Re: [PATCH] ARM: zynq: dts: Setting default i2c clock frequency to 400kHz

[Michal Simek]

On 5/3/23 10:06, Krzysztof Kozlowski wrote:
> On 03/05/2023 10:02, Michal Simek wrote:
> > On 5/3/23 09:40, Krzysztof Kozlowski wrote:
> > > On 03/05/2023 09:27, Michal Simek wrote:
> > > > On 5/2/23 22:13, Krzysztof Kozlowski wrote:
> > > > > CAUTION: This message has originated from an External Source. Please use proper judgment and caution when opening attachments, clicking links, or responding to this email.
> > > > >
> > > > >
> > > > > On 02/05/2023 15:53, Michal Simek wrote:
> > > > > > From: Varalaxmi Bingi <varalaxmi.bingi@xxxxxxx>
> > > > > >
> > > > > > Setting default i2c clock frequency for Zynq to maximum rate of 400kHz.
> > > > > > Current default value is 100kHz.
> > > > > >
> > > > > > Signed-off-by: Varalaxmi Bingi <varalaxmi.bingi@xxxxxxx>
> > > > > > Signed-off-by: Michal Simek <michal.simek@xxxxxxx>
> > > > > > ---
> > > > > >
> > > > > >     arch/arm/boot/dts/zynq-7000.dtsi | 2 ++
> > > > > >     1 file changed, 2 insertions(+)
> > > > > >
> > > > > > diff --git a/arch/arm/boot/dts/zynq-7000.dtsi b/arch/arm/boot/dts/zynq-7000.dtsi
> > > > > > index cd9931f6bcbd..a7db3f3009f2 100644
> > > > > > --- a/arch/arm/boot/dts/zynq-7000.dtsi
> > > > > > +++ b/arch/arm/boot/dts/zynq-7000.dtsi
> > > > > > @@ -149,6 +149,7 @@ i2c0: i2c@e0004000 {
> > > > > >                          clocks = <&clkc 38>;
> > > > > >                          interrupt-parent = <&intc>;
> > > > > >                          interrupts = <0 25 4>;
> > > > > > +                     clock-frequency = <400000>;
> > > > >
> > > > > I think this should be rather property of the board, because it depends
> > > > > on I2C devices, right?
> > > >
> > > > We have 15+ boards with i2c connected and from this count I am aware about only
> > > > one configuration which is not working on 400k.
> > > > It is a question if make sense to update all boards (except for 1 and not all in
> > > > kernel yet) to 400k or just say 400k is default and if there is any issue use
> > > > lower frequency.
> > > > Obviously this patch is setting up 400k as default and let "problematic" boards
> > > > to setup lower freq.
> > > > The same approach was used for modepin description.
> > > >
> > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm64/boot/dts/xilinx/zynqmp.dtsi?h=v6.3&id=53ba1b2bdaf7f481fdd878e9c18cd0e54081fac9
> > > >
> > > > The next point is that 100k is default in Linux but doesn't mean it is default
> > > > in other projects.
> > > >
> > > > But if you think that it must be board property I think we should setup 100k as
> > > > default in this file too to make it clear.
> > >
> > > No, if it is conscious choice, it's fine.
> >
> > Is it Ack then or you want me to extend commit message?
>
> Ack, although you don't need my acks for your platform :)

you spell that properly. But I can. :-)

> FWIW:
>
> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>

Thanks,
Michal