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rtc: ds1307: Fix alarm programming for mcp794xx

Message ID 1445581797-19693-1-git-send-email-t-kristo@ti.com
State Accepted
Commit 62c8c20af92ea312ecb22cec4e83082e5843076b
Headers show

Commit Message

Tero Kristo Oct. 23, 2015, 6:29 a.m. UTC 
mcp794xx alarm registers must be written in BCD format. However, the
alarm programming logic neglected this by adding one to the value
after bin2bcd conversion has been already done, writing bad values
to month register in case the alarm being set is in October. In this
case, the alarm month value becomes 0x0a instead of the expected 0x10.

Fix by moving the +1 addition within the bin2bcd call also.

Fixes: 1d1945d261a2 ("drivers/rtc/rtc-ds1307.c: add alarm support for mcp7941x chips")

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
 drivers/rtc/rtc-ds1307.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index a705e64..188006c 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -718,9 +718,9 @@  static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 	regs[3] = bin2bcd(t->time.tm_sec);
 	regs[4] = bin2bcd(t->time.tm_min);
 	regs[5] = bin2bcd(t->time.tm_hour);
-	regs[6] = bin2bcd(t->time.tm_wday) + 1;
+	regs[6] = bin2bcd(t->time.tm_wday + 1);
 	regs[7] = bin2bcd(t->time.tm_mday);
-	regs[8] = bin2bcd(t->time.tm_mon) + 1;
+	regs[8] = bin2bcd(t->time.tm_mon + 1);
 
 	/* Clear the alarm 0 interrupt flag. */
 	regs[6] &= ~MCP794XX_BIT_ALMX_IF;