Re: [PATCH v2 4/5] arm64: dts: google: Add initial dts for frankel/blazer/mustang

Linus Walleij <[email protected]>
Newsgroups dev.linux.lists.soc,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel,org.kernel.vger.linux-samsung-soc,org.kernel.vger.linux-serial
Message-ID <CAD++jLnQGy_LvRxMjq1s2Hs9Hn4LNTFZ0W17zC1YLs5StwfqMg@mail.gmail.com>
Hi Doug,

note: I know what it is like to be in active product development
with a product organization with one finger constantly on the
fast forward button to get products out the door. This creates
unacceptable stress for engineers trying to at the same time
establish standards and pass formal and slow reviews.

On Wed, Aug 19, 2026 at 12:13 AM Doug Anderson <[email protected]> wrote:

> Is there some other documentation saying "aliases == evil" that I
> missed? Maybe some email thread we're all supposed to have read?

Yes, kind of, it was 10 years ago and about MMC aliases for
selecting a primary device for boot:
https://lore.kernel.org/lkml/CAD=FV=XLuPWKjQBMLApRQxk0K30p_TPcztB7g_1DB7iRA9BGRQ@mail.gmail.com/T/
and you were in the thread, it's not pretty, leaves a bad aftertaste.
For, I think, reasons stated in my initial paragraph.

The takeway is something like "the device enumeration is policy,
not hardware information, so it should not be encoded into
the device tree", and that is not an argument about aliases
per se.

As a result (as I think, I may be wrong) MMC gained a few
properties such as:
non-removable;
no-sd;
no-mmc;
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml

These provide a heuristic for which devices to inspect for boot.
Then on top of that I think people use schemes like EFI for finding
boot devices. (Or they still live with their quirks...)

Now this ufs0 node seems to be about calibration of some sort,
which is a more hardware adjacent subject. Is there a way to
add the entity that needs this calibration to the device tree and
reference the UFS device with a phandle along the lines of:

calibration-storage = <&ufs_node>;

?

Even say adding a synthetic modem node if the calibration is
for a modem is probably going to be more acceptable than an
alias.

Yours,
Linus Walleij
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