rtc: sh: Fix invalid alarm warning for non-enabled alarm

geertu · alexandrebelloni · commit 15d82d224987 · 2019-03-20T11:37:50.000+01:00
When no alarm has been programmed on RSK-RZA1, an error message is
printed during boot:

    rtc rtc0: invalid alarm value: 2019-03-14T255:255:255

sh_rtc_read_alarm_value() returns 0xff when querying a hardware alarm
field that is not enabled.  __rtc_read_alarm() validates the received
alarm values, and fills in missing fields when needed.
While 0xff is handled fine for the year, month, and day fields, and
corrected as considered being out-of-range, this is not the case for the
hour, minute, and second fields, where -1 is expected for missing
fields.

Fix this by returning -1 instead, as this value is handled fine for all
fields.

Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Signed-off-by: Alexandre Belloni &lt;alexandre.belloni@bootlin.com&gt;
diff --git a/drivers/rtc/rtc-sh.c b/drivers/rtc/rtc-sh.c
@@ -374,7 +374,7 @@ static int sh_rtc_set_time(struct device *dev, struct rtc_time *tm)
 static inline int sh_rtc_read_alarm_value(struct sh_rtc *rtc, int reg_off)
 {
 	unsigned int byte;
-	int value = 0xff;	/* return 0xff for ignored values */
+	int value = -1;			/* return -1 for ignored values */
 
 	byte = readb(rtc->regbase + reg_off);
 	if (byte & AR_ENB) {

Original file line number	Diff line number	Diff line change
`@@ -374,7 +374,7 @@ static int sh_rtc_set_time(struct device dev, struct rtc_time tm)`
`374`	`374`	`static inline int sh_rtc_read_alarm_value(struct sh_rtc *rtc, int reg_off)`
`375`	`375`	`{`
`376`	`376`	`unsigned int byte;`
`377`		`- int value = 0xff; /* return 0xff for ignored values */`
	`377`	`+ int value = -1; /* return -1 for ignored values */`
`378`	`378`
`379`	`379`	`byte = readb(rtc->regbase + reg_off);`
`380`	`380`	`if (byte & AR_ENB) {`