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SubjectRe: [PATCH v2 5/6] clocksource: Add a new timer-ingenic driver
On Wed, Jan 3, 2018 at 3:56 PM, Paul Cercueil <paul@crapouillou.net> wrote:
> Hi,
>
> Le mer. 3 janv. 2018 à 22:08, Rob Herring <robh@kernel.org> a écrit :
>>
>> On Mon, Jan 01, 2018 at 03:33:43PM +0100, Paul Cercueil wrote:
>>>
>>> This driver will use the TCU (Timer Counter Unit) present on the Ingenic
>>> JZ47xx SoCs to provide the kernel with a clocksource and timers.
>>>
>>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>>> ---
>>> .../devicetree/bindings/timer/ingenic,tcu.txt | 35 +++
>>
>>
>> Separate patch please.
>
>
> OK.
>
>
>>> drivers/clocksource/Kconfig | 8 +
>>> drivers/clocksource/Makefile | 1 +
>>> drivers/clocksource/timer-ingenic.c | 256
>>> +++++++++++++++++++++
>>> 4 files changed, 300 insertions(+)
>>> create mode 100644
>>> Documentation/devicetree/bindings/timer/ingenic,tcu.txt
>>> create mode 100644 drivers/clocksource/timer-ingenic.c
>>>
>>> v2: Use SPDX identifier for the license
>>>
>>> diff --git a/Documentation/devicetree/bindings/timer/ingenic,tcu.txt
>>> b/Documentation/devicetree/bindings/timer/ingenic,tcu.txt
>>> new file mode 100644
>>> index 000000000000..e4944972ea53
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/timer/ingenic,tcu.txt
>>> @@ -0,0 +1,35 @@
>>> +Ingenic JZ47xx SoCs Timer/Counter Unit driver
>>> +---------------------------------------------
>>> +
>>> +Required properties:
>>> +
>>> +- compatible : should be "ingenic,<socname>-tcu". Valid strings are:
>>> + * ingenic,jz4740-tcu
>>> + * ingenic,jz4770-tcu
>>> + * ingenic,jz4780-tcu
>>> +- interrupt-parent : phandle of the TCU interrupt controller.
>>> +- interrupts : Specifies the interrupts the controller is connected to.
>>> +- clocks : List of phandle & clock specifiers for the TCU clocks.
>>> +- clock-names : List of name strings for the TCU clocks.
>>> +- ingenic,channels: a list of TCU channels to be used as timers.
>>
>>
>> Why is this needed? This looks like you are trying to assign certain
>> timers to clocksource and clockevent. A common problem, but one that
>> should be decided by describing h/w features. There must be some
>> property present or missing to make you decide to use a given channel or
>> not.
>
>
> Well, it's not easy; some TCU channels will be used as PWM, and there's no
> way
> to know that when the clocksource driver probes. And which ones are PWM /
> which
> ones are not, is board-specific. If you have a better solution though, I
> take it.

Aren't the PWMs connected to something? Describe those in DT and then
you can find the free ones.

Rob

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