rtc/hctosys: only claim the RTC provided the system time if it did

Without this patch /sys/class/rtc/$CONFIG_RTC_HCTOSYS_DEVICE/hctosys
contains a 1 (meaning "This rtc was used to initialize the system clock")
even if reading the time at bootup failed.

Moreover change error handling in rtc_hctosys() to use goto and so reduce
the indention level.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c
index 33c0e98..bc90b09 100644 (file)
--- a/drivers/rtc/hctosys.c
+++ b/drivers/rtc/hctosys.c
@@ -22,48 +22,57 @@
  * the best guess is to add 0.5s.
  */
 
+int rtc_hctosys_ret = -ENODEV;
+
 static int __init rtc_hctosys(void)
 {
-       int err;
+       int err = -ENODEV;
        struct rtc_time tm;
+       struct timespec tv = {
+               .tv_nsec = NSEC_PER_SEC >> 1,
+       };
        struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
 
        if (rtc == NULL) {
-               printk("%s: unable to open rtc device (%s)\n",
+               pr_err("%s: unable to open rtc device (%s)\n",
                        __FILE__, CONFIG_RTC_HCTOSYS_DEVICE);
-               return -ENODEV;
+               goto err_open;
        }
 
        err = rtc_read_time(rtc, &tm);
-       if (err == 0) {
-               err = rtc_valid_tm(&tm);
-               if (err == 0) {
-                       struct timespec tv;
+       if (err) {
+               dev_err(rtc->dev.parent,
+                       "hctosys: unable to read the hardware clock\n");
+               goto err_read;
 
-                       tv.tv_nsec = NSEC_PER_SEC >> 1;
+       }
 
-                       rtc_tm_to_time(&tm, &tv.tv_sec);
+       err = rtc_valid_tm(&tm);
+       if (err) {
+               dev_err(rtc->dev.parent,
+                       "hctosys: invalid date/time\n");
+               goto err_invalid;
+       }
 
-                       do_settimeofday(&tv);
+       rtc_tm_to_time(&tm, &tv.tv_sec);
 
-                       dev_info(rtc->dev.parent,
-                               "setting system clock to "
-                               "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
-                               tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
-                               tm.tm_hour, tm.tm_min, tm.tm_sec,
-                               (unsigned int) tv.tv_sec);
-               }
-               else
-                       dev_err(rtc->dev.parent,
-                               "hctosys: invalid date/time\n");
-       }
-       else
-               dev_err(rtc->dev.parent,
-                       "hctosys: unable to read the hardware clock\n");
+       do_settimeofday(&tv);
 
+       dev_info(rtc->dev.parent,
+               "setting system clock to "
+               "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n",
+               tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+               tm.tm_hour, tm.tm_min, tm.tm_sec,
+               (unsigned int) tv.tv_sec);
+
+err_invalid:
+err_read:
        rtc_class_close(rtc);
 
-       return 0;
+err_open:
+       rtc_hctosys_ret = err;
+
+       return err;
 }
 
 late_initcall(rtc_hctosys);

diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c
index 7dd23a6..380083c 100644 (file)
--- a/drivers/rtc/rtc-sysfs.c
+++ b/drivers/rtc/rtc-sysfs.c
@@ -107,8 +107,9 @@ rtc_sysfs_show_hctosys(struct device *dev, struct device_attribute *attr,
                char *buf)
 {
 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
-       if (strcmp(dev_name(&to_rtc_device(dev)->dev),
-                  CONFIG_RTC_HCTOSYS_DEVICE) == 0)
+       if (rtc_hctosys_ret == 0 &&
+                       strcmp(dev_name(&to_rtc_device(dev)->dev),
+                               CONFIG_RTC_HCTOSYS_DEVICE) == 0)
                return sprintf(buf, "1\n");
        else
 #endif

diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 60f88a7..14dbc83 100644 (file)
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -238,6 +238,12 @@ static inline bool is_leap_year(unsigned int year)
        return (!(year % 4) && (year % 100)) || !(year % 400);
 }
 
+#ifdef CONFIG_RTC_HCTOSYS
+extern int rtc_hctosys_ret;
+#else
+#define rtc_hctosys_ret -ENODEV
+#endif
+
 #endif /* __KERNEL__ */
 
 #endif /* _LINUX_RTC_H_ */