From: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@xxxxxx>
rtc_irq_set_freq() function takes only powers of 2 as a valid
argument. This stipulates that an ioctl call on /dev/rtc0
can accept values of 1,2,4 and 8 only. But the function
twl4030_rtc_irq_set_freq() takes only values 0-3. RTC_INTERRUPTS_REG
of TWL4030 also requires value in the range 0-3 for the interrupt
period. Hence it is required to map the argument from the powers of 2,
to the corresponding numbers 0-3, via a call to ilog2.
Signed-off-by: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@xxxxxx>
---
Index: my-local-git-dir/drivers/rtc/rtc-twl4030.c
===================================================================
--- my-local-git-dir.orig/drivers/rtc/rtc-twl4030.c 2008-08-22 17:37:33.000000000 +0530
+++ my-local-git-dir/drivers/rtc/rtc-twl4030.c 2008-08-22 19:25:41.616786397 +0530
@@ -38,6 +38,7 @@
#include <linux/i2c/twl4030-rtc.h>
#include <linux/io.h>
#include <linux/irq.h>
+#include <linux/log2.h>
#include <asm/mach/time.h>
#include <asm/system.h>
@@ -363,14 +364,26 @@ out:
static int twl4030_rtc_irq_set_freq(struct device *dev, int freq)
{
struct rtc_device *rtc = dev_get_drvdata(dev);
+ u8 value;
- if (freq < 0 || freq > 3)
+ /* RTC_INTERRUPTS_REG takes the value of 0 for interrupts every
+ * second, 1 for every minute, 2 every hour and 3 every day.
+ * But freq is in 2^N format, which needs to be converted back.
+ */
+ value = ilog2(freq);
+ if (value < 0 || value > 3)
return -EINVAL;
- rtc->irq_freq = freq;
+ rtc->irq_freq = value;
+
+ /* Clear the current periodicity of irq*/
+ mask_rtc_irq_bit(0x3);
- /* set rtc irq freq to user defined value */
- set_rtc_irq_bit(freq);
+ /* If the new value is non-zero, set the new periodicity */
+ if (value) {
+ /* set rtc irq freq to user defined value */
+ set_rtc_irq_bit(freq);
+ }
return 0;
}
--
With Regards,
Jagadeesh Bhaskar P
----------------------------
Some men see things as they are and say why - I dream things that never were and say why not.
- George Bernard Shaw
-------------------
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