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

Message ID 20220119002438.106079-1-sean.anderson@seco.com
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Series usb: dwc3: Calculate REFCLKPER et. al. from reference clock | expand

Message

Sean Anderson Jan. 19, 2022, 12:24 a.m. UTC 
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.

[1] https://lore.kernel.org/linux-usb/20220114044230.2677283-1-robert.hancock@calian.com/

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(-)

Comments

Sean Anderson Jan. 19, 2022, 6:23 p.m. UTC | #1 
Hi Baruch,

On 1/19/22 1:14 PM, 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. From the documentation for GFLADJ_REFCLK_240MHZ_DECR:

> Examples:
> If the ref_clk is 24 MHz then
> - GUCTL.REF_CLK_PERIOD = 41
> - GFLADJ.GFLADJ_REFCLK_240MHZ_DECR = 240/24 = 10

And 41 == 0x29.

--Sean