libi2c: Properly propagate real error codes on read errors

git-svn-id: http://lm-sensors.org/svn/i2c-tools/trunk@6058 7894878c-1315-0410-8ee3-d5d059ff63e0

CHANGES

@@ -9,6 +9,7 @@ SVN HEAD
              Move SMBus helper functions to include/i2c/smbus.h
   i2c-stub-from-dump: Be more tolerant on input dump format
   library: New libi2c library
+           Properly propagate real error codes on read errors
 
 3.1.0 (2011-12-04)
   decode-dimms: Decode module configuration type of DDR SDRAM

lib/smbus.c

@@ -3,6 +3,7 @@
 
     Copyright (C) 1995-97 Simon G. Vogl
     Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
+    Copyright (C) 2012    Jean Delvare <khali@linux-fr.org>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -20,6 +21,7 @@
     MA 02110-1301 USA.
 */
 
+#include <errno.h>
 #include <i2c/smbus.h>
 #include <sys/ioctl.h>
 #include <linux/types.h>
@@ -38,12 +40,17 @@ __s32 i2c_smbus_access(int file, char read_write, __u8 command,
 		       int size, union i2c_smbus_data *data)
 {
 	struct i2c_smbus_ioctl_data args;
+	__s32 err;
 
 	args.read_write = read_write;
 	args.command = command;
 	args.size = size;
 	args.data = data;
-	return ioctl(file, I2C_SMBUS, &args);
+
+	err = ioctl(file, I2C_SMBUS, &args);
+	if (err == -1)
+		err = -errno;
+	return err;
 }
 
 
@@ -55,9 +62,12 @@ __s32 i2c_smbus_write_quick(int file, __u8 value)
 __s32 i2c_smbus_read_byte(int file)
 {
 	union i2c_smbus_data data;
-	if (i2c_smbus_access(file, I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data))
-		return -1;
-	else
+	int err;
+
+	err = i2c_smbus_access(file, I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data);
+	if (err < 0)
+		return err;
+
 	return 0x0FF & data.byte;
 }
 
@@ -70,10 +80,13 @@ __s32 i2c_smbus_write_byte(int file, __u8 value)
 __s32 i2c_smbus_read_byte_data(int file, __u8 command)
 {
 	union i2c_smbus_data data;
-	if (i2c_smbus_access(file, I2C_SMBUS_READ, command,
-			     I2C_SMBUS_BYTE_DATA, &data))
-		return -1;
-	else
+	int err;
+
+	err = i2c_smbus_access(file, I2C_SMBUS_READ, command,
+			       I2C_SMBUS_BYTE_DATA, &data);
+	if (err < 0)
+		return err;
+
 	return 0x0FF & data.byte;
 }
 
@@ -88,10 +101,13 @@ __s32 i2c_smbus_write_byte_data(int file, __u8 command, __u8 value)
 __s32 i2c_smbus_read_word_data(int file, __u8 command)
 {
 	union i2c_smbus_data data;
-	if (i2c_smbus_access(file, I2C_SMBUS_READ, command,
-			     I2C_SMBUS_WORD_DATA, &data))
-		return -1;
-	else
+	int err;
+
+	err = i2c_smbus_access(file, I2C_SMBUS_READ, command,
+			       I2C_SMBUS_WORD_DATA, &data);
+	if (err < 0)
+		return err;
+
 	return 0x0FFFF & data.word;
 }
 
@@ -118,15 +134,16 @@ __s32 i2c_smbus_process_call(int file, __u8 command, __u16 value)
 __s32 i2c_smbus_read_block_data(int file, __u8 command, __u8 *values)
 {
 	union i2c_smbus_data data;
-	int i;
-	if (i2c_smbus_access(file, I2C_SMBUS_READ, command,
-			     I2C_SMBUS_BLOCK_DATA, &data))
-		return -1;
-	else {
+	int i, err;
+
+	err = i2c_smbus_access(file, I2C_SMBUS_READ, command,
+			       I2C_SMBUS_BLOCK_DATA, &data);
+	if (err < 0)
+		return err;
+
 	for (i = 1; i <= data.block[0]; i++)
 		values[i-1] = data.block[i];
 	return data.block[0];
-	}
 }
 
 __s32 i2c_smbus_write_block_data(int file, __u8 command, __u8 length,
@@ -151,20 +168,21 @@ __s32 i2c_smbus_read_i2c_block_data(int file, __u8 command, __u8 length,
 				    __u8 *values)
 {
 	union i2c_smbus_data data;
-	int i;
+	int i, err;
 
 	if (length > 32)
 		length = 32;
 	data.block[0] = length;
-	if (i2c_smbus_access(file, I2C_SMBUS_READ, command,
+
+	err = i2c_smbus_access(file, I2C_SMBUS_READ, command,
 			       length == 32 ? I2C_SMBUS_I2C_BLOCK_BROKEN :
-			      I2C_SMBUS_I2C_BLOCK_DATA, &data))
-		return -1;
-	else {
+				I2C_SMBUS_I2C_BLOCK_DATA, &data);
+	if (err < 0)
+		return err;
+
 	for (i = 1; i <= data.block[0]; i++)
 		values[i-1] = data.block[i];
 	return data.block[0];
-	}
 }
 
 __s32 i2c_smbus_write_i2c_block_data(int file, __u8 command, __u8 length,
@@ -186,18 +204,20 @@ __s32 i2c_smbus_block_process_call(int file, __u8 command, __u8 length,
 				   __u8 *values)
 {
 	union i2c_smbus_data data;
-	int i;
+	int i, err;
+
 	if (length > 32)
 		length = 32;
 	for (i = 1; i <= length; i++)
 		data.block[i] = values[i-1];
 	data.block[0] = length;
-	if (i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
-			     I2C_SMBUS_BLOCK_PROC_CALL, &data))
-		return -1;
-	else {
+
+	err = i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
+			       I2C_SMBUS_BLOCK_PROC_CALL, &data);
+	if (err < 0)
+		return err;
+
 	for (i = 1; i <= data.block[0]; i++)
 		values[i-1] = data.block[i];
 	return data.block[0];
-	}
 }