From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ramuthevar, Vadivel MuruganX" Subject: Re: [PATCH v12 1/4] dt-bindings: spi: Add schema for Cadence QSPI Controller driver Date: Fri, 20 Mar 2020 14:19:37 +0800 Message-ID: <13a92ddd-b7dd-0465-d747-cda9bca21dbf@linux.intel.com> References: <20200310015213.1734-1-vadivel.muruganx.ramuthevar@linux.intel.com> <20200310015213.1734-2-vadivel.muruganx.ramuthevar@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org, simon.k.r.goldschmidt-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, dinguyen-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, tien.fong.chee-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, marex-ynQEQJNshbs@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, richard-/L3Ra7n9ekc@public.gmane.org, computersforpeace-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, cyrille.pitchen-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org, david.oberhollenzer-S6VGOU4v5edDinCvNWH78Q@public.gmane.org, miquel.raynal-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org, tudor.ambarus-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, cheol.yong.kim-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, qi-ming.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org To: Vignesh Raghavendra , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Return-path: In-Reply-To: Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-spi.vger.kernel.org Hi, On 20/3/2020 2:05 pm, Vignesh Raghavendra wrote: > > On 10/03/20 7:22 am, Ramuthevar,Vadivel MuruganX wrote: >> From: Ramuthevar Vadivel Murugan >> >> Add dt-bindings documentation for Cadence-QSPI controller to support >> spi based flash memories. >> >> Signed-off-by: Ramuthevar Vadivel Murugan >> --- >> .../devicetree/bindings/mtd/cadence-quadspi.txt | 67 ----------- >> .../devicetree/bindings/spi/cdns,qspi-nor.yaml | 127 +++++++++++++++++++++ >> 2 files changed, 127 insertions(+), 67 deletions(-) >> delete mode 100644 Documentation/devicetree/bindings/mtd/cadence-quadspi.txt >> create mode 100644 Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml >> > [...] > >> + >> +# subnode's properties >> +patternProperties: >> + "^.*@[0-9a-fA-F]+$": >> + type: object >> + description: >> + flash device uses the subnodes below defined properties. >> + >> + cdns,read-delay: >> + $ref: /schemas/types.yaml#/definitions/uint32 >> + description: >> + Delay in 4 microseconds, read capture logic, in clock cycles. > > Not its not... See the old binding description please: > > -- cdns,read-delay : Delay for read capture logic, in clock cycles > > There is no mention of 4us. Range is 0x0 - 0xF Sure, will update as you have suggested. >> + >> + cdns,tshsl-ns: >> + description: | >> + Delay in 50 nanoseconds, for the length that the master mode chip select >> + outputs are de-asserted between transactions. > Again see the description in old binding file: > > cdns,tshsl-ns : Delay in nanoseconds for the length that the master > mode chip select outputs are de-asserted between > transactions. > > Need not be 50ns or its multiple Sure, will update as you have suggested. >> + >> + cdns,tsd2d-ns: >> + description: | >> + Delay in 50 nanoseconds, between one chip select being de-activated >> + and the activation of another. >> + > same here > >> + cdns,tchsh-ns: >> + description: | >> + Delay in 4 nanoseconds, between last bit of current transaction and >> + deasserting the device chip select (qspi_n_ss_out). >> + > Same here... Need not be 4ns... > >> + cdns,tslch-ns: >> + description: | >> + Delay in 4 nanoseconds, between setting qspi_n_ss_out low and >> + first bit transfer. > > Same here... > > Above four values ( cdns,*-ns) come directly from the flash datasheets. > > These values are converted appropriate number of cycles depending upon > the QSPI ref_clk frequency. So, there is no easy way to express the > constraint (or range) in DT schema. I would recommend to just stick with > the description that is there in the old binding file without any > modifications. Noted, will update. Regards Vadivel > > Regards > Vignesh