dma: timb-dma: Update comment and fix compiler warning

An incremental patch which clarifies what the spinlock is used for
and fixes a compiler warning.

Signed-off-by: Richard Röjfors <richard.rojfors@pelagicore.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/dma/timb_dma.c b/drivers/dma/timb_dma.c
index 4dd710246c79..145f1c23408f 100644
--- a/drivers/dma/timb_dma.c
+++ b/drivers/dma/timb_dma.c
@@ -79,7 +79,10 @@ struct timb_dma_desc {
 struct timb_dma_chan {
         struct dma_chan         chan;
         void __iomem            *membase;
-        spinlock_t              lock; /* Used for mutual exclusion */
+        spinlock_t              lock; /* Used to protect data structures,
+                                        especially the lists and descriptors,
+                                        from races between the tasklet and calls
+                                        from above */
         dma_cookie_t            last_completed_cookie;
         bool                    ongoing;
         struct list_head        active_list;
@@ -197,7 +200,7 @@ static int td_fill_desc(struct timb_dma_chan *td_chan, u8 *dma_desc,
         }
 
         dev_dbg(chan2dev(&td_chan->chan), "desc: %p, addr: %p\n",
-                dma_desc, (void *)(int)sg_dma_address(sg));
+                dma_desc, (void *)sg_dma_address(sg));
 
         dma_desc[7] = (sg_dma_address(sg) >> 24) & 0xff;
         dma_desc[6] = (sg_dma_address(sg) >> 16) & 0xff;