LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Frank Lee <tiny.windzz@gmail.com>,
	Icenowy Zheng <icenowy@aosc.io>,
	Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org, lars@metafoo.de,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-iio@vger.kernel.org, Chen-Yu Tsai <wens@csie.org>,
	robh+dt@kernel.org,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	pmeerw@pmeerw.net, knaack.h@gmx.de,
	Lee Jones <lee.jones@linaro.org>,
	Jonathan Cameron <jic23@kernel.org>
Subject: Re: [PATCH 1/7] iio: adc: sun4i-gpadc: rework for support multiple thermal sensor
Date: Tue, 7 May 2019 15:59:12 +0200	[thread overview]
Message-ID: <20190507135912.4lev7ly2w4drlt7s@flea> (raw)
In-Reply-To: <20190506175525.swc5u7j6ntry7v3g@core.my.home>

[-- Attachment #1: Type: text/plain, Size: 5231 bytes --]

On Mon, May 06, 2019 at 07:55:25PM +0200, Ondřej Jirman wrote:
> On Tue, May 07, 2019 at 01:08:39AM +0800, Frank Lee wrote:
> > On Tue, May 7, 2019 at 12:52 AM Icenowy Zheng <icenowy@aosc.io> wrote:
> > >
> > > 在 2019-05-06一的 14:28 +0200,Maxime Ripard写道:
> > > > Hi,
> > > >
> > > > On Sun, May 05, 2019 at 04:22:15PM +0100, Jonathan Cameron wrote:
> > > > > On Fri,  3 May 2019 03:28:07 -0400
> > > > > Yangtao Li <tiny.windzz@gmail.com> wrote:
> > > > >
> > > > > > For some SOCs, there are more than one thermal sensor, and there
> > > > > > are
> > > > > > currently four sensors on the A80. So we need to do some work in
> > > > > > order
> > > > > > to support multiple thermal sensors:
> > > > > >
> > > > > >   1) add sensor_count in gpadc_data.
> > > > > >   2) introduce sun4i_sensor_tzd in sun4i_gpadc_iio, to support
> > > > > > multiple
> > > > > >      thermal_zone_device and distinguish between different
> > > > > > sensors.
> > > > > >   3) modify read temperature and initialization function.
> > > > >
> > > > > This comment doesn't mention the devm change. If it had it would
> > > > > have
> > > > > raised immediate alarm bells.
> > > > >
> > > > > I'm also not keen on the web of pointers that this driver is
> > > > > steadily
> > > > > evolving.  I can't immediately see how to reduce that complexity
> > > > > however.
> > > >
> > > > So I might be responsible for that, and looking back, this has been a
> > > > mistake.
> > > >
> > > > This driver was initally put together to support a controller found
> > > > in
> > > > older (A10 up to A31) Allwinner SoCs. This controller had an ADC
> > > > driver that could be operated as a touchscreen controller, and was
> > > > providing a CPU temperature sensor and a general purpose ADC.
> > > >
> > > > However, we already had a driver for that controller in drivers/input
> > > > to report the CPU temperature, and the one in IIO was introduced to
> > > > support the general purpose ADC (and the CPU temperature). The long
> > > > term goal was to add the touchscreen feature as well eventually so
> > > > that we could remove the one in drivers/input. That didn't happen.
> > > >
> > > > At the same time, the Allwinner hardware slowly evolved to remove the
> > > > touchscreen and ADC features, and only keep the CPU temperature
> > > > readout. It then evolved further on to support multiple temperatures
> > > > (for different clusters, the GPU, and so on).
> > > >
> > > > So, today, we're in a situation where I was pushing everything into
> > > > that IIO drivers since there was similiraties between all the
> > > > generations, but the fact that we have to support so many odd cases
> > > > (DT bindings compatibility, controllers with and without ADC, etc)
> > > > that it becomes a real mess.
> > > >
> > > > And that mess isn't really used by anybody, since we want to have the
> > > > touchscreen.
> > > >
> > > > There's only one SoC that is supported only by that driver, which is
> > > > the A33 that only had a CPU temperature readout, and is still pretty
> > > > similar to the latest SoC from Allwinner (that is supported by this
> > > > series).
> > > >
> > > > I guess, for everyone's sanity and in order to not stall this
> > > > further,
> > > > it would just be better to create an hwmon driver for the A33 (and
> > > > onwards, including the H6) for the SoC that just have the temperature
> > > > readout feature. And for the older SoC, we just keep the older driver
> > > > under input/. Once the A33 is supported, we'll remove the driver in
> > > > IIO (and the related bits in drivers/mfd).
> >
> > a hwmon driver or a thermal driver?
> >
> > >
> > > I think a thermal driver is better.
> >
> > This is what I hope to see a few months ago.
> >
> > >
> > > Other SoCs' thermal sensor drivers are all thermal drivers.
> > >
> > > >
> > > > Armbian already has a driver for that they never upstreamed iirc, so
> > > > it might be a good starting point, and we would add the support for
> > > > the H6. How does that sound?
> > >
> > > I think the developer abandoned to upstream it because of the previous
> > > problem ;-)
> > >
> > > Maybe it can be taken and add A33&H6 support.
> >
> > If OK, I am going to start some thermal driver work this weekend.  : )
>
> There are plenty of thermal drivers flying around, with varying levels
> of support for various SoCs:
>
> - H3/H5: https://megous.com/git/linux/commit/?h=ths-5.1&id=b8e20c5da7a00b3a3fa1b274fc8d5bea95872b0a
> - A83T: https://megous.com/git/linux/commit/?h=ths-5.1&id=796dff9a946fd475cc1e4bb948a723ea841c640c
> - H6: https://megous.com/git/linux/commit/?h=opi3-5.1&id=aeab762c19b4aa228a295258c9d6b2e1f143bf86
>
> For H3/H5 Icenowy also tried to upstream some variant of my THS driver, with
> better SID/calibration data reading support.
>
> I'd suggest starting with the H6 driver above (as that implements the
> calibration data readout correctly), and make it so that it can support multiple
> SoCs.

