Hi, On Thursday 02 March 2017 10:10 PM, Vivek Gautam wrote: > 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 ? sure, lets hold the phy configuration binding and complete the rest of the patch. Thanks Kishon -- 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
