From de986764d4c84217e979f84c7a8956cadc69fd24 Mon Sep 17 00:00:00 2001
From: Mihai Tudor Panu <mihai.tudor.panu@intel.com>
Date: Thu, 12 May 2016 13:48:06 -0700
Subject: [PATCH] lcm1602: added backlight control and default bus/address for
 I2C variants

Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>
---
 src/lcd/lcm1602.cxx | 18 ++++++++++++++++--
 src/lcd/lcm1602.hpp | 31 ++++++++++++++++++++++++++-----
 2 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/src/lcd/lcm1602.cxx b/src/lcd/lcm1602.cxx
index 57d039ee..e39d5939 100644
--- a/src/lcd/lcm1602.cxx
+++ b/src/lcd/lcm1602.cxx
@@ -50,6 +50,7 @@ Lcm1602::Lcm1602(int bus_in, int addr_in, bool isExpander,
     mraa::Result error = mraa::SUCCESS;
     m_name = "Lcm1602 (I2C)";
     m_isI2C = true;
+    m_backlight = LCD_BACKLIGHT;
 
     m_lcd_control_address = addr_in;
 
@@ -73,7 +74,7 @@ Lcm1602::Lcm1602(int bus_in, int addr_in, bool isExpander,
       return;
 
     usleep(50000);
-    expandWrite(LCD_BACKLIGHT);
+    backlightOn();
     usleep(100000);
 
     write4bits(0x03 << 4);
@@ -111,6 +112,7 @@ Lcm1602::Lcm1602(uint8_t rs,  uint8_t enable, uint8_t d0,
     mraa::Result error = mraa::SUCCESS;
     m_name = "Lcm1602 (4-bit GPIO)";
     m_isI2C = false;
+    m_backlight = LCD_BACKLIGHT;
 
     // setup our gpios
 
@@ -322,6 +324,18 @@ mraa::Result Lcm1602::cursorBlinkOff()
   return command(LCD_DISPLAYCONTROL | m_displayControl);
 }
 
+mraa::Result Lcm1602::backlightOn()
+{
+  m_backlight = LCD_BACKLIGHT;
+  return expandWrite(m_backlight);
+}
+
+mraa::Result Lcm1602::backlightOff()
+{
+  m_backlight = LCD_NOBACKLIGHT;
+  return expandWrite(m_backlight);
+}
+
 mraa::Result Lcm1602::scrollDisplayLeft()
 {
   return command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
@@ -431,7 +445,7 @@ Lcm1602::expandWrite(uint8_t value)
     if (!m_isI2C)
         return mraa::ERROR_INVALID_RESOURCE;
 
-    uint8_t buffer = value | LCD_BACKLIGHT;
+    uint8_t buffer = value | m_backlight;
     return m_i2c_lcd_control->writeByte(buffer);
 }
 
diff --git a/src/lcd/lcm1602.hpp b/src/lcd/lcm1602.hpp
index 5f5d5835..5f37cf51 100644
--- a/src/lcd/lcm1602.hpp
+++ b/src/lcd/lcm1602.hpp
@@ -73,13 +73,15 @@ class Lcm1602 : public LCD
     /**
      * Lcm1602 constructor; calls libmraa initialisation functions
      *
-     * @param bus I2C bus to use
-     * @param address Slave address the LCD is registered on
+     * @param bus I2C bus to use. Default 0 (autodetect).
+     * @param address Slave address the LCD is registered on. Default 0x27
      * @param isExpander True if we are dealing with an I2C expander,
      * false otherwise. Default is true.
+     * @param numColumns Number of columns the display has. Default 16.
+     * @param numRows Number of rows the display has. Default 2.
      */
-  Lcm1602(int bus, int address, bool isExpander=true,
-          uint8_t numColumns = 16, uint8_t numRows = 4);
+  Lcm1602(int bus = 0, int address = 0x27, bool isExpander=true,
+          uint8_t numColumns = 16, uint8_t numRows = 2);
 
     /**
      * Lcm1602 alternate constructor, used for GPIO based HD44780
@@ -92,10 +94,12 @@ class Lcm1602 : public LCD
      * @param d1 Data 1 pin
      * @param d2 Data 2 pin
      * @param d3 Data 3 pin
+     * @param numColumns Number of columns the display has. Default 16.
+     * @param numRows Number of rows the display has. Default 2.
      */
     Lcm1602(uint8_t rs,  uint8_t enable,
             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
-            uint8_t numColumns = 16, uint8_t numRows = 4);
+            uint8_t numColumns = 16, uint8_t numRows = 2);
 
     /**
      * Lcm1602 destructor
@@ -181,6 +185,20 @@ class Lcm1602 : public LCD
      */
     mraa::Result cursorBlinkOff();
 
+    /**
+     * Turn backlight on
+     *
+     * @return Result of operation
+     */
+    mraa::Result backlightOn();
+    
+    /**
+     * Turn backlight off
+     *
+     * @return Result of operation
+     */
+    mraa::Result backlightOff();    
+    
     /**
      * Scroll the display left, without changing the character RAM
      *
@@ -236,6 +254,9 @@ class Lcm1602 : public LCD
     // Display size
     uint8_t m_numColumns;
     uint8_t m_numRows;
+    
+    // Backlight
+    uint8_t m_backlight;
 
     // Add a command() and data() virtual member functions, with a
     // default implementation in lcm1602.  This is expected to be