Yeah, that seems like a good plan

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

  reply	other threads:[~2019-05-07 13:59 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-03  7:28 [PATCH 0/7] Add support for H6 " Yangtao Li
2019-05-03  7:28 ` [PATCH 1/7] iio: adc: sun4i-gpadc: rework for support multiple " Yangtao Li
2019-05-05 15:22   ` Jonathan Cameron
2019-05-06 12:28     ` Maxime Ripard
2019-05-06 16:52       ` Icenowy Zheng
2019-05-06 17:08         ` Frank Lee
2019-05-06 17:55           ` Ondřej Jirman
2019-05-07 13:59             ` Maxime Ripard [this message]
2019-05-03  7:28 ` [PATCH 2/7] iio: adc: sun4i-gpadc: introduce temp_data in gpadc_data Yangtao Li
2019-05-03  7:28 ` [PATCH 3/7] iio: adc: sun4i-gpadc: introduce gpadc_enable and gpadc_disable " Yangtao Li
2019-05-03  7:28 ` [PATCH 4/7] iio: adc: sun4i-gpadc-iio: support clocks and reset Yangtao Li
2019-05-03  7:28 ` [PATCH 5/7] dt-bindings: mfd: Add H6 GPADC binding Yangtao Li
2019-05-08 11:44   ` Lee Jones
2019-05-03  7:28 ` [PATCH 6/7] iio: adc: sun4i-gpadc-iio: add support for H6 thermal sensor Yangtao Li
2019-05-05 15:25   ` Jonathan Cameron
2019-05-08 11:45   ` Lee Jones
2019-05-03  7:28 ` [PATCH 7/7] iio: adc: sun4i-gpadc-iio convert to SPDX license tags Yangtao Li
2019-05-03  9:18   ` Maxime Ripard

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=20190507135912.4lev7ly2w4drlt7s@flea \
    --to=maxime.ripard@bootlin.com \
    --cc=devicetree@vger.kernel.org \
    --cc=icenowy@aosc.io \
    --cc=jic23@kernel.org \
    --cc=knaack.h@gmx.de \
    --cc=lars@metafoo.de \
    --cc=lee.jones@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-iio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=pmeerw@pmeerw.net \
    --cc=robh+dt@kernel.org \
    --cc=tiny.windzz@gmail.com \
    --cc=wens@csie.org \
    --subject='Re: [PATCH 1/7] iio: adc: sun4i-gpadc: rework for support multiple thermal sensor' \
    /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).