[PATCH v2] i2c-mpc: generate START condition after STOP caused by read i2c_msg

[Joakim Tjernlund]

>
> On Thu, Dec 03, 2009 at 04:09:57PM +0100, Michael Lawnick wrote:
> > Ben Dooks said the following:
> > > On Tue, May 26, 2009 at 01:30:21PM +0200, Esben Haabendal wrote:
> > >> On Tue, May 19, 2009 at 7:22 AM, Esben Haabendal <eha at doredevelopment.dk> wrote:
> > >> > This fixes MAL (arbitration lost) bug caused by illegal use of
> > >> > RSTA (repeated START) after STOP condition generated after last byte
> > >> > of reads. With this patch, it is possible to do an i2c_transfer() with
> > >> > additional i2c_msg's following the I2C_M_RD messages.
> > >> >
> > >> > It still needs to be resolved if it is possible to fix this issue
> > >> > by removing the STOP condition after reads in a robust way.
> > >> >
> > >> > Signed-off-by: Esben Haabendal <eha at doredevelopment.dk>
> > >> > ---
> > >> > ?drivers/i2c/busses/i2c-mpc.c | ? ?9 +++++++--
> > >> > ?1 files changed, 7 insertions(+), 2 deletions(-)
> > >>
> > >> Any blockers to get this accepted?
> > >
> > > It would be nice to get an ack from someone who can actually test
> > > the driver before getting this merged.
> > >
> > What is the state of this patch?
> > Shouldn't we attack the problem on a more general way by inventing a
> > Flag I2C_M_RESTART (or better I2C_M_NO_RESTART for backward compatibility)?
> > This way the client driver is able to decide what it needs. If we do the
> > choice within adapter, chance is about 50% to be wrong.
>
> The documentation for 'struct i2c_msg' already says the STOP should only
> be generated for the last message of the transfer. If STOP is being
> generated for a message that isn't the last in the transfer than this
> is incorrect behaviour.
>
> Unless otherwise indicated, I'll put the patch in the series that I'll
> send to Linus early next week.

Don't, already fixed properly and in Linus tree already.