There are three different kinds of EEPROM possibly present on boards.
1. 1byte address. For those we should avoid 2byte address in order
not to rewrite the data. Second byte of the address can potentially
be interpreted as the data to write.
2. 2byte address with defined behaviour. When we try to use 1byte
address they just return "FF FF FF FF ... FF"
3. 2byte address with undefined behaviour (for instance, 24LC32AI).
When we try to use 1byte address, then their internal read
pointer is changed to some value. Subsequential reads may be
broken.
To gracefully handle both case #1 and case #3 we read all required
data from EEPROM at once (about 80 bytes). So either all the data is
valid or we fallback to 2byte address.
Cc: Nishanth Menon <nm@ti.com>
Fixes: a58147c2db ("board: ti: common: board_detect: Do 1byte address checks first.")
Reference: https://lore.kernel.org/all/CAJs94Ebdd4foOjhGFu9Bop0v=B1US9neDLxfhgcY23ukgLzFOQ@mail.gmail.com/
Signed-off-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
Acked-by: Nishanth Menon <nm@ti.com>
bf6376642f