From: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
To: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
Vishnu Patekar
<vishnupatekar0510-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
devicetree <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
Subject: Re: [PATCH v2 6/6] ARM: sun8i: dts: Add Ippo-q8h v1.2 with A33 and 1024x600 lcd support
Date: Wed, 3 Jun 2015 11:45:35 +0200 [thread overview]
Message-ID: <20150603094535.GI23777@lukather> (raw)
In-Reply-To: <556D6955.8030708-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
[-- Attachment #1: Type: text/plain, Size: 2692 bytes --]
On Tue, Jun 02, 2015 at 10:29:09AM +0200, Hans de Goede wrote:
> Hi,
>
> On 02-06-15 10:14, Maxime Ripard wrote:
> >On Sat, May 30, 2015 at 04:55:06PM +0200, Hans de Goede wrote:
> >>The Ippo-q8h is a tablet circuit board commonly found in cheap Android
> >>tablets. The v1.2 version can be used with either an A23 or A33 SoC.
> >>
> >>This adds a dts file for the v1.2 board with an A33 SoC and a 1024x600
> >>LCD screen (most of these tablets have a 800x480 screen).
> >
> >I think the difference between the resolution here is more of a case
> >for the DT quirks interface:
> >https://lkml.org/lkml/2015/2/18/258
>
> I would expect the only difference between the 2 dts files to be the
> node describing the lcd panel, so yes that makes somewhat sense.
>
> >Do you know if there's some way to autodetect the two board versions
> >(like a board id somewhere in an EEPROM)?
>
> No, AFAIK there is no way to tell the difference. There is no eeprom no
> the board, and we really cannot rely on the nand contents.
Ok.
> >If not, then maybe u-boot can simply add that board compatible to the
> >list, and we'll base our logic on that when we'll need it.
>
> That means extra logic in u-boot, and on the kernel side, for what
> benefit exactly? Such logic would make sense if there was one u-boot
> image which runtime adjusted itself, but that is not an option.
For what benefit? One kernel image which runtime adjusts itself. It's
especially possible if u-boot's image is not, which seems to be what
you're saying.
> And we can avoid copy and paste on the dts side by putting all
> the common stuff in a common file and including that, I believe
> that that is better (KISS = better) since we've no way to runtime
> do the right thing AFAICT.
My concern is about the ever-growing number of DTS that just are small
variations of one or the other. What about the time when we'll
discover that this board has a variant that has an emmc, and some that
don't have any button, or the i2c bus 2 not wired, and one other that
doesn't have any HDMI?
Do we really want to have a dts called
sun8i-a33-q8h-emmc-lcd800x600-nohdmi-noi2c2-nobuttons.dts?
Especially when we will have the one that we include here that will
not have followed this convention because it was introduced before
that, and that we have a way to deal with this nicely?
You chose to consider the DTS names an ABI, the best way to handle
this is to have a DTS as generic as possible, and leave all these
small variations outside of the name.
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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WARNING: multiple messages have this Message-ID (diff)
From: maxime.ripard@free-electrons.com (Maxime Ripard)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 6/6] ARM: sun8i: dts: Add Ippo-q8h v1.2 with A33 and 1024x600 lcd support
Date: Wed, 3 Jun 2015 11:45:35 +0200 [thread overview]
Message-ID: <20150603094535.GI23777@lukather> (raw)
In-Reply-To: <556D6955.8030708@redhat.com>
On Tue, Jun 02, 2015 at 10:29:09AM +0200, Hans de Goede wrote:
> Hi,
>
> On 02-06-15 10:14, Maxime Ripard wrote:
> >On Sat, May 30, 2015 at 04:55:06PM +0200, Hans de Goede wrote:
> >>The Ippo-q8h is a tablet circuit board commonly found in cheap Android
> >>tablets. The v1.2 version can be used with either an A23 or A33 SoC.
> >>
> >>This adds a dts file for the v1.2 board with an A33 SoC and a 1024x600
> >>LCD screen (most of these tablets have a 800x480 screen).
> >
> >I think the difference between the resolution here is more of a case
> >for the DT quirks interface:
> >https://lkml.org/lkml/2015/2/18/258
>
> I would expect the only difference between the 2 dts files to be the
> node describing the lcd panel, so yes that makes somewhat sense.
>
> >Do you know if there's some way to autodetect the two board versions
> >(like a board id somewhere in an EEPROM)?
>
> No, AFAIK there is no way to tell the difference. There is no eeprom no
> the board, and we really cannot rely on the nand contents.
Ok.
> >If not, then maybe u-boot can simply add that board compatible to the
> >list, and we'll base our logic on that when we'll need it.
>
> That means extra logic in u-boot, and on the kernel side, for what
> benefit exactly? Such logic would make sense if there was one u-boot
> image which runtime adjusted itself, but that is not an option.
For what benefit? One kernel image which runtime adjusts itself. It's
especially possible if u-boot's image is not, which seems to be what
you're saying.
> And we can avoid copy and paste on the dts side by putting all
> the common stuff in a common file and including that, I believe
> that that is better (KISS = better) since we've no way to runtime
> do the right thing AFAICT.
My concern is about the ever-growing number of DTS that just are small
variations of one or the other. What about the time when we'll
discover that this board has a variant that has an emmc, and some that
don't have any button, or the i2c bus 2 not wired, and one other that
doesn't have any HDMI?
Do we really want to have a dts called
sun8i-a33-q8h-emmc-lcd800x600-nohdmi-noi2c2-nobuttons.dts?
