Re: [PATCH 6/8] mfd: max77714: Add driver for Maxim MAX77714 PMIC

From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To: Luca Ceresoli <luca@lucaceresoli.net>, linux-kernel@vger.kernel.org
Cc: Lee Jones <lee.jones@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Alessandro Zummo <a.zummo@towertech.it>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Chanwoo Choi <cw00.choi@samsung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Wim Van Sebroeck <wim@linux-watchdog.org>,
	Guenter Roeck <linux@roeck-us.net>,
	devicetree@vger.kernel.org, linux-rtc@vger.kernel.org,
	linux-watchdog@vger.kernel.org,
	Chiwoong Byun <woong.byun@samsung.com>,
	Laxman Dewangan <ldewangan@nvidia.com>
Subject: Re: [PATCH 6/8] mfd: max77714: Add driver for Maxim MAX77714 PMIC
Date: Thu, 14 Oct 2021 09:40:19 +0200	[thread overview]
Message-ID: <b4ee3175-5bd7-cf75-2d2b-2cc9368842e7@canonical.com> (raw)
In-Reply-To: <5236720c-96b0-3e18-e08f-a5dde982eab5@lucaceresoli.net>

On 13/10/2021 23:39, Luca Ceresoli wrote:
> Hi,
> 
> On 12/10/21 10:32, Krzysztof Kozlowski wrote:
>> On 11/10/2021 17:56, Luca Ceresoli wrote:
>>> Add a simple driver for the Maxim MAX77714 PMIC, supporting RTC and
>>> watchdog only.
>>>
>>> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
>>> ---
>>>  MAINTAINERS                  |   2 +
>>>  drivers/mfd/Kconfig          |  14 ++++
>>>  drivers/mfd/Makefile         |   1 +
>>>  drivers/mfd/max77714.c       | 151 +++++++++++++++++++++++++++++++++++
>>>  include/linux/mfd/max77714.h |  68 ++++++++++++++++
>>>  5 files changed, 236 insertions(+)
>>>  create mode 100644 drivers/mfd/max77714.c
>>>  create mode 100644 include/linux/mfd/max77714.h
>>>
>>
>> (...)
>>
>>> +
>>> +static const struct of_device_id max77714_dt_match[] = {
>>> +	{ .compatible = "maxim,max77714" },
>>> +	{},
>>> +};
>>
>> When converting to module - don't forget the MODULE_DEVICE_TABLE
>>
>>> +
>>> +static struct i2c_driver max77714_driver = {
>>> +	.driver = {
>>> +		.name = "max77714",
>>> +		.of_match_table = of_match_ptr(max77714_dt_match),
>>
>> Kbuild robot pointed it out - of_matc_ptr should not be needed, even for
>> compile testing without OF.
> 
> I wonder whether it's better to add '#ifdef CONFIG_OF / #endif' around
> the struct of_device_id declaration. I think it's what most drivers do,
> even though I tend to prefer not adding #ifdefs making code less clean
> only for COMPILE_TESTING.

No, most drivers added it long time ago before we switched it to a new
way - either __maybe_unused or without anything even. The point is that
OF driver can be reused for ACPI platforms. If you limit it with ifdef
or of_match_ptr, the ACPI platform won't have any table to use for binding.

Best regards,
Krzysztof