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>

2 files changed, 37 insertions, 27 deletions

diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c
index 33c0e98243ee..bc90b091f195 100644
--- 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 7dd23a6fc825..380083ca572f 100644
--- 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