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Subject[PATCH v4] spi: spi-ep93xx: Use dma_data_direction for ep93xx_spi_dma_{finish,prepare}
Date
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
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 expect an enum of type dma_data_direction but this
driver uses dma_transfer_direction for everything. Convert the driver to
use dma_data_direction for these two functions.

There are two places that strictly require an enum of type
dma_transfer_direction: the direction member in struct dma_slave_config
and the direction parameter in dmaengine_prep_slave_sg. To avoid using
an explicit cast, add a simple function, ep93xx_dma_data_to_trans_dir,
to safely map between the two types because they are not 1 to 1 in
meaning.

Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

v1 -> v2:

* Fix escaped hash symbols for '#define' lines (\# -> #).

v2 -> v3:

* Instead of changing the dir parameter in the prepare and finish
functions, convert the driver to use dma_data_direction for everywhere
that makes sense, thanks to review from Mika. Add a helper function to
convert between the two types as there is still a couple of locations
that need a transfer enum (and no such function exists).

v3 -> v4:

* Use 'conf.direction' in dmaengine_prep_slave_sg instead of the new
function since the value was already set earlier in the function and
never changed, thanks to review from Nick.

drivers/spi/spi-ep93xx.c | 36 +++++++++++++++++++++++++-----------
1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-ep93xx.c b/drivers/spi/spi-ep93xx.c
index f1526757aaf6..79fc3940245a 100644
--- a/drivers/spi/spi-ep93xx.c
+++ b/drivers/spi/spi-ep93xx.c
@@ -246,6 +246,19 @@ static int ep93xx_spi_read_write(struct spi_master *master)
return -EINPROGRESS;
}

+static enum dma_transfer_direction
+ep93xx_dma_data_to_trans_dir(enum dma_data_direction dir)
+{
+ switch (dir) {
+ case DMA_TO_DEVICE:
+ return DMA_MEM_TO_DEV;
+ case DMA_FROM_DEVICE:
+ return DMA_DEV_TO_MEM;
+ default:
+ return DMA_TRANS_NONE;
+ }
+}
+
/**
* ep93xx_spi_dma_prepare() - prepares a DMA transfer
* @master: SPI master
@@ -257,7 +270,7 @@ static int ep93xx_spi_read_write(struct spi_master *master)
*/
static struct dma_async_tx_descriptor *
ep93xx_spi_dma_prepare(struct spi_master *master,
- enum dma_transfer_direction dir)
+ enum dma_data_direction dir)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct spi_transfer *xfer = master->cur_msg->state;
@@ -277,9 +290,9 @@ ep93xx_spi_dma_prepare(struct spi_master *master,
buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;

memset(&conf, 0, sizeof(conf));
- conf.direction = dir;
+ conf.direction = ep93xx_dma_data_to_trans_dir(dir);

- if (dir == DMA_DEV_TO_MEM) {
+ if (dir == DMA_FROM_DEVICE) {
chan = espi->dma_rx;
buf = xfer->rx_buf;
sgt = &espi->rx_sgt;
@@ -343,7 +356,8 @@ ep93xx_spi_dma_prepare(struct spi_master *master,
if (!nents)
return ERR_PTR(-ENOMEM);

- txd = dmaengine_prep_slave_sg(chan, sgt->sgl, nents, dir, DMA_CTRL_ACK);
+ txd = dmaengine_prep_slave_sg(chan, sgt->sgl, nents, conf.direction,
+ DMA_CTRL_ACK);
if (!txd) {
dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
return ERR_PTR(-ENOMEM);
@@ -360,13 +374,13 @@ ep93xx_spi_dma_prepare(struct spi_master *master,
* unmapped.
*/
static void ep93xx_spi_dma_finish(struct spi_master *master,
- enum dma_transfer_direction dir)
+ enum dma_data_direction dir)
{
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct dma_chan *chan;
struct sg_table *sgt;

- if (dir == DMA_DEV_TO_MEM) {
+ if (dir == DMA_FROM_DEVICE) {
chan = espi->dma_rx;
sgt = &espi->rx_sgt;
} else {
@@ -381,8 +395,8 @@ static void ep93xx_spi_dma_callback(void *callback_param)
{
struct spi_master *master = callback_param;

- ep93xx_spi_dma_finish(master, DMA_MEM_TO_DEV);
- ep93xx_spi_dma_finish(master, DMA_DEV_TO_MEM);
+ ep93xx_spi_dma_finish(master, DMA_TO_DEVICE);
+ ep93xx_spi_dma_finish(master, DMA_FROM_DEVICE);

spi_finalize_current_transfer(master);
}
@@ -392,15 +406,15 @@ static int ep93xx_spi_dma_transfer(struct spi_master *master)
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct dma_async_tx_descriptor *rxd, *txd;

- rxd = ep93xx_spi_dma_prepare(master, DMA_DEV_TO_MEM);
+ rxd = ep93xx_spi_dma_prepare(master, DMA_FROM_DEVICE);
if (IS_ERR(rxd)) {
dev_err(&master->dev, "DMA RX failed: %ld\n", PTR_ERR(rxd));
return PTR_ERR(rxd);
}

- txd = ep93xx_spi_dma_prepare(master, DMA_MEM_TO_DEV);
+ txd = ep93xx_spi_dma_prepare(master, DMA_TO_DEVICE);
if (IS_ERR(txd)) {
- ep93xx_spi_dma_finish(master, DMA_DEV_TO_MEM);
+ ep93xx_spi_dma_finish(master, DMA_FROM_DEVICE);
dev_err(&master->dev, "DMA TX failed: %ld\n", PTR_ERR(txd));
return PTR_ERR(txd);
}
--
2.19.0
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