Re: [PATCH] usb: ulpi: warn when a PHY with no DT node cannot be read

[sashiko-bot@kernel.org]

> From: Brian Ellis <brianellis@gotenna.com>
> 
> ulpi_read_id() checks that the PHY's registers can be reached by writing
> ULPI_SCRATCH and reading it back.  If the write fails or the value does
> not come back, it falls back to OF matching and returns success, with
> nothing logged and ulpi->id left at 0000:0000.
> 
> Commit ef6a7bcfb01c ("usb: ulpi: Support device discovery via DT") added
> that fallback for PHYs described in DT, which may not be powered yet when
> the ID is read.  For a PHY with no DT node it does nothing:
> of_request_module() returns -ENODEV for a NULL node, and ulpi_match() can
> only match a zero vendor ID through OF.  The PHY is never identified and
> nothing says why, so code that keys off ulpi->id, such as dwc3's USB3340
> detection, silently does not apply.
> 
> [ ... ]
> Warn when register access fails and there is no DT node to fall back on.
> PHYs described in DT, and PHYs whose registers work but report no vendor
> ID, stay silent as before.
> 
> Signed-off-by: Brian Ellis <brianellis@gotenna.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261109-ulpi-warn-unidentified-phy-v1-1-64537f455dd8@gotenna.com?part=1