[PATCH v2 4/6] usb: dwc3: reference clock period configuration

[Baruch Siach]

Hi Felipe,

On Wed, Aug 04 2021, Felipe Balbi wrote:
> Baruch Siach <baruch at tkos.co.il> writes:
>> @@ -1371,6 +1398,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>>  				    &dwc->hsphy_interface);
>>  	device_property_read_u32(dev, "snps,quirk-frame-length-adjustment",
>>  				 &dwc->fladj);
>> +	device_property_read_u32(dev, "snps,ref-clock-period",
>> +				 &dwc->ref_clk_per);
>
> I wonder if it would make more sense to pass an actual clock reference
> here. If valid, then reconfigure the period to the value returned by
> clk_get_rate(). It would avoid yet another DT binding. If we make the
> clock optional, then we won't affect any other platforms. The clock
> itself could be a regular fixed clock node.

Thinh Nguyen asked to add a dedicated DT property. He explained that
clk_get_rate() does not work for PCI hosted dwc3. This is the most
complete summary of the discussion:

  https://lore.kernel.org/r/c797e9cb-cae6-c0b6-5714-169c2ad79d32@synopsys.com

baruch

-- 
                                                     ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -