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Subject: Re: [PATCH 1/2] dt-bindings: phy: Add YAML schemas for Intel Combo
 phy
To:     Rob Herring <robh@kernel.org>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        devicetree@vger.kernel.org, Kishon Vijay Abraham I <kishon@ti.com>,
        Andy Shevchenko <andriy.shevchenko@intel.com>,
        cheol.yong.kim@intel.com, chuanhua.lei@linux.intel.com,
        qi-ming.wu@intel.com, yixin.zhu@intel.com
References: <9f3df8c403bba3633391551fc601cbcd2f950959.1576824311.git.eswara.kota@linux.intel.com>
 <20200108141855.GA14868@bogus>
 <0e797d57-66a6-39ec-6388-5af47e9b0726@linux.intel.com>
 <CAL_JsqLaiiYxaWjWRr3S7Q8j5YCxB_v2Lt_m5fwHnZU1e27MdA@mail.gmail.com>
From:   Dilip Kota <eswara.kota@linux.intel.com>
Message-ID: <bee95b99-027e-45eb-d2f2-bfa5bbfda9cd@linux.intel.com>
Date:   Wed, 15 Jan 2020 15:52:46 +0800
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On 1/14/2020 10:31 PM, Rob Herring wrote:
> On Tue, Jan 14, 2020 at 3:18 AM Dilip Kota <eswara.kota@linux.intel.com> wrote:
>>
>> On 1/8/2020 10:18 PM, Rob Herring wrote:
>>> On Fri, Dec 20, 2019 at 03:28:27PM +0800, Dilip Kota wrote:
>>>> Combo phy subsystem provides PHY support to number of
>>>> controllers, viz. PCIe, SATA and EMAC.
>>>> Adding YAML schemas for the same.
>>>>
>>>> Signed-off-by: Dilip Kota <eswara.kota@linux.intel.com>
>>>> ---
>>>>    .../devicetree/bindings/phy/intel,combo-phy.yaml   | 147 +++++++++++++++++++++
>>>>    1 file changed, 147 insertions(+)
>>>>    create mode 100644 Documentation/devicetree/bindings/phy/intel,combo-phy.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/phy/intel,combo-phy.yaml b/Documentation/devicetree/bindings/phy/intel,combo-phy.yaml
>>>> new file mode 100644
>>>> index 000000000000..fc9cbad9dd88
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/phy/intel,combo-phy.yaml
>>>> @@ -0,0 +1,147 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/phy/intel,combo-phy.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: Intel Combo phy Subsystem
>>>> +
>>>> +maintainers:
>>>> +  - Dilip Kota <eswara.kota@linux.intel.com>
>>>> +
>>>> +description: |
>>>> +  Intel combo phy subsystem supports PHYs for PCIe, EMAC and SATA
>>>> +  controllers. A single combo phy provides two PHY instances.
>>>> +
>>>> +properties:
>>>> +  $nodename:
>>>> +    pattern: "^combophy@[0-9]+$"
>>>> +
>>>> +  compatible:
>>>> +    items:
>>>> +      - const: intel,combo-phy
>>>> +      - const: simple-bus
>>> This will cause the schema to be applied to every 'simple-bus'. You need
>>> a custom 'select' to prevent that. There's several examples in the tree.
>> Ok, i will add as below:
>>
>> # We need a select here so we don't match all nodes with 'simple-bus'
>> select:
>>     properties:
>>       compatible:
>>         contains:
>>           const: intel,combo-phy
>>     required:
>>       - compatible
>>
>>> Though I'm not sure you need child nodes here.
>>>
>>>> +
>>>> +  cell-index:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>>> +    description: Index of Combo phy hardware instance.
>>> Drop this. Not used for FDT.
>> Ok, I will remove this and use the 'aliases' to get the hardware instance.
>>>> +
>>>> +  resets:
>>>> +    maxItems: 2
>>>> +
>>>> +  reset-names:
>>>> +    items:
>>>> +      - const: phy
>>>> +      - const: core
>>>> +
>>>> +  intel,syscfg:
>>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>>> +    description: Chip configuration registers handle
>>>> +
>>>> +  intel,hsio:
>>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>>> +    description: HSIO registers handle
>>>> +
>>>> +  intel,bid:
>>>> +    description: Index of HSIO bus
>>>> +    allOf:
>>>> +      - $ref: /schemas/types.yaml#/definitions/uint32
>>>> +      - minimum: 0
>>>> +      - maximum: 1
>>> If this is related to intel,hsio, just make it an args cell for
>>> intel,hsio.
>> No. Actually, this is specific to the combophy instance on the HSIO bus.
>> I see , this can be removed and value can be derived from the hardware
>> instance value mentioned through 'aliases'
> Generally, 'aliases' should be optional. Why do you need an index?
> What's the difference between the blocks?
>
> If it wasn't clear, I was suggesting doing:
>
> intel,hsio = <&hsio 1>;
On the SoC, total 4 combophy (0,1,2 and 3) instances are present -> 
'cell-index'
2 instances (0,1) are present on the HSIOL NoC
Other 2 instances (2,3) are present on the HSIOR NoC
On the both HSIO NoCs, combophy instances are referred as 0 and 1 -> 'bid'

'bid' is required while accessing the registers in hsio block, to 
configure the COMBOPHY mode and clock
'cell-index' is required while accessing sysconfig registers to enable 
the pcie phy pad ref clock.

<&hsio 1>
'bid' is specific to the combophy, not all the DT nodes using &hsio has 
a need.
I think it is better to pass the bid value as a entry of combophy DT node.

I will add dt entry something like 'hw-instance-id' instead of 
cell-index or aliases.

Regards,
Dilip

>
> Rob