w1/w1.c: w1 address crc quick for DS28E04 eeproms
Onewire addresses are 64bit family(8bit), unique_id(48bit), crc(8bit)
(LSBt to MSB) and self-consistent: crc = crc8(family, unique).
DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO have strap pins
to set 7 LSB of the address, unfortunately without updating the crc
part of the address. It is only consistent if all strap pins float high.
[see datasheet 19-6134; Rev 12/11 page 6: 64-bit device id number]
We therefore introduce a special handling of family 0x1c (DS28E04) to
check address consistency with 7 LSBs of the unique_id set to 1.
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Christian Vogel <vogelchr@vogel.cx>
Link: https://lore.kernel.org/r/20210113195018.7498-2-vogelchr@vogel.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed