All of lore.kernel.org
 help / color / mirror / Atom feed
From: Tomasz Figa <t.figa@samsung.com>
To: devicetree-discuss@lists.ozlabs.org
Cc: Tushar Behera <tushar.behera@linaro.org>,
	Girish KS <girishks2000@gmail.com>,
	"linux-samsung-soc@vger.kernel.org"
	<linux-samsung-soc@vger.kernel.org>,
	"patches@linaro.org" <patches@linaro.org>,
	dtor@mail.ru, Manish Badarkhe <badarkhe.manish@gmail.com>,
	"kgene.kim@samsung.com" <kgene.kim@samsung.com>,
	david@protonic.nl, "Kumar, Anil" <anilkumar.v@ti.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/5] ARM: dts: exynos5250-arndale: Add node entry for gpio-buttons
Date: Thu, 07 Feb 2013 12:25:25 +0100	[thread overview]
Message-ID: <18141670.7lKVRsjORY@amdc1227> (raw)
In-Reply-To: <5113768B.90102@linaro.org>

On Thursday 07 of February 2013 15:10:27 Tushar Behera wrote:
> +CC: David Jander <david@protonic.nl>
> +CC: Dmitry Torokhov <dtor@mail.ru>
> 
> On 02/07/2013 01:13 PM, Girish KS wrote:
> >>>>>> +
> >>>>>> +    gpio_keys {
> >>>>>> +            compatible = "gpio-keys";
> >>>>>> +            #address-cells = <1>;
> >>>>>> +            #size-cells = <0>;
> >>>>> 
> >>>>> Just want to understand why these properties are here?
> >>>>> As these properties are for child dt node. But have not seen
> >>>>> anyone is using here.
> >>>> 
> >>>> That is how gpio_keys node entries are defined in other .dts files.
> >>> 
> >>> I have gone through example for address-cells and size-cells in
> >>> following link:
> >>> http://devicetree.org/mediawiki/index.php?title=Device_Tree_Usage&s
> >>> table=1#CPU_addressing
> >>> 
> >>> which indicates that these fields are for child "reg".
> >>> I think, here in child node there is no "reg". so there is no use
> >>> of address-cells and size-cells propeties.
> >> 
> >> Please check Documentation/devicetree/bindings/gpio/gpio_keys.txt
> >> 
> >> And whether these properties are required or not, I will let device
> >> tree experts to comment on that.
> >> 
> >> As such, currently all node entries for gpio_keys use these
> >> properties.
> > 
> > you can just verify by a simple test.
> > delete the 2 lines. address-cells and size cells.
> > this will have no affect.
> > now with these 2 lines deleted lines add a dummy reg property with
> > address and cell. dtb compiler will warn.
> > So I think what manish reffered is right.
> > There is also a reference of smdk4210 for kepads.
> 
> Right. Compilation is ok even after removing the address-cell and
> size-cell properties.
> 
> But since this is used across all the instances, I would like to know
> the view of the authors on this.
> 
> David, Dimitry,
> 
> Can you please let us know your opinion on this? If these properties are
> not required, then we can remove them from the documentation and from
> node entries in several other dts files.

The #address-cells and #size-cells are used only together with reg 
properties of sub nodes. They define how many cells in reg specifier are 
used for registers address and length.

So, if you have #address-cells = <1> and #size-cells = <0>, then your reg 
specifier will be simply <addr>. You can get more complex specifiers using 
more address cells and size cells, like:

#address-cells = <3>;
#size-cells = <1>;

subdev@1,2,3 {
	reg = <1 2 3 0x1000>;
	/* ... */
};

If you don't intend to use reg property for child device addressing then 
you don't define #address-cells and #size-cells properties.

I think that the documentation of gpio_keys binding should be corrected 
and possibly also moved to bindings/input instead of bindings/gpio, as 
this directory is intended to be used for GPIO controllers, not GPIO 
consumers.

Best regards,
-- 
Tomasz Figa
Samsung Poland R&D Center
SW Solution Development, Linux Platform

WARNING: multiple messages have this Message-ID
From: t.figa@samsung.com (Tomasz Figa)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/5] ARM: dts: exynos5250-arndale: Add node entry for gpio-buttons
Date: Thu, 07 Feb 2013 12:25:25 +0100	[thread overview]
Message-ID: <18141670.7lKVRsjORY@amdc1227> (raw)
In-Reply-To: <5113768B.90102@linaro.org>

