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Date:   Thu, 31 Dec 2020 15:38:43 -0700
From:   Rob Herring <robh@kernel.org>
To:     Sergio Paracuellos <sergio.paracuellos@gmail.com>
Cc:     sboyd@kernel.org, john@phrozen.org, tsbogend@alpha.franken.de,
        gregkh@linuxfoundation.org, gch981213@gmail.com,
        hackpascal@gmail.com, linux-clk@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mips@vger.kernel.org, devel@driverdev.osuosl.org,
        neil@brown.name
Subject: Re: [PATCH v5 2/6] dt: bindings: add mt7621-clk device tree binding
 documentation
Message-ID: <20201231223843.GA2494920@robh.at.kernel.org>
References: <20201220093724.4906-1-sergio.paracuellos@gmail.com>
 <20201220093724.4906-3-sergio.paracuellos@gmail.com>
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On Sun, Dec 20, 2020 at 10:37:20AM +0100, Sergio Paracuellos wrote:
> Adds device tree binding documentation for clocks in the
> MT7621 SOC.
> 
> Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
> ---
>  .../bindings/clock/mediatek,mt7621-clk.yaml   | 52 +++++++++++++++++++
>  1 file changed, 52 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/mediatek,mt7621-clk.yaml
> 
> diff --git a/Documentation/devicetree/bindings/clock/mediatek,mt7621-clk.yaml b/Documentation/devicetree/bindings/clock/mediatek,mt7621-clk.yaml
> new file mode 100644
> index 000000000000..f58d01bdc82c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/mediatek,mt7621-clk.yaml
> @@ -0,0 +1,52 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/mediatek,mt7621-clk.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MT7621 Clock Device Tree Bindings
> +
> +maintainers:
> +  - Sergio Paracuellos <sergio.paracuellos@gmail.com>
> +
> +description: |
> +  The MT7621 has a PLL controller from where the cpu clock is provided
> +  as well as derived clocks for the bus and the peripherals. It also
> +  can gate SoC device clocks.
> +
> +  Each clock is assigned an identifier and client nodes use this identifier
> +  to specify the clock which they consume.
> +
> +  All these identifiers could be found in:
> +  [1]: <include/dt-bindings/clock/mt7621-clk.h>.
> +
> +properties:
> +  compatible:
> +    const: mediatek,mt7621-clk
> +
> +  "#clock-cells":
> +    description:
> +      The first cell indicates the clock number, see [1] for available
> +      clocks.
> +    const: 1
> +
> +  clock-output-names:
> +    maxItems: 8
> +
> +required:
> +  - compatible
> +  - '#clock-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/mt7621-clk.h>
> +
> +    pll {
> +      compatible = "mediatek,mt7621-clk";
> +      #clock-cells = <1>;
> +      clock-output-names = "xtal", "cpu", "bus",
> +                           "50m", "125m", "150m",
> +                           "250m", "270m";

How do you access this h/w. There's nothing defined like 'reg' or 
a parent node or...

The suggestion on v4 was to get rid of the child node by merging it with 
the parent like this:

+    sysc: sysc@0 {
+      compatible = "mediatek,mt7621-sysc", "syscon";
+      reg = <0x0 0x100>;
+      #clock-cells = <1>;
+      clock-output-names = "xtal", "cpu", "bus",
+                             "50m", "125m", "150m",
+                             "250m", "270m";
+    };

Whether you need child nodes or not really depends on what all is in the 
'mt7621-sysc' h/w block.

Rob