From: Matti Vaittinen <mazziesaccount@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>,
Lee Jones <lee@kernel.org>, Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Conor Dooley <conor+dt@kernel.org>,
Liam Girdwood <lgirdwood@gmail.com>,
Wim Van Sebroeck <wim@linux-watchdog.org>,
Guenter Roeck <linux@roeck-us.net>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-watchdog@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC PATCH 0/6] Support ROHM BD96801 scalable PMIC
Date: Thu, 9 May 2024 10:03:43 +0300 [thread overview]
Message-ID: <0674ca23-2cf2-48a6-84d3-e0936d50dd8c@gmail.com> (raw)
In-Reply-To: <ZjxaP_BNWVufJb_X@finisterre.sirena.org.uk>
On 5/9/24 08:08, Mark Brown wrote:
> On Mon, Apr 22, 2024 at 01:52:27PM +0300, Matti Vaittinen wrote:
>> On 4/5/24 12:19, Matti Vaittinen wrote:
>>> On 4/4/24 16:15, Matti Vaittinen wrote:
>
>>>>> I would expect each parent interrupt to show up as a separate remap_irq.
>
>>>>> So if we arrange to supply a name when we register multiple domains
>>>>> things should work fine?
>
>>> After my latest findings, yes, I think so. How to do this correctly is
>>> beyond me though. The __irq_domain_create() seems to me that the name is
>>> meant to be the dt-node name when the controller is backed by a real
>>> dt-node. Naming of the irq_domain_alloc_named_fwnode() sounds to me like
>
> ...
>
>> If we wanted to support multiple HWIRQs / regmap-IRQ controller, it would
>> require us to duplicate almost everything in the struct regmap_irq_chip for
>> every new parent IRQ. The status/mask register information, IRQ type, etc.
>> Naturally, it would require also duplicating lot of the data contained in
>> the struct regmap_irq_chip_data. I am not sure if this could be done so the
>> change is not reflected in the existing IRQ data initialization macros etc.
>> Furthermore, some API changes would be required like changes to
>> regmap_irq_get_domain().
>
> I don't understand what the difficulty is here - we're creating multiple
> interrupt controllers so I'd expect to have to have full definitions of
> each, and since everything is referenced by name from the root
> regmap_irq_chip which gets registered it's just a case of supplying
> different names and all the helpers should be fine?
>
>> Thus, forcing the regmap-IRQ to support multiple parents instead of having
>> own regmap-IRQ instance / parent IRQ feels like fitting square item to a
>> round hole. I am sure fixing all the bugs I caused would give donate a lot
>> of EXP-points though :rolleyes:
>
> Right, my suggestion is to register multiple regmap_irq instrances - one
> per parent - and supply a name that allows all the display/debugfs stuff
> that currently uses the dev_name() to deduplicate. You'd end up
> sticking -primary, -secondary or whatever name was supplied onto the
> names we currently use.
>
>> Another option I see, is trying to think if irq-domain name could be
>> changed. (This is what the RFC v3 does, [ab]using the
>> irq_domain_update_bus_token()). I was a bit put off by the idea of
>> 'instantiating' multiple domains (or regmap-IRQ controllers) from a single
>> node, but more I think of this, more I lean towards it. Besides, this is not
>
> Yes, register mutliple controllers with different names.
Thanks for the guidance Mark. The controller name is not a problem.
Problem is that I don't see a (proper) way to supply a name for the IRQ
domain which gets registered by regmap-IRQ. IRQ domain code picks the
name for the domain by the device-tree node. Both of our IRQ controllers
would be instantiated from same node => the IRQ domain will get same
name => debugfs will conflict.
My "solution" was simply dropping the ERRB IRQ from the driver (for now
at least). I did send that as a series without 'RFC' - but made a
mistake and restarted the versioning from v1. I am currently working
with 2 other PMICs, one of them does also provide similar setup of two
IRQ lines. Thus, I think being able to provide a name (suffix?) for IRQ
domain when registering it instead of just using the name of the DT node
is something I should look into. It's just nice to know someone else
thinks it is valid approach.
Thanks for the input!
Yours,
-- Matti
--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland
~~ When things go utterly wrong vim users can always type :help! ~~
next prev parent reply other threads:[~2024-05-09 7:03 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-02 13:07 [RFC PATCH 0/6] Support ROHM BD96801 scalable PMIC Matti Vaittinen
2024-04-02 13:07 ` [RFC PATCH 1/6] dt-bindings: ROHM BD96801 PMIC regulators Matti Vaittinen
2024-04-02 13:08 ` [RFC PATCH 2/6] dt-bindings: mfd: bd96801 PMIC core Matti Vaittinen
2024-04-02 13:08 ` [RFC PATCH 3/6] mfd: support ROHM BD96801 " Matti Vaittinen
2024-04-11 14:38 ` Lee Jones
2024-04-12 5:40 ` Matti Vaittinen
2024-04-12 5:50 ` Matti Vaittinen
2024-04-12 7:23 ` Lee Jones
2024-04-12 8:58 ` Matti Vaittinen
2024-04-17 12:24 ` Lee Jones
2024-04-02 13:11 ` [RFC PATCH 5/6] watchdog: ROHM BD96801 PMIC WDG driver Matti Vaittinen
2024-04-02 16:15 ` Krzysztof Kozlowski
2024-04-02 17:11 ` Guenter Roeck
2024-04-03 6:34 ` Matti Vaittinen
2024-04-03 12:41 ` Guenter Roeck
2024-04-03 12:47 ` Matti Vaittinen
2024-04-03 13:26 ` Guenter Roeck
2024-04-02 13:12 ` [RFC PATCH 6/6] MAINTAINERS: Add ROHM BD96801 'scalable PMIC' entries Matti Vaittinen
2024-04-04 7:26 ` [RFC PATCH 0/6] Support ROHM BD96801 scalable PMIC Matti Vaittinen
2024-04-04 12:09 ` Mark Brown
2024-04-04 13:15 ` Matti Vaittinen
2024-04-05 9:19 ` Matti Vaittinen
2024-04-05 21:27 ` Mark Brown
2024-04-22 10:52 ` Matti Vaittinen
2024-05-09 5:08 ` Mark Brown
2024-05-09 7:03 ` Matti Vaittinen [this message]
2024-05-09 15:38 ` Mark Brown
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