[RESEND PATCH] board: ti: common: board_detect: Fix EEPROM offset read for 1-byte

[Nishanth Menon]

On 20:52-20231020, Kumar, Udit wrote:
> Thanks Prasanth
> 
> On 10/20/2023 12:31 PM, Prasanth Babu Mantena wrote:
> > EEPROM detection logic in ti_i2c_eeprom_get() involves reading the total
> > size followed by reading 1-byte size with an offset 1. This commit fixes
> > the header matching issue in commit 9f393a2d7af8 ("board: ti: common:
> > board_detect: Fix EEPROM read quirk for 2-byte").
> You can fixes below as well. I think you can avoid this in commit message
> > 
> > In the previous commit, the value with one offset is being read into
> > offset_test, but the pointer used to match was still ep. After reading
> > with an offset 1, the second byte of the header is compared with the 1-byte
> > data read from EEPROM. This is taken care by comparing proper first byte
> > value from the header.
> Nice catch

Yes indeed.. here is a possible improvement of  commit message:

EEPROM detection logic in ti_i2c_eeprom_get() involves reading the
total size and the 1-byte size with an offset 1.

The value with one offset is read into "offset_test," but the pointer
used to match was still "ep". This results in comparing results
against the previously read data while the intent is to ensure the
detection of the bad 2-byte addressing eeproms that get stuck after
responding initially to 1- byte accesses. This behavior was detected
on BeagleBone-AI64.

> > 
> > Signed-off-by: Prasanth Babu Mantena <p-mantena at ti.com>
> > Fixes: 9f393a2d7af8 (board: ti: common: board_detect: Fix EEPROM read quirk for 2-byte)
> Please consider Fixes line, first than Signed-off-by

Yup, fixes and SoB (checkpatch typically warns)
> 
> 
> Please copy Nishanth in patch as well .
> 
> > ---
> > Resending due to incorrect patch tag last time.
> > 
> >   board/ti/common/board_detect.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/board/ti/common/board_detect.c b/board/ti/common/board_detect.c
> > index 9a53884c98..17fe8f8069 100644
> > --- a/board/ti/common/board_detect.c
> > +++ b/board/ti/common/board_detect.c
> > @@ -128,7 +128,7 @@ static int __maybe_unused ti_i2c_eeprom_get(int bus_addr, int dev_addr,
> >   	rc = dm_i2c_read(dev, 0x1, &offset_test, sizeof(offset_test));
> > -	if (*((u32 *)ep) != (header & 0xFF))
> > +	if (offset_test != ((header >> 8) & 0xFF))
> >   		one_byte_addressing = false;
> >   	/* Corrupted data??? */


You missed the else CONFIG_IS_ENABLED(DM_I2C)  case with the same
bug?

Also please CC Matwey V. Kornilov <matwey.kornilov at gmail.com> ,  Jason
Kridner <jkridner at beagleboard.org> and Robert Nelson <robertcnelson at gmail.com>

So that we don't have regressions on their boards.

https://lore.kernel.org/all/CAJs94Ebdd4foOjhGFu9Bop0v=B1US9neDLxfhgcY23ukgLzFOQ@mail.gmail.com/

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D