> -----Original Message----- > From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of David > Brownell > Sent: Thursday, September 04, 2008 11:19 PM > To: linux-omap@xxxxxxxxxxxxxxx > Subject: Re: [patch 2.6.27-rc5-omap1] rtc-twl4030 cleanup > > On Thursday 04 September 2008, David Brownell wrote: > > Update IRQs still misbehave (two per > second, not one!), > > Someone with docs will need to sort this one out. The > appended test program will illustrate the problem; it > was sitting around to help sort out bugs in way x86 > "HPET Emulation" reports update IRQs. > > Output on twl4030 is like: > > Read using select(2) on /dev/rtc0: > 1 0.562852 (+0.358789) 0190 > -3 * 0.563770 (+0.359707) 0190 > -2 1.562741 (+0.358678) 0190 > -6 * 1.563712 (+0.359649) 0190 > -5 2.562825 (+0.358762) 0190 > -9 * 2.563737 (+0.359674) 0190 > -8 3.562817 (+0.358754) 0190 > -12 * 3.563722 (+0.359659) 0190 > -11 4.562975 (+0.358912) 0190 > -15 * 4.563923 (+0.359860) 0190 > -14 5.563039 (+0.358976) 0190 > -18 * 5.564048 (+0.359985) 0190 > ^C > > The "*" indicates bogus IRQ reports ... in this case it > looks like each update IRQ is reported TWICE, with the > second one being about one millisec after the first one. > Since this test waits for five consecutive non-bogus > interrupts, it never stops ... > David, Could you please try with this patch? <CUT HERE> 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), all we need is one more read. Signed-off-by: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@xxxxxx> 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; -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
