From: Rob Herring <robh@kernel.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>,
Jean Delvare <jdelvare@suse.com>,
Linux HWMON List <linux-hwmon@vger.kernel.org>,
devicetree@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH v2 1/2] dt-bindings: hwmon: add binding documentation for adt7475
Date: Mon, 19 Nov 2018 15:40:20 -0600 [thread overview]
Message-ID: <CAL_JsqKgBkR4WN+aTKdHSfCZ8EH39yLCeLwXwmf+nd0_cAy+mw@mail.gmail.com> (raw)
In-Reply-To: <f3a29bc9-dbfc-bfb8-8707-2b67d96c2e04@roeck-us.net>
On Sun, Nov 18, 2018 at 4:56 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 11/17/18 7:29 AM, Rob Herring wrote:
> > On Fri, Nov 09, 2018 at 11:56:06AM +1300, Chris Packham wrote:
> >> With the addition of the invert-pwm property the adt7475 needs its own
> >> binding documentation rather being captured under trivial-devices.txt.
> >>
> >> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> >> ---
> >> Changes in v2:
> >> - use pwm-polarity attiribute to indicate normal or inverted polarity.
> >>
> >> .../devicetree/bindings/hwmon/adt7475.txt | 24 +++++++++++++++++++
> >> .../devicetree/bindings/trivial-devices.txt | 4 ----
> >> 2 files changed, 24 insertions(+), 4 deletions(-)
> >> create mode 100644 Documentation/devicetree/bindings/hwmon/adt7475.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt b/Documentation/devicetree/bindings/hwmon/adt7475.txt
> >> new file mode 100644
> >> index 000000000000..d9212b5e9036
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt
> >> @@ -0,0 +1,24 @@
> >> +*ADT7475 hwmon sensor.
> >> +
> >> +Required properties:
> >> +- compatible: One of
> >> + "adi,adt7473"
> >> + "adi,adt7475"
> >> + "adi,adt7476"
> >> + "adi,adt7490"
> >> +
> >> +- reg: I2C address
> >> +
> >> +optional properties:
> >> +
> >> +- pwm-polarity: This configures the polarity of the PWM. 0
> >> + (PWM_POLARITY_NORMAL) uses logic high for 100% duty cycle. 1
> >> + (PWM_POLARITY_INVERSED) uses logic low for 100% duty cycle.
> >
> > So we're using part of the PWM binding, but none of the rest of it? What
> > is the PWM connection here?
> > The chip has a built-in PWM controller to control fan speeds. PWM frequency
> as well as PWM polarity are configurable. I had suggested to use the terminology
> from Documentation/devicetree/bindings/pwm/pwm.txt. Other than terminology there
> is no connection to a standard pwm controller.
Ah, a fan controller. Please make that clear.
The fan related bindings need a bit of work IMO. We have the start of
something somewhat common with aspeed and npcm bindings, but they
could use a bit more work. We need the fan and controller bindings to
be somewhat separate where a fan node for a given type of fan doesn't
depend on the controller node.
AIUI, all fans are not the same, so does this controller only work
with 1 type of fan and not need any more board level config? Isn't fan
speed not linear with PWM duty cycle and need some sort of map.
> Another option/possibility would be to use a boolean, such as pwm-polarity-inverted.
> We are open to suggestions.
>
> > It sounds like this is common for sensors, so this should be documented
> > somewhere common.
> >
> Sure, no problem. Any suggestion where ?
hwmon/fan.txt (that doesn't exist yet.)
Probably all of bindings/hwmon/ should be split up by class of device.
Rob
next prev parent reply other threads:[~2018-11-19 21:40 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-08 22:56 [PATCH v2 0/2] hwmon: (adt7475): inverted PWM output Chris Packham
2018-11-08 22:56 ` [PATCH v2 1/2] dt-bindings: hwmon: add binding documentation for adt7475 Chris Packham
2018-11-12 0:34 ` Chris Packham
2018-11-17 15:29 ` Rob Herring
2018-11-18 22:56 ` Guenter Roeck
2018-11-19 21:40 ` Rob Herring [this message]
2018-11-19 21:55 ` Chris Packham
2018-11-08 22:56 ` [PATCH v2 2/2] hwmon: (adt7475): add support for inverting the pwm output Chris Packham
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAL_JsqKgBkR4WN+aTKdHSfCZ8EH39yLCeLwXwmf+nd0_cAy+mw@mail.gmail.com \
--to=robh@kernel.org \
--cc=chris.packham@alliedtelesis.co.nz \
--cc=devicetree@vger.kernel.org \
--cc=jdelvare@suse.com \
--cc=linux-hwmon@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@roeck-us.net \
--cc=mark.rutland@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).