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Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes

Started byMaxime Ripard <maxime.ripard@free-electrons.com>
First post2016-11-25 16:30 +0100
Last post2016-12-05 10:50 +0100
Articles 6 — 2 participants

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  Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-11-25 16:30 +0100
    Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes Emmanuel Vadot <manu@bidouilliste.com> - 2016-11-25 22:10 +0100
      Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-12-01 10:30 +0100
        Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes Emmanuel Vadot <manu@bidouilliste.com> - 2016-12-01 11:30 +0100
          Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-12-05 10:30 +0100
            Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes Emmanuel Vadot <manu@bidouilliste.com> - 2016-12-05 10:50 +0100

#1530350 — Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes

FromMaxime Ripard <maxime.ripard@free-electrons.com>
Date2016-11-25 16:30 +0100
SubjectRe: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes
Message-ID<sHqBP-2hw-15@gated-at.bofh.it>

[Multipart message — attachments visible in raw view] — view raw

On Thu, Nov 24, 2016 at 09:05:09PM +0100, Emmanuel Vadot wrote:
> On Thu, 24 Nov 2016 20:55:17 +0100
> Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> 
> > On Tue, Nov 22, 2016 at 06:06:16PM +0100, Emmanuel Vadot wrote:
> > > The spi0 controller on the A20 have up to 4 CS (Chip Select) while the
> > > others three only have 1.
> > > Add the num-cs property to each node.
> > > 
> > > Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
> > 
> > I don't think we have any code that uses it at the moment. What is the
> > rationale behind this patch?
> > 
> > Thanks!
> > Maxime
> > 
> > -- 
> > Maxime Ripard, Free Electrons
> > Embedded Linux and Kernel engineering
> > http://free-electrons.com
> 
>  Hi Maxime,
> 
>  If num-cs isn't present nothing prevent to start a transfer with a
> non-valid CS pin, resulting in an error.
>  num-cs are default property especially made for this and a SPI driver
> should try to get the property at probe/attach time.

Yes, but as far as I know, our driver doesn't. I'm all in for having
support for that in our driver, but without it, that patch is kind of
useless.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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#1530529

FromEmmanuel Vadot <manu@bidouilliste.com>
Date2016-11-25 22:10 +0100
Message-ID<sHvUR-5L2-11@gated-at.bofh.it>
In reply to#1530350
On Fri, 25 Nov 2016 16:20:47 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> On Thu, Nov 24, 2016 at 09:05:09PM +0100, Emmanuel Vadot wrote:
> > On Thu, 24 Nov 2016 20:55:17 +0100
> > Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> > 
> > > On Tue, Nov 22, 2016 at 06:06:16PM +0100, Emmanuel Vadot wrote:
> > > > The spi0 controller on the A20 have up to 4 CS (Chip Select) while the
> > > > others three only have 1.
> > > > Add the num-cs property to each node.
> > > > 
> > > > Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
> > > 
> > > I don't think we have any code that uses it at the moment. What is the
> > > rationale behind this patch?
> > > 
> > > Thanks!
> > > Maxime
> > > 
> > > -- 
> > > Maxime Ripard, Free Electrons
> > > Embedded Linux and Kernel engineering
> > > http://free-electrons.com
> > 
> >  Hi Maxime,
> > 
> >  If num-cs isn't present nothing prevent to start a transfer with a
> > non-valid CS pin, resulting in an error.
> >  num-cs are default property especially made for this and a SPI driver
> > should try to get the property at probe/attach time.
> 
> Yes, but as far as I know, our driver doesn't. I'm all in for having
> support for that in our driver, but without it, that patch is kind of
> useless.
> 
> Maxime
> 
> -- 
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

 Yes the Linux driver doesn't use it but my upcoming one for FreeBSD
uses it. So it is not useless for downstream user of DTS.

