On 17.07.2018 08:50, A.s. Dong wrote: >> -----Original Message----- >> From: Oleksij Rempel [mailto:o.rempel@xxxxxxxxxxxxxx] >> Sent: Tuesday, July 17, 2018 2:32 PM >> To: A.s. Dong <aisheng.dong@xxxxxxx>; Shawn Guo >> <shawnguo@xxxxxxxxxx>; Fabio Estevam <fabio.estevam@xxxxxxx>; Rob >> Herring <robh+dt@xxxxxxxxxx>; Mark Rutland <mark.rutland@xxxxxxx> >> Cc: devicetree@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; linux-arm- >> kernel@xxxxxxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx> >> Subject: Re: [PATCH v3 1/3] dt-bindings: arm: fsl: add mu binding doc >> >> >> >> On 17.07.2018 08:26, A.s. Dong wrote: >>>> -----Original Message----- >>>> From: Oleksij Rempel [mailto:o.rempel@xxxxxxxxxxxxxx] >>>> Sent: Tuesday, July 17, 2018 1:45 PM >>>> To: A.s. Dong <aisheng.dong@xxxxxxx>; Shawn Guo >>>> <shawnguo@xxxxxxxxxx>; Fabio Estevam <fabio.estevam@xxxxxxx>; >> Rob >>>> Herring <robh+dt@xxxxxxxxxx>; Mark Rutland <mark.rutland@xxxxxxx> >>>> Cc: devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; >>>> kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx> >>>> Subject: Re: [PATCH v3 1/3] dt-bindings: arm: fsl: add mu binding doc >>>> >>>> >>>> >>>> On 17.07.2018 07:00, A.s. Dong wrote: >>>>>> -----Original Message----- >>>>>> From: Oleksij Rempel [mailto:o.rempel@xxxxxxxxxxxxxx] >>>>>> Sent: Monday, July 16, 2018 7:42 PM >>>>>> To: Shawn Guo <shawnguo@xxxxxxxxxx>; Fabio Estevam >>>>>> <fabio.estevam@xxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Mark >>>>>> Rutland <mark.rutland@xxxxxxx>; A.s. Dong >> <aisheng.dong@xxxxxxx> >>>>>> Cc: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>; >>>>>> kernel@xxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; >>>>>> devicetree@xxxxxxxxxxxxxxx; >>>>>> dl-linux- imx <linux-imx@xxxxxxx> >>>>>> Subject: [PATCH v3 1/3] dt-bindings: arm: fsl: add mu binding doc >>>>>> >>>>>> The Messaging Unit module enables two processors within the SoC to >>>>>> communicate and coordinate by passing messages (e.g. data, status >>>>>> and >>>>>> control) through the MU interface. >>>>>> >>>>>> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> >>>>>> --- >>>>>> .../devicetree/bindings/mailbox/fsl,mu.txt | 32 >>>> +++++++++++++++++++ >>>>>> 1 file changed, 32 insertions(+) >>>>>> create mode 100644 >>>>>> Documentation/devicetree/bindings/mailbox/fsl,mu.txt >>>>>> >>>>>> diff --git a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt >>>>>> b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt >>>>>> new file mode 100644 >>>>>> index 000000000000..5d48dd75b98d >>>>>> --- /dev/null >>>>>> +++ b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt >>>>>> @@ -0,0 +1,32 @@ >>>>>> +NXP i.MX Messaging Unit (MU) >>>>>> +------------------------------------------------------------------ >>>>>> +-- >>>>>> + >>>>>> +Required properties: >>>>>> +------------------- >>>>>> +- compatible : should be "fsl,<chip>-mu", the supported chips >>>> include: >>>>>> + imx6sx - i.MX 6SoloX >>>>>> + imx7d - i.MX 7Dual >>>>>> + imx7s - i.MX 7Solo >>>>>> + imx7ulp - i.MX 7ULP >>>>>> + imx8qm - i.MX 8QM >>>>>> + imx8qxp - i.MX 8QXP >>>>>> +- reg : Should contain the registers location and length >>>>>> +- interrupts : Interrupt number. The interrupt specifier format >>>> depends >>>>>> + on the interrupt controller parent. >>>>>> +- #mbox-cells: Must be: >>>>>> + 0 - for single channel mode. i.MX8* SCU protocol specific. >>>>>> + 1 - for multichannel (generic) mode. >>>>>> + >>>>>> +Optional properties: >>>>>> +------------------- >>>>>> +- clocks : phandle to the input clock. >>>>>> +- fsl,mu-side-a : Should be set for side A MU. >>>>> >>>>> For this property, how about doing like: >>>>> fsl,mu-side: An Integer represents the MU side. >>>> >>>> All this SoCs have MUs with only two sides. Why do we need explicit >>>> annotation for both parts? >>>> >>>>> If missing this property, it's default to Side A >>>> >>>> So, why do we need optional integer, which is set by default as side A? >>>> This is why I made it bool. >>> >>> Yes, A bool probably is better. >>> >>>> >>>>> which is mostly used by A core. >>>> >>>> And you will need to explicit set side=B for SCU. Correct? >>> >>> SCU is using side A. AFAIK all SoC A core is using side A by default. >>> That's why I think it can be default one. User is free to specify both >>> In device tree. Does it make sense to you? >> >> Ok. > > My original assumption is we can specify the side explicitly in device tree > (default to side A if missing) like: > mu0a: mailbox@30aa0000 { > compatible = "fsl,imx7s-mu"; > ... > fsl,mu-side = <0>; > }; > > mu0b: mailbox@30ab0000 { > compatible = "fsl,imx7s-mu"; > ... > fsl,mu-side = <1>; > }; > > But you're right it can be simply indicated by a bool as well. > mu0a: mailbox@30aa0000 { > compatible = "fsl,imx7s-mu"; > ... > }; > > mu0b: mailbox@30ab0000 { > compatible = "fsl,imx7s-mu"; > ... > fsl,mu-side-b; > }; > > I'm okay with both. You can prefer as you wish. There are advantages and disadvantages in both cases: - bool is using less space and limited to only needed part but mistakes can happen and some will forget to add this line. - int part is good only if it is not optional.
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