Hi Andi,
On Wed, Dec 18, 2024 at 07:16:23PM +0100, Andi Shyti wrote:
> Hi Stefan,
>
> On Mon, Dec 16, 2024 at 04:16:40PM +0100, Stefan Eichenberger wrote:
> > From: Stefan Eichenberger <stefan.eichenberger@xxxxxxxxxxx>
> >
> > A regression was introduced with the implementation of single-master
> > mode, preventing proper stop conditions from being generated. Devices
> > that require a valid stop condition, such as EEPROMs, fail to function
> > correctly as a result.
> >
> > The issue only affects devices with the single-master property enabled.
> >
> > This commit resolves the issue by re-enabling I2C bus busy bit (IBB)
> > polling for single-master mode when generating a stop condition. The fix
> > further ensures that the i2c_imx->stopped flag is cleared at the start
> > of each transfer, allowing the stop condition to be correctly generated
> > in i2c_imx_stop().
> >
> > According to the reference manual (IMX8MMRM, Rev. 2, 09/2019, page
> > 5270), polling the IBB bit to determine if the bus is free is only
> > necessary in multi-master mode. Consequently, the IBB bit is not polled
> > for the start condition in single-master mode.
> >
> > Fixes: 6692694aca86 ("i2c: imx: do not poll for bus busy in single master mode")
> > Signed-off-by: Stefan Eichenberger <stefan.eichenberger@xxxxxxxxxxx>
> > ---
> > drivers/i2c/busses/i2c-imx.c | 8 +++-----
> > 1 file changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> > index f751d231ded8..cbf66a69e20b 100644
> > --- a/drivers/i2c/busses/i2c-imx.c
> > +++ b/drivers/i2c/busses/i2c-imx.c
> > @@ -534,20 +534,18 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool a
> > {
> > unsigned long orig_jiffies = jiffies;
> > unsigned int temp;
> > -
> > - if (!i2c_imx->multi_master)
> > - return 0;
> > + bool multi_master = i2c_imx->multi_master;
>
> with this small adjustment, I have applied your patch to
> i2c/i2c-host-fixes.
>
> The idea behind the change is that variables are sorted by
> length, forming a kind of reversed Christmas tree shape. It's
> not a strict rule—some communities enforce it, others don't, and
> some follow entirely different conventions.
>
> Since it feels somewhat arbitrary to me, I don't enforce it
> strictly. However, I personally try to adhere to the reversed
> Christmas tree rule whenever possible.
Thanks a lot for doing the change and for the explanation. I will keep
it in mind for future patches.
Best regards,
Stefan
