dw_spi: Fix missing final read in some polling situations

There is a possibility that the last word of a transaction will be lost if data is not ready. Re-read in poll_transfer() to solve this issue when poll_mode is enabled. Verified on SPI touch screen device. Signed-off-by: Major Lee <major_lee@wistron.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dw_spi: Fix missing final read in some polling situations
There is a possibility that the last word of a transaction will be lost if data is not ready. Re-read in poll_transfer() to solve this issue when poll_mode is enabled. Verified on SPI touch screen device. Signed-off-by: Major Lee <major_lee@wistron.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Major Lee · Linus Torvalds
1 parent 54efdfeb49
Showing 1 changed file with 5 additions and 0 deletions Side-by-side Diff
drivers/spi/dw_spi.c
@@ -413,6 +413,11 @@
 {
 	while (dws->write(dws))
 		dws->read(dws);
+	/*
+	 * There is a possibility that the last word of a transaction
+	 * will be lost if data is not ready. Re-read to solve this issue.
+	 */
+	dws->read(dws);
  
 	transfer_complete(dws);
 }
...	...	@@ -413,6 +413,11 @@
413	413	{
414	414	while (dws->write(dws))
415	415	dws->read(dws);
	416	+ /*
	417	+ * There is a possibility that the last word of a transaction
	418	+ * will be lost if data is not ready. Re-read to solve this issue.
	419	+ */
	420	+ dws->read(dws);
416	421
417	422	transfer_complete(dws);
418	423	}