linux-kernel - Re: [PATCH v6 00/41] ARM: davinci: convert to common clock framework

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Date:   Wed, 24 Jan 2018 09:03:45 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     David Lechner <david@...hnology.com>
Cc:     Adam Ford <aford173@...il.com>, linux-clk@...r.kernel.org,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel@...ts.infradead.org,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 00/41] ARM: davinci: convert to common clock framework

2018-01-23 21:23 GMT+01:00 David Lechner <david@...hnology.com>:
> On 01/23/2018 02:05 PM, David Lechner wrote:
>>
>> On 01/23/2018 02:01 PM, David Lechner wrote:
>>>
>>> On 01/23/2018 01:53 PM, Bartosz Golaszewski wrote:
>>>>
>>>>
>>>> In the mdio case - the problem is that devm_clk_get() doesn't fail,
>>>> but somehow the clock doesn't end up in the list of the device's
>>>> clocks - which is why it's not enabled by pm_runtime_get_sync().
>>>>
>>>
>>>
>>> Right. This is because devm_clk_get() now finds the clock via device
>>> tree instead of a clkdev lookup entry. However, I think that the PM
>>> notifier registered in arch/arm/mach-davinci/pm_domain.c only uses
>>> the clkdev lookup to match the con_id and does not use device tree.
>>> The same thing is happing in mdio, emac and lcdc.
>>>
>>
>> Minor correction: It looks like emac doesn't do this because it doesn't
>> have a con_id of "fck". But, the same clock is shared by emac and mdio, so
>> since mdio enables the clock, emac doesn't notice or care that it did
>> not enable the clock itself.
>
>
> How about using pm_clk_add_clk() in these drivers to explicitly use the
> clocks for power management instead of relying on pm_clk_add_notifier()
> to do this implicitly?

Yes, this sounds good.

Bartosz