Re: [PATCH 3/7] dmaengine: st_fdma: Add STMicroelectronics FDMA engine driver support

[Maxime Coquelin]

On 08/31/2015 10:08 AM, Paul Bolle wrote:
> Hi Maxime,
>
> On ma, 2015-08-31 at 09:49 +0200, Maxime Coquelin wrote:
> > On 07/09/2015 10:17 AM, Paul Bolle wrote:
> > > > > +static int __exit st_fdma_remove(struct platform_device *pdev)
> > > > > +{
> > > > > +	struct st_fdma_dev *fdev = platform_get_drvdata(pdev);
> > > > > +
> > > > > +	wait_for_completion(&fdev->fw_ack);
> > > > > +
> > > > > +	st_fdma_clk_disable(fdev);
> > > > > +
> > > > > +	return 0;
> > > > > +}
> > > Since this driver is built-in only this means st_fdma_remove() can
> > > never be used, right?
> > It's not because a driver is built-in only that it does not need a
> > remove callback.
> > An instance can be probed/removed any time via driver's bind/unbind
> > SysFS entries.
> > Am I missing something?
> (This discussion is moot because Peter already stated that a new version
> will be modular.)
>
> It follows from the __exit tag that st_fdma_remove() should never be
> part of the kernel image (in this version of the patch), doesn't it?
Yes, you are right.
The remove callback is relevant, but without the __exit tag.
> (I don't know what happens in this situation if an unbind sysfs entry is
> used to remove a driver. I've never tried that.)
Not checked whether the function is omitted when built-in, but in any 
case, I thnk remove callbacks should not be tagged with __exit.

Regards,
Maxime


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