From 87cf5127968ab3c543ebd98253052b928f9b47da Mon Sep 17 00:00:00 2001 From: Quan Nguyen Date: Wed, 19 May 2021 14:49:28 +0700 Subject: [PATCH] i2c: core-smbus: Expose PEC calculate function for generic use Expose the PEC calculation i2c_smbus_pec() for generic use. Signed-off-by: Quan Nguyen Acked-by: Matt Johnston Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core-smbus.c | 12 ++++++++++-- include/linux/i2c.h | 1 + 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index d2d32c0fd8c3..e5b2d1465e7e 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -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) diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 953a4eecb88f..685f8c73d99e 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -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);