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authorJan Kardell <jan.kardell@telliq.com>2014-12-10 15:53:34 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-10 17:41:15 -0800
commit45ef0458fb2b931962f8558e1fd145e63ea990ab (patch)
tree855096740546378aafbed1b89a7e3eb2964e70f7 /drivers/rtc
parent17a1e5e830723f18eeb4ec00fa5a1032e378f06e (diff)
rtc: pcf8563: fix write of invalid bits to ST2 reg
The NXP datasheet says: "Bits labeled as N should always be written with logic 0." At least one of those bits is sometime read as a 1, therfore violating this rule. To fix this we mask away those bits. Signed-off-by: Jan Kardell <jan.kardell@telliq.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Grant Likely <grant.likely@linaro.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Vincent Donnefort <vdonnefort@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/rtc-pcf8563.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index 1a865c9f1127..8c23606ce2cc 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -28,6 +28,7 @@
#define PCF8563_REG_ST2 0x01
#define PCF8563_BIT_AIE (1 << 1)
#define PCF8563_BIT_AF (1 << 3)
+#define PCF8563_BITS_ST2_N (7 << 5)
#define PCF8563_REG_SC 0x02 /* datetime */
#define PCF8563_REG_MN 0x03
@@ -130,7 +131,7 @@ static int pcf8563_set_alarm_mode(struct i2c_client *client, bool on)
else
buf &= ~PCF8563_BIT_AIE;
- buf &= ~PCF8563_BIT_AF;
+ buf &= ~(PCF8563_BIT_AF | PCF8563_BITS_ST2_N);
err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
if (err < 0) {