> -----Original Message-----
> From: Francesco Dolcini <francesco@xxxxxxxxxx>
> Sent: Tuesday, October 22, 2024 3:40 PM
> To: Carlos Song <carlos.song@xxxxxxx>
> Cc: Francesco Dolcini <francesco@xxxxxxxxxx>; robh@xxxxxxxxxx;
> krzk+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx; shawnguo@xxxxxxxxxx;
> s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx;
> Frank Li <frank.li@xxxxxxx>; Bough Chen <haibo.chen@xxxxxxx>;
> devicetree@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [EXT] Re: [PATCH] ARM: dts: imx7s: change i2c compatible string for
> applying errata ERR007805
>
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> On Mon, Oct 21, 2024 at 10:07:23AM +0000, Carlos Song wrote:
> > > From: Francesco Dolcini <francesco@xxxxxxxxxx>
> > >
> > > On Mon, Oct 21, 2024 at 11:11:48AM +0800, carlos.song@xxxxxxx wrote:
> > > > From: Carlos Song <carlos.song@xxxxxxx>
> > > >
> > > > Compatible string "fsl,imx7d-i2c" is not exited at i2c-imx driver
> > > > compatible string table, at the result, "fsl,imx21-i2c" will be
> > > > matched, but it will cause errata ERR007805 not be applied in fact.
> > > >
> > > > Replace "fsl,imx7d-i2c" by "fsl,imx7s-i2c" compatible string in
> > > > dts file for appling the errata ERR007805.
> > >
> > > Did you considered changing the driver instead? If I understand this
> > > correctly it would be a better solution.
> >
> > This errata fix patch has been applied on i2c-imx.c driver: 39c025721d70 i2c:
> > imx: Implement errata ERR007805 or e7805 bus frequency limit
> >
> > The patch commit log says: this errata is found on all MX7{S,D},
> > MX6{UL{,L,Z},S{,LL,X},S,D,DL,Q,DP,QP} and MX8M{M,N,P,Q}. So imx7d and
> > imx7s both needs this errata fix. "fsl,imx7s-i2c" was added into
> > compatible string table in the i2c-imx patch, this is the patch diff
> > snap. So when "fsl,imx7s-i2c" is matched, the arrata fix will be applied.
>
> It is clear what you did. What I wrote is that IMO it's not the correct solution.
>
> Kernel and the FDT can be updated indipendently, with the FDT being part of the
> firmware, and you should not expect people to update the FDT to fix an errata
> that is implemented in the driver.
>
> My suggestion is that the errata should be applied in the driver to both
> compatibles, and such a fix should be backported to stable kernel.
>
> Francesco
Hi, Francesco
Thanks! I get it. I will send V2 patch in i2c-imx.c driver to add one compatible string for imx7d
to fix this errata.
Carlos
