linux-kernel - Re: [PATCH] ARM: dts: at91sam9261ek: remove unused chosen nodes

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Date:   Sun, 28 Apr 2019 14:47:24 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Rob Herring <robh+dt@...nel.org>
Cc:     Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: dts: at91sam9261ek: remove unused chosen nodes

ping ?


On 08/04/2019 18:30, Daniel Lezcano wrote:
> 
> Hi Rob,
> 
> the following patch has been pushed in 2016 by commit 51f0aeb2d21f1.
> 
> Being able to specify which timer should act as a clocksource or a
> clockevent is often requested. Doing this from the driver itself forces
> to do some assumption in the timer definition ordering in the DT.
> 
> That impacts badly the resulting code and its self-encapsulation.
> 
>  - There is one node and the driver hardcodes the value and initializes
> a clocksource and a clockevent
> 
>  - There are several nodes, one for the clocksource and one for the
> clockevent, and the driver assumes the order of the node in the DT
> 
>  - There are several nodes and multiple channels and those are used for
> PWM. It is impossible to know which one are used for PWM or for the
> clocksource or for the clockevent
> 
> For example with STM32, we should be able to specify which timer to use.
> There are 16 timers IIRC, they can be used for PWM, clocksource or
> clockevent. Half is 16 bits, other half is 32 bits, depending on the
> destination of the platform we can be interested to use one or another
> without recompiling a kernel but just the DT.
> 
> We need a way to specify which timer to be used from the DT. The patch
> below sounded like a good way to characterize the nodes as they belong
> to the 'chosen' node and we stay to a 'linux' thing.
> 
> What do you think ?
> 
> 
> On 08/04/2019 17:11, Alexandre Belloni wrote:
>> The chosen clocksource and clockevent bindings have never been accepted and
>> parsed, remove them.
>>
>> Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
>> ---
>>  arch/arm/boot/dts/at91sam9261ek.dts | 8 --------
>>  1 file changed, 8 deletions(-)
>>
>> diff --git a/arch/arm/boot/dts/at91sam9261ek.dts b/arch/arm/boot/dts/at91sam9261ek.dts
>> index a57f2d435dca..11ed55d8a87d 100644
>> --- a/arch/arm/boot/dts/at91sam9261ek.dts
>> +++ b/arch/arm/boot/dts/at91sam9261ek.dts
>> @@ -15,14 +15,6 @@
>>  	chosen {
>>  		bootargs = "rootfstype=ubifs ubi.mtd=5 root=ubi0:rootfs rw";
>>  		stdout-path = "serial0:115200n8";
>> -
>> -		clocksource {
>> -			timer = <&timer0>;
>> -		};
>> -
>> -		clockevent {
>> -			timer = <&timer1>;
>> -		};
>>  	};
>>  
>>  	memory {
>>
> 
> 


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