Commit 19409796 authored by Ahmad Fatoum's avatar Ahmad Fatoum Committed by Alexandre Belloni
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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: default avatarAhmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20221123095527.2771434-2-s.hauer@pengutronix.de


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 04596d4b

include/linux/bcd.h

+4 −0
Original line number Diff line number Diff line
@@ -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__;