diff options
| -rw-r--r-- | Documentation/i2c/smbus-protocol | 8 | ||||
| -rw-r--r-- | include/linux/i2c.h | 17 |
2 files changed, 25 insertions, 0 deletions
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 <linux/sched.h> /* for completion */ #include <linux/mutex.h> #include <linux/of.h> /* for struct device_node */ +#include <linux/swab.h> /* 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); |