rtc: Fix RTC PIE frequency limit

Thomas earlier submitted a fix to limit the RTC PIE freq, but
picked 5000Hz out of the air. Willy noticed that we should
instead use the 8192Hz max from the rtc man documentation.

Cc: Willy Tarreau <w@1wt.eu>
Cc: stable@kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 3195dbd..eb4c883 100644 (file)
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -708,7 +708,7 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
        int err = 0;
        unsigned long flags;
 
-       if (freq <= 0 || freq > 5000)
+       if (freq <= 0 || freq > RTC_MAX_FREQ)
                return -EINVAL;
 retry:
        spin_lock_irqsave(&rtc->irq_task_lock, flags);

diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index b27ebea..93f4d03 100644 (file)
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -97,6 +97,9 @@ struct rtc_pll_info {
 #define RTC_AF 0x20    /* Alarm interrupt */
 #define RTC_UF 0x10    /* Update interrupt for 1Hz RTC */
 
+
+#define RTC_MAX_FREQ   8192
+
 #ifdef __KERNEL__
 
 #include <linux/types.h>