Received-SPF: pass (google.com: domain of linux-kernel+bounces-33014-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Message-ID: <34a421e3-b11f-4e61-b894-0b42a1330d8f@linaro.org>
Date: Mon, 22 Jan 2024 13:29:14 +0100
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH 2/3] ASoC: dt-bindings: xmos,xvf3500: add bindings for
 XMOS XVF3500
To: Javier Carrasco <javier.carrasco@wolfvision.net>,
 Rob Herring <robh+dt@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>, Liam Girdwood <lgirdwood@gmail.com>,
 Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>,
 Takashi Iwai <tiwai@suse.com>
Cc: Rob Herring <robh@kernel.org>, devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org,
 linux-usb@vger.kernel.org
References: <20240115-feature-xvf3500_driver-v1-0-ed9cfb48bb85@wolfvision.net>
 <20240115-feature-xvf3500_driver-v1-2-ed9cfb48bb85@wolfvision.net>
 <333c2986-c7c2-4a46-90cf-b59ae206e55a@linaro.org>
 <96abddcc-fa65-4f27-84fe-2281fe0fcf1c@wolfvision.net>
 <644f7f02-405d-47fb-bc72-4d54e897255f@linaro.org>
 <5db4b898-93d5-446f-bfed-b57847f9967a@wolfvision.net>
 <435f502c-1e1b-4d40-8dcc-34487905d69c@linaro.org>
 <b7f76546-9998-43e0-abff-a4e73817dbae@wolfvision.net>
 <47bdc31c-50d2-4d33-9339-5132b6364539@linaro.org>
 <16027339-0a82-4dd1-86aa-19fda6e23f88@wolfvision.net>
 <aeeb0dfb-87e2-4024-9d4a-0b9529477315@linaro.org>
 <b888d958-4eb0-4c1f-ace6-b2b85faa5113@wolfvision.net>
Content-Language: en-US
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Autocrypt: addr=krzysztof.kozlowski@linaro.org; keydata=
 xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79
 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu
 JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH
 gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE
 J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj
 NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS
 BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU
 vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM
 Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD
 TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzTRLcnp5c3p0b2Yg
 S296bG93c2tpIDxrcnp5c3p0b2Yua296bG93c2tpQGxpbmFyby5vcmc+wsGUBBMBCgA+FiEE
 m9B+DgxR+NWWd7dUG5NDfTtBYpsFAmI+BxMCGwMFCRRfreEFCwkIBwIGFQoJCAsCBBYCAwEC
 HgECF4AACgkQG5NDfTtBYptgbhAAjAGunRoOTduBeC7V6GGOQMYIT5n3OuDSzG1oZyM4kyvO
 XeodvvYv49/ng473E8ZFhXfrre+c1olbr1A8pnz9vKVQs9JGVa6wwr/6ddH7/yvcaCQnHRPK
 mnXyP2BViBlyDWQ71UC3N12YCoHE2cVmfrn4JeyK/gHCvcW3hUW4i5rMd5M5WZAeiJj3rvYh
 v8WMKDJOtZFXxwaYGbvFJNDdvdTHc2x2fGaWwmXMJn2xs1ZyFAeHQvrp49mS6PBQZzcx0XL5
 cU9ZjhzOZDn6Apv45/C/lUJvPc3lo/pr5cmlOvPq1AsP6/xRXsEFX/SdvdxJ8w9KtGaxdJuf
 rpzLQ8Ht+H0lY2On1duYhmro8WglOypHy+TusYrDEry2qDNlc/bApQKtd9uqyDZ+rx8bGxyY
 qBP6bvsQx5YACI4p8R0J43tSqWwJTP/R5oPRQW2O1Ye1DEcdeyzZfifrQz58aoZrVQq+innR
 aDwu8qDB5UgmMQ7cjDSeAQABdghq7pqrA4P8lkA7qTG+aw8Z21OoAyZdUNm8NWJoQy8m4nUP
 gmeeQPRc0vjp5JkYPgTqwf08cluqO6vQuYL2YmwVBIbO7cE7LNGkPDA3RYMu+zPY9UUi/ln5
 dcKuEStFZ5eqVyqVoZ9eu3RTCGIXAHe1NcfcMT9HT0DPp3+ieTxFx6RjY3kYTGLOwU0EVUNc
 NAEQAM2StBhJERQvgPcbCzjokShn0cRA4q2SvCOvOXD+0KapXMRFE+/PZeDyfv4dEKuCqeh0
 hihSHlaxTzg3TcqUu54w2xYskG8Fq5tg3gm4kh1Gvh1LijIXX99ABA8eHxOGmLPRIBkXHqJY
 oHtCvPc6sYKNM9xbp6I4yF56xVLmHGJ61KaWKf5KKWYgA9kfHufbja7qR0c6H79LIsiYqf92
 H1HNq1WlQpu/fh4/XAAaV1axHFt/dY/2kU05tLMj8GjeQDz1fHas7augL4argt4e+jum3Nwt
 yupodQBxncKAUbzwKcDrPqUFmfRbJ7ARw8491xQHZDsP82JRj4cOJX32sBg8nO2N5OsFJOcd
 5IE9v6qfllkZDAh1Rb1h6DFYq9dcdPAHl4zOj9EHq99/CpyccOh7SrtWDNFFknCmLpowhct9
 5ZnlavBrDbOV0W47gO33WkXMFI4il4y1+Bv89979rVYn8aBohEgET41SpyQz7fMkcaZU+ok/
 +HYjC/qfDxT7tjKXqBQEscVODaFicsUkjheOD4BfWEcVUqa+XdUEciwG/SgNyxBZepj41oVq
 FPSVE+Ni2tNrW/e16b8mgXNngHSnbsr6pAIXZH3qFW+4TKPMGZ2rZ6zITrMip+12jgw4mGjy
 5y06JZvA02rZT2k9aa7i9dUUFggaanI09jNGbRA/ABEBAAHCwXwEGAEKACYCGwwWIQSb0H4O
 DFH41ZZ3t1Qbk0N9O0FimwUCYDzvagUJFF+UtgAKCRAbk0N9O0Fim9JzD/0auoGtUu4mgnna
 oEEpQEOjgT7l9TVuO3Qa/SeH+E0m55y5Fjpp6ZToc481za3xAcxK/BtIX5Wn1mQ6+szfrJQ6
 59y2io437BeuWIRjQniSxHz1kgtFECiV30yHRgOoQlzUea7FgsnuWdstgfWi6LxstswEzxLZ
 Sj1EqpXYZE4uLjh6dW292sO+j4LEqPYr53hyV4I2LPmptPE9Rb9yCTAbSUlzgjiyyjuXhcwM
 qf3lzsm02y7Ooq+ERVKiJzlvLd9tSe4jRx6Z6LMXhB21fa5DGs/tHAcUF35hSJrvMJzPT/+u
 /oVmYDFZkbLlqs2XpWaVCo2jv8+iHxZZ9FL7F6AHFzqEFdqGnJQqmEApiRqH6b4jRBOgJ+cY
 qc+rJggwMQcJL9F+oDm3wX47nr6jIsEB5ZftdybIzpMZ5V9v45lUwmdnMrSzZVgC4jRGXzsU
 EViBQt2CopXtHtYfPAO5nAkIvKSNp3jmGxZw4aTc5xoAZBLo0OV+Ezo71pg3AYvq0a3/oGRG
 KQ06ztUMRrj8eVtpImjsWCd0bDWRaaR4vqhCHvAG9iWXZu4qh3ipie2Y0oSJygcZT7H3UZxq
 fyYKiqEmRuqsvv6dcbblD8ZLkz1EVZL6djImH5zc5x8qpVxlA0A0i23v5QvN00m6G9NFF0Le
 D2GYIS41Kv4Isx2dEFh+/Q==
In-Reply-To: <b888d958-4eb0-4c1f-ace6-b2b85faa5113@wolfvision.net>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit

