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From: Linus Walleij on 27 May 2010 21:00
The registers on the AB8500 are only 8 bits wide, so the content
of the remaining bits is undefined. Let's mask off the undefined
stuff when returning a register in an SPI read.

Acked-by: Rabin Vincent <rabin.vincent(a)stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij(a)stericsson.com>
---
drivers/mfd/ab8500-spi.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/drivers/mfd/ab8500-spi.c b/drivers/mfd/ab8500-spi.c
index b81d4f7..e1c8b62 100644
--- a/drivers/mfd/ab8500-spi.c
+++ b/drivers/mfd/ab8500-spi.c
@@ -68,7 +68,12 @@ static int ab8500_spi_read(struct ab8500 *ab8500, u16 addr)

ret = spi_sync(spi, &msg);
if (!ret)
- ret = ab8500->rx_buf[0];
+ /*
+ * Only the 8 lowermost bytes are
+ * defined with value, the rest may
+ * vary depending on chip/board noise.
+ */
+ ret = ab8500->rx_buf[0] & 0xFFU;

return ret;
}
--
1.6.3.3

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