Re: [PATCH] board: ti: common: board_detect: Fix EEPROM read quirk

On Tue, Aug 23, 2022 at 07:05:34PM +0300, Matwey V. Kornilov wrote:

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: a58147c2dbbf ("board: ti: common: board_detect: Do 1byte address checks first.") Reference: https://lore.kernel.org/all/CAJs94Ebdd4foOjhGFu9Bop0v=B1US9neDLxfhgcY23ukgLz... Signed-off-by: Matwey V. Kornilov matwey.kornilov@gmail.com Acked-by: Nishanth Menon nm@ti.com

Applied to u-boot/master, thanks!