[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <5bffef40-a4a7-5f7d-a448-b2a381c57822@nvidia.com>
Date: Thu, 8 Mar 2018 11:36:24 +0530
From: Laxman Dewangan <ldewangan@...dia.com>
To: Guenter Roeck <linux@...ck-us.net>,
Rajkumar Rampelli <rrajk@...dia.com>,
Mikko Perttunen <cyndis@...si.fi>, <robh+dt@...nel.org>,
<mark.rutland@....com>, <thierry.reding@...il.com>,
<jonathanh@...dia.com>, <jdelvare@...e.com>, <corbet@....net>,
<catalin.marinas@....com>, <will.deacon@....com>,
<kstewart@...uxfoundation.org>, <gregkh@...uxfoundation.org>,
<pombredanne@...b.com>, <mmaddireddy@...dia.com>,
<mperttunen@...dia.com>, <arnd@...db.de>, <timur@...eaurora.org>,
<andy.gross@...aro.org>, <xuwei5@...ilicon.com>,
<elder@...aro.org>, <heiko@...ech.de>, <krzk@...nel.org>,
<ard.biesheuvel@...aro.org>
CC: <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-pwm@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
<linux-hwmon@...r.kernel.org>, <linux-doc@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 05/10] hwmon: generic-pwm-tachometer: Add generic PWM
based tachometer
On Wednesday 07 March 2018 07:50 PM, Guenter Roeck wrote:
> On 03/07/2018 01:47 AM, Rajkumar Rampelli wrote:
>>
>>>
>>> While I am not opposed to ABI changes, the merits of those would
>>> need to be
>>> discussed on the mailing list. But replacing "fan1_input" with "rpm" is
>>> not an acceptable ABI change, even if it may measure something that
>>> turns
>>> but isn't a fan.
>>>
>>> If this _is_ in fact supposed to be used for something else but
>>> fans, we
>>> would have to discuss what that might be, and if hwmon is the
>>> appropriate
>>> subsystem to measure and report it. This does to some degree lead
>>> back to
>>> my concern of having the "fan" part of this patch series in the pwm
>>> core.
>>> I am still not sure if that makes sense.
>>>
>>> Thanks,
>>> Guenter
>> I am planning to add tachometer support in pwm-fan.c driver
>> (drivers/hwmon/) instead of adding new generic-pwm-tachometer.c
>> driver. Measuring RPM value will be done in pwm-fan driver itself
>> using pwm capture feature and will add new sysfs attributes under
>> this driver to report rpm value of fan.
>
> There is an existing attribute to report the RPM of fans. It is called
> fan[1..n]_input.
>
> "replacing "fan1_input" with "rpm" is not an acceptable ABI change"
>
> Preemptive NACK.
The RPM is measured speed via PWM signal capture which is output from fan.
So should we have the fan[1..n]_output_rpm?
Powered by blists - more mailing lists