From: Major Lee <major_lee@wistron.com>
Date: Fri, 10 Dec 2010 10:13:49 +0000 (+0000)
Subject: dw_spi: Fix missing final read in some polling situations
X-Git-Tag: firefly_0821_release~7613^2~3242
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3d0b6087f3f2c88caef25e1455ff8db0816d4e11;p=firefly-linux-kernel-4.4.55.git

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>
---

diff --git a/drivers/spi/dw_spi.c b/drivers/spi/dw_spi.c
index 90439314cf67..0838c79861e4 100644
--- a/drivers/spi/dw_spi.c
+++ b/drivers/spi/dw_spi.c
@@ -413,6 +413,11 @@ static void poll_transfer(struct dw_spi *dws)
 {
 	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);
 }