On Thu, Sep 30, 2021 at 11:12:28AM +0800, Chunyan Zhang wrote:

> On different platforms, sc27xx_spi consists of different sub-devices
> with different compatible string, to avoid adding mfd_cells to
> sc27xx_spi driver each time we add a new platform support, we changed
> to use devm_of_platform_populate() which can automatically register
> sun-devices listed in devicetree.

> The above is my understand, please correct me if I'm missing something
> @Lee Jones

Right, so my pushback here is that it's not clear to me that avoiding
adding compatibles to the MFD is a strong enough goal to justify
creating ABI - it's hard to see the upsides.  This is particularly the
case here where the subdevice is really a random collection of devices
that's particularly likely to change between variants and more likely
that other OSs would want something different so it's even harder to
achieve reuse.