From: Stefan Wahren <wahrenst@gmx.net>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: linux-pwm@vger.kernel.org,
Florian Fainelli <f.fainelli@gmail.com>,
Scott Branden <sbranden@broadcom.com>,
Ray Jui <rjui@broadcom.com>, Eric Anholt <eric@anholt.net>,
Thierry Reding <thierry.reding@gmail.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 0/3] pwm: bcm2835: Minor fixes
Date: Sat, 24 Aug 2019 16:17:56 +0200 [thread overview]
Message-ID: <c6d26f19-a9ef-1c64-b8e2-94b7a4f93487@gmx.net> (raw)
In-Reply-To: <20190824105614.wpkvqqxjey6umhrs@pengutronix.de>
Hi Uwe,
Am 24.08.19 um 12:56 schrieb Uwe Kleine-König:
> Hello Stefan,
>
> On Sat, Aug 24, 2019 at 12:05:00PM +0200, Stefan Wahren wrote:
>> Am 24.08.19 um 11:25 schrieb Uwe Kleine-König:
>>> Hello Stefan,
>>>
>>> On Sat, Aug 24, 2019 at 09:07:22AM +0200, Stefan Wahren wrote:
>>>> This small patch series contains minor fixes for clock handling and the
>>>> period range check.
>>> I'd like to understand the various different usecases of PWMs. The
>>> in-kernel consumers are kind of obvious, but sysfs users are not. It
>>> seems you are one of the latter.
>>>
>>> Would you mind sharing what you control using the PWM?
>> not really a PWM user with BCM2835. It's more the motivation as a
>> platform maintainer to keep the drivers in shape. At work we are using
>> sysfs interface for user applications to control ventilation (via hwmon
>> interface) and EV charging (IEC 61851) with a different SoC.
> I don't understand how you use the sysfs interface and still interact
> with the hwmon interface. Other than that, thanks for sharing.
I meant the hwmon sysfs interface. Sure using with pwm sysfs in parallel
isn't possible.
>
>
>>> Assuming you have some interest in this driver: It still uses the legacy
>>> stuff implementing .config, .enable, .disable, .set_polarity. Are you
>>> willing to test (or even implement) a switch to .apply instead?
>> Yes, definitely. This is one of my never ending TODO list [1]. But i
>> would be suprised that you wont have access to a Raspberry Pi.
> So be surprised :-)
>
>>> Just from a quick lock into the driver I wonder a few things, maybe you
>>> can shed some light here. If there is publicly available documenation
>>> for this piece of hardware, feel free to point this out, then I might be
>>> able to work out some of the answers myself.
>> Fortunately yes [2]
> Care to add a link to this document in the driver for others to easily
> find it?
I don't think it's necessary. This document is easy to find via "bcm2835
datasheet".
>
> Best regards
> Uwe
>
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prev parent reply other threads:[~2019-08-24 14:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-24 7:07 [PATCH 0/3] pwm: bcm2835: Minor fixes Stefan Wahren
2019-08-24 7:07 ` [PATCH 1/3] pwm: bcm2835: suppress error message for invalid period_ns Stefan Wahren
2019-08-24 9:26 ` Uwe Kleine-König
2019-08-24 7:07 ` [PATCH 2/3] pwm: bcm2835: fix period_ns range check Stefan Wahren
2019-08-24 9:26 ` Uwe Kleine-König
2019-08-24 7:07 ` [PATCH 3/3] pwm: bcm2835: suppress error message during deferred probe Stefan Wahren
2019-08-24 9:30 ` Uwe Kleine-König
2019-08-24 9:44 ` Stefan Wahren
2019-08-24 9:25 ` [PATCH 0/3] pwm: bcm2835: Minor fixes Uwe Kleine-König
2019-08-24 10:05 ` Stefan Wahren
2019-08-24 10:56 ` Uwe Kleine-König
2019-08-24 14:17 ` Stefan Wahren [this message]
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