From 06a67848c6681a73e621e47c056490d51a07289f Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Sun, 30 Oct 2011 13:47:25 +0100 Subject: [PATCH] i2c: Functions for byte-swapped smbus_write/read_word_data Reimplemented at least 17 times discounting error mangling cases where it could be used. Signed-off-by: Jonathan Cameron Signed-off-by: Jean Delvare --- Documentation/i2c/smbus-protocol | 8 ++++++++ include/linux/i2c.h | 17 +++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol index 7c19d1a2bea0..49f5b680809d 100644 --- a/Documentation/i2c/smbus-protocol +++ b/Documentation/i2c/smbus-protocol @@ -88,6 +88,10 @@ byte. But this time, the data is a complete word (16 bits). S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P +Note the convenience function i2c_smbus_read_word_swapped is +available for reads where the two data bytes are the other way +around (not SMBus compliant, but very popular.) + SMBus Write Byte: i2c_smbus_write_byte_data() ============================================== @@ -108,6 +112,10 @@ specified through the Comm byte. S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] P +Note the convenience function i2c_smbus_write_word_swapped is +available for writes where the two data bytes are the other way +around (not SMBus compliant, but very popular.) + SMBus Process Call: i2c_smbus_process_call() ============================================= diff --git a/include/linux/i2c.h b/include/linux/i2c.h index a6c652ef516d..38a21c3edd2c 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -34,6 +34,7 @@ #include /* for completion */ #include #include /* for struct device_node */ +#include /* for swab16 */ extern struct bus_type i2c_bus_type; extern struct device_type i2c_adapter_type; @@ -88,6 +89,22 @@ extern s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command); extern s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command, u16 value); + +static inline s32 +i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command) +{ + s32 value = i2c_smbus_read_word_data(client, command); + + return (value < 0) ? value : swab16(value); +} + +static inline s32 +i2c_smbus_write_word_swapped(const struct i2c_client *client, + u8 command, u16 value) +{ + return i2c_smbus_write_word_data(client, command, swab16(value)); +} + /* Returns the number of read bytes */ extern s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command, u8 *values); -- 2.30.2