linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Lee Jones <lee.jones@linaro.org>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Rob Herring <robh@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kernel@stlinux.com,
	maxime.coquelin@st.com, patrice.chotard@st.com,
	linux-pwm@vger.kernel.org, devicetree@vger.kernel.org
Subject: Re: [PATCH v3 20/20] dt-bindings: pwm: sti: Update DT bindings with recent changes
Date: Wed, 13 Jul 2016 10:02:46 +0100	[thread overview]
Message-ID: <20160713090246.GA11154@dell> (raw)
In-Reply-To: <20160610145323.GO27142@ulmo.ba.sec>

On Fri, 10 Jun 2016, Thierry Reding wrote:
> On Fri, Jun 10, 2016 at 03:06:35PM +0100, Lee Jones wrote:
> > On Fri, 10 Jun 2016, Thierry Reding wrote:
> > 
> > > > > > The second documentation adaption entails adding support for PWM
> > > > > > capture devices.  A new clock is required as well as an IRQ line.
> > > > > > We're also adding a new property similar to the one described
> > > > > > above, but for capture channels.  Typically, there will be less
> > > > > > capture channels than PWM-out, since all channels have the latter
> > > > > > capability, but only some have capture support.
> > > > > 
> > > > > Humm, sounds like all of this should be implied from compatible strings.
> > > > 
> > > > You mean have a bunch of of_machine_is_compatibles() scattered around?
> > > 
> > > I don't understand why you need this at all. Quite frankly I don't even
> > > know why st,pwm-num-devs exists. I probably missed it back at the time.
> > > Usually, like Rob suggests, this should be inferred from the compatible
> > > string. One commonly used way to avoid scattering explicit checks for
> > > the compatible string is to add this information to the of_device_id
> > > table. See a bunch of existing drivers for reference.
> > 
> > Yes, I am aware of the strategy, and happy to oblige if this is your
> > suggestion.  I'll move all platform data into the driver and eradicate
> > the DT properties.
> 
> Great!

Sorry it's taken so long to get back around to this.

So I just had a crack at implementing this solution and ran into
issues.  Unfortunately, the configuration isn't easy to describe using
compatible strings.

Unless we are prepared to have strings like:

  st,sti-pwm-stih407-pwm0
  st,sti-pwm-stih407-pwm1
  st,sti-pwm-stih416-pwm0
  st,sti-pwm-stih416-pwm1

Or perhaps:

  st,sti-pwm-4out-2cpt
  st,sti-pwm-1out-1cpt

... since some of the PWMs have an odd number of OUT and CPT
channels/devices.  In my opinion however, this is ugly.  I don't think
we do this for any other type of channel/device/port etc, do we?

Personally I think there isn't anything wrong with having DT
properties describing how many channels/devices there are, but I'm
okay with whatever you both decide.  No skin of my nose really. :)

What say you?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

  parent reply	other threads:[~2016-07-13  9:02 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-08  9:21 [PATCH v3 00/20] pwm: Add support for PWM Capture Lee Jones
2016-06-08  9:21 ` [PATCH v3 01/20] ARM: dts: STi: Rename properites in line with PWM naming conventions Lee Jones
2016-06-08  9:21 ` [PATCH v3 02/20] ARM: dts: STiH407: Supply PWM Capture IRQ Lee Jones
2016-06-08  9:21 ` [PATCH v3 03/20] ARM: dts: STiH407: Declare PWM Capture data lines via Pinctrl Lee Jones
2016-06-08  9:21 ` [PATCH v3 04/20] ARM: dts: STiH416: Supply PWM Capture IRQs Lee Jones
2016-06-08  9:21 ` [PATCH v3 05/20] ARM: dts: STiH416: Declare PWM Capture data lines via Pinctrl Lee Jones
2016-06-08  9:21 ` [PATCH v3 06/20] ARM: dts: STiH416: Define PWM Capture clock Lee Jones
2016-06-08  9:21 ` [PATCH v3 07/20] ARM: dts: STiH416: Define the number of PWM Capture channels Lee Jones
2016-06-08  9:21 ` [PATCH v3 08/20] pwm: Add PWM Capture support Lee Jones
2016-06-10 13:53   ` Thierry Reding
2016-06-10 14:38     ` Lee Jones
2016-06-10 16:39       ` Thierry Reding
2016-06-20 11:14         ` Lee Jones
2016-06-08  9:21 ` [PATCH v3 09/20] pwm: sti: Rename channel => device Lee Jones
2016-06-08  9:21 ` [PATCH v3 10/20] pwm: sysfs: Add PWM Capture support Lee Jones
2016-06-10 14:04   ` Thierry Reding
2016-06-10 14:36     ` Lee Jones
2016-06-08  9:21 ` [PATCH v3 11/20] pwm: sti: Reorganise register names in preparation for new functionality Lee Jones
2016-06-08  9:21 ` [PATCH v3 12/20] pwm: sti: Only request clock rate when you need to Lee Jones
2016-06-08  9:21 ` [PATCH v3 13/20] pwm: sti: Supply PWM Capture register addresses and bit locations Lee Jones
2016-06-08  9:21 ` [PATCH v3 14/20] pwm: sti: Supply PWM Capture clock handling Lee Jones
2016-06-08  9:21 ` [PATCH v3 15/20] pwm: sti: Initialise PWM Capture device data Lee Jones
2016-06-08  9:21 ` [PATCH v3 16/20] pwm: sti: Add support for PWM Capture IRQs Lee Jones
2016-06-08  9:21 ` [PATCH v3 17/20] pwm: sti: Add PWM Capture call-back Lee Jones
2016-06-08  9:21 ` [PATCH v3 18/20] pwm: sti: It's now valid for number of PWM channels to be zero Lee Jones
2016-06-08  9:21 ` [PATCH v3 19/20] pwm: sti: Take the opportunity to conduct a little house keeping Lee Jones
2016-06-08  9:21 ` [PATCH v3 20/20] dt-bindings: pwm: sti: Update DT bindings with recent changes Lee Jones
2016-06-08 20:51   ` Rob Herring
2016-06-09 11:41     ` Lee Jones
2016-06-10 13:18       ` Thierry Reding
2016-06-10 14:06         ` Lee Jones
2016-06-10 14:53           ` Thierry Reding
2016-06-10 15:19             ` Lee Jones
2016-07-13  9:02             ` Lee Jones [this message]
2016-06-10 13:10     ` Thierry Reding

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=20160713090246.GA11154@dell \
    --to=lee.jones@linaro.org \
    --cc=devicetree@vger.kernel.org \
    --cc=kernel@stlinux.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pwm@vger.kernel.org \
    --cc=maxime.coquelin@st.com \
    --cc=patrice.chotard@st.com \
    --cc=robh@kernel.org \
    --cc=thierry.reding@gmail.com \
    --subject='Re: [PATCH v3 20/20] dt-bindings: pwm: sti: Update DT bindings with recent changes' \
    /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

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).