Message-ID: <c4669a04-ed3c-da7e-b04c-813122385e1c@gmail.com>
Date:   Mon, 6 Mar 2023 19:57:48 -0800
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Subject: Re: [PATCH v1] serdev: Set fwnode for serdev devices
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To:     Stefan Wahren <stefan.wahren@i2se.com>,
        Saravana Kannan <saravanak@google.com>
Cc:     Rob Herring <robh@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>, kernel-team@android.com,
        linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230302023509.319903-1-saravanak@google.com>
 <2cc752fb-a25d-0789-0fad-54b99f08ced7@i2se.com>
 <CAGETcx_nCdm2WYLC7h1s8i9tnHc_LcHk2oZUQ0sUDr-PBsUWDg@mail.gmail.com>
 <faad8810-7aa4-e122-f497-73553feb8bcd@gmail.com>
 <98f5abe2-3d25-661a-a2b8-a50e2d27f085@i2se.com>
 <667f007f-1cb0-7e89-242a-c41823e82bee@gmail.com>
 <05bc8f6e-b0cc-2ae6-db7a-ad90b3e69778@i2se.com>
From:   Florian Fainelli <f.fainelli@gmail.com>
In-Reply-To: <05bc8f6e-b0cc-2ae6-db7a-ad90b3e69778@i2se.com>
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On 3/5/2023 7:00 AM, Stefan Wahren wrote:
> Hi,
> 
> Am 03.03.23 um 18:22 schrieb Florian Fainelli:
>> On 3/3/23 03:57, Stefan Wahren wrote:
>>> Hi,
>>>
>>> Am 02.03.23 um 18:51 schrieb Florian Fainelli:
>>>>
>>>>
>>>> On 3/2/2023 9:20 AM, Saravana Kannan wrote:
>>>>> On Thu, Mar 2, 2023 at 9:01 AM Stefan Wahren 
>>>>> <stefan.wahren@i2se.com> wrote:
>>>>>>
>>>>>> Hi Saravana,
>>>>>>
>>>>>> Am 02.03.23 um 03:35 schrieb Saravana Kannan:
>>>>>>> This allow fw_devlink to do dependency tracking for serdev devices.
>>>>>>>
>>>>>>> Reported-by: Florian Fainelli <f.fainelli@gmail.com>
>>>>>>> Link: 
>>>>>>> https://lore.kernel.org/lkml/03b70a8a-0591-f28b-a567-9d2f736f17e5@gmail.com/
>>>>>>> Cc: Stefan Wahren <stefan.wahren@i2se.com>
>>>>>>> Signed-off-by: Saravana Kannan <saravanak@google.com>
>>>>>>
>>>>>> since this fixes an issue on Raspberry Pi 4, shouldn't this be 
>>>>>> mentioned
>>>>>> in the commit message and providing a Fixes tag?
>>>>>
>>>>> So RPi 4 was never creating a device links between serdev devices and
>>>>> their consumers. The error message was just a new one I added and we
>>>>> are noticing and catching the fact that serdev wasn't setting fwnode
>>>>> for a device.
>>>>>
>>>>> I'm also not sure if I can say this commit "Fixes" an issue in serdev
>>>>> core because when serdev core was written, fw_devlink wasn't a thing.
>>>>> Once I add Fixes, people will start pulling this into stable
>>>>> branches/other trees where I don't think this should be pulled into
>>>>> older stable branches.
>>>>
>>>> That is kind of the point of Fixes: tag, is not it? It is 
>>>> appropriate to list a commit that is not specific to serdev, but 
>>>> maybe a particular point into the fw_devlink history. Given this did 
>>>> not appear to have a functional impact, we could go without one.
>>>
>>> i was under the impression that this issue breaks at least Bluetooth 
>>> on Raspberry Pi 4 because the driver is never probed. I cannot see 
>>> the success output in Florian's trace. Something like this:
>>>
>>> [    7.124879] hci_uart_bcm serial0-0: supply vbat not found, using 
>>> dummy regulator
>>> [    7.131743] hci_uart_bcm serial0-0: supply vddio not found, using 
>>> dummy regulator
>>> ...
>>> [    7.517249] Bluetooth: hci0: BCM: chip id 107
>>> [    7.517499] Bluetooth: hci0: BCM: features 0x2f
>>> [    7.519757] Bluetooth: hci0: BCM4345C0
>>> [    7.519768] Bluetooth: hci0: BCM4345C0 (003.001.025) build 0000
>>> [    7.539495] Bluetooth: hci0: BCM4345C0 'brcm/BCM4345C0.hcd' Patch
>>> ...
>>> [    8.348831] Bluetooth: hci0: BCM43455 37.4MHz Raspberry Pi 3+
>>> [    8.348845] Bluetooth: hci0: BCM4345C0 (003.001.025) build 0342
>>>
>>> I just want to make sure that 6.2 doesn't have a regression.
>>
>> My configuration uses hci_uart as a module, and it would always load 
>> fine, but I suppose I can make sure that even built-in this works 
>> properly. Give me a day or two to test that.
> 
> okay, this is fine. From my point of view this is not necessary to test 
> built-in.
> 
> I tested latest mainline with Raspberry Pi 4 (multi_v7_defconfig + 
> ARM_LPAE) and there is no regression:
> 
> Tested-by: Stefan Wahren <stefan.wahren@i2se.com>

Tested with making the BT drivers built-in with and without the patch 
and it still worked OK in both cases.
-- 
Florian