Messages in this thread | | | From | Sean Anderson <> | Subject | Re: [PATCH v2 0/7] usb: dwc3: Calculate REFCLKPER et. al. from reference clock | Date | Wed, 19 Jan 2022 13:23:44 -0500 |
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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
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