From 1b85b12738b985d554021a5fdafa1da121dda9f0 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Tue, 15 Jul 2014 03:50:47 +0000
Subject: [PATCH] HAL_Linux: made I2C driver more portable

this uses a typeof() to cope with different kernel data types for I2C
messages
---
 libraries/AP_HAL_Linux/I2CDriver.cpp | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/libraries/AP_HAL_Linux/I2CDriver.cpp b/libraries/AP_HAL_Linux/I2CDriver.cpp
index beee6a4f22..aee6cb1977 100644
--- a/libraries/AP_HAL_Linux/I2CDriver.cpp
+++ b/libraries/AP_HAL_Linux/I2CDriver.cpp
@@ -15,12 +15,6 @@
 #include <linux/i2c.h>
 #endif
 
-#if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_NONE
-#define I2C_DATA_TYPE char
-#else
-#define I2C_DATA_TYPE __u8
-#endif
-
 using namespace Linux;
 
 /*
@@ -151,13 +145,13 @@ uint8_t LinuxI2CDriver::readRegisters(uint8_t addr, uint8_t reg,
         addr  : addr,
         flags : 0,
         len   : 1,
-        buf   : (I2C_DATA_TYPE *)&reg
+        buf   : (typeof(msgs->buf))&reg
         },
         {
         addr  : addr,
         flags : I2C_M_RD,
         len   : len,
-        buf   : (I2C_DATA_TYPE *)data,
+        buf   : (typeof(msgs->buf))data,
         }
     };
     struct i2c_rdwr_ioctl_data i2c_data = {
@@ -188,17 +182,17 @@ uint8_t LinuxI2CDriver::readRegistersMultiple(uint8_t addr, uint8_t reg,
         struct i2c_msg msgs[2*n];
         struct i2c_rdwr_ioctl_data i2c_data = {
         msgs : msgs,
-        nmsgs : 2*n
+        nmsgs : (typeof(i2c_data.nmsgs))(2*n)
         };
         for (uint8_t i=0; i<n; i++) {
             msgs[i*2].addr = addr;
             msgs[i*2].flags = 0;
             msgs[i*2].len = 1;
-            msgs[i*2].buf = (I2C_DATA_TYPE *)&reg;
+            msgs[i*2].buf = (typeof(msgs->buf))&reg;
             msgs[i*2+1].addr = addr;
             msgs[i*2+1].flags = I2C_M_RD;
             msgs[i*2+1].len = len;
-            msgs[i*2+1].buf = (I2C_DATA_TYPE *)data;
+            msgs[i*2+1].buf = (typeof(msgs->buf))data;
             data += len;
         };
         if (ioctl(_fd, I2C_RDWR, &i2c_data) == -1) {