linux-kernel - Re: [EXT] Re: [PATCH v4 2/2] dt-bindings: media: imx-jpeg: Assign slot for imx jpeg encoder/decoder

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Date:   Thu, 28 Sep 2023 11:47:20 -0500
From:   Rob Herring <robh@...nel.org>
To:     Ming Qian <ming.qian@....com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        "Mirela Rabulea (OSS)" <mirela.rabulea@....nxp.com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        "conor+dt@...nel.org" <conor+dt@...nel.org>,
        "mchehab@...nel.org" <mchehab@...nel.org>,
        "hverkuil-cisco@...all.nl" <hverkuil-cisco@...all.nl>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "X.H. Bao" <xiahong.bao@....com>, Eagle Zhou <eagle.zhou@....com>,
        Tao Jiang <tao.jiang_2@....com>,
        dl-linux-imx <linux-imx@....com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [EXT] Re: [PATCH v4 2/2] dt-bindings: media: imx-jpeg: Assign
 slot for imx jpeg encoder/decoder

On Wed, Sep 27, 2023 at 09:10:52AM +0000, Ming Qian wrote:
> >From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> >
> >On 26/09/2023 12:10, Ming Qian wrote:
> >> There are total 4 slots available in the IP, and we only need to use
> >> one slot in one os, assign a single slot, configure interrupt and
> >> power domain only for 1 slot, not for the all 4 slots.
> >>
> >> Signed-off-by: Ming Qian <ming.qian@....com>
> >> ---
> >> v4
> >> - improve commit message
> >> - don't make an ABI break
> >> v3
> >> - add vender prefix, change property slot to nxp,slot
> >> - add type for property slot
> >>
> >>  .../bindings/media/nxp,imx8-jpeg.yaml         | 45 +++++++++----------
> >>  1 file changed, 21 insertions(+), 24 deletions(-)
> >>
> >> diff --git
> >> a/Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml
> >> b/Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml
> >> index 3d9d1db37040..4bcfc815c894 100644
> >> --- a/Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml
> >> +++ b/Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml
> >> @@ -32,19 +32,26 @@ properties:
> >>      maxItems: 1
> >>
> >>    interrupts:
> >> -    description: |
> >> -      There are 4 slots available in the IP, which the driver may use
> >> -      If a certain slot is used, it should have an associated interrupt
> >> -      The interrupt with index i is assumed to be for slot i
> >> -    minItems: 1               # At least one slot is needed by the driver
> >> -    maxItems: 4               # The IP has 4 slots available for use
> >> +    description:
> >> +      Interrupt number for slot
> >> +    maxItems: 1
> >>
> >>    power-domains:
> >>      description:
> >>        List of phandle and PM domain specifier as documented in
> >>        Documentation/devicetree/bindings/power/power_domain.txt
> >> -    minItems: 2               # Wrapper and 1 slot
> >> -    maxItems: 5               # Wrapper and 4 slots
> >> +    minItems: 1               # VPUMIX
> >> +    maxItems: 2               # Wrapper and 1 slot
> >> +
> >> +  nxp,slot:
> >> +    $ref: /schemas/types.yaml#/definitions/uint32
> >> +    description:
> >> +      Integer number of slot index used. There are 4 slots available in the IP,
> >> +      and driver can use a certain slot, it should have an associated interrupt
> >> +      and power-domain. In theory, it supports 4 os or vm. If not specified, 0
> >> +      is used by default.
> >> +    minimum: 0
> >> +    maximum: 3
> >
> >NAK, you still did not answer concerns why this is needed and justified.
> >I keep asking and you keep ignoring...
> >
> >Best regards,
> >Krzysztof
> 
> Hi Krzysztof,
> 
> > Nothing explains what is a slot and nothing explains why do you need this property.
> 
> I thought I had answered that question, but seems you don't agree with that explanation. 
> Would the following description be any better?
> 
> The slot is the IP used to share the jpeg engine across multiple VMS 
> and os, there are 4 slots available in the IP. We can use one slot in 
> linux. The slot index indicates which slot we choose. If not 
> specified, 0 is used by default.

If you have to modify the DT to update 'nxp,slot', then you can modify 
the DT to just expose the parts of the h/w for the assigned slot. For 
example, only put slot 1's power-domains entry in the DT when slot 1 is 
assigned.

As far as formatting your emails, talk to your NXP colleagues. They've 
figured it out. If you've configured git-send-email successfully, then 
using mutt should be possible. You can use 'b4' to get the thread mbox, 
and read it in mutt.

Rob