Hi Kishon, On Wed, Feb 22, 2017 at 9:29 AM, Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> wrote: > Hi Kishon, > > > On Fri, Jan 27, 2017 at 11:54 AM, Vivek Gautam > <vivek.gautam@xxxxxxxxxxxxxx> wrote: >> >> >> On 01/26/2017 11:45 PM, Bjorn Andersson wrote: >>> >>> On Tue 24 Jan 01:19 PST 2017, Kishon Vijay Abraham I wrote: >>>> >>>> On Monday 23 January 2017 03:43 PM, Vivek Gautam wrote: >>>>> >>>>> On Wed, Jan 18, 2017 at 11:33 PM, Bjorn Andersson >>> >>> [..] >>>>> >>>>> Yes, that's correct. The QMP and QUSB2 phy init sequences are a bunch >>>>> of static values for a particular IP version. These values hardly give a >>>>> meaningful data to put few phy bindings that could be referenced >>>>> to configure the phy further. >>>> >>>> Not really. You can have clearly defined phy binding to give meaningful >>>> data. >>>> Every driver doing the same configuration bloats the driver and these >>>> configuration values are just magic values which hardly can be reviewed >>>> by anyone. >>>>>> >>>>>> Further more moving this blob to devicetree will not allow us to treat >>>>>> the various QMP configurations as one HW block, as there are other >>>>>> differences as well. >>>>>> >>>>>> Like many other drivers it's possible to create a generic version that >>>>>> has every bit of logic driven by configuration from devicetree, but >>>>>> like >>>>>> most of those cases this is not the way we split things. >>>>>> >>>>>> And this has the side effect of keeping the dts files human readable, >>>>>> human understandable and human maintainable. >>>> >>>> right. That's why I recommend having clearly defined bindings. >>>> phy,tx-<param1> = <val, offset, mask> >>>> phy,tx-<param2> = <val, offset, mask> >>>> phy,tx-<param3> = <val, offset, mask> >>> >>> There's no doubt that this table needs to be encoded somewhere, so the >>> question is should we hard code this in a C file or in a DTSI file. >>> >>> Skimming through [1] I see examples of things that differs based on how >>> the specific component is integrated in a SoC or on a particular board - >>> properties that are relevant to a "system integrator". >>> >>> As far as I can tell this blob will, if ever, only be changed by a >>> driver developer and as such it's not carry information about how this >>> component relates to the rest of the system and should as such not be >>> part of the device tree. >>> >>> >>> If there are properties of the hardware that is affected by how the >>> component is integrated in the system I really would like for those to >>> be exposed as human-readable properties that I can understand and alter >>> without deep knowledge about the register map of the hardware block. >> >> >> I am reaching out to our internal teams to get more information >> on different possible phy configurations, based on which the registers >> values are decided. >> This is something that i tried to understand in the past as well, but >> couldn't >> grab much information that time. >> Will come back with relevant information on this. >> > > We have started looking into understanding the PHYs on msm and > eventually create a set of generic phy bindings that can serve multiple > platforms. > But this task, I presume, will take its course and will involve multi-party > discussions. > > For these QUSB2 and QMP phy drivers, a good amount of work has > already gone in getting these drivers in upstream state. > The common QMP phy driver supports a bunch of controllers on msm > platforms - USB, PCIe and UFS and there are platforms such as DB820c > and others that want to pull in these changes from upstream. > The future phy controllers also depend on these drivers and we don't want > to hold other developers to contribute to these drivers. > So, we wish to not delay these drivers further because of the phy bindings. > I see that there are phys that still program the registers-value pairs for > phy initialization. > > We will keep working on the bindings while these patches > make way to upstream. > > Can you consider pulling in these drivers? > I can send the next version of these drivers with other comments addressed. > Please let me know your comments. Gentle ping. Any thoughts on this ? >> >>>> [1] -> https://www.linuxplumbersconf.org/2016/ocw/proposals/4047 >>> >>> Regards, >>> Bjorn -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
