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Date: Fri, 22 Dec 2017 11:07:27 +0100
From: Emmanuel Vadot <manu@bidouilliste.com>
To: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Mark Rutland <mark.rutland@arm.com>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Russell King <linux@armlinux.org.uk>,
        linux-sunxi@googlegroups.com, Rob Herring <robh+dt@kernel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Kyle Evans <kevans91@ksu.edu>, Chen-Yu Tsai <wens@csie.org>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] ARM: dts: sunxi: Add sid for a83t
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On Fri, 22 Dec 2017 09:35:08 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> On Thu, Dec 21, 2017 at 07:09:03PM +0100, Emmanuel Vadot wrote:
> > 
> >  Hi Maxime,
> > 
> > On Thu, 21 Dec 2017 16:26:30 +0100
> > Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
> > 
> > > Hi,
> > > 
> > > On Thu, Dec 21, 2017 at 09:19:24AM -0600, Kyle Evans wrote:
> > > > On Thu, Dec 21, 2017 at 8:55 AM, Maxime Ripard
> > > > <maxime.ripard@free-electrons.com> wrote:
> > > > > Hi Kyle,
> > > > >
> > > > > On Tue, Dec 19, 2017 at 03:05:23PM -0600, kevans91@ksu.edu wrote:
> > > > >> Allwinner a83t has a 1 KB sid block with efuse for security rootkey and
> > > > >> thermal calibration data, add node to describe it.
> > > > >>
> > > > >> a83t-sid is not currently supported by nvmem/sunxi-sid, but it is
> > > > >> supported in an external driver for FreeBSD.
> > > > >>
> > > > >> Signed-off-by: Kyle Evans <kevans91@ksu.edu>
> > > > >
> > > > > The patch looks fine in itself, but we've had a number of issues with
> > > > > the register layout (and access patterns) in the past, so I'd rather
> > > > > have something that works in Linux too if possible.
> > > > 
> > > > I have a patch that I think should make it work fine on Linux [1], but
> > > > I'm afraid I have little to no capability to test it myself and so I
> > > > did not add it as well.
> > > > 
> > > > I do know that the rootkey is offset 0x200 into the given space [2],
> > > > as is the case with the H3, and that the readout quirk is not needed.
> > > > I wasn't 100% sure that the a83t has 2Kbit worth of efuse space as the
> > > > H3, but I do know that thermal data can be found at 0x34 and 0x38 in
> > > > this space.
> > > 
> > > Then maybe we should leave it aside until someone takes some time on
> > > the A83t. 
> > 
> >  Take some time on the Linux driver and do not apply this patch for
> > now you mean ?
> 
> Yep.
> 
> Maxime

 Since linux doesn't have the compatible in it's driver what would
be the harm to add the node in the DTS ? If a quirks is needed because
some region is weird this would go in the driver right ? I don't see a
technical problem for adding this node right now.
 If Kyle confirm the lenght of the region and that no quirk is needed
will it be enough ?

 Cheers,

-- 
Emmanuel Vadot <manu@bidouilliste.com>