Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document

From: Geert Uytterhoeven
Date: Fri Mar 18 2016 - 08:05:40 EST

Hi Jon,

On Fri, Mar 18, 2016 at 11:56 AM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
> On 18/03/16 10:52, Geert Uytterhoeven wrote:
>> On Fri, Mar 18, 2016 at 11:13 AM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
>>> On 18/03/16 09:13, Geert Uytterhoeven wrote:
>>>> On Thu, Mar 17, 2016 at 3:19 PM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
>>>>> Commit afbbd2338176 ("irqchip/gic: Document optional Clock and Power
>>>>> Domain properties") documented optional clock and power-dmoain properties
>>>>> for the ARM GIC. Currently, there are no users of these and for the
>>>>> Tegra210 Audio GIC (based upon the GIC-400) there are two clocks, a
>>>>> functional clock and interface clock, that need to be enabled.
>>>> The reason that there are no users for this is twofold:
>>>> 1. The GIC driver doesn't have Runtime PM support yet,
>>>> 2. There was no clean way to prevent the GIC's clock from being disabled.
>>>> Due to this, adding the clocks to the DTSes would mean that they will be
>>>> disabled during boot up as unused clocks, leading to a system lock-up.
>>>> I had hoped your series would fix part 1. I gave it a try on r8a7791/koelsch,
>>>> but unfortunately it seems the platform driver only supports non-root
>>>> controllers, while the r8a7791 GIC is the primary one...
>>> Can you try making the following change ...
>> Thanks! I gave it a try, but no difference.
> I assume you added the appropriate compatible flag? Any more details you

Doh... bad assumption... Silly me.

> can share about why it is not working? Is it not registered early enough?


+ { .compatible = "arm,gic-400", },

the kernel no longer crashes due to accessing the GIC registers while the
GIC module clock is disabled.

However, the system doesn't boot completely, and time outs on SPI transfers
make me believe interrupts are not working.
Both with and without "the following change".



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds