From: Tony Lindgren <tony@atomide.com>
To: Lokesh Vutla <lokeshvutla@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>,
linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
nm@ti.com, linux@arm.linux.org.uk, nsekhar@ti.com
Subject: Re: [PATCH V2 4/4] ARM: OMAP2+: AM43x: Use gptimer as clocksource
Date: Fri, 28 Feb 2014 15:34:02 -0800 [thread overview]
Message-ID: <20140228233402.GY13624@atomide.com> (raw)
In-Reply-To: <530B4391.2050205@ti.com>
* Lokesh Vutla <lokeshvutla@ti.com> [140224 05:08]:
> Hi Tony,
> On Friday 14 February 2014 02:16 PM, Rajendra Nayak wrote:
> > On Friday 14 February 2014 04:49 AM, Tony Lindgren wrote:
> >> * Lokesh Vutla <lokeshvutla@ti.com> [140207 02:24]:
> >>> From: Rajendra Nayak <rnayak@ti.com>
> >>>
> >>> The SyncTimer in AM43x is clocked using the following two sources:
> >>> 1) An inaccuarte 32k clock (CLK_32KHZ) derived from PER DPLL, causing system
> >>> time to go slowly (~10% deviation).
> >>> 2) external 32KHz RTC clock, which may not always be available on board like
> >>> in the case of ePOS EVM
> >>>
> >>> Use gptimer as clocksource instead, as is done in the case of AM335x
> >>> (which does not have a SyncTimer). With this, system time keeping works
> >>> accurately.
> >>
> >> Hmm doesn't this also mean that PM for any deeper idle states won't
> >> work properly?
> >
> > Thats true. This would mean we cannot put the peripheral/core domain down
> > in idle. Suspend however can still work if suspend/resume callbacks are added
> > to the clockevent and clocksource code to shut the non-wakeup domain timer.
> This is a platform level limitation that only MPU domain can be put down in idle, just like AM335x.
OK applying all four into omap-for-v3.15/soc thanks.
Tony
prev parent reply other threads:[~2014-02-28 23:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-07 10:21 [PATCH V2 0/4] ARM: OMAP2+: AM43x: Enable in OMAP2PLUS and add ID for ES1.1 Lokesh Vutla
2014-02-07 10:21 ` [PATCH V2 1/4] ARM: OMAP2+: AM43x: enable in default config Lokesh Vutla
2014-02-07 10:21 ` [PATCH V2 2/4] ARM: OMAP2+: AM43x: Add ID for ES1.1 Lokesh Vutla
2014-02-07 10:21 ` [PATCH V2 3/4] ARM: OMAP2+: AM43x: determine features Lokesh Vutla
2014-02-07 10:21 ` [PATCH V2 4/4] ARM: OMAP2+: AM43x: Use gptimer as clocksource Lokesh Vutla
2014-02-13 23:19 ` Tony Lindgren
2014-02-14 8:46 ` Rajendra Nayak
2014-02-24 13:05 ` Lokesh Vutla
2014-02-28 23:34 ` Tony Lindgren [this message]
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