Hi Geert, On Fri, Jan 3, 2025 at 4:09 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > > Hi Prabhakar, > > On Fri, Jan 3, 2025 at 10:19 AM Prabhakar <prabhakar.csengg@xxxxxxxxx> wrote: > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > > > > Introduce a new `riic_bus_barrier()` function to verify bus availability > > before initiating an I2C transfer. This function enhances the bus > > arbitration check by ensuring that the SDA and SCL lines are not held low, > > in addition to checking the BBSY flag using `readb_poll_timeout()`. > > > > Previously, only the BBSY flag was checked to determine bus availability. > > However, it is possible for the SDA line to remain low even when BBSY = 0. > > This new implementation performs an additional check on the SDA and SCL > > lines to avoid potential bus contention issues. > > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > > Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > > Reviewed-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> > > Tested-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> > > Tested-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx> > > Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx> > > --- > > v3->v4 > > - Propogated error code when readb_poll_timeout() failed > > - I've kept the RB/TB tags as the changes were minimal. > > OK. > > + you removed a superfluous initialization of riic->err (last change below). > This change was requested by Wolfram on v2. [0] https://lore.kernel.org/all/Z2XhI4L9nzUqa22Z@ninjato/ Cheers, Prabhakar > > --- a/drivers/i2c/busses/i2c-riic.c > > +++ b/drivers/i2c/busses/i2c-riic.c > > @@ -149,13 +173,11 @@ static int riic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) > > if (ret) > > return ret; > > > > - if (riic_readb(riic, RIIC_ICCR2) & ICCR2_BBSY) { > > - riic->err = -EBUSY; > > + riic->err = riic_bus_barrier(riic); > > + if (riic->err) > > goto out; > > - } > > > > reinit_completion(&riic->msg_done); > > - riic->err = 0; > > > > riic_writeb(riic, 0, RIIC_ICSR2); > > > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds
