* [PATCH] dw_spi: Fix missing final read in some polling situations
@ 2010-12-10 10:13 Alan Cox
0 siblings, 0 replies; only message in thread
From: Alan Cox @ 2010-12-10 10:13 UTC (permalink / raw)
To: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f,
torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b
From: Major Lee <major_lee-8+ZHUTgF1KZBDgjK7y7TUQ@public.gmane.org>
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.
Patch is against mainline (2.6.37-rc5).
Verified on SPI touch screen device.
Signed-off-by: Major Lee <major_lee-8+ZHUTgF1KZBDgjK7y7TUQ@public.gmane.org>
Signed-off-by: Alan Cox <alan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
drivers/spi/dw_spi.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/drivers/spi/dw_spi.c b/drivers/spi/dw_spi.c
index 9c1d07b..497ecb3 100644
--- a/drivers/spi/dw_spi.c
+++ b/drivers/spi/dw_spi.c
@@ -419,6 +419,11 @@ 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);
dw_spi_xfer_done(dws);
}
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2010-12-10 10:13 [PATCH] dw_spi: Fix missing final read in some polling situations Alan Cox
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