Re: [PATCH 5/6] arm64: dts: ls1028a-qds: make the QIXIS CPLD use the simple-mfd-i2c.c driver

[Krzysztof Kozlowski <krzk@kernel.org>]

On 06/05/2025 16:21, Ioana Ciornei wrote:
> On Fri, May 02, 2025 at 09:04:03AM +0200, Krzysztof Kozlowski wrote:
>> On Wed, Apr 30, 2025 at 06:36:33PM GMT, Ioana Ciornei wrote:
>>> From: Vladimir Oltean <vladimir.oltean@nxp.com>
>>>
>>> The MDIO mux on the LS1028A-QDS never worked in mainline. The device
>>> tree was submitted as-is, and there is a downstream driver for the QIXIS
>>> FPGA:
>>>
>>> https://github.com/nxp-qoriq/linux/blob/lf-6.12.y/drivers/soc/fsl/qixis_ctrl.c
>>>
>>> That driver is very similar to the already existing drivers/mfd/simple-mfd-i2c.c,
>>> and the hardware works with the simple-mfd-i2c driver, so there isn't
>>> any reason to upstream the other one.
>>>
>>> Adapt the compatible string and child node format of the FPGA node, so
>>> that the simple-mfd-i2c driver accepts it.
>>
>> Why do you break the users based on some driver differences? Fix the
>> drivers, not the DTS.
>>
>>>
>>> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
>>> Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
>>> ---
>>>  arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts | 9 +++++----
>>>  1 file changed, 5 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts b/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts
>>> index 0bb2f28a0441..58b54d521d75 100644
>>> --- a/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts
>>> +++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts
>>> @@ -338,17 +338,18 @@ sgtl5000: audio-codec@a {
>>>  	};
>>>  
>>>  	fpga@66 {
>>> -		compatible = "fsl,ls1028aqds-fpga", "fsl,fpga-qixis-i2c",
>>> -			     "simple-mfd";
>>> +		compatible = "fsl,ls1028a-qds-qixis-i2c";
>>
>> This breaks all the existing users. NAK.
> 
> Using a mainline kernel, this DT node was never used or probed by a
> driver since that driver was never submitted. I am not breaking any user
> of the mainline kernel.
1. Users of DTS is plural, so what about all other projects and out of
tree users?
2. Did you remove simple-mfd from kernel or what? How can you claim
there is no driver for simple-mfd?

Best regards,
Krzysztof