linux-kernel - Re: [PATCH 3/3] ARM: dts: omap4-sdp: add dynamic pin states for uart3/4

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Message-ID: <20130718080953.GR7656@atomide.com>
Date:	Thu, 18 Jul 2013 01:09:53 -0700
From:	Tony Lindgren <tony@...mide.com>
To:	Grygorii Strashko <grygorii.strashko@...com>
Cc:	Kevin Hilman <khilman@...aro.org>,
	linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree-discuss@...ts.ozlabs.org,
	Benoit Cousson <benoit.cousson@...aro.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Stephen Warren <swarren@...dotorg.org>
Subject: Re: [PATCH 3/3] ARM: dts: omap4-sdp: add dynamic pin states for
 uart3/4

* Grygorii Strashko <grygorii.strashko@...com> [130717 09:48]:
> Hi,
> 
> On 07/17/2013 06:32 PM, Tony Lindgren wrote:
> >* Grygorii Strashko <grygorii.strashko@...com> [130717 04:49]:
> >>Add dynamic "active"/"idle" pin states for uart3/4 which will be applied
> >>when uart3/4 state is switched from active to idle and back by Runtime
> >>PM or during system suspend.
> >
> >This is good for testing code, but should not be merged because
> >omap4 has the iopad wake-ups available for uarts. So those can
> >be always enabled.
> 
> In this case, 2 IRQ will be received per each UART RX event - one from
> PRCM and from UART - and that's not good from PM perspective (It will
> affect on CPUIdle and CPUFreq at least).

Oh I see, that's because I accidentally left the debug code enabled
to make it easier to test the wake-up events without having to
have working off-idle. The wake flags can be kept on always for
sure.

The patch below should sort out the issue of getting wake-up interrupts
during runtime as long as you don't have DEBUG defined.

Regards,

Tony

--- a/drivers/pinctrl/pinctrl-single-omap.c
+++ b/drivers/pinctrl/pinctrl-single-omap.c
@@ -140,9 +140,17 @@ static irqreturn_t pcs_omap_handle_irq(int irq, void *data)
 		if ((val & OMAP_WAKEUP_EVENT_MASK) == OMAP_WAKEUP_EVENT_MASK)
 			generic_handle_irq(wakeirq);
 	}
-
+#ifdef DEBUG
+	/*
+	 * This enables wake-up interrupts during runtime also
+	 * causing duplicate interrupts. But it also makes debugging
+	 * the wake-up events easy as deeper idle states often are
+	 * not working for new devices while the drivers are being
+	 * developed.
+	 */
 	if (pcso->reconfigure_io_chain)
 		pcso->reconfigure_io_chain();
+#endif
 
 	return IRQ_HANDLED;
 }
--
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