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From: Eric Anholt <eric@anholt.net>
To: Robin Murphy <robin.murphy@arm.com>,
	Stefan Wahren <stefan.wahren@i2se.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>
Cc: linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org,
	Florian Fainelli <f.fainelli@gmail.com>,
	Scott Branden <sbranden@broadcom.com>,
	Ray Jui <rjui@broadcom.com>, Phil Elwell <phil@raspberrypi.org>,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH RFC 2/6] dt-bindings: hwmon: Add Raspberry Pi voltage sensor
Date: Wed, 16 May 2018 18:51:39 +0100	[thread overview]
Message-ID: <874lj7cwus.fsf@anholt.net> (raw)
In-Reply-To: <30fc5bac-0c4a-b2c4-a018-ea521510aaea@arm.com>


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Robin Murphy <robin.murphy@arm.com> writes:

> On 16/05/18 14:37, Stefan Wahren wrote:
>> Recent VC4 firmware provides a hardware-independent way to retrieve the
>> under-voltage sensor on the following Raspberry Pi boards:
>>    - Raspberry Pi B+ (via GPIO on SoC)
>>    - Raspberry Pi A+ (via GPIO on SoC)
>>    - Raspberry Pi 2 B (via GPIO on SoC)
>>    - Raspberry Pi 3 B (via GPIO on port expander)
>>    - Raspberry Pi 3 B+ (via PMIC)
>> 
>> TODO:
>>    - try to make bcm2835 firmware a bus driver
>
> Do you actually need a DT binding? From the probe routine in patch 2 it 
> looks like this capability can be discovered dynamically by asking the 
> firmware, therefore it might be more straightforward for the firmware 
> driver itself to probe that and create a child device iff the feature is 
> present, which the hwmon driver can then bind to as a pure platform driver.

Agreed, let's skip doing this in DT.  I just switched the bcm2835-camera
driver over to not need DT, and I think you could do something similar
(and use the pdev->dev.parent to get at the firmware device).

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  reply	other threads:[~2018-05-16 17:51 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-16 13:37 [PATCH RFC 0/6] hwmon: Add support for Raspberry Pi voltage sensor Stefan Wahren
2018-05-16 13:37 ` [PATCH RFC 1/6] ARM: bcm2835: Add GET_THROTTLED firmware property Stefan Wahren
2018-05-16 13:37 ` [PATCH RFC 2/6] dt-bindings: hwmon: Add Raspberry Pi voltage sensor Stefan Wahren
2018-05-16 14:23   ` Robin Murphy
2018-05-16 17:51     ` Eric Anholt [this message]
2018-05-16 14:52   ` Guenter Roeck
2018-05-16 13:37 ` [PATCH RFC 3/6] hwmon: Add support for RPi " Stefan Wahren
2018-05-16 13:51   ` Robin Murphy
2018-05-16 18:05     ` Guenter Roeck
2018-05-16 18:23       ` Robin Murphy
2018-05-16 18:21   ` Guenter Roeck
2018-05-16 19:59     ` Stefan Wahren
2018-05-17 16:43       ` Guenter Roeck
2018-05-17 17:25         ` Eric Anholt
2018-05-16 13:37 ` [PATCH RFC 4/6] ARM: bcm2835_defconfig: Enable " Stefan Wahren
2018-05-16 13:37 ` [PATCH RFC 5/6] ARM: multi_v7_defconfig: " Stefan Wahren
2018-05-16 13:37 ` [PATCH RFC 6/6] arm64: defconfig: " Stefan Wahren

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