[ARM] Kirkwood: fail the probe if internal RTC does not work

Having a RTC that doesn't maintain proper time across a reboot is one
thing.  But a RTC that doesn't work at all and only causes timeouts is
another.

Tested-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-mv.c b/drivers/rtc/rtc-mv.c
index 45f12dcd3716..e0263d2005ee 100644
--- a/drivers/rtc/rtc-mv.c
+++ b/drivers/rtc/rtc-mv.c
@@ -12,6 +12,7 @@
 #include <linux/bcd.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/delay.h>
 
 
 #define RTC_TIME_REG_OFFS       0
@@ -119,6 +120,16 @@ static int __init mv_rtc_probe(struct platform_device *pdev)
                 return -EINVAL;
         }
 
+        /* make sure it is actually functional */
+        if (rtc_time == 0x01000000) {
+                ssleep(1);
+                rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
+                if (rtc_time == 0x01000000) {
+                        dev_err(&pdev->dev, "internal RTC not ticking\n");
+                        return -ENODEV;
+                }
+        }
+
         platform_set_drvdata(pdev, pdata);
         pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
                                          &mv_rtc_ops, THIS_MODULE);