Message-ID: <bf4ce87a-51ab-49e1-ac70-c463d8008a62@linaro.org>
Date: Tue, 20 Feb 2024 12:41:54 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Yang Xiwen <forbidden405@...look.com>, Vinod Koul <vkoul@...nel.org>,
 Kishon Vijay Abraham I <kishon@...nel.org>, Rob Herring
 <robh+dt@...nel.org>, Krzysztof Kozlowski
 <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>,
 Jiancheng Xue <xuejiancheng@...ilicon.com>, Shawn Guo
 <shawn.guo@...aro.org>, Philipp Zabel <p.zabel@...gutronix.de>
Cc: linux-phy@...ts.infradead.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, Kishon Vijay Abraham I <kishon@...com>,
 David Yang <mmyangfl@...il.com>
Subject: Re: [PATCH RFC v3 1/5] dt-bindings: phy: hisi-inno-usb2: convert to
 YAML

On 20/02/2024 11:40, Yang Xiwen wrote:
> On 2/20/2024 4:16 PM, Krzysztof Kozlowski wrote:
>> On 19/02/2024 22:49, Yang Xiwen wrote:
>>> On 2/20/2024 5:37 AM, Krzysztof Kozlowski wrote:
>>>> On 19/02/2024 22:35, Yang Xiwen wrote:
>>>>> On 2/20/2024 5:32 AM, Krzysztof Kozlowski wrote:
>>>>>> On 19/02/2024 22:27, Yang Xiwen via B4 Relay wrote:
>>>>>>> From: Yang Xiwen <forbidden405@...look.com>
>>>>>>>
>>>>>>> Add missing compatible "hisilicon,hi3798mv100-usb2-phy" to compatible
>>>>>>> list due to prior driver change.
>>>>>>>
>>>>>>> Also rename to hisilicon,inno-usb2-phy.yaml and add this name to
>>>>>>> compatible lists.
>>>>>>>
>>>>>>> Fixes: 3940ffc65492 ("phy: hisilicon: Add inno-usb2-phy driver for Hi3798MV100")
>>>>>>> Signed-off-by: Yang Xiwen <forbidden405@...look.com>
>>>>>>> ---
>>>>>>>     .../bindings/phy/hisilicon,inno-usb2-phy.yaml      | 95 ++++++++++++++++++++++
>>>>>>>     .../devicetree/bindings/phy/phy-hisi-inno-usb2.txt | 71 ----------------
>>>>>>>     2 files changed, 95 insertions(+), 71 deletions(-)
>>>>>>>
>>>>>>> diff --git a/Documentation/devicetree/bindings/phy/hisilicon,inno-usb2-phy.yaml b/Documentation/devicetree/bindings/phy/hisilicon,inno-usb2-phy.yaml
>>>>>>> new file mode 100644
>>>>>>> index 000000000000..1b57e0396209
>>>>>>> --- /dev/null
>>>>>>> +++ b/Documentation/devicetree/bindings/phy/hisilicon,inno-usb2-phy.yaml
>>>>>>> @@ -0,0 +1,95 @@
>>>>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>>>>> +%YAML 1.2
>>>>>>> +---
>>>>>>> +$id: http://devicetree.org/schemas/phy/hisilicon,inno-usb2-phy.yaml#
>>>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>>>>> +
>>>>>>> +title: HiSilicon HiSTB SoCs INNO USB2 PHY device
>>>>>>> +
>>>>>>> +maintainers:
>>>>>>> +  - Yang Xiwen <forbidden405@...look.com>
>>>>>>> +
>>>>>>> +properties:
>>>>>>> +  compatible:
>>>>>>> +    items:
>>>>>>> +      - enum:
>>>>>>> +          - hisilicon,hi3798cv200-usb2-phy
>>>>>>> +          - hisilicon,hi3798mv100-usb2-phy
>>>>>>> +      - const: hisilicon,inno-usb2-phy
>>>>>> According to your driver hisilicon,hi3798mv100-usb2-phy and
>>>>>> hisilicon,inno-usb2-phy are not compatible.
>>>>> Ah, i didn't pay too much attention to that. I should remove the entry
>>>>> for hisilicon,inno-usb2-phy in the driver. Sorry for that.
>>>> We don't talk here about driver, although I used the driver as proof or
>>>> argument, because I don't have access to hardware datasheet (and no
>>>> intention to look there).
>>>>
>>>> What I claim is these are not compatible, so respond to this argument,
>>>> not some other one.
>>> Why not? Of course they are compatible. All 3 SoCs are using
>> Why? Because...
>>
>>> inno-usb2-phy. The only difference here is the method to access the
>> ... here! Different programming interface means not compatible.
>>
>> Please provide instead any argument that they are compatible, in the
>> meaning of Devicetree of course. You are claiming inno-usb2-phy  can be
>> used for hi3798mv100 and it will work fine?
>>
>>> registers. They are all enabled by `writing BIT(2) to address 0x6`. In
>>> the cover letter, I said the driver is actually doing things wrong.
>> Cover letter does not matter, I don't even read them. Your commits matter.
>>
>>> Especially the commit adding PHY_TYPE enums, the name is confusing and
>>> conveys the wrong info. It's not PHY which are not compatible, it's the
>>> bus. I'll fix the driver, but still the PHY hardwares are compatible
>>> between these 3 SoCs.
>> Provide any argument.
> 
> Just take a look at the driver. hisi_inno_phy_write_reg() is the 
> function that differs between different models. But for all of them, 
> hisi_inno_phy_setup() is the same.
> 
> 
> hisi_inno_phy_write_reg() should be moved to a separate bus driver. It's 
> bus-related, not phy. PHY driver should not care how to access the bus, 

So drivers are compatible or hardware? We talk about hardware, not
drivers...

> but the bus driver should. The PHY driver only needs to use regmap_* 
> APIs to "write BIT(2) to addr 6".

Different programming interface, so not compatible.

> 
> 
> For mv100 and cv200, the PHY master bus interface is attached to the 
> perictrl core in SoC (though the perictrl core provides slightly 
> different register offsets to access the PHY bus). For mv200, it is 
> directly attached to AHB/APB system bus so we don't need to put it under 
> a perictrl node anymore. So here, clearly it's the bus the PHY attached 

Different programming interface, so not compatible.

> to which is different, not the PHY itself.
> 
> 
> That's why i say the driver is wrong from the beginning. It's mixing PHY 


I don't care. We do not talk about drivers.

> driver and bus driver together but they ought to be different. PHY is 
> always compatible, but the bus is not.

Do you understand what does it mean "compatible" in DT?

> 
> 
> The correct fix should be moving hisi_inno_phy_write_reg() to a new bus 
> driver and migrating to regmap_* APIs in PHY driver. But i'll have to 

Don't care. Driver stuff.

> write a new driver for that, which i try to avoid (it takes too much 
> time!). So i said clearly in the cover-letter this should be considered 
> a hack.


Best regards,
Krzysztof

Powered by blists - more mailing lists