Messages in this thread Patch in this message | | | From | Jan Kardell <> | Subject | [PATCH 2/6] rtc: pcf8563 Fix write of invalid bits to ST2 reg | Date | Mon, 27 Oct 2014 15:16:57 +0100 |
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From the NXP datasheet: "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> --- drivers/rtc/rtc-pcf8563.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c index 1a865c9..8c23606 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) { -- 1.8.4.5
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