Re: [PATCH v1 0/7] Add rtc refclk support for PolarFire SoC

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Conor Dooley <mail@conchuod.ie>,
	Conor Dooley <conor.dooley@microchip.com>,
	sboyd@kernel.org, aou@eecs.berkeley.edu,
	paul.walmsley@sifive.com, palmer@rivosinc.com,
	a.zummo@towertech.it, alexandre.belloni@bootlin.com,
	robh+dt@kernel.org, krzk+dt@kernel.org, mturquette@baylibre.com
Cc: daire.mcnamara@microchip.com, linux-rtc@vger.kernel.org,
	devicetree@vger.kernel.org, linux-clk@vger.kernel.org,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH v1 0/7] Add rtc refclk support for PolarFire SoC
Date: Sat, 9 Apr 2022 12:48:18 +0200	[thread overview]
Message-ID: <7e6a0489-f90f-a362-e37b-b219fe2d71fe@linaro.org> (raw)
In-Reply-To: <98026c4a-a065-3965-27f0-71de29cdb264@conchuod.ie>

On 09/04/2022 09:14, Conor Dooley wrote:
> 
> 
> On 08/04/2022 16:29, Conor Dooley wrote:
>>
>>
>> On 08/04/2022 15:57, Krzysztof Kozlowski wrote:
>>> On 08/04/2022 16:36, Conor Dooley wrote:
>>>> Hey,
>>>> As I mentioned in my fixes for 5.18 [0], found out that the reference
>>>> clock for the rtc is actually missing from the clock driver (and the
>>>> dt binding).
>>>>
>>>> Currently the mpfs clock driver uses a reference clock called the
>>>> "msspll", set in the device tree, as the parent for the cpu/axi/ahb
>>>> (config) clocks. The frequency of the msspll is determined by the FPGA
>>>> bitstream & the bootloader configures the clock to match the bitstream.
>>>> The real reference is provided by a 100 or 125 MHz off chip oscillator.
>>>>
>>>> However, the msspll clock is not actually the parent of all clocks on
>>>> the system - the reference clock for the rtc/mtimer actually has the
>>>> off chip oscillator as its parent.
>>>>
>>>> This series enables reading the rate of the msspll clock, converts
>>>> the refclock in the device tree to the external reference & adds
>>>> the missing rtc reference clock.
>>>>
>>>> I assume it is okay not to add fixes tags for the rtc dt binding?
>>>> Since the clock was previously missing, the binding is wrong, but
>>>> idk if that qualifies as a fix?
>>>
>>> Usually ABI breakage, even if accepted, should be be tagged as fix
>>> because it is clearly then a break of other peoples' trees...
>>>
>>
>> That means either a) do something messy in the clock driver or b) mark
>> the whole series as fixes (and roll it into [0]).
>>
>> The second option seems far more sensible to me, do you agree?
> 
> Having thought some more about it, patches 2, 3 and the rtc part of 7
> should be moved into [0] since they're fixing a binding that only
> arrived in 5.18-rc1.
> For the rest, make the second part of the reg optional and if it doesnt
> exist just return prate for the msspll clock?

Ah, so this got into v5.18-rc1? I think I missed that information from
the patches description and focused on backporting to stables. Then
indeed you could combine all fixes together, mark them with Fixes.

Best regards,
Krzysztof

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