From: Marc Kleine-Budde <mkl@pengutronix.de>
To: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Kedareswara rao Appana <appana.durga.rao@xilinx.com>,
wg@grandegger.com, michal.simek@xilinx.com,
grant.likely@linaro.org, robh+dt@kernel.org,
linux-can@vger.kernel.org, netdev@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
Kedareswara rao Appana <appanad@xilinx.com>
Subject: Re: [PATCH v2] can: Fix bug in suspend/resume
Date: Fri, 14 Nov 2014 16:09:35 +0100 [thread overview]
Message-ID: <54661B2F.2000704@pengutronix.de> (raw)
In-Reply-To: <e5f5913b51a54222aa1bb0680a77e56d@BN1AFFO11FD055.protection.gbl>
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On 11/14/2014 04:05 PM, Sören Brinkmann wrote:
> On Fri, 2014-11-14 at 09:54AM +0100, Marc Kleine-Budde wrote:
>> On 11/14/2014 09:16 AM, Kedareswara rao Appana wrote:
>>> The drvdata in the suspend/resume is of type struct net_device,
>>> not the platform device.Enable the clocks in the suspend before
>>> accessing the registers of the CAN.
>>>
>>> Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
>>> ---
>>> Changes for v2:
>>> - Removed the struct platform_device* from suspend/resume
>>> as suggest by Lothar.
>>> - The clocks are getting disabled and un prepared at the end of the probe.
>>> In the suspend the driver is doing a register write.In order
>>> To do that register write we have to again enable and prepare the clocks.
>>
>> Please look the at suspend/resume code and count the
>> clock_enable/disable manually. After a suspend/resume cycle, you have
>> enabled the clock twice, but disabled it once.
>>
>> I think you have to abstract the clock handling behind runtime PM. I
>> haven't done this myself yet, but the strong feeling that this is a
>> possible solution to your problem. These links might help:
>
> I agree, the clock handling looks weird. Also the clk_disable calls in
> xcan_get_berr_counter() look suspicious to me, but I might be wrong.
> I think you can take a look at gpio-zynq for an example for runtime_pm
> usage. I think the usage model in that driver is similar to here.
The xcan_get_berr_counter() function is correct, when doing manual (i.e.
non runtime-pm) clock handling. This function might be called if the
interface is down, this means clocks are disabled.
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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next prev parent reply other threads:[~2014-11-14 15:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-14 8:16 [PATCH v2] can: Fix bug in suspend/resume Kedareswara rao Appana
2014-11-14 8:54 ` Marc Kleine-Budde
2014-11-14 15:05 ` Sören Brinkmann
2014-11-14 15:09 ` Marc Kleine-Budde [this message]
2014-11-14 15:20 ` Sören Brinkmann
2014-11-14 15:35 ` Marc Kleine-Budde
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