Rob Herring wrote: > On Wed, Aug 04, 2021 at 05:22:27PM +0300, Baruch Siach wrote: >> Hi Felipe, >> >> On Wed, Aug 04 2021, Felipe Balbi wrote: >>> Baruch Siach <baruch@xxxxxxxxxx> 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://urldefense.com/v3/__https://lore.kernel.org/r/c797e9cb-cae6-c0b6-5714-169c2ad79d32@synopsys.com__;!!A4F2R9G_pg!Nh6rqp_aOd8XIvqELvDRQe5ooZf13UZKwmn9lWcRgdbyMKpTMzL8HasrB1X2Ojvumo8g$ > > PCI devices can have DT nodes with clock properties too. Or use the > VID/PID to infer the frequency. Or use 'clock-frequency' property. > > It boils down to we have lots of standard properties for clocks and > clock configuration, so custom properties are a NAK. > Do we have DT node for the PCI device before discovering the device from PCI bus enumeration? I don't think we can find the clock properties from its configuration space. For our HAPS devices, we can't use VID/PID to infer the frequency since our phy and ref clock may change. Does "clock-frequency" mean ref clock? If so, let's use that? Thanks, Thinh