Especially when we will have the one that we include here that will
not have followed this convention because it was introduced before
that, and that we have a way to deal with this nicely?
You chose to consider the DTS names an ABI, the best way to handle
this is to have a DTS as generic as possible, and leave all these
small variations outside of the name.
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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next prev parent reply other threads:[~2015-06-03 9:45 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-30 14:55 [PATCH v2 0/6] Introduce Allwinner A33 support Hans de Goede
2015-05-30 14:55 ` Hans de Goede
[not found] ` <1432997706-20172-1-git-send-email-hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-30 14:55 ` [PATCH v2 1/6] ARM: sunxi: Add Machine support for A33 Hans de Goede
2015-05-30 14:55 ` Hans de Goede
[not found] ` <1432997706-20172-2-git-send-email-hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-02 7:28 ` Maxime Ripard
2015-06-02 7:28 ` Maxime Ripard
2015-05-30 14:55 ` [PATCH v2 2/6] pinctrl: sunxi: Add allwinner A33 PIO controller support Hans de Goede
2015-05-30 14:55 ` Hans de Goede
2015-05-30 14:55 ` [PATCH v2 3/6] ARM: dts: sun8i: Add sun8i-a23-a33 dtsi Hans de Goede
2015-05-30 14:55 ` Hans de Goede
[not found] ` <1432997706-20172-4-git-send-email-hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-02 7:51 ` Maxime Ripard
2015-06-02 7:51 ` Maxime Ripard
2015-06-02 8:08 ` Hans de Goede
2015-06-02 8:08 ` Hans de Goede
[not found] ` <556D6487.4010207-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-02 8:21 ` Maxime Ripard
2015-06-02 8:21 ` Maxime Ripard
2015-05-30 14:55 ` [PATCH v2 4/6] ARM: dts: sun8i: Add sun8i-a33 dtsi Hans de Goede
2015-05-30 14:55 ` Hans de Goede
[not found] ` <1432997706-20172-5-git-send-email-hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-02 7:55 ` Maxime Ripard
2015-06-02 7:55 ` Maxime Ripard
2015-05-30 14:55 ` [PATCH v2 5/6] ARM: dts: sun8i: Add ET-Q8 A33 support Hans de Goede
2015-05-30 14:55 ` Hans de Goede
[not found] ` <1432997706-20172-6-git-send-email-hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-02 7:56 ` Maxime Ripard
2015-06-02 7:56 ` Maxime Ripard
2015-05-30 14:55 ` [PATCH v2 6/6] ARM: sun8i: dts: Add Ippo-q8h v1.2 with A33 and 1024x600 lcd support Hans de Goede
2015-05-30 14:55 ` Hans de Goede
[not found] ` <1432997706-20172-7-git-send-email-hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-02 8:14 ` Maxime Ripard
2015-06-02 8:14 ` Maxime Ripard
2015-06-02 8:29 ` Hans de Goede
2015-06-02 8:29 ` Hans de Goede
[not found] ` <556D6955.8030708-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-03 9:45 ` Maxime Ripard [this message]
2015-06-03 9:45 ` Maxime Ripard
2015-06-03 11:12 ` Hans de Goede
2015-06-03 11:12 ` Hans de Goede
[not found] ` <556EE104.3090803-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-13 13:50 ` Maxime Ripard
2015-06-13 13:50 ` Maxime Ripard
2015-06-13 14:18 ` Hans de Goede
2015-06-13 14:18 ` Hans de Goede
[not found] ` <557C3BD3.6030105-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-16 17:41 ` Maxime Ripard
2015-06-16 17:41 ` Maxime Ripard
2015-06-17 7:16 ` Hans de Goede
2015-06-17 7:16 ` Hans de Goede
[not found] ` <55811EB2.4060302-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-18 18:37 ` Maxime Ripard
2015-06-18 18:37 ` Maxime Ripard
2015-06-18 20:16 ` Hans de Goede
2015-06-18 20:16 ` Hans de Goede
2015-06-14 18:16 ` Pantelis Antoniou
2015-06-14 18:16 ` Pantelis Antoniou
[not found] ` <85E62D2D-5387-433B-A944-7F2145459F08-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
2015-06-16 17:55 ` Maxime Ripard
2015-06-16 17:55 ` Maxime Ripard
2015-06-16 19:33 ` Pantelis Antoniou
2015-06-16 19:33 ` Pantelis Antoniou
[not found] ` <D4216F2D-0556-4849-B1DF-8E4D250006B4-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
2015-06-17 7:19 ` Hans de Goede
2015-06-17 7:19 ` Hans de Goede
[not found] ` <55811F94.3080608-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-17 7:26 ` Pantelis Antoniou
2015-06-17 7:26 ` Pantelis Antoniou
2015-06-17 7:16 ` Hans de Goede
2015-06-17 7:16 ` Hans de Goede
[not found] ` <55811ED9.9090503-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-06-18 17:52 ` Maxime Ripard
2015-06-18 17:52 ` Maxime Ripard
2015-05-30 20:43 ` [PATCH v2 0/6] Introduce Allwinner A33 support jonsmirl-Re5JQEeQqe8AvxtiuMwx3w
2015-05-30 20:43 ` [linux-sunxi] " jonsmirl at gmail.com
2015-06-02 7:43 ` Chen-Yu Tsai
2015-06-02 7:43 ` Chen-Yu Tsai
2016-06-13 19:10 ` ernestovm07
2016-06-13 19:10 ` ernestovm07 at gmail.com
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