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Message-ID: <458f8b1c-d750-424c-99dd-d31fde036314@foss.st.com>
Date: Tue, 11 Jun 2024 13:57:47 +0200
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Subject: Re: [PATCH 2/3] media: vgxy61: Add legacy compatible string
To: Krzysztof Kozlowski <krzk@kernel.org>,
        Sakari Ailus
	<sakari.ailus@linux.intel.com>
CC: Mauro Carvalho Chehab <mchehab@kernel.org>, Rob Herring <robh@kernel.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Sylvain Petinot <sylvain.petinot@foss.st.com>,
        Laurent Pinchart
	<laurent.pinchart@ideasonboard.com>,
        <linux-media@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20240610150815.228790-1-benjamin.mugnier@foss.st.com>
 <20240610150815.228790-3-benjamin.mugnier@foss.st.com>
 <b4de42ba-d884-44b1-9f0e-12f5818c6781@kernel.org>
 <ZmgIiaqJy1tWL4Yz@kekkonen.localdomain>
 <b7514285-7a05-4874-a0fd-59ef16d5bce1@kernel.org>
Content-Language: en-US
From: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
In-Reply-To: <b7514285-7a05-4874-a0fd-59ef16d5bce1@kernel.org>
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Hi Sakari and Krzysztof,

On 6/11/24 10:38, Krzysztof Kozlowski wrote:
> On 11/06/2024 10:19, Sakari Ailus wrote:
>> Hi Krzysztof,
>>
>> On Tue, Jun 11, 2024 at 08:47:25AM +0200, Krzysztof Kozlowski wrote:
>>> On 10/06/2024 17:08, Benjamin Mugnier wrote:
>>>> As the driver has been renamed from 'st-vgxy61' to 'vgxy61', its
>>>> compatible string has been updated to reflect this change. Therefore old
>>>> device trees will not work anymore.
>>>> Add the old driver name as another compatible name to handle the
>>>> retro compatibility.
>>>>
>>>> Signed-off-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
>>>> ---
>>>>  drivers/media/i2c/vgxy61.c | 5 +++++
>>>>  1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/drivers/media/i2c/vgxy61.c b/drivers/media/i2c/vgxy61.c
>>>> index 30378e962016..ca3b43608dad 100644
>>>> --- a/drivers/media/i2c/vgxy61.c
>>>> +++ b/drivers/media/i2c/vgxy61.c
>>>> @@ -1867,6 +1867,11 @@ static void vgxy61_remove(struct i2c_client *client)
>>>>  }
>>>>  
>>>>  static const struct of_device_id vgxy61_dt_ids[] = {
>>>> +	{ .compatible = "st,vgxy61" },
>>>> +	/*
>>>> +	 * Previously the driver was named 'st-vgxy61' instead of simply
>>>> +	 * 'vgxy61', keep it for retrocompatibility purposes.
>>>
>>> NAK.
>>
>> Is that because the comment says "driver" rather than "device"?
>>

You're correct, I'll replace all occurrences for the series.

>> Please try to express clearer what you'd expect from the patch author.
> 
> There is almost never a need to rename compatible or add new compatible
> matching existing one. There are exceptions, like development or work in
> progress with no users at all (and really no users!).
> 
> The commit did not provide any rationale for binding change.
> 
> Additionally, it does not make any sense. There is no point in doing it
> at all. No benefit.
> 

Thanks, here is a draft of a new commit message for v2 highlighting the
rationale :

The previous binding 'st,st-vgxy61' did not reflect the actual device
name : vgxy61 (and not st-vgxy61 as ST is the vendor prefix), and was
changed to 'st,vgxy61'.
Still some device trees uses the old binding. This commit adds back the
'st,vgxy61' binding in addition to the new one to ensure retro
compatibility.

Will this be ok for you ? Tell me your thoughts.

> Best regards,
> Krzysztof
> 

-- 
Regards,

Benjamin