Re: [PATCH] spi: spi-ep93xx: Change dir type in ep93xx_spi_dma_{finish,prepare}

[Nathan Chancellor <natechancellor@gmail.com>]

On Thu, Oct 04, 2018 at 11:32:47AM +0100, Mark Brown wrote:
> On Wed, Oct 03, 2018 at 07:39:26PM -0700, Nathan Chancellor wrote:
> > Clang warns when one enumerated type is implicitly converted to another.
> > 
> > drivers/spi/spi-ep93xx.c:342:62: warning: implicit conversion from
> > enumeration type 'enum dma_transfer_direction' to different enumeration
> 
> Please remember to CC driver maintainers and authors on patch
> submissions so they can review things, copying in Hartley and Mika.
> 

Hi Mark,

Thank you for that, I usually just rely on get_maintainer.pl but I'll be
better about looking at git history for major patch authors as well.

$ ./scripts/get_maintainer.pl drivers/spi/spi-ep93xx.c
Mark Brown <broonie@kernel.org> (maintainer:SPI SUBSYSTEM)
linux-spi@vger.kernel.org (open list:SPI SUBSYSTEM)
linux-kernel@vger.kernel.org (open list)

Nathan

> > type 'enum dma_data_direction' [-Wenum-conversion]
> >         nents = dma_map_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
> >                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
> > ./include/linux/dma-mapping.h:428:58: note: expanded from macro
> > 'dma_map_sg'
> > \#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)
> >                                ~~~~~~~~~~~~~~~~          ^
> > drivers/spi/spi-ep93xx.c:348:57: warning: implicit conversion from
> > enumeration type 'enum dma_transfer_direction' to different enumeration
> > type 'enum dma_data_direction' [-Wenum-conversion]
> >                 dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
> >                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
> > ./include/linux/dma-mapping.h:429:62: note: expanded from macro
> > 'dma_unmap_sg'
> > \#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, 0)
> >                                  ~~~~~~~~~~~~~~~~~~          ^
> > drivers/spi/spi-ep93xx.c:377:56: warning: implicit conversion from
> > enumeration type 'enum dma_transfer_direction' to different enumeration
> > type 'enum dma_data_direction' [-Wenum-conversion]
> >         dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
> >         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
> > ./include/linux/dma-mapping.h:429:62: note: expanded from macro
> > 'dma_unmap_sg'
> > \#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, 0)
> >                                  ~~~~~~~~~~~~~~~~~~          ^
> > 3 warnings generated.
> > 
> > dma_{,un}map_sg expects an enum of type dma_data_direction but this
> > driver uses dma_transfer_direction for everything. Converting to
> > dma_data_direction would be desirable but there are a few shared
> > structures that expect dma_transfer_direction so it is just simpler to
> > change the parameter here. dma_transfer_direction and dma_data_direction
> > are different sizes but this driver only uses the 1 and 2 values which
> > mean the same thing so this change is safe.
> > 
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > ---
> >  drivers/spi/spi-ep93xx.c | 6 ++----
> >  1 file changed, 2 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/spi/spi-ep93xx.c b/drivers/spi/spi-ep93xx.c
> > index f1526757aaf6..189fc2225b69 100644
> > --- a/drivers/spi/spi-ep93xx.c
> > +++ b/drivers/spi/spi-ep93xx.c
> > @@ -256,8 +256,7 @@ static int ep93xx_spi_read_write(struct spi_master *master)
> >   * in case of failure.
> >   */
> >  static struct dma_async_tx_descriptor *
> > -ep93xx_spi_dma_prepare(struct spi_master *master,
> > -		       enum dma_transfer_direction dir)
> > +ep93xx_spi_dma_prepare(struct spi_master *master, int dir)
> >  {
> >  	struct ep93xx_spi *espi = spi_master_get_devdata(master);
> >  	struct spi_transfer *xfer = master->cur_msg->state;
> > @@ -359,8 +358,7 @@ ep93xx_spi_dma_prepare(struct spi_master *master,
> >   * Function finishes with the DMA transfer. After this, the DMA buffer is
> >   * unmapped.
> >   */
> > -static void ep93xx_spi_dma_finish(struct spi_master *master,
> > -				  enum dma_transfer_direction dir)
> > +static void ep93xx_spi_dma_finish(struct spi_master *master, int dir)
> >  {
> >  	struct ep93xx_spi *espi = spi_master_get_devdata(master);
> >  	struct dma_chan *chan;
> > -- 
> > 2.19.0
> >