Messages in this thread | | | From | Han Xu <> | Subject | RE: [PATCH 07/11] dt-bindings: spi: spi-nxp-fspi: add a new property nxp,fspi-dll-slvdly | Date | Tue, 5 Jul 2022 13:19:56 +0000 |
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>-----Original Message----- >From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> >Sent: Tuesday, July 5, 2022 5:37 AM >To: Bough Chen <haibo.chen@nxp.com>; ashish.kumar@nxp.com; >yogeshgaur.83@gmail.com; broonie@kernel.org; robh+dt@kernel.org; >krzysztof.kozlowski+dt@linaro.org; Han Xu <han.xu@nxp.com>; >singh.kuldeep87k@gmail.com; tudor.ambarus@microchip.com; p.yadav@ti.com; >michael@walle.cc; miquel.raynal@bootlin.com; richard@nod.at; vigneshr@ti.com; >shawnguo@kernel.org; s.hauer@pengutronix.de; kernel@pengutronix.de >Cc: linux-spi@vger.kernel.org; linux-kernel@vger.kernel.org; >devicetree@vger.kernel.org; linux-mtd@lists.infradead.org; festevam@gmail.com; >dl-linux-imx <linux-imx@nxp.com>; linux-arm-kernel@lists.infradead.org; >zhengxunli@mxic.com.tw >Subject: Re: [PATCH 07/11] dt-bindings: spi: spi-nxp-fspi: add a new property >nxp,fspi-dll-slvdly > >On 05/07/2022 12:28, Bough Chen wrote: >>> -----Original Message----- >>> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> >>> Sent: 2022年7月5日 17:48 >>> To: Bough Chen <haibo.chen@nxp.com>; ashish.kumar@nxp.com; >>> yogeshgaur.83@gmail.com; broonie@kernel.org; robh+dt@kernel.org; >>> krzysztof.kozlowski+dt@linaro.org; Han Xu <han.xu@nxp.com>; >>> singh.kuldeep87k@gmail.com; tudor.ambarus@microchip.com; >>> p.yadav@ti.com; michael@walle.cc; miquel.raynal@bootlin.com; >>> richard@nod.at; vigneshr@ti.com; shawnguo@kernel.org; >>> s.hauer@pengutronix.de; kernel@pengutronix.de >>> Cc: linux-spi@vger.kernel.org; linux-kernel@vger.kernel.org; >>> devicetree@vger.kernel.org; linux-mtd@lists.infradead.org; >>> festevam@gmail.com; dl-linux-imx <linux-imx@nxp.com>; >>> linux-arm-kernel@lists.infradead.org; zhengxunli@mxic.com.tw >>> Subject: Re: [PATCH 07/11] dt-bindings: spi: spi-nxp-fspi: add a new >>> property nxp,fspi-dll-slvdly >>> >>> On 05/07/2022 11:11, haibo.chen@nxp.com wrote: >>>> From: Haibo Chen <haibo.chen@nxp.com> >>>> >>>> Add one optional property nxp,fspi-dll-slvdly >>>> >>>> Signed-off-by: Haibo Chen <haibo.chen@nxp.com> >>>> --- >>>> Documentation/devicetree/bindings/spi/spi-nxp-fspi.yaml | 6 ++++++ >>>> 1 file changed, 6 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/spi/spi-nxp-fspi.yaml >>> b/Documentation/devicetree/bindings/spi/spi-nxp-fspi.yaml >>>> index 1b552c298277..6bd61565686a 100644 >>>> --- a/Documentation/devicetree/bindings/spi/spi-nxp-fspi.yaml >>>> +++ b/Documentation/devicetree/bindings/spi/spi-nxp-fspi.yaml >>>> @@ -45,6 +45,12 @@ properties: >>>> - const: fspi_en >>>> - const: fspi >>>> >>>> + nxp,fspi-dll-slvdly: >>>> + $ref: /schemas/types.yaml#/definitions/uint32 >>>> + description: | >>>> + Specify the DLL slave line delay value. >>> >>> What are the units? >> >> Do you mean here need to give more detail explain about this properity? >> >> How about change like this? >> Specify the DLL slave line delay value. The delay target for slave delay line is: >((nxp,fspi-dll-slvdly+1) * 1/32 * clock cycle of reference clock (serial root clock). > >This would be good. > >> The range of this value is 0~16. > >This needs to go to schema instead as "maximum: 16". > >But still the question is - what are the units used in this "delay"? ms? us?
HI Krzysztof,
According to the formula, the range should be 0~15, 16 should do nothing or no delay.
The unit should be clock phase. In other words, the delay can be in range of 1/32~1/2 clock cycle.
> >Best regards, >Krzysztof
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