From: Jason Gunthorpe <jgg@ziepe.ca>
To: Javier Martinez Canillas <javierm@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org,
Peter Huewe <peterhuewe@gmx.de>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: Re: [PATCH] tpm: remove type and name fields from the I2C Infineon OF table entries
Date: Mon, 4 Dec 2017 11:03:24 -0700 [thread overview]
Message-ID: <20171204180324.GB18059@ziepe.ca> (raw)
In-Reply-To: <20171204173916.4874-1-javierm@redhat.com>
On Mon, Dec 04, 2017 at 06:39:16PM +0100, Javier Martinez Canillas wrote:
> The commit 21dc02eab989 ("tpm/tpm_i2c_infineon.c: Add OF attributes type
> and name to the of_device_id table entries") added type and name fields
> to the OF device ID table entries for the I2C Infineon TPM driver.
>
> The only justification for the change in the commit message is that it's
> probably a good idea to have these fields populated in the OF entries.
>
> But I don't think that's true. In fact, I believe that's not correct to
> add these fields for the following reasons:
>
> * The struct of_device_id .type field matches the device_type property
> in the Device Tree nodes. The ePAPR document says that new use of the
> property is deprecated and should only be included in cpu and memory
> nodes for compatibility with the IEEE 1275-derived Device Trees.
> Also, mainline Device Tree source files don't include this property
> in the TPM nodes defined.
>
> * The struct of_device_id .name field matches the Device Tree node name
> but the ePAPR document says that the node name should be generic and
> reflect the function of the device, not it's programming model. So in
> the case of TPM chips, it should just be "tpm" but the name fields are
> set in the OF table entries to the actual device model (i.e: slb9645tt).
>
> Now, from a practical point of view this means that the OF module aliases
> for the supported devices include the name and type of the device entries:
>
> $ modinfo drivers/char/tpm/tpm_i2c_infineon.ko | grep alias
> alias: of:Nslb9645ttTtpm*Cinfineon,slb9645ttC*
> alias: of:Nslb9645ttTtpm*Cinfineon,slb9645tt
> alias: of:Nslb9635ttTtpm*Cinfineon,slb9635ttC*
> alias: of:Nslb9635ttTtpm*Cinfineon,slb9635tt
> alias: of:Ntpm_i2c_infineonTtpm*Cinfineon,tpm_i2c_infineonC*
> alias: of:Ntpm_i2c_infineonTtpm*Cinfineon,tpm_i2c_infineon
>
> But since the device_type isn't set in the tpm DT nodes and the node name
> is a generic one, the reported MODALIAS when a device is registered via OF
> won't match the driver's module aliases:
>
> $ cat /sys/class/tpm/tpm0/device/modalias
> of:NtpmT<NULL>Cinfineon,slb9645tt
>
> So remove these fields from the OF entries to allow the module aliases to
> match the MODALIAS reported by the kernel when the device is registered:
>
> $ modinfo drivers/char/tpm/tpm_i2c_infineon.ko | grep alias
> alias: of:N*T*Cinfineon,slb9645ttC*
> alias: of:N*T*Cinfineon,slb9645tt
> alias: of:N*T*Cinfineon,slb9635ttC*
> alias: of:N*T*Cinfineon,slb9635tt
> alias: of:N*T*Cinfineon,tpm_i2c_infineonC*
> alias: of:N*T*Cinfineon,tpm_i2c_infineon
>
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
I concur
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Jason
next prev parent reply other threads:[~2017-12-04 18:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-04 17:39 [PATCH] tpm: remove type and name fields from the I2C Infineon OF table entries Javier Martinez Canillas
2017-12-04 18:03 ` Jason Gunthorpe [this message]
2017-12-15 12:03 ` Jarkko Sakkinen
2017-12-16 19:59 ` Javier Martinez Canillas
2017-12-17 16:27 ` Jarkko Sakkinen
2017-12-17 18:19 ` Javier Martinez Canillas
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=20171204180324.GB18059@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=jarkko.sakkinen@linux.intel.com \
--cc=javierm@redhat.com \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=peterhuewe@gmx.de \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).