From: Jagadeesh Bhaskar Pakaravoor <[EMAIL PROTECTED]>
RTC generates an extra spurious interrupt for every actual periodic
interrupt. This is due to a problem with the RTC_IT bit of
REG_PWR_ISR1. It requires two writes or two reads (when COR is
enabled) to clear it. Since COR is enabled and one read of the same
register is done already (inside twl4030-pwrirq.c do_twl4030_pwrirq()
function), we can do away with a need to add one more write into the
same register inside the interrupt handler, by replacing the write
currently present with just one extra read.
Signed-off-by: Jagadeesh Bhaskar Pakaravoor <[EMAIL PROTECTED]>
---
David Brownell reported this issue earlier. This patch fixes it.
Index: linux-omap-2.6/drivers/rtc/rtc-twl4030.c
===================================================================
--- linux-omap-2.6.orig/drivers/rtc/rtc-twl4030.c 2008-09-05
12:22:23.089855991 +0530
+++ linux-omap-2.6/drivers/rtc/rtc-twl4030.c 2008-09-05 12:49:55.634939761
+0530
@@ -446,8 +446,13 @@ static irqreturn_t twl4030_rtc_interrupt
REG_RTC_STATUS_REG);
if (res)
goto out;
- res = twl4030_i2c_write_u8(TWL4030_MODULE_INT,
- PWR_RTC_INT_CLR, REG_PWR_ISR1);
+
+ /* Clear on Read enabled. RTC_IT bit of REG_PWR_ISR1 needs
+ * 2 reads to clear the interrupt. One read is done in
+ * do_twl4030_pwrirq(). Doing the second read, to clear
+ * the bit.
+ */
+ res = twl4030_i2c_read_u8(TWL4030_MODULE_INT, &rd_reg, REG_PWR_ISR1);
if (res)
goto out;
--
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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