[alsa-devel] [PATCH 2/7] ASoC: amd: Registering device endpoints using MFD framework

[Deucher, Alexander]

> -----Original Message-----
> From: Lee Jones <lee.jones at linaro.org>
> Sent: Wednesday, October 2, 2019 8:38 AM
> To: Deucher, Alexander <Alexander.Deucher at amd.com>
> Cc: RAVULAPATI, VISHNU VARDHAN RAO
> <Vishnuvardhanrao.Ravulapati at amd.com>; Liam Girdwood
> <lgirdwood at gmail.com>; Mark Brown <broonie at kernel.org>; Jaroslav
> Kysela <perex at perex.cz>; Takashi Iwai <tiwai at suse.com>; Mukunda,
> Vijendar <Vijendar.Mukunda at amd.com>; Maruthi Srinivas Bayyavarapu
> <Maruthi.Bayyavarapu at amd.com>; Mehta, Sanju
> <Sanju.Mehta at amd.com>; Colin Ian King <colin.king at canonical.com>; Dan
> Carpenter <dan.carpenter at oracle.com>; moderated list:SOUND - SOC LAYER
> / DYNAMIC AUDIO POWER MANAGEM... <alsa-devel at alsa-project.org>;
> open list <linux-kernel at vger.kernel.org>
> Subject: Re: [PATCH 2/7] ASoC: amd: Registering device endpoints using MFD
> framework
> 
> On Tue, 01 Oct 2019, Deucher, Alexander wrote:
> 
> > > -----Original Message-----
> > > From: Lee Jones <lee.jones at linaro.org>
> > > Sent: Tuesday, October 1, 2019 8:00 AM
> > > To: RAVULAPATI, VISHNU VARDHAN RAO
> > > <Vishnuvardhanrao.Ravulapati at amd.com>
> > > Cc: RAVULAPATI, VISHNU VARDHAN RAO
> > > <Vishnuvardhanrao.Ravulapati at amd.com>; Deucher, Alexander
> > > <Alexander.Deucher at amd.com>; Liam Girdwood
> <lgirdwood at gmail.com>;
> > > Mark Brown <broonie at kernel.org>; Jaroslav Kysela <perex at perex.cz>;
> > > Takashi Iwai <tiwai at suse.com>; Mukunda, Vijendar
> > > <Vijendar.Mukunda at amd.com>; Maruthi Srinivas Bayyavarapu
> > > <Maruthi.Bayyavarapu at amd.com>; Mehta, Sanju
> <Sanju.Mehta at amd.com>;
> > > Colin Ian King <colin.king at canonical.com>; Dan Carpenter
> > > <dan.carpenter at oracle.com>; moderated list:SOUND - SOC LAYER /
> > > DYNAMIC AUDIO POWER MANAGEM... <alsa-devel at alsa-project.org>;
> open
> > > list <linux-kernel at vger.kernel.org>
> > > Subject: Re: [PATCH 2/7] ASoC: amd: Registering device endpoints
> > > using MFD framework
> > >
> > > On Tue, 01 Oct 2019, vishnu wrote:
> > >
> > > > Hi Jones,
> > > >
> > > > I am very Thankful to your review comments.
> > > >
> > > > Actually The driver is not totally based on MFD. It just uses
> > > > mfd_add_hotplug_devices() and mfd_remove_devices() for adding
> the
> > > > devices automatically.
> > > >
> > > > Remaining code has nothing to do with MFD framework.
> > > >
> > > > So I thought It would not break the coding style and moved ahead
> > > > by using the MFD API by adding its header file.
> > > >
> > > > If it is any violation of coding standard then I can move it to
> > > > drivers/mfd.
> > > >
> > > > This patch could be a show stopper for us.Please suggest us how
> > > > can we move ahead ASAP.
> > >
> > > Either move the MFD parts to drivers/mfd, or stop using the MFD API.
> >
> > There are more drivers outside of drivers/mfd using this API than
> > drivers in drivers/mfd.
> 
> People do wrong things all the time.  It doesn't make them right.
> 
> > In a lot of cases it doesn't make sense to move the driver to drivers/mfd.
> 
> In those cases, the platform_device_*() API should be used.

Why do we have both?  It's not clear to me on when we should use one vs the other.  These are not platforms per se, they are PCI devices that happen to have other devices on them.  On previous projects, I was told to use mfd and no objections were raised at that time.

Alex