As per code flow s3c_rtc_setfreq() will get called with rtc clock disabled
and in set_freq we perform h/w registers read/write, which results in a
kernel crash on exynos7 platform while probing rtc driver.
Below is code flow:
s3c_rtc_probe()
clk_prepare_enable(info->rtc_clk) // rtc clock enabled
s3c_rtc_gettime() // will enable clk if not done, and disable it upon exit
s3c_rtc_setfreq() //then this will be called with clk disabled
This patch take cares of such issue by adding s3c_rtc_{enable/disable}_clk in
s3c_rtc_setfreq().
Fixes: 24e1455493da ("drivers/rtc/rtc-s3c.c: delete duplicate clock control")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
Reviewed-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
Tested-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
---
drivers/rtc/rtc-s3c.c | 2 ++
1 file changed, 2 insertions(+)
* Changes from v1
-updated commit message as suggested by Krzysztof.
-updated reviewed-by, tested-by tags
diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
index b083840..1168814 100644
--- a/drivers/rtc/rtc-s3c.c
+++ b/drivers/rtc/rtc-s3c.c
@@ -149,12 +149,14 @@ static int s3c_rtc_setfreq(struct s3c_rtc *info, int freq)
if (!is_power_of_2(freq))
return -EINVAL;
+ s3c_rtc_enable_clk(info);
spin_lock_irq(&info->pie_lock);
if (info->data->set_freq)
info->data->set_freq(info, freq);
spin_unlock_irq(&info->pie_lock);
+ s3c_rtc_disable_clk(info);
return 0;
}
--
1.7.10.4
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