Re: [PATCH 3/6] ARM: dts: broadcom: Fix SP804 node

From: Florian Fainelli <f.fainelli@gmail.com>
To: "Florian Fainelli" <f.fainelli@gmail.com>,
	"André Przywara" <andre.przywara@arm.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	devicetree@vger.kernel.org
Cc: Scott Branden <sbranden@broadcom.com>,
	Ray Jui <rjui@broadcom.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	linux-kernel@vger.kernel.org,
	bcm-kernel-feedback-list@broadcom.com,
	Haojian Zhuang <haojian.zhuang@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 3/6] ARM: dts: broadcom: Fix SP804 node
Date: Wed, 26 Aug 2020 13:55:29 -0700	[thread overview]
Message-ID: <ecb277f9-1328-c64c-dd42-7a346ba61f8e@gmail.com> (raw)
In-Reply-To: <3a3ce1d4-ddd5-f000-9cf0-5d06e2cc2047@gmail.com>

On 8/26/20 11:59 AM, Florian Fainelli wrote:
> On 8/26/20 11:53 AM, André Przywara wrote:
>> On 26/08/2020 19:42, Florian Fainelli wrote:
>>
>> Hi,
>>
>>> On 8/26/20 11:38 AM, Andre Przywara wrote:
>>>> The DT binding for SP804 requires to have an "arm,primecell" compatible
>>>> string.
>>>> Add this string so that the Linux primecell bus driver picks the device
>>>> up and activates the clock.
>>>>
>>>> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
>>>
>>> The commit subject should be:
>>>
>>> ARM: dts: NSP: Fix SP804 compatible node
>>>
>>> and we should probably have a Fixes tag that is:
>>>
>>> Fixes: a0efb0d28b77 ("ARM: dts: NSP: Add SP804 Support to DT")
>>>
>>> Could you please re-submit with those things corrected? Thanks
>>
>> Sure, will include that in a v2.
>>
>> Out of curiosity, do you have the hardware and can check the impact that
>> has?
> 
> I have the hardware and could run some tests if you would like.
> 
>> Not sure we actually create the device without the primecell compatible?
>> Or is the sp804 an exception here, compared to the other AMBA devices
>> (SP805, PL011)?
> 
> No idea, I have never used those timers personally, and I doubt that
> anybody besides me within broadcom and hobbyists actually care about NSP
> these days.

Seems to be working fine for me with your patch applied, it probes:

# dmesg | grep sp804
[    0.035363] clocksource: arm,sp804: mask: 0xffffffff max_cycles:
0xffffffff, max_idle_ns: 15290083572 ns

and it is usable:

# cat clocksource0/available_clocksource
arm_global_timer arm,sp804

and appears to work:

# echo "arm,sp804" > clocksource0/current_clocksource
[  105.108547] clocksource: Switched to clocksource arm,sp804

# date; sleep 5; date
Thu Jan  1 00:01:51 UTC 1970
Thu Jan  1 00:01:56 UTC 1970

Feel free to add Tested-by: Florian Fainelli <f.fainelli@gmail.com> in
your v2, thanks André!
-- 
Florian

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