Re: [PATCH] i2c: k1: check for transfer error

[Alex Elder]

On 6/12/25 9:12 PM, Troy Mitchell wrote:
> On Thu, Jun 12, 2025 at 05:56:25PM -0500, Alex Elder wrote:
> > If spacemit_i2c_xfer_msg() times out waiting for a message transfer to
> > complete, or if the hardware reports an error, it returns a negative
> > error code (-ETIMEDOUT, -EAGAIN, -ENXIO. or -EIO).
> >
> > The sole caller of spacemit_i2c_xfer_msg() is spacemit_i2c_xfer(),
> > which is the i2c_algorithm->xfer callback function.  It currently
> > does not save the value returned by spacemit_i2c_xfer_msg().
> >
> > The result is that transfer errors go unreported, and a caller
> > has no indication anything is wrong.
> >
> > When this code was out for review, the return value *was* checked
> > in early versions.  But for some reason, that assignment got dropped
> > between versions 5 and 6 of the series, perhaps related to reworking
> > the code to merge spacemit_i2c_xfer_core() into spacemit_i2c_xfer().
> >
> > Simply assigning the value returned to "ret" fixes the problem.
> >
> > Fixes: 5ea558473fa31 ("i2c: spacemit: add support for SpacemiT K1 SoC")
> > Signed-off-by: Alex Elder <elder@xxxxxxxxxxxx>
> > Reviewed-by: Troy Mitchell <troymitchell988@xxxxxxxxx>
> > ---
> > v2: Added Troy's Reviewed-by
> Hi Alex, you added the changelog, but the subject line
> doesn't have the "V2" suffix. Is this a mistake?

Yes it's a mistake.  I contemplated sending an immediate
"oops, this was v2!!!" but opted to wait until someone
like you asked about it.

This *is* version 2, and I made the updates I describe.

					-Alex
>              - Troy
>
> >   drivers/i2c/busses/i2c-k1.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
> > index 5965b4cf6220e..b68a21fff0b56 100644
> > --- a/drivers/i2c/busses/i2c-k1.c
> > +++ b/drivers/i2c/busses/i2c-k1.c
> > @@ -477,7 +477,7 @@ static int spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg *msgs, in
> >   
> >   	ret = spacemit_i2c_wait_bus_idle(i2c);
> >   	if (!ret)
> > -		spacemit_i2c_xfer_msg(i2c);
> > +		ret = spacemit_i2c_xfer_msg(i2c);
> >   	else if (ret < 0)
> >   		dev_dbg(i2c->dev, "i2c transfer error: %d\n", ret);
> >   	else
> >
> > base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
> > --
> > 2.45.2