linux-kernel - Re: [PATCH v1 4/5] of: property: Make sure child dependencies don't block probing of parent

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Date:   Mon, 4 Nov 2019 11:04:24 -0800
From:   Saravana Kannan <saravanak@...gle.com>
To:     Rob Herring <robh+dt@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Len Brown <lenb@...nel.org>,
        Android Kernel Team <kernel-team@...roid.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, linux-acpi@...r.kernel.org
Subject: Re: [PATCH v1 4/5] of: property: Make sure child dependencies don't
 block probing of parent

On Mon, Nov 4, 2019 at 9:01 AM Rob Herring <robh+dt@...nel.org> wrote:
>
> On Mon, Oct 28, 2019 at 5:00 PM Saravana Kannan <saravanak@...gle.com> wrote:
> >
> > When creating device links to proxy the sync_state() needs of child
> > dependencies, create SYNC_STATE_ONLY device links so that children
> > dependencies don't block probing of the parent.
> >
> > Also, differentiate between missing suppliers of parent device vs
> > missing suppliers of child devices so that driver core doesn't block
> > parent device probing when only child supplier dependencies are missing.
> >
> > Signed-off-by: Saravana Kannan <saravanak@...gle.com>
> > ---
> >  drivers/of/property.c | 17 ++++++++++++-----
> >  1 file changed, 12 insertions(+), 5 deletions(-)
>
> Reviewed-by: Rob Herring <robh@...nel.org>

Thank you!

> One nit below:
>
> >
> > diff --git a/drivers/of/property.c b/drivers/of/property.c
> > index 2808832b2e86..f16f85597ccc 100644
> > --- a/drivers/of/property.c
> > +++ b/drivers/of/property.c
> > @@ -1032,10 +1032,10 @@ static bool of_is_ancestor_of(struct device_node *test_ancestor,
> >   * - -EINVAL if the supplier link is invalid and should not be created
> >   * - -ENODEV if there is no device that corresponds to the supplier phandle
> >   */
> > -static int of_link_to_phandle(struct device *dev, struct device_node *sup_np)
> > +static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
> > +                             u32 dl_flags)
> >  {
> >         struct device *sup_dev;
> > -       u32 dl_flags = DL_FLAG_AUTOPROBE_CONSUMER;
> >         int ret = 0;
> >         struct device_node *tmp_np = sup_np;
> >
> > @@ -1195,13 +1195,20 @@ static int of_link_property(struct device *dev, struct device_node *con_np,
> >         unsigned int i = 0;
> >         bool matched = false;
> >         int ret = 0;
> > +       u32 dl_flags;
> > +
> > +       if (dev->of_node == con_np)
> > +               dl_flags = DL_FLAG_AUTOPROBE_CONSUMER;
> > +       else
> > +               dl_flags = DL_FLAG_SYNC_STATE_ONLY;
> >
> >         /* Do not stop at first failed link, link all available suppliers. */
> >         while (!matched && s->parse_prop) {
> >                 while ((phandle = s->parse_prop(con_np, prop_name, i))) {
> >                         matched = true;
> >                         i++;
> > -                       if (of_link_to_phandle(dev, phandle) == -EAGAIN)
> > +                       if (of_link_to_phandle(dev, phandle, dl_flags)
> > +                                                               == -EAGAIN)
>
> nit: I'd just keep this one line or at least move '==' up.

You'd keep it one line even if it's > 80 cols? Ok, I'll move the "==" up.


-Saravana