From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Gautam Subject: Re: [PATCH] dt-bindings: ufs: Fix the compatible string definition Date: Tue, 16 Oct 2018 11:21:30 +0530 Message-ID: References: <20181012213926.253765-1-dianders@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Doug Anderson Cc: robh+dt , "Martin K. Petersen" , Can Guo , evgreen@chromium.org, linux-arm-msm , sayalil@codeaurora.org, asutoshd@codeaurora.org, "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , liwei213@huawei.com, open list , malat@debian.org, Mark Rutland List-Id: linux-arm-msm@vger.kernel.org On Mon, Oct 15, 2018 at 10:54 PM Doug Anderson wrote: > > Vivek, > > On Mon, Oct 15, 2018 at 8:23 AM Vivek Gautam > wrote: > > > > Hi Doug, > > > > On Sat, Oct 13, 2018 at 3:09 AM Douglas Anderson wrote: > > > > > > If you look at the bindings for the UFS Host Controller it says: > > > > > > - compatible: must contain "jedec,ufs-1.1" or "jedec,ufs-2.0", may > > > also list one or more of the following: > > > "qcom,msm8994-ufshc" > > > "qcom,msm8996-ufshc" > > > "qcom,ufshc" > > > > > > My reading of that is that it's fine to just have either of these: > > > 1. "qcom,msm8996-ufshc", "jedec,ufs-2.0" > > > 2. "qcom,ufshc", "jedec,ufs-2.0" > > > > > > As far as I can tell neither of the above is actually a good idea. > > > > > > For #1 it turns out that the driver currently only keys off the > > > compatible string "qcom,ufshc" so it won't actually probe. > > > > > > For #2 the driver won't probe but it's not a good idea to keep the SoC > > > name out of the compatible string. > > > > > > Let's update the compatible string to make it really explicit. We'll > > > include a nod to the existing driver and the old binding and say that > > > we should always include the "qcom,ufshc" string in addition to the > > > SoC compatible string. > > > > > > While we're at it we'll also include another example SoC known to have > > > UFS: sdm845. > > > > > > Fixes: 47555a5c8a11 ("scsi: ufs: make the UFS variant a platform device") > > > Signed-off-by: Douglas Anderson > > > --- > > > > > > .../devicetree/bindings/ufs/ufshcd-pltfrm.txt | 13 ++++++++----- > > > 1 file changed, 8 insertions(+), 5 deletions(-) > > > > > > diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt > > > index 2df00524bd21..69a06a1b732e 100644 > > > --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt > > > +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt > > > @@ -4,11 +4,14 @@ UFSHC nodes are defined to describe on-chip UFS host controllers. > > > Each UFS controller instance should have its own node. > > > > > > Required properties: > > > -- compatible : must contain "jedec,ufs-1.1" or "jedec,ufs-2.0", may > > > - also list one or more of the following: > > > - "qcom,msm8994-ufshc" > > > - "qcom,msm8996-ufshc" > > > - "qcom,ufshc" > > > +- compatible : must contain "jedec,ufs-1.1" or "jedec,ufs-2.0" > > > + > > > + For Qualcomm SoCs must contain, as below, an > > > + SoC-specific compatible along with "qcom,ufshc" and > > > + the appropriate jedec string: > > > + "qcom,msm8994-ufshc", "qcom,ufshc", "jedec,ufs-2.0" > > > + "qcom,msm8996-ufshc", "qcom,ufshc", "jedec,ufs-2.0" > > > + "qcom,sdm845-ufshc", "qcom,ufshc", "jedec,ufs-2.0" > > > > Thanks for the patch. It looks good to me. > > Reviewed-by: Vivek Gautam > > Thanks for the review! > > > > P.S.: While you are at it, can you please move 'ufs-qcom.txt' > > to Documentation/devicetree/bindings/phy/qcom,ufs-phy.txt. > > The current name and file location is misleading. > > I'd rather someone at Qualcomm do this. Do you have a suggested > person? The reason I feel that Qualcomm needs to get involved is that > I see that when I look at the file you refer to says it's for: > > "qcom,ufs-phy-qmp-20nm" for 20nm ufs phy, > "qcom,ufs-phy-qmp-14nm" for legacy 14nm ufs phy, > "qcom,msm8996-ufs-phy-qmp-14nm" for 14nm ufs phy > present on MSM8996 chipset. > > ...but there's another Qualcomm file, 'qcom-qmp-phy.txt'. That > handles the compatible string: > > "qcom,sdm845-qmp-ufs-phy" for UFS QMP phy on sdm845. > > So I'm a little confused. Should the SDM845 UFS PHY been handled by > the older UFS PHY driver? ...or should all the older UFS PHYs be > moved to be handled by the newer QMP PHY driver? ...or are they > really different hardware blocks, in which case how would you describe > the difference (both are described as UFS QMP PHYs I think). As you rightly said "ufs/ufs-qcom.txt" describes the bindings for 14nm, and 20nm ufs phy. These phys are however handled by the older ufs phy driver present at: drivers/phy/qualcomm/phy-qcom-ufs-qmp-{14nm,20nm}.c The sdm845 UFS phy driver is handled by the new consolidated qmp phy driver: drivers/phy/qualcomm/phy-qcom-qmp.c whose bindings are described by 'qcom-qmp-phy.txt'. We didn't attempt to move the 14nm phy to new driver as we already had 8996 using the bindings. So, really these are two separate drivers with different bindings. I believe it should be okay to move the file. If you are fine, I can attempt to post a small patch to do that. Thanks. > > BTW: I have a patch attempting to fixup the QMP PHY bindings at > . Sure, I will review this as well. Thanks for reminiding. Best regards Vivek -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation