From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Luba Subject: Re: [PATCH v6 04/10] Documentation: dt: device tree bindings for LPDDR3 memories Date: Tue, 30 Apr 2019 22:04:31 +0200 Message-ID: References: <1555683568-20882-1-git-send-email-l.luba@partner.samsung.com> <1555683568-20882-5-git-send-email-l.luba@partner.samsung.com> <20190425195156.GA31128@bogus> <86715dda-c1b0-5354-17d2-419f8137cb91@partner.samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Rob Herring Cc: devicetree@vger.kernel.org, "linux-kernel@vger.kernel.org" , "open list:THERMAL" , linux-samsung-soc , Bartlomiej Zolnierkiewicz , Krzysztof Kozlowski , Kukjin Kim , Chanwoo Choi , Kyungmin Park , Marek Szyprowski , Sylwester Nawrocki , MyungJoo Ham , Kees Cook , Tony Lindgren , Joerg Roedel , Thierry Reding , Dmitry Osipenko , willy.mh.wolff.ml@gmail.com List-Id: devicetree@vger.kernel.org Hi Rob, On 4/29/19 6:36 PM, Rob Herring wrote: > On Mon, Apr 29, 2019 at 7:05 AM Lukasz Luba wrote: >> >> Hi Rob, >> >> On 4/25/19 9:51 PM, Rob Herring wrote: >>> On Fri, Apr 19, 2019 at 04:19:22PM +0200, Lukasz Luba wrote: >>>> The device tree bindings for LPDDR3 SDRAM memories. >>>> >>>> For specifying the AC timing parameters of the memory device >>>> the 'lpddr3' binding uses binding 'lpddr2-timings'. >>>> >>>> Signed-off-by: Lukasz Luba >>>> --- >>>> .../devicetree/bindings/lpddr3/lpddr3-timings.txt | 57 +++++++++++++ >>>> .../devicetree/bindings/lpddr3/lpddr3.txt | 93 ++++++++++++++++++++++ >>> >>> Please rename the lpddr2 directory to 'ddr' and add these to it. >> OK, I will rename it in the nex patch set. >>> >>> Maybe whatever properties are common should be put in a common doc. >> There are maybe a few common properties, but I would not dare to merge >> lpddr2 and lpddr3 before consulting it with TI engineers who made >> LPDDR2 support. > > Why not. You aren't changing anything. Just rearranging. True. > >> Could we work on a common file after the patch set got merged? > > Yes, but please still move everything to a common directory. OK, I am currently working on it and moving these lpddr* files into Documentation/devicetree/bindings/ddr/ Then after acceptance I will find the common stuff and do the merge. > >>> >>>> 2 files changed, 150 insertions(+) >>>> create mode 100644 Documentation/devicetree/bindings/lpddr3/lpddr3-timings.txt >>>> create mode 100644 Documentation/devicetree/bindings/lpddr3/lpddr3.txt >>>> >>>> diff --git a/Documentation/devicetree/bindings/lpddr3/lpddr3-timings.txt b/Documentation/devicetree/bindings/lpddr3/lpddr3-timings.txt >>>> new file mode 100644 >>>> index 0000000..ebf3e00 >>>> --- /dev/null >>>> +++ b/Documentation/devicetree/bindings/lpddr3/lpddr3-timings.txt >>>> @@ -0,0 +1,57 @@ >>>> +* AC timing parameters of LPDDR3 memories for a given speed-bin. >>>> +* The structures are based on LPDDR2 and extended where needed. >>>> + >>>> +Required properties: >>>> +- compatible : Should be "jedec,lpddr3-timings" >>>> +- min-freq : minimum DDR clock frequency for the speed-bin. Type is >>>> +- max-freq : maximum DDR clock frequency for the speed-bin. Type is >>>> + >>>> +Optional properties: >>>> + >>>> +The following properties represent AC timing parameters from the memory >>>> +data-sheet of the device for a given speed-bin. All these properties are >>>> +of type and the default unit is ps (pico seconds). >>>> +- tRFC >>>> +- tRRD >>>> +- tRPab >>>> +- tRPpb >>>> +- tRCD >>>> +- tRC >>>> +- tRAS >>>> +- tWTR >>>> +- tWR >>>> +- tRTP >>>> +- tW2W-C2C >>>> +- tR2R-C2C >>>> +- tFAW >>>> +- tXSR >>>> +- tXP >>>> +- tCKE >>>> +- tCKESR >>>> +- tMRD >>>> + >>>> +Example: >>>> + >>>> +timings_samsung_K3QF2F20DB_800mhz: lpddr3-timings@0 { >>> >>> Since the lpddr2 version was written, we've gotten stricter about >>> allowing unit-address without reg property. Perhaps 'reg' should be the >>> max-freq instead. >> OK, so I will rename 'max-freq' to 'reg' and add a comment with: >> '/* workaround: it shows max-freq */ >> Does it make sense? > > Sure. OK. Thank you. Regards, Lukasz > > Rob > >