2020-12-11 14:45:11

by Sam Protsenko

Subject: [PATCH] usb: dwc3: drd: Avoid error when extcon is missing

If "port" node is missing in PHY controller node, dwc3_get_extcon()
isn't able to find extcon device. This is perfectly fine in case when
"usb-role-switch" or OTG is used, but next misleading error message is
printed in that case, from of_graph_get_remote_node():

OF: graph: no port node found in /phy@1234abcd

Avoid printing that message by checking if port node exists in PHY node
before calling of_graph_get_remote_node().

Signed-off-by: Sam Protsenko <[email protected]>
---
drivers/usb/dwc3/drd.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index 3e1c1aacf002..eaf389d3f3c5 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -441,8 +441,8 @@ static int dwc3_drd_notifier(struct notifier_block *nb,
static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
{
struct device *dev = dwc->dev;
- struct device_node *np_phy, *np_conn;
- struct extcon_dev *edev;
+ struct device_node *np_phy;
+ struct extcon_dev *edev = NULL;
const char *name;

if (device_property_read_bool(dev, "extcon"))
@@ -462,15 +462,22 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
return edev;
}

+ /*
+ * Try to get extcon device from USB PHY controller's "port" node.
+ * Check if it has the "port" node first, to avoid printing the error
+ * message from underlying code, as it's a valid case: extcon device
+ * (and "port" node) may be missing in case of "usb-role-switch" or OTG
+ * mode.
+ */
np_phy = of_parse_phandle(dev->of_node, "phys", 0);
- np_conn = of_graph_get_remote_node(np_phy, -1, -1);
+ if (of_graph_is_present(np_phy)) {
+ struct device_node *np_conn;

- if (np_conn)
- edev = extcon_find_edev_by_node(np_conn);
- else
- edev = NULL;
-
- of_node_put(np_conn);
+ np_conn = of_graph_get_remote_node(np_phy, -1, -1);
+ if (np_conn)
+ edev = extcon_find_edev_by_node(np_conn);
+ of_node_put(np_conn);
+ }
of_node_put(np_phy);

return edev;
--
2.29.2

2020-12-11 14:55:22

by Andy Shevchenko

Subject: Re: [PATCH] usb: dwc3: drd: Avoid error when extcon is missing

On Fri, Dec 11, 2020 at 04:24:21PM +0200, Sam Protsenko wrote:
> If "port" node is missing in PHY controller node, dwc3_get_extcon()
> isn't able to find extcon device. This is perfectly fine in case when
> "usb-role-switch" or OTG is used, but next misleading error message is
> printed in that case, from of_graph_get_remote_node():
>
> OF: graph: no port node found in /phy@1234abcd
>
> Avoid printing that message by checking if port node exists in PHY node
> before calling of_graph_get_remote_node().

So, this has to be v2...
Anyway, see below.

...

> static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> {
> struct device *dev = dwc->dev;
> - struct device_node *np_phy, *np_conn;
> - struct extcon_dev *edev;
> + struct device_node *np_phy;
> + struct extcon_dev *edev = NULL;
> const char *name;
>
> if (device_property_read_bool(dev, "extcon"))
> @@ -462,15 +462,22 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> return edev;
> }
>
> + /*
> + * Try to get extcon device from USB PHY controller's "port" node.
> + * Check if it has the "port" node first, to avoid printing the error
> + * message from underlying code, as it's a valid case: extcon device
> + * (and "port" node) may be missing in case of "usb-role-switch" or OTG
> + * mode.
> + */
> np_phy = of_parse_phandle(dev->of_node, "phys", 0);
> - np_conn = of_graph_get_remote_node(np_phy, -1, -1);
> + if (of_graph_is_present(np_phy)) {
> + struct device_node *np_conn;
>
> - if (np_conn)
> - edev = extcon_find_edev_by_node(np_conn);
> - else
> - edev = NULL;
> -
> - of_node_put(np_conn);
> + np_conn = of_graph_get_remote_node(np_phy, -1, -1);
> + if (np_conn)
> + edev = extcon_find_edev_by_node(np_conn);
> + of_node_put(np_conn);
> + }
> of_node_put(np_phy);
>
> return edev;


Why not do it slightly different, i.e.

- np_conn = of_graph_get_remote_node(np_phy, -1, -1);
+ if (of_graph_is_present(np_phy))
+ np_conn = of_graph_get_remote_node(np_phy, -1, -1);
+ else
+ np_conn = NULL;

?

--
With Best Regards,
Andy Shevchenko

2020-12-13 03:14:40

by Sam Protsenko

Subject: Re: [PATCH] usb: dwc3: drd: Avoid error when extcon is missing

On Fri, 11 Dec 2020 at 16:48, Andy Shevchenko
<[email protected]> wrote:
>
> On Fri, Dec 11, 2020 at 04:24:21PM +0200, Sam Protsenko wrote:
> > If "port" node is missing in PHY controller node, dwc3_get_extcon()
> > isn't able to find extcon device. This is perfectly fine in case when
> > "usb-role-switch" or OTG is used, but next misleading error message is
> > printed in that case, from of_graph_get_remote_node():
> >
> > OF: graph: no port node found in /phy@1234abcd
> >
> > Avoid printing that message by checking if port node exists in PHY node
> > before calling of_graph_get_remote_node().
>
> So, this has to be v2...
> Anyway, see below.
>
> ...
>
> > static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> > {
> > struct device *dev = dwc->dev;
> > - struct device_node *np_phy, *np_conn;
> > - struct extcon_dev *edev;
> > + struct device_node *np_phy;
> > + struct extcon_dev *edev = NULL;
> > const char *name;
> >
> > if (device_property_read_bool(dev, "extcon"))
> > @@ -462,15 +462,22 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> > return edev;
> > }
> >
> > + /*
> > + * Try to get extcon device from USB PHY controller's "port" node.
> > + * Check if it has the "port" node first, to avoid printing the error
> > + * message from underlying code, as it's a valid case: extcon device
> > + * (and "port" node) may be missing in case of "usb-role-switch" or OTG
> > + * mode.
> > + */
> > np_phy = of_parse_phandle(dev->of_node, "phys", 0);
> > - np_conn = of_graph_get_remote_node(np_phy, -1, -1);
> > + if (of_graph_is_present(np_phy)) {
> > + struct device_node *np_conn;
> >
> > - if (np_conn)
> > - edev = extcon_find_edev_by_node(np_conn);
> > - else
> > - edev = NULL;
> > -
> > - of_node_put(np_conn);
> > + np_conn = of_graph_get_remote_node(np_phy, -1, -1);
> > + if (np_conn)
> > + edev = extcon_find_edev_by_node(np_conn);
> > + of_node_put(np_conn);
> > + }
> > of_node_put(np_phy);
> >
> > return edev;
>
>
> Why not do it slightly different, i.e.
>
> - np_conn = of_graph_get_remote_node(np_phy, -1, -1);
> + if (of_graph_is_present(np_phy))
> + np_conn = of_graph_get_remote_node(np_phy, -1, -1);
> + else
> + np_conn = NULL;
>
> ?
>

Thanks for the review, Andy! I'll address this in v3.

> --
> With Best Regards,
> Andy Shevchenko
>
>