lib/crc-ccitt: Add CCITT-FALSE CRC16 variant
In support of a soon to be published MFD driver using serdev to talk to
a supervisory processor that uses the CCITT-FALSE CRC16 variant in it's
protocol, this patch was tested successfully on an i.MX6 ARM platform.
Link: http://lkml.kernel.org/r/20170413142932.27287-1-andrew.smirnov@gmail.com
Signed-off-by: Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/include/linux/crc-ccitt.h b/include/linux/crc-ccitt.h
index cd4f420..72c92c3 100644
--- a/include/linux/crc-ccitt.h
+++ b/include/linux/crc-ccitt.h
@@ -5,12 +5,19 @@
#include <linux/types.h>
extern u16 const crc_ccitt_table[256];
+extern u16 const crc_ccitt_false_table[256];
extern u16 crc_ccitt(u16 crc, const u8 *buffer, size_t len);
+extern u16 crc_ccitt_false(u16 crc, const u8 *buffer, size_t len);
static inline u16 crc_ccitt_byte(u16 crc, const u8 c)
{
return (crc >> 8) ^ crc_ccitt_table[(crc ^ c) & 0xff];
}
+static inline u16 crc_ccitt_false_byte(u16 crc, const u8 c)
+{
+ return (crc << 8) ^ crc_ccitt_false_table[(crc >> 8) ^ c];
+}
+
#endif /* _LINUX_CRC_CCITT_H */