Re: [PATCH 2/5] spi: bcm2835: Fix controller unregister order

[Lukas Wunner <lukas@xxxxxxxxx>]

On Fri, May 15, 2020 at 05:29:03PM +0100, Mark Brown wrote:
> On Fri, May 15, 2020 at 05:58:02PM +0200, Lukas Wunner wrote:
> > Fix by using the non-devm variant spi_register_controller().  Note that
> > the struct spi_controller as well as the driver-private data are not
> > freed until after bcm2835_spi_remove() has finished, so accessing them
> > is safe.
> 
> Why not use managed allocations of clocks and DMA channels?  This is a
> standard issue with the devm APIs, if you're using them you basically
> need to use them for *everything* up to the point where you start using
> them.

There is no devm version of clk_prepare_enable(), dma_request_chan()
and various other functions invoked on ->probe() by spi-bcm2835.c.
So tearing down DMA channels, disabling clocks etc needs to happen
in the ->remove() hook and consequently devm_spi_register_controller()
cannot be used.

So I respectfully submit that the patch is fine.

Thanks,

Lukas