Re: [PATCH v5 5/9] media: staging: rkisp1: remove unecessary clocks

[Rob Herring <robh+dt@kernel.org>]

On Wed, Oct 14, 2020 at 11:46 AM Helen Koike <helen.koike@collabora.com> wrote:
>
> Hi Rob,
>
> Thnaks for your reply.
>
> On 9/22/20 11:24 AM, Rob Herring wrote:
> > On Wed, Jul 22, 2020 at 9:56 AM Helen Koike <helen.koike@collabora.com> wrote:
> >>
> >> aclk_isp_wrap is a child of aclk_isp, and hclk_isp_wrap is a child of
> >> hclk_isp, thus we can remove parents from the list.
> >>
> >> Also, for the isp0, we only need the ISP clock, ACLK and HCLK.
> >> In the future we'll need a pixel clock for RK3288 and RK3399, and a JPEG
> >> clock for RK3288.
> >>
> >> So with the goal to cleanup the dt-bindings and remove it from staging,
> >> simplify clock names to isp, aclk and hclk.
> >>
> >> Assigned clocks are meant to refer to the full path in the clock tree,
> >> i.e. the leaf in the tree.
> >> For instance, in RK3399, the clock responsible for ACLK (ISP AXI CLOCK)
> >> is aclk_isp0_wrapper.
> >>
> >> For reference, this is the isp clock topology on RK3399:
> >>
> >>  xin24m
> >>     pll_npll
> >>        npll
> >>           clk_isp1
> >>           clk_isp0
> >>     pll_cpll
> >>        cpll
> >>           aclk_isp1
> >>              aclk_isp1_noc
> >>              hclk_isp1
> >>                 aclk_isp1_wrapper
> >>                 hclk_isp1_noc
> >>           aclk_isp0
> >>              hclk_isp1_wrapper
> >>              aclk_isp0_wrapper
> >>              aclk_isp0_noc
> >>              hclk_isp0
> >>                 hclk_isp0_wrapper
> >>                 hclk_isp0_noc
> >>  pclkin_isp1_wrapper
> >>
> >> Signed-off-by: Helen Koike <helen.koike@collabora.com>
> >>
> >> ---
> >> Changes in V5:
> >> - Use if/then schema as suggested by Rob Herring on
> >> https://patchwork.linuxtv.org/project/linux-media/patch/20200702191322.2639681-6-helen.koike@collabora.com/#119729
> >>
> >> Changes in V4:
> >> - update binding according to suggestion by Robin Murphy
> >> on https://patchwork.kernel.org/patch/11475007/
> >>
> >> Changes in V3:
> >> - this is a new patch in the series
> >> ---
> >>  .../bindings/media/rockchip-isp1.yaml         | 50 ++++++++++++-------
> >>  drivers/staging/media/rkisp1/rkisp1-dev.c     |  8 ++-
> >>  2 files changed, 36 insertions(+), 22 deletions(-)
> >>
> >> diff --git a/drivers/staging/media/rkisp1/Documentation/devicetree/bindings/media/rockchip-isp1.yaml b/drivers/staging/media/rkisp1/Documentation/devicetree/bindings/media/rockchip-isp1.yaml
> >> index 62a6b9c959498..23c677d15037a 100644
> >> --- a/drivers/staging/media/rkisp1/Documentation/devicetree/bindings/media/rockchip-isp1.yaml
> >> +++ b/drivers/staging/media/rkisp1/Documentation/devicetree/bindings/media/rockchip-isp1.yaml
> >> @@ -24,20 +24,10 @@ properties:
> >>      maxItems: 1
> >>
> >>    clocks:
> >> -    items:
> >> -      - description: ISP clock
> >> -      - description: ISP AXI clock clock
> >> -      - description: ISP AXI clock  wrapper clock
> >> -      - description: ISP AHB clock clock
> >> -      - description: ISP AHB wrapper clock
> >> +    minItems: 3
> >
> > You need maxItems here too or it will always be 3.
> >
> >>
> >>    clock-names:
> >> -    items:
> >> -      - const: clk_isp
> >> -      - const: aclk_isp
> >> -      - const: aclk_isp_wrap
> >> -      - const: hclk_isp
> >> -      - const: hclk_isp_wrap
> >> +    minItems: 3
> >>
> >>    iommus:
> >>      maxItems: 1
> >> @@ -116,6 +106,34 @@ required:
> >>    - power-domains
> >>    - ports
> >>
> >> +if:
> >> +  properties:
> >> +    compatible:
> >> +      contains:
> >> +        const: rockchip,rk3399-cif-isp
> >> +then:
> >> +  properties:
> >> +    clocks:
> >> +      maxItems: 4
> >> +      minItems: 3
> >
> > For a single compatible you shouldn't really have a variable number of clocks.
>
> I'm not entirely sure how to make this separation, since isp0 and isp1 (not yet supported)
> would use the same compatible.
> Unless if we separate in two compatibles, but maybe this is an overhead just for an extra clock.
> What do you think?

In that case, it's fine.

>
> >
> >> +      items:
> >> +        # isp0 and isp1
> >> +        - description: ISP clock
> >> +        - description: ISP AXI clock
> >> +        - description: ISP AHB clock
> >> +        # only for isp1
> >> +        - description: ISP Pixel clock
> >> +    clock-names:
> >> +      maxItems: 4
> >> +      minItems: 3
> >> +      items:
> >> +        # isp0 and isp1
> >> +        - const: isp
> >> +        - const: aclk
> >> +        - const: hclk
> >> +        # only for isp1
> >> +        - const: pclk_isp
> >
> > Don't you need an 'else' clause. For not rockchip,rk3399-cif-isp,
> > there's no definition of what clocks there are.
>
> There is only one compatible defined for now, rk3288 will be added later.
> The idea to add if/then is to make it easier to add rk3288:
>
> https://patchwork.kernel.org/project/linux-media/patch/20200406073017.19462-4-karthik.poduval@gmail.com/

Hopefully, the clock names will be aligned? Looks like they are the
same with just 1 additional clock. Ideally, you define them all at the
top level and the if/then schema just defines how many clocks for each
compatible.

Rob
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