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

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Date:   Tue, 23 Jan 2018 20:53:20 +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 20:24 GMT+01:00 David Lechner <david@...hnology.com>:
> On 01/23/2018 12:34 PM, Bartosz Golaszewski wrote:
>>
>> 2018-01-23 19:26 GMT+01:00 David Lechner <david@...hnology.com>:
>>>
>>> On 01/23/2018 12:10 PM, Bartosz Golaszewski wrote:
>>>>
>>>>
>>>> 2018-01-23 18:03 GMT+01:00 Adam Ford <aford173@...il.com>:
>>>>>
>>>>>
>>>>> On Tue, Jan 23, 2018 at 10:06 AM, David Lechner <david@...hnology.com>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>> On 01/23/2018 10:03 AM, David Lechner wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> You can see if the clock is enabled by running:
>>>>>>>
>>>>>>>        cat /sys/kernel/debug/clk/clk_summary
>>>>>>>
>>>>>>
>>>>>> I just realized if you can't boot, you can't do this. :-/
>>>>>
>>>>>
>>>>>
>>>>> I can boot with the latest set in your git repo, but the Ethernet
>>>>> doesn't apparently fully operate.  I don't get errors, but I cannot
>>>>> get a dhcp address.
>>>>>
>>>>> I'll try to do a more exhaustive test later today to get an idea of
>>>>> what works and what doesn't.  When I ran my basic tests, I just did a
>>>>> feel-good boot test (and reboot test)
>>>>>
>>>>> adam
>>>>
>>>>
>>>>
>>>> FYI: manually calling clk_prepare_enable() in the davinci_mdio driver
>>>> seems to at least fix the ethernet. In master branch it's done by
>>>> pm_runtime_get_sync() (in davinci_mdio_reset()). However I'm still
>>>> getting several oopses and WARNs so there's some more work to do.
>>>>
>>>
>>> Hmm... I'm wondering if we need to also add #power-domain-cells to the
>>> PSC clocks and power-domains properties to the consumers.
>>>
>>> For this specific case though, it seems strange to me that the drivers
>>> to clk_get() and clk_get_rate() but never enable the clocks.
>>>
>>>
>>> Also, are the oopses and WARNs the same as before?
>>
>>
>> No, the ones before were all related to the ethernet failing, now I
>> get several stack traces from drm. Posted them on pastebin[1].
>>
>
> It looks like the LCDC driver is the same way. It does clk_get() but
> not clk_prepare_enable().
>
>

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().

Bartosz