From: Faiz Abbas <faiz_abbas@ti.com>
To: Marc Kleine-Budde <mkl@pengutronix.de>, <wg@grandegger.com>,
<robh+dt@kernel.org>, <mark.rutland@arm.com>
Cc: <linux-can@vger.kernel.org>, <netdev@vger.kernel.org>,
<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<nsekhar@ti.com>, <fcooper@ti.com>, <robh@kernel.org>,
<Wenyou.Yang@microchip.com>, <sergei.shtylyov@cogentembedded.com>
Subject: Re: [PATCH v6 3/6] can: m_can: Add PM Runtime
Date: Thu, 4 Jan 2018 20:47:00 +0530 [thread overview]
Message-ID: <6bdaab16-cb16-e039-473c-52dd295bd4ba@ti.com> (raw)
In-Reply-To: <cb306ae5-87c5-f6ef-0c40-3b47e208d256@pengutronix.de>
Hi,
On Wednesday 03 January 2018 08:47 PM, Marc Kleine-Budde wrote:
> On 01/03/2018 04:06 PM, Faiz Abbas wrote:
>> Hi,
>>
>> On Wednesday 03 January 2018 07:55 PM, Marc Kleine-Budde wrote:
>>> On 01/03/2018 01:39 PM, Faiz Abbas wrote:
>>>> On Tuesday 02 January 2018 09:37 PM, Marc Kleine-Budde wrote:
>>>>> On 12/22/2017 02:31 PM, Faiz Abbas wrote:
>>>>>> From: Franklin S Cooper Jr <fcooper@ti.com>
>>>>>>
>>>>>> Add support for PM Runtime which is the new way to handle managing clocks.
>>>>>> However, to avoid breaking SoCs not using PM_RUNTIME leave the old clk
>>>>>> management approach in place.
>>>>>
>>>>> There is no PM_RUNTIME anymore since 464ed18ebdb6 ("PM: Eliminate
>>>>> CONFIG_PM_RUNTIME")
>>>>
>>>> Ok. Will change the commit message.
>>>>
>>>>>
>>>>> Have a look at the discussion: https://patchwork.kernel.org/patch/9436507/ :
>>>>>
>>>>>>> Well, I admit it would be nicer if drivers didn't have to worry about
>>>>>>> whether or not CONFIG_PM was enabled. A slightly cleaner approach
>>>>>>> from the one outlined above would have the probe routine do this:
>>>>>>>
>>>>>>> my_power_up(dev);
>>>>>>> pm_runtime_set_active(dev);
>>>>>>> pm_runtime_get_noresume(dev);
>>>>>>> pm_runtime_enable(dev);
>>>>
>>>> This discussion seems to be about cases in which CONFIG_PM is not
>>>> enabled. CONFIG_PM is always selected in the case of omap devices.
>>>
>>> Yes, but in the commit message you state that you need to support
>>> systems that don't have PM_RUNTIME enabled. The only mainline SoCs I see
>>> is "arch/arm/boot/dts/sama5d2.dtsi" so far. Please check if they select
>>> CONFIG_PM, then we can make the driver much simpler.
>>
>> Actually the old clock management (for hclk which is the interface
>> clock) is still required as mentioned in the cover letter. Will change
>> the rather misleading description.
>
> Ok. So you can use the code as discussed on
> https://patchwork.kernel.org/patch/9436507/ ?
Looking at the kernel configuration, it seems like SAMA5D2 platform
selects CONFIG_PM (Wenyou, please confirm). So, it seems like the only
users of this driver always have CONFIG_PM enabled.
So I guess the best way is to maintain the current code for pm_runtime_*
and move the clock enable/disable to pm_runtime callbacks.
Something like this:
m_can_runtime_resume()
{
clk_prepare_enable(cclk);
clk_prepare_enable(hclk);
}
m_can_runtime_suspend()
{
clk_disable_unprepare(cclk);
clk_disable_unprepare(hclk);
}
SET_RUNTIME_PM_OPS(m_can_runtime_suspend, m_can_runtime_resume, NULL)
static void m_can_start(struct net_device *dev)
{
pm_runtime_get_sync(dev)
...
}
static void m_can_stop(struct net_device *dev)
{
...
pm_runtime_put_sync(dev)
}
Does that sound okay? If yes, I will go work on the implementation.
Thanks,
Faiz
next prev parent reply other threads:[~2018-01-04 15:16 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-22 13:31 [PATCH v6 0/6] Add M_CAN Support for Dra76 platform Faiz Abbas
2017-12-22 13:31 ` [PATCH v6 1/6] can: dev: Add support for limiting configured bitrate Faiz Abbas
2018-01-02 13:00 ` Marc Kleine-Budde
2018-01-03 12:19 ` Faiz Abbas
2018-01-02 16:15 ` Marc Kleine-Budde
2018-01-03 12:21 ` Faiz Abbas
2017-12-22 13:31 ` [PATCH v6 2/6] can: m_can: Add call to of_can_transceiver Faiz Abbas
2017-12-22 13:31 ` [PATCH v6 3/6] can: m_can: Add PM Runtime Faiz Abbas
2018-01-02 16:07 ` Marc Kleine-Budde
2018-01-03 12:39 ` Faiz Abbas
2018-01-03 14:25 ` Marc Kleine-Budde
2018-01-03 15:06 ` Faiz Abbas
2018-01-03 15:17 ` Marc Kleine-Budde
2018-01-04 15:17 ` Faiz Abbas [this message]
2018-01-04 15:18 ` Marc Kleine-Budde
2018-01-05 1:23 ` Yang, Wenyou
2017-12-22 13:31 ` [PATCH v6 4/6] can: m_can: Support higher speed CAN-FD bitrates Faiz Abbas
2018-01-02 13:35 ` Marc Kleine-Budde
2018-01-03 12:55 ` Faiz Abbas
2017-12-22 13:31 ` [PATCH v6 5/6] dt-bindings: can: m_can: Document new can transceiver binding Faiz Abbas
2017-12-22 13:31 ` [PATCH v6 6/6] dt-bindings: can: can-transceiver: Document new binding Faiz Abbas
2017-12-29 3:38 ` [PATCH v6 0/6] Add M_CAN Support for Dra76 platform Yang, Wenyou
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