+ */
+
+/**
+ * @brief API for DS1808 Dual Log Digital Potentiometer as a Light Controller
+ *
+ * The Maxim Integrated
+ * [DS1808](http://www.maximintegrated.com/en/products/analog/data-converters/digital-potentiometers/DS1808.html)
+ * Dual Log Digital Potentiometer
+ *
+ * 
+ * @library ds1808lc
+ * @sensor ds1808lc
+ * @comname Maxim  DS1808 as lighting controller
+ * @altname DS1808LC
+ * @type light
+ * @man maxim
+ * @con i2c
+ * @if ilightcontroller
+ */
+class DS1808LC : public upm::ILightController
+{
+public:
+   DS1808LC(int gpioPower, int i2cBus);
+   ~DS1808LC();
+
+protected:
+   bool isConfigured();
+   const char* getModuleName() { return "ds1808lc"; }   
+   bool isPowered();
+   void setPowerOn();
+   void setPowerOff();
+   int getBrightness();
+   void setBrightness(int dutyPercent);
+
+private:
+   int getPercentBrightness(uint8_t val1, uint8_t val2);
+   uint8_t getPot1Value(int dutyPercent);
+   uint8_t getPot2Value(int dutyPercent);
+   int getScaledResistance(int dutyPercent);
+
+   mraa::Result status;
+   mraa::I2c* i2c;
+   int pinPower;
+};
+
+
+}
+

src/ds1808lc/jsupm_ds1808lc.i

@@ -0,0 +1,8 @@
+%module jsupm_tubelight
+%include "../upm.i"
+
+%{
+    #include "tubelight.h"
+%}
+
+%include "tubelight.h"

src/ds1808lc/mraa-utils.cxx

@@ -0,0 +1,72 @@
+/*
+ * Author: Henry Bruce <henry.bruce@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "mraa-utils.h"
+#include "mraa/gpio.hpp"
+
+ #define UPM_THROW(msg) throw std::runtime_error(std::string(__FUNCTION__) + ": " + (msg))
+
+void MraaUtils::setGpio(int pin, int level)
+{
+/*
+   mraa_result_t status = MRAA_ERROR_NO_RESOURCES; 
+   mraa_gpio_context gpio = mraa_gpio_init(pin);
+   if (gpio != NULL) 
+   {
+      mraa_gpio_dir(gpio, MRAA_GPIO_OUT);
+      status = mraa_gpio_write(gpio, level);
+      mraa_gpio_close(gpio);
+   } 
+   return status;
+*/
+   mraa::Gpio gpio(pin);
+   gpio.dir(mraa::DIR_OUT);
+   if (gpio.write(level) != mraa::SUCCESS)
+      UPM_THROW("gpio write failed");
+}
+
+
+int MraaUtils::getGpio(int pin)
+{
+/*
+   mraa_result_t status = MRAA_ERROR_NO_RESOURCES; 
+   mraa_gpio_context gpio = mraa_gpio_init(pin);
+   if (gpio != NULL) 
+   {
+      status = mraa_gpio_dir(gpio, MRAA_GPIO_IN);
+      int value = mraa_gpio_read(gpio);
+      if (value != -1)
+         *level = value;
+      else
+         status = MRAA_ERROR_NO_RESOURCES; 
+      mraa_gpio_close(gpio);
+   }
+   return status;       
+*/
+   mraa::Gpio gpio(pin);
+   gpio.dir(mraa::DIR_IN);
+   return gpio.read();
+}
+
+

src/ds1808lc/mraa-utils.h

@@ -0,0 +1,37 @@
+/*
+ * Author: Henry Bruce <henry.bruce@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "mraa/types.h"
+
+class __attribute__ ((visibility("hidden"))) MraaUtils
+{
+public:
+   static void setGpio(int pin, int level);
+   static int getGpio(int pin);
+};
+
+
+

src/ds1808lc/pyupm_ds1808lc.i

@@ -0,0 +1,9 @@
+%module pyupm_tubelight
+%include "../upm.i"
+
+%feature("autodoc", "3");
+
+%include "tubelight.h"
+%{
+    #include "tubelight.h"
+%}