On 16/01/2024 08:29, Javier Carrasco wrote:
> On 15.01.24 21:43, Krzysztof Kozlowski wrote:
>> On 15/01/2024 20:43, Javier Carrasco wrote:
>>> On 15.01.24 19:11, Krzysztof Kozlowski wrote:
>>>> On 15/01/2024 17:24, Javier Carrasco wrote:
>>>>> Do you mean that the XVF3500 should not be represented as a platform
>>>>> device and instead it should turn into an USB device represented as a
>>>>> node of an USB controller? Something like this (Rockchip SoC):
>>>>>
>>>>> &usb_host1_xhci {
>>>>> 	...
>>>>>
>>>>> 	xvf3500 {
>>>>> 		...
>>>>> 	};
>>>>> };
>>>>>
>>>>> Did I get you right or is that not the correct representation? Thank you
>>>>> again.
>>>>
>>>> I believe it should be just like onboard hub. I don't understand why
>>>> onboard hub was limited to hub, because other USB devices also could be
>>>> designed similarly by hardware folks :/
>>>>
>>>> And if we talk about Linux drivers, then your current solution does not
>>>> support suspend/resume and device unbind.
>>>>
>>>> Best regards,
>>>> Krzysztof
>>>>
>>>
>>> Actually this series is an attempt to get rid of a misuse of the
>>> onboard_usb_hub driver by a device that is not a HUB, but requires the
>>> platform-part of that driver for the initialization.
>>
>> That's just naming issue, isn't it?
>>
>>>
>>> What would be the best approach to provide support upstream? Should I
>>> turn this driver into a generic USB driver that does what the
>>> platform-part of the onboard HUB does? Or are we willing to accept
>>
>> No, because you did not solve the problems I mentioned. This is neither
>> accurate hardware description nor proper Linux driver model handling PM
>> and unbind.
>>
> You mentioned the PM handling twice, but I am not sure what you mean.
> The driver provides callbacks for SIMPLE_DEV_PM_OPS, which I tested in
> freeze and memory power states with positive results. On the other hand,
> I suppose that you insisted for a good reason, so I would be grateful if
> you could show me what I am doing wrong. The macro pattern was taken
> from other devices under sound/, which also check CONFIG_PM_SLEEP,
> but maybe I took a bad example or missed something.

You have two Linux devices: USB device and platform device. The platform
device controls power of USB device. If platform device goes to some
variant of sleep (PRM, system PM) before the USB device, how will USB
device react? Will it work? I doubt.

You have no ordering / dependencies / device links between these devices
thus possible problems.

>>> non-HUB devices in the onboard_usb_hub driver even though it supports
>>> more operations?
>>>
>>> I am adding linux-usb to this thread in case someone has other suggestions.
>>
>> I don't see any difference between this device and onboard hub. The
>> concept and the problem is the same. Therefore either treat it as as
>> onboard hub or come with USB-version of PCI power sequencing.
>>
> I have nothing against adding this device to onboard_usb_hub as long as
> it is valid upstream, so no conflicts arise with new additions to the
> list (which was the trigger for all of this with v6.7). That is

I am sorry, but we talk here only about upstream. I don't know therefore
what "valid upstream" means. You cannot send a patch which is "not valid
upstream". I mean, technically you can, but this would be waste of our
time and receive rather annoyed responses.

> obviously the most trivial solution and as you said, it is justs a
> naming issue because the power sequence is not HUB-specific.

I would ack it. Others? No clue, I also do not remember full story
behind onboard USB hub and why it was called "hub" instead of "onboard
USB device".

Best regards,
Krzysztof