Re: [PATCH v2 0/7] usb: dwc3: Calculate REFCLKPER et. al. from reference clock

[Kathiravan Thirumoorthy]

Hi Baruch,

On 1/20/2022 3:59 PM, Baruch Siach wrote:
> Hi Kathiravan,
>
> On Thu, Jan 20 2022, Kathiravan T wrote:
> > On 2022-01-19 23:44, Baruch Siach wrote:
> > > Hi Sean,
> > > On Tue, Jan 18 2022, Sean Anderson wrote:
> > > > This is a rework of patches 3-5 of [1]. It attempts to correctly program
> > > > REFCLKPER and REFCLK_FLADJ based on the reference clock frequency. Since
> > > > we no longer need a special property duplicating this configuration,
> > > > snps,ref-clock-period-ns is deprecated.
> > > > Please test this! Patches 3/4 in this series have the effect of
> > > > programming REFCLKPER and REFCLK_FLADJ on boards which already configure
> > > > the "ref" clock. I have build tested, but not much else.
> > > Tested here on IPQ6010 based system. USB still works. But the with
> > > "ref"
> > > clock at 24MHz, period is calculated as 0x29. Previous
> > > snps,ref-clock-period-ns value used to be 0x32.
> > > Is that expected?
> > Yes, it is 0x29 for IPQ60xx based SoCs. In downstream it was wrongly mentioned
> > as 0x32, which was corrected recently.
> Thanks for the update. This needs fixing in upstream kernel. I'll send a
> patch.
>
> For some reason USB appears to work here with both values. Is it because
> I only use USB2 signals? If this is the case them I can not actually
> test this series on my system.

I could recollect we did see some issue on USB2.0 port as well, but it 
wasn't fatal one. Anyways it is better to test it.

Thanks,

Kathiravan T.

> Thanks,
> baruch
>
> > > > [1]
> > > > https://lore.kernel.org/linux-usb/20220114044230.2677283-1-robert.hancock@xxxxxxxxxx/
> > > > Changes in v2:
> > > > - Document clock members
> > > > - Also program GFLADJ.240MHZDECR
> > > > - Don't program GFLADJ if the version is < 2.50a
> > > > - Add snps,ref-clock-frequency-hz property for ACPI
> > > > Sean Anderson (7):
> > > >    dt-bindings: usb: dwc3: Deprecate snps,ref-clock-period-ns
> > > >    usb: dwc3: Get clocks individually
> > > >    usb: dwc3: Calculate REFCLKPER based on reference clock
> > > >    usb: dwc3: Program GFLADJ
> > > >    usb: dwc3: Add snps,ref-clock-frequency-hz property for ACPI
> > > >    arm64: dts: zynqmp: Move USB clocks to dwc3 node
> > > >    arm64: dts: ipq6018: Use reference clock to set dwc3 period
> > > >   .../devicetree/bindings/usb/snps,dwc3.yaml    |   7 +-
> > > >   arch/arm64/boot/dts/qcom/ipq6018.dtsi         |   3 +-
> > > >   .../arm64/boot/dts/xilinx/zynqmp-clk-ccf.dtsi |   4 +-
> > > >   arch/arm64/boot/dts/xilinx/zynqmp.dtsi        |   4 +-
> > > >   drivers/usb/dwc3/core.c                       | 112 +++++++++++++++---
> > > >   drivers/usb/dwc3/core.h                       |  17 ++-
> > > >   6 files changed, 120 insertions(+), 27 deletions(-)