On Thursday 07 of February 2013 15:10:27 Tushar Behera wrote:
> +CC: David Jander <david@protonic.nl>
> +CC: Dmitry Torokhov <dtor@mail.ru>
> 
> On 02/07/2013 01:13 PM, Girish KS wrote:
> >>>>>> +
> >>>>>> +    gpio_keys {
> >>>>>> +            compatible = "gpio-keys";
> >>>>>> +            #address-cells = <1>;
> >>>>>> +            #size-cells = <0>;
> >>>>> 
> >>>>> Just want to understand why these properties are here?
> >>>>> As these properties are for child dt node. But have not seen
> >>>>> anyone is using here.
> >>>> 
> >>>> That is how gpio_keys node entries are defined in other .dts files.
> >>> 
> >>> I have gone through example for address-cells and size-cells in
> >>> following link:
> >>> http://devicetree.org/mediawiki/index.php?title=Device_Tree_Usage&s
> >>> table=1#CPU_addressing
> >>> 
> >>> which indicates that these fields are for child "reg".
> >>> I think, here in child node there is no "reg". so there is no use
> >>> of address-cells and size-cells propeties.
> >> 
> >> Please check Documentation/devicetree/bindings/gpio/gpio_keys.txt
> >> 
> >> And whether these properties are required or not, I will let device
> >> tree experts to comment on that.
> >> 
> >> As such, currently all node entries for gpio_keys use these
> >> properties.
> > 
> > you can just verify by a simple test.
> > delete the 2 lines. address-cells and size cells.
> > this will have no affect.
> > now with these 2 lines deleted lines add a dummy reg property with
> > address and cell. dtb compiler will warn.
> > So I think what manish reffered is right.
> > There is also a reference of smdk4210 for kepads.
> 
> Right. Compilation is ok even after removing the address-cell and
> size-cell properties.
> 
> But since this is used across all the instances, I would like to know
> the view of the authors on this.
> 
> David, Dimitry,
> 
> Can you please let us know your opinion on this? If these properties are
> not required, then we can remove them from the documentation and from
> node entries in several other dts files.

The #address-cells and #size-cells are used only together with reg 
properties of sub nodes. They define how many cells in reg specifier are 
used for registers address and length.

So, if you have #address-cells = <1> and #size-cells = <0>, then your reg 
specifier will be simply <addr>. You can get more complex specifiers using 
more address cells and size cells, like:

#address-cells = <3>;
#size-cells = <1>;

subdev at 1,2,3 {
	reg = <1 2 3 0x1000>;
	/* ... */
};

If you don't intend to use reg property for child device addressing then 
you don't define #address-cells and #size-cells properties.

I think that the documentation of gpio_keys binding should be corrected 
and possibly also moved to bindings/input instead of bindings/gpio, as 
this directory is intended to be used for GPIO controllers, not GPIO 
consumers.

Best regards,
-- 
Tomasz Figa
Samsung Poland R&D Center
SW Solution Development, Linux Platform

  reply	other threads:[~2013-02-07 11:25 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-07  5:15 Tushar Behera
2013-02-07  5:15 ` Tushar Behera
2013-02-07  5:15 ` [PATCH 2/5] ARM: dts: exynos5250-arndale: Add PMIC node entry Tushar Behera
2013-02-07  5:15   ` Tushar Behera
2013-02-07  5:49   ` Kumar, Anil
2013-02-07  5:49     ` Kumar, Anil
2013-02-07  5:56     ` Tushar Behera
2013-02-07  5:56       ` Tushar Behera
2013-02-11  0:38       ` amit daniel kachhap
2013-02-11  0:38         ` amit daniel kachhap
2013-03-11  2:05         ` Kukjin Kim
2013-03-11  2:05           ` Kukjin Kim
2013-02-07  5:15 ` [PATCH 3/5] ARM: dts: exynos5250-arndale: Add vmmc regulator support Tushar Behera
2013-02-07  5:15   ` Tushar Behera
2013-02-07  5:15 ` [PATCH 4/5] ARM: dts: exynos5250-arndale: Add MFC codec support Tushar Behera
2013-02-07  5:15   ` Tushar Behera
2013-02-07  5:15 ` [PATCH 5/5] ARM: dts: exynos5250-arndale: Add HDMI HPD and regulator node Tushar Behera
2013-02-07  5:15   ` Tushar Behera
2013-02-07  6:17 ` [PATCH 1/5] ARM: dts: exynos5250-arndale: Add node entry for gpio-buttons Kumar, Anil
2013-02-07  6:17   ` Kumar, Anil
2013-02-07  6:26   ` Tushar Behera
2013-02-07  6:26     ` Tushar Behera
2013-02-07  6:36     ` Manish Badarkhe
2013-02-07  6:36       ` Manish Badarkhe
2013-02-07  6:56       ` Tushar Behera
2013-02-07  6:56         ` Tushar Behera
2013-02-07  7:43         ` Girish KS
2013-02-07  7:43           ` Girish KS
2013-02-07  9:40           ` Tushar Behera
2013-02-07  9:40             ` Tushar Behera
2013-02-07 11:25             ` Tomasz Figa [this message]
2013-02-07 11:25               ` Tomasz Figa
2013-02-07 10:30 ` Tomasz Figa
2013-02-07 10:30   ` Tomasz Figa
2013-03-11  2:05   ` Kukjin Kim
2013-03-11  2:05     ` Kukjin Kim
2013-03-11  9:44     ` Tushar Behera
2013-03-11  9:44       ` Tushar Behera

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=18141670.7lKVRsjORY@amdc1227 \
    --to=t.figa@samsung.com \
    --cc=anilkumar.v@ti.com \
    --cc=badarkhe.manish@gmail.com \
    --cc=david@protonic.nl \
    --cc=devicetree-discuss@lists.ozlabs.org \
    --cc=dtor@mail.ru \
    --cc=girishks2000@gmail.com \
    --cc=kgene.kim@samsung.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=patches@linaro.org \
    --cc=tushar.behera@linaro.org \
    --subject='Re: [PATCH 1/5] ARM: dts: exynos5250-arndale: Add node entry for gpio-buttons' \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.