Re: [PATCH v1 1/7] spmi: Implement spmi_subdevice_alloc_and_add() and devm variant

From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
To: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: sboyd@kernel.org, jic23@kernel.org, dlechner@baylibre.com,
	nuno.sa@analog.com, andy@kernel.org, arnd@arndb.de,
	gregkh@linuxfoundation.org, srini@kernel.org, vkoul@kernel.org,
	kishon@kernel.org, sre@kernel.org,
	krzysztof.kozlowski@linaro.org, u.kleine-koenig@baylibre.com,
	linux-arm-msm@vger.kernel.org, linux-iio@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-pm@vger.kernel.org, kernel@collabora.com,
	wenst@chromium.org
Subject: Re: [PATCH v1 1/7] spmi: Implement spmi_subdevice_alloc_and_add() and devm variant
Date: Mon, 21 Jul 2025 15:00:13 +0200	[thread overview]
Message-ID: <cb34fd4e-d87a-4a98-b27e-93ecb851e85e@collabora.com> (raw)
In-Reply-To: <aH4lwVpaiau1Ick3@smile.fi.intel.com>

Il 21/07/25 13:34, Andy Shevchenko ha scritto:
> On Mon, Jul 21, 2025 at 09:55:19AM +0200, AngeloGioacchino Del Regno wrote:
>> Some devices connected over the SPMI bus may be big, in the sense
>> that those may be a complex of devices managed by a single chip
>> over the SPMI bus, reachable through a single SID.
>>
>> Add new functions aimed at managing sub-devices of a SPMI device
>> spmi_subdevice_alloc_and_add() and a spmi_subdevice_put_and_remove()
>> for adding a new subdevice and removing it respectively, and also
>> add their devm_* variants.
>>
>> The need for such functions comes from the existance of	those
>> complex Power Management ICs (PMICs), which feature one or many
>> sub-devices, in some cases with these being even addressable on
>> the chip in form of SPMI register ranges.
>>
>> Examples of those devices can be found in both Qualcomm platforms
>> with their PMICs having PON, RTC, SDAM, GPIO controller, and other
>> sub-devices, and in newer MediaTek platforms showing similar HW
>> features and a similar layout with those also having many subdevs.
> 
> ...
> 
>>   EXPORT_SYMBOL_GPL(devm_spmi_controller_add);
> 
>> +EXPORT_SYMBOL_GPL(devm_spmi_subdevice_alloc_and_add);
> 
> I am wondering how hard to move these to a dedicated namespace.
> Basically you can define a default namespace, and at the same time
> add import to all (current) users.
> 

I can check if this can be done "relatively easily" (as in, if I can do that
without requiring "a hundred" immutable branches for every subsystem using
SPMI).

If turns out being feasible - I do actually like the idea so yes I'd be pleased
to do that... even though honestly it's completely out of scope for this series.

In case I can't - it's still something that can be done later.

> ...
> 
>> +	dev_set_name(&sdev->dev,
>> +		     "%d-%02x.%d.auto", sdev->ctrl->nr, sdev->usid, sub_sdev->devid);
> 
> No error check?
> 

Heh, whoops, forgot about it :-)

Thanks for catching that - adding the check for v2.

Cheers,
Angelo