On Fri, Jun 28, 2024 at 12:29 PM claudiu beznea
<claudiu.beznea@xxxxxxxxx> wrote:
> On 28.06.2024 12:13, Geert Uytterhoeven wrote:
> > On Fri, Jun 28, 2024 at 10:12 AM claudiu beznea
> > <claudiu.beznea@xxxxxxxxx> wrote:
> >> On 28.06.2024 11:09, Biju Das wrote:
> >>>> -----Original Message-----
> >>>> From: claudiu beznea <claudiu.beznea@xxxxxxxxx>
> >>>> On 28.06.2024 10:55, Biju Das wrote:
> >>>>>> -----Original Message-----
> >>>>>> From: claudiu beznea <claudiu.beznea@xxxxxxxxx>
> >>>>>> Patch 09/12 "i2c: riic: Add support for fast mode plus" adds a new member to struct
> >>>> riic_of_data.
> >>>>>> That new member is needed to differentiate b/w hardware versions
> >>>>>> supporting fast mode plus based on compatible.
> >>>>>
> >>>>> Are we sure RZ/A does not support fast mode plus?
> >>>>
> >>>> From commit description of patch 09/12:
> >>>>
> >>>> Fast mode plus is available on most of the IP variants that RIIC driver is working with. The
> >>>> exception is (according to HW manuals of the SoCs where this IP is available) the Renesas RZ/A1H.
> >>>> For this, patch introduces the struct riic_of_data::fast_mode_plus.
> >>>>
> >>>> I checked the manuals of all the SoCs where this driver is used.
> >>>>
> >>>> I haven't checked the H/W manual?
> >>>>
> >>>> On the manual I've downloaded from Renesas web site the FMPE bit of RIICnFER is not available on
> >>>> RZ/A1H.
> >>>
> >>> I just found RZ/A2M manual, it supports FMP and register layout looks similar to RZ/G2L.
> >>
> >> I introduced struct riic_of_data::fast_mode_plus because of RZ/A1H.
> >
> > Do you need to check for that?
> >
> > The ICFER_FMPE bit won't be set unless the user specifies the FM+
> > clock-frequency. Setting clock-frequency beyond Fast Mode on RZ/A1H
> > would be very wrong.
>
> I need it to avoid this scenario ^. In patch 09/12 there is this code:
>
> + if ((!info->fast_mode_plus && t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ) ||
> + (info->fast_mode_plus && t->bus_freq_hz > I2C_MAX_FAST_MODE_PLUS_FREQ)) {
> + dev_err(dev, "unsupported bus speed (%dHz). %d max\n", t->bus_freq_hz,
> + info->fast_mode_plus ? I2C_MAX_FAST_MODE_PLUS_FREQ :
> + I2C_MAX_FAST_MODE_FREQ);
> return -EINVAL;
>
> to avoid giving the user the possibility to set FM+ freq on platforms not
> supporting it.
>
> Please let me know if I'm missing something (or wrongly understood your
> statement).
Wolfram/Andi: what is your view on this?
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
