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 <quan@os.amperecomputing.com>
Acked-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index d2d32c0..e5b2d14 100644 (file)
--- 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 953a4ee..685f8c7 100644 (file)
--- 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);