Re: [PATCH 7/8 v2] ASoC: fsi: remove slave_id settings for DMAEngine

[Arnd Bergmann <arnd@arndb.de>]

On Wednesday 21 January 2015 01:33:10 Kuninori Morimoto wrote:
> Hi Arnd
> 
> > > diff --git a/sound/soc/sh/fsi.c b/sound/soc/sh/fsi.c
> > > index 8869971..c4eb234 100644
> > > --- a/sound/soc/sh/fsi.c
> > > +++ b/sound/soc/sh/fsi.c
> > > @@ -1374,10 +1374,9 @@ static int fsi_dma_probe(struct fsi_priv *fsi, struct fsi_stream *io, struct dev
> > >                                 shdma_chan_filter, (void *)io->dma_id,
> > >                                 dev, is_play ? "tx" : "rx");
> > >         if (io->chan) {
> > > -               struct dma_slave_config cfg;
> > > +               struct dma_slave_config cfg = {};
> > >                 int ret;
> > >  
> > > -               cfg.slave_id    = io->dma_id;
> > >                 cfg.dst_addr    = 0; /* use default addr */
> > >                 cfg.src_addr    = 0; /* use default addr */
> > >                 cfg.direction   = is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
> > 
> > As the dma_slave_config structure is now initialized to all-zeroes, the
> > two address assignments are not strictly required any more.
> > 
> > However, I also suspect that that particular initialization to zero
> > is also incorrect: When booting with DT, the dst_addr/src_addr fields
> > are no longer passed in the platform data for the DMA engine but
> > are expected to be set by the slave driver.
> > 
> > Also set the correct address width, which has the same problem.
> 
> Thank you for pointing it.
> But, unfortunately, this FSI driver is not used from DT.
> (It is supporting DT probe, but no one use it)
> So, it is assuming that dst_addr/src_addr fields are come
> from platform data.

I see. My patch would still be correct, right?

I think the way that Guennadi Liakhovetski started the conversion of
shmobile dmaengine drivers, each slave driver either uses a custom
filter function that relies on the platform data and will not work
with DT, or it uses dma_request_slave_channel_compat() which will
work on both, and then uses dmaengine_slave_config() to pass the
extra settings. This driver is the one exception you have since it
uses a combination of the two approaches.

	Arnd