Commit 87cf5127 authored by Quan Nguyen's avatar Quan Nguyen Committed by Wolfram Sang
Browse files

i2c: core-smbus: Expose PEC calculate function for generic use 



Expose the PEC calculation i2c_smbus_pec() for generic use.

Signed-off-by: default avatarQuan Nguyen <quan@os.amperecomputing.com>
Acked-by: default avatarMatt Johnston <matt@codeconstruct.com.au>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 31df7195

drivers/i2c/i2c-core-smbus.c

+10 −2
Original line number Diff line number Diff line
@@ -37,8 +37,15 @@ static u8 crc8(u16 data) 
	return (u8)(data >> 8);

}



/* Incremental CRC8 over count bytes in the array pointed to by p */

static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)

/**

 * i2c_smbus_pec - Incremental CRC8 over the given input data array

 * @crc: previous return crc8 value

 * @p: pointer to data buffer.

 * @count: number of bytes in data buffer.

 *

 * Incremental CRC8 over count bytes in the array pointed to by p

 */

u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)

{

	int i;
@@ -46,6 +53,7 @@ static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count) 
		crc = crc8((crc ^ p[i]) << 8);

	return crc;

}

EXPORT_SYMBOL(i2c_smbus_pec);



/* Assume a 7-bit address, which is reasonable for SMBus */

static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)

include/linux/i2c.h

+1 −0
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, 
/* Now follow the 'nice' access routines. These also document the calling

   conventions of i2c_smbus_xfer. */



u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count);

s32 i2c_smbus_read_byte(const struct i2c_client *client);

s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);

s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command);