 Cheers,

-- 
Emmanuel Vadot <manu@bidouilliste.com> <manu@freebsd.org>

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#1533926

FromMaxime Ripard <maxime.ripard@free-electrons.com>
Date2016-12-01 10:30 +0100
Message-ID<sJvQK-20y-9@gated-at.bofh.it>
In reply to#1530529

[Multipart message — attachments visible in raw view] — view raw

Hi Emmanuel,

On Fri, Nov 25, 2016 at 10:07:52PM +0100, Emmanuel Vadot wrote:
> On Fri, 25 Nov 2016 16:20:47 +0100
> Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> 
> > On Thu, Nov 24, 2016 at 09:05:09PM +0100, Emmanuel Vadot wrote:
> > > On Thu, 24 Nov 2016 20:55:17 +0100
> > > Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> > > 
> > > > On Tue, Nov 22, 2016 at 06:06:16PM +0100, Emmanuel Vadot wrote:
> > > > > The spi0 controller on the A20 have up to 4 CS (Chip Select) while the
> > > > > others three only have 1.
> > > > > Add the num-cs property to each node.
> > > > > 
> > > > > Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
> > > > 
> > > > I don't think we have any code that uses it at the moment. What is the
> > > > rationale behind this patch?
> > > > 
> > > > Thanks!
> > > > Maxime
> > > > 
> > > > -- 
> > > > Maxime Ripard, Free Electrons
> > > > Embedded Linux and Kernel engineering
> > > > http://free-electrons.com
> > > 
> > >  Hi Maxime,
> > > 
> > >  If num-cs isn't present nothing prevent to start a transfer with a
> > > non-valid CS pin, resulting in an error.
> > >  num-cs are default property especially made for this and a SPI driver
> > > should try to get the property at probe/attach time.
> > 
> > Yes, but as far as I know, our driver doesn't. I'm all in for having
> > support for that in our driver, but without it, that patch is kind of
> > useless.
> 
>  Yes the Linux driver doesn't use it but my upcoming one for FreeBSD
> uses it. So it is not useless for downstream user of DTS.

Ah, I didn't know this was for FreeBSD. So you started to use our DTs,
or do you have some modifications to it? How does that work?

Anyway, the fact that it isn't used by our driver at the moment and
that it's meant for other OSes should be mentionned in the commit log.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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#1533956

FromEmmanuel Vadot <manu@bidouilliste.com>
Date2016-12-01 11:30 +0100
Message-ID<sJwMO-2D6-9@gated-at.bofh.it>
In reply to#1533926
 Hi Maxime,

On Thu, 1 Dec 2016 10:21:50 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> Hi Emmanuel,
> 
> On Fri, Nov 25, 2016 at 10:07:52PM +0100, Emmanuel Vadot wrote:
> > On Fri, 25 Nov 2016 16:20:47 +0100
> > Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> > 
> > > On Thu, Nov 24, 2016 at 09:05:09PM +0100, Emmanuel Vadot wrote:
> > > > On Thu, 24 Nov 2016 20:55:17 +0100
> > > > Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> > > > 
> > > > > On Tue, Nov 22, 2016 at 06:06:16PM +0100, Emmanuel Vadot wrote:
> > > > > > The spi0 controller on the A20 have up to 4 CS (Chip Select) while the
> > > > > > others three only have 1.
> > > > > > Add the num-cs property to each node.
> > > > > > 
> > > > > > Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
> > > > > 
> > > > > I don't think we have any code that uses it at the moment. What is the
> > > > > rationale behind this patch?
> > > > > 
> > > > > Thanks!
> > > > > Maxime
> > > > > 
> > > > > -- 
> > > > > Maxime Ripard, Free Electrons
> > > > > Embedded Linux and Kernel engineering
> > > > > http://free-electrons.com
> > > > 
> > > >  Hi Maxime,
> > > > 
> > > >  If num-cs isn't present nothing prevent to start a transfer with a
> > > > non-valid CS pin, resulting in an error.
> > > >  num-cs are default property especially made for this and a SPI driver
> > > > should try to get the property at probe/attach time.
> > > 
> > > Yes, but as far as I know, our driver doesn't. I'm all in for having
> > > support for that in our driver, but without it, that patch is kind of
> > > useless.
> > 
> >  Yes the Linux driver doesn't use it but my upcoming one for FreeBSD
> > uses it. So it is not useless for downstream user of DTS.
> 
> Ah, I didn't know this was for FreeBSD. So you started to use our DTs,
> or do you have some modifications to it? How does that work?

