Hi Mark and Arnd, I am planning the v2 of this patch set. I have a doubt in the version compatibility strings... The core driver must support the UFS 2.0 controller and this patch set includes a patch that adds 2.0 capabilities to it. The core driver can get from the controller's version and with that use or not a specific 2.0 feature. What would be the real added-value of having a compatibility string like "snps,ufshcd-1.1" and "snps,ufshcd-2.0" if the driver can perform as 2.0 if it detects a 2.0 controller? Are you saying that a user that puts "snps,ufshcd-1.1" in the DT compatibility string disables the UFS 2.0 in the core driver despite the controller is 2.0? Please clarify. Thanks, Joao On 2/4/2016 4:27 PM, Mark Rutland wrote: > On Wed, Feb 03, 2016 at 03:54:48PM +0000, Joao Pinto wrote: >> Hi, >> >> On 2/3/2016 3:39 PM, Arnd Bergmann wrote: >>> On Wednesday 03 February 2016 15:01:34 Joao Pinto wrote: >>>> >>>> Hi Arnd, >>>> >>>> On 2/3/2016 12:54 PM, Arnd Bergmann wrote: >>>>> On Wednesday 03 February 2016 11:28:26 Joao Pinto wrote: >>>>>> >>>>>> Signed-off-by: Joao Pinto <jpinto@xxxxxxxxxxxx> >>>>> >>>>> This needs a changelog comment, like every patch. >>>>> >>>>>> @@ -0,0 +1,16 @@ >>>>>> +* Universal Flash Storage (UFS) DesignWare Host Controller >>>>>> + >>>>>> +DWC_UFSHC nodes are defined to describe on-chip UFS host controllers. >>>>>> +Each UFS controller instance should have its own node. >>>>>> + >>>>>> +Required properties: >>>>>> +- compatible : compatible list, contains "snps,ufshcd" >>>>> >>>>> Are there multiple versions of this controller? Usually for designware >>>>> parts the version is known, so we should document which versions exist >>>> >>>> This controller recent releases was 2.0, but we released last year 1.1. The >>>> driver works with both. The driver must work with all DWC UFS versions. >>> >>> Ok, then make the driver match on the "snps,ufshcd-1.1" compatible >>> string, but document both strings in the binding document, and make >>> it mandatory to specify the 1.1 version as a compatible fallback. >>> >>> If we ever need to handle a quirk for the 2.0 version then, it can >>> easily be done. >> >> We need the driver to support UFS 2.0 because it is our latest release and is >> the done that Synopsys is focused now. We could call it "snps, ufshcd-2.0" then. >> What do you think? > > Arnd's point was that the driver can handle only "snps,ufshcd-1.1" for > now, and in your DT you can have: > > compatible = "snps,ufshcd-2.0", "snps,ufshcd-1.1"; > > That allows driver to handle 2.0 and 1.1 without knowing anything about > 2.0 for now. If in future the two need to be handled differently we can > update the driver to explicitly match "snps,ufshcd-2.0". > > Regardless, both compatible string should go in the documentation, and > it should be explicitly mentioned that "snps,ufshcd-1.1" should be used > as a fallback entry. > > Mark. > -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
