From 19409796578c879a41e88ddbdbce50c19457658d Mon Sep 17 00:00:00 2001 From: Ahmad Fatoum Date: Wed, 23 Nov 2022 10:55:26 +0100 Subject: [PATCH] include/linux/bcd.h: provide bcd_is_valid() helper bcd2bin(0x0A) happily returns 10, despite this being an invalid BCD value. RTC drivers converting possibly corrupted BCD timestamps might want to validate their input before calling bcd2bin(). Provide a macro to do so. Unlike bcd2bin and bin2bcd, out-of-line versions are not implemented. Should the macro experience enough use, this can be retrofitted. Signed-off-by: Ahmad Fatoum Signed-off-by: Sascha Hauer Link: https://lore.kernel.org/r/20221123095527.2771434-2-s.hauer@pengutronix.de Signed-off-by: Alexandre Belloni --- include/linux/bcd.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/bcd.h b/include/linux/bcd.h index 118bea3..abbc814 100644 --- a/include/linux/bcd.h +++ b/include/linux/bcd.h @@ -14,8 +14,12 @@ const_bin2bcd(x) : \ _bin2bcd(x)) +#define bcd_is_valid(x) \ + const_bcd_is_valid(x) + #define const_bcd2bin(x) (((x) & 0x0f) + ((x) >> 4) * 10) #define const_bin2bcd(x) ((((x) / 10) << 4) + (x) % 10) +#define const_bcd_is_valid(x) (((x) & 0x0f) < 10 && ((x) >> 4) < 10) unsigned _bcd2bin(unsigned char val) __attribute_const__; unsigned char _bin2bcd(unsigned val) __attribute_const__; -- 2.7.4