On Mon, Mar 04, 2019 at 12:13:49PM +0100, Wolfram Sang wrote:
> On Mon, Mar 04, 2019 at 11:59:48AM +0100, Marek Vasut wrote:
> > On 3/4/19 11:57 AM, Wolfram Sang wrote:
> > >
> > >>> Add DA9063 PMIC node to the I2C bus.
> > >>>
> > >>> Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxx>
> > >>
> > >> Thanks for your patch!
> > >>
> > >> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > >
> > > Thanks for CCing me, I didn't get and missed the original patch.
> > >
> > >>> +++ b/arch/arm/boot/dts/r8a7794-alt.dts
> > >>> @@ -377,6 +377,27 @@
> > >>> pinctrl-names = "i2c-exio4";
> > >>> };
> > >>>
> > >>> +&i2c7 {
> > >>> + status = "okay";
> > >>> + clock-frequency = <100000>;
> > >>
> > >> According to the DA9063 datasheet, the PMIC supports up to 400 kHz.
> > >> It looks like there are no other devices on the bus.
> > >>
> > >> Wolfram, what's your stance on this?
> > >
> > > Yes, please. I thought this was standard on Gen2 IIC_DVFS busses, but
> > > seems not. Probably it slipped through the cracks.
> >
> > Do we want to update all of the other boards too ?
> >
> > I'd be cautious about the DVFS I2C, running faster while talking to the
> > PMIC and reading/writing a few registers brings little benefit, while
> > the signal integrity might be impacted.
>
> Can be argued. I think if we would apply some testing on top of this
> change, we will find that it will work. But we would in deed need this
> testing as verification, and this is not our top priority project. But
> if someone feels like running some i2c dumping over night, well,
> why not..
Thanks,
I've applied this patch for v5.2.
We can do a sweep of frequency updates as a follow-up if we decide
that is the right way to go.