 Yes we use the DTS from linux from quite some times now. We're
currently synced with 4.7-ish.
 We either use them directly or modify them according to our needs and
driver support.

> Anyway, the fact that it isn't used by our driver at the moment and
> that it's meant for other OSes should be mentionned in the commit log.

 Yeah I understand, I'll send a v2 with this in the commit log.

> Thanks!
> Maxime
> 
> -- 
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com


-- 
Emmanuel Vadot <manu@bidouilliste.com> <manu@freebsd.org>

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#1535934

FromMaxime Ripard <maxime.ripard@free-electrons.com>
Date2016-12-05 10:30 +0100
Message-ID<sKXKV-2Ja-11@gated-at.bofh.it>
In reply to#1533956

[Multipart message — attachments visible in raw view] — view raw

On Thu, Dec 01, 2016 at 11:24:14AM +0100, Emmanuel Vadot wrote:
> > > > >  If num-cs isn't present nothing prevent to start a transfer
> > > > > with a non-valid CS pin, resulting in an error.  num-cs are
> > > > > default property especially made for this and a SPI driver
> > > > > should try to get the property at probe/attach time.
> > > > 
> > > > Yes, but as far as I know, our driver doesn't. I'm all in for
> > > > having support for that in our driver, but without it, that
> > > > patch is kind of useless.
> > > 
> > >  Yes the Linux driver doesn't use it but my upcoming one for FreeBSD
> > > uses it. So it is not useless for downstream user of DTS.
> > 
> > Ah, I didn't know this was for FreeBSD. So you started to use our DTs,
> > or do you have some modifications to it? How does that work?
> 
> Yes we use the DTS from linux from quite some times now. We're
> currently synced with 4.7-ish.  We either use them directly or
> modify them according to our needs and driver support.

Do you have a link to those modifications?

Thanks,
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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#1535940

FromEmmanuel Vadot <manu@bidouilliste.com>
Date2016-12-05 10:50 +0100
Message-ID<sKY4h-2Pg-9@gated-at.bofh.it>
In reply to#1535934
On Mon, 5 Dec 2016 10:28:21 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> On Thu, Dec 01, 2016 at 11:24:14AM +0100, Emmanuel Vadot wrote:
> > > > > >  If num-cs isn't present nothing prevent to start a transfer
> > > > > > with a non-valid CS pin, resulting in an error.  num-cs are
> > > > > > default property especially made for this and a SPI driver
> > > > > > should try to get the property at probe/attach time.
> > > > > 
> > > > > Yes, but as far as I know, our driver doesn't. I'm all in for
> > > > > having support for that in our driver, but without it, that
> > > > > patch is kind of useless.
> > > > 
> > > >  Yes the Linux driver doesn't use it but my upcoming one for FreeBSD
> > > > uses it. So it is not useless for downstream user of DTS.
> > > 
> > > Ah, I didn't know this was for FreeBSD. So you started to use our DTs,
> > > or do you have some modifications to it? How does that work?
> > 
> > Yes we use the DTS from linux from quite some times now. We're
> > currently synced with 4.7-ish.  We either use them directly or
> > modify them according to our needs and driver support.
> 
> Do you have a link to those modifications?
> 
> Thanks,
> Maxime
> 
> -- 
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

 Sure,

 https://svnweb.freebsd.org/base/head/sys/boot/fdt/dts/arm/

-- 
Emmanuel Vadot <manu@bidouilliste.com> <manu@freebsd.org>

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