linux-kernel - Re: [PATCH] of: property: Add device link support for interrupt-parent, dmas and -gpio(s)

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Date:   Fri, 22 Nov 2019 11:18:47 -0800
From:   Saravana Kannan <saravanak@...gle.com>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Vinod Koul <vkoul@...nel.org>,
        Android Kernel Team <kernel-team@...roid.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] of: property: Add device link support for
 interrupt-parent, dmas and -gpio(s)

On Thu, Nov 21, 2019 at 11:38 PM Linus Walleij <linus.walleij@...aro.org> wrote:
>
> On Wed, Nov 20, 2019 at 8:13 AM Saravana Kannan <saravanak@...gle.com> wrote:
>
> > Add support for creating device links out of more DT properties.
> >
> > Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> > Cc: Thomas Gleixner <tglx@...utronix.de>
> > Cc: Vinod Koul <vkoul@...nel.org>
> > Cc: Linus Walleij <linus.walleij@...aro.org>
> > Signed-off-by: Saravana Kannan <saravanak@...gle.com>
>
> This looks to me like doing the right thing and making sure that
> the GPIO drivers get probed before their consumers and thus
> speed up boot.
> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>

Thanks!

>
> I guess I should get on with adding device links at runtime
> as well, both for GPIO and pin control so that things work
> with runtime-added devices and boardfiles and ACPI, if I
> understand correctly it's fine to add the same link twice, it
> will just be ignored?

It's actually ref counted. So do check that the device_link_add()
succeeds before trying to release it later on [1].

-Saravana
[1] - https://lore.kernel.org/lkml/20191115000438.45970-1-saravanak@google.com/