From: Johan Hovold <johan@kernel.org>
To: Matthias Kaehlcke <mka@chromium.org>, Rob Herring <robh@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Douglas Anderson <dianders@chromium.org>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
Stefan Wahren <stefan.wahren@i2se.com>,
Ravi Chandra Sadineni <ravisadineni@chromium.org>
Subject: Re: [PATCH] usb: misc: onboard_usb_hub: Don't defer probing for 'incomplete' DT nodes
Date: Tue, 20 Dec 2022 08:55:52 +0100 [thread overview]
Message-ID: <Y6FqiA/SoZHr36jl@hovoldconsulting.com> (raw)
In-Reply-To: <20221220004427.1.If5e7ec83b1782e4dffa6ea759416a27326c8231d@changeid>
On Tue, Dec 20, 2022 at 12:45:01AM +0000, Matthias Kaehlcke wrote:
> Some boards have device tree nodes for USB hubs supported by the
> onboard_usb_hub driver, but the nodes don't have all properties
> needed for the driver to work properly (which is not necessarily
> an error in the DT). Currently _find_onboard_hub() returns
> -EPROBE_DEFER in such cases, which results in an unusable USB hub,
> since successive probes fail in the same way. Use the absence of
> the "vdd" supply as an indicator of such 'incomplete' DT nodes
> and return -ENODEV.
>
> Fixes: 8bc063641ceb ("usb: misc: Add onboard_usb_hub driver")
> Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
>
> drivers/usb/misc/onboard_usb_hub.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/usb/misc/onboard_usb_hub.c b/drivers/usb/misc/onboard_usb_hub.c
> index d63c63942af1..2968da515016 100644
> --- a/drivers/usb/misc/onboard_usb_hub.c
> +++ b/drivers/usb/misc/onboard_usb_hub.c
> @@ -363,6 +363,15 @@ static struct onboard_hub *_find_onboard_hub(struct device *dev)
> hub = dev_get_drvdata(&pdev->dev);
> put_device(&pdev->dev);
>
> + /*
> + * Some boards have device tree nodes for USB hubs supported by this
> + * driver, but the nodes don't have all properties needed for the driver
> + * to work properly. Use the absence of the "vdd" supply as an indicator
> + * of such nodes.
> + */
> + if (!of_get_property(pdev->dev.of_node, "vdd", NULL))
> + return ERR_PTR(-ENODEV);
Does this not break your original use case? Don't you want "vdd-supply"
here?
That said, this seems like the wrong property to look for both in
principle and as it is described as optional by the binding:
Documentation/devicetree/bindings/usb/realtek,rts5411.yaml
It seems that you should use the compatible property and check that it
holds one of the expected values:
- usbbda,5411
- usbbda,411
rather than treat every hub node as describing a realtek hub (AFAIK,
there is no generic binding for this yet).
> +
> /*
> * The presence of drvdata ('hub') indicates that the platform driver
> * finished probing. This handles the case where (conceivably) we could
Johan
next prev parent reply other threads:[~2022-12-20 7:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-20 0:45 [PATCH] usb: misc: onboard_usb_hub: Don't defer probing for 'incomplete' DT nodes Matthias Kaehlcke
2022-12-20 6:24 ` Thorsten Leemhuis
2022-12-20 6:58 ` Greg Kroah-Hartman
2022-12-20 7:55 ` Johan Hovold [this message]
2022-12-20 14:15 ` Matthias Kaehlcke
2022-12-23 13:42 ` Johan Hovold
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