Re: [PATCH i2c-tools v3 0/2] Add support for message modifier flags

["Benoît Monin" <benoit.monin@bootlin.com>]

Hello Wolfram,

On Tuesday, 17 February 2026 at 13:13:48 CET, Jean Delvare wrote:
> Hi Benoît,
> 
> On Tue, 27 Jan 2026 10:25:56 +0100, Benoît Monin wrote:
> > I2C messages can be modified with a set of flags covered by the protocol
> > mangling and the skip repeated start functionalities. This series add
> > support for such flags to i2cdetect and i2ctransfer.
> > 
> > The first patch shows the support of protocol mangling and repeated
> > start skipping in the output of 'i2cdetect -F'.
> > 
> > The second patch adds the parsing of optional flags to i2ctransfer
> > message description. Those command-line flags then set the i2c message
> > flags alongside the read/write flag.
> > 
> > I wrote these changes to test the insertion of I2C_M_STOP flag in
> > multi-message transactions with i2ctransfer, but the other flags may be
> > useful for various test scenarios. 
> > 
> > Signed-off-by: Benoît Monin <benoit.monin@bootlin.com>
> > ---
> > Changes in v3:
> > - Use ifdefs to check that the flags and functionalities are known
> >   at compile-time.
> > - Check that the adapter supports the requested flags before using them
> >   in i2ctransfer.
> > - Add a warning in i2ctransfer man page about the risk of using these
> >   flags.
> > - Link to v2: https://lore.kernel.org/r/20251223-msg-flags-v2-0-8d934a4366e2@bootlin.com
> > 
> > Changes in v2:
> > - Document the flags in i2ctransfer.8 man page.
> > - Link to v1: https://lore.kernel.org/r/20251128-msg-flags-v1-0-6353f26fa6bc@bootlin.com
> > 
> > ---
> > Benoît Monin (2):
> >       i2cdetect: Display mangling and nostart support
> >       i2ctransfer: Add optional message modifier flags
> > 
> >  tools/i2cdetect.c   |   8 ++++
> >  tools/i2ctransfer.8 |  28 ++++++++++++-
> >  tools/i2ctransfer.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++------
> >  3 files changed, 141 insertions(+), 14 deletions(-)
> 
> Both patches look very good to me. I was able to test the i2cdetect
> patch and did not find any issue. I can't easily test the i2ctransfer
> patch though.
> 
> Wolfram, can you please give some basic testing to the i2ctransfer
> patch? Not necessarily with the mangling flags, but at least test that
> the changes do not introduce any regression for your own use cases?
> 
> Thanks,
> 
Did you have a chance to test the patches?

Best regards,
-- 
Benoît Monin, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com