From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To: Saravana Kannan <saravanak@google.com>
Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: fw_devlink on will break all snps,dw-apb-gpio users
Date: Thu, 15 Oct 2020 12:02:06 +0800 [thread overview]
Message-ID: <20201015120206.41b6a454@xhacker.debian> (raw)
In-Reply-To: <CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@mail.gmail.com>
On Wed, 14 Oct 2020 10:29:36 -0700
Saravana Kannan <saravanak@google.com> wrote:
> CAUTION: Email originated externally, do not click links or open attachments unless you recognize the sender and know the content is safe.
>
>
> On Wed, Oct 14, 2020 at 4:12 AM Jisheng Zhang
> <Jisheng.Zhang@synaptics.com> wrote:
> >
> > Hi,
> >
> > If set fw_devlink as on, any consumers of dw apb gpio won't probe.
> >
> > The related dts looks like:
> >
> > gpio0: gpio@2400 {
> > compatible = "snps,dw-apb-gpio";
> > #address-cells = <1>;
> > #size-cells = <0>;
> >
> > porta: gpio-port@0 {
> > compatible = "snps,dw-apb-gpio-port";
> > gpio-controller;
> > #gpio-cells = <2>;
> > ngpios = <32>;
> > reg = <0>;
> > };
> > };
> >
> > device_foo {
> > status = "okay"
> > ...;
> > reset-gpio = <&porta, 0, GPIO_ACTIVE_HIGH>;
> > };
> >
> > If I change the reset-gpio property to use another kind of gpio phandle,
> > e.g gpio expander, then device_foo can be probed successfully.
> >
> > The gpio expander dt node looks like:
> >
> > expander3: gpio@44 {
> > compatible = "fcs,fxl6408";
> > pinctrl-names = "default";
> > pinctrl-0 = <&expander3_pmux>;
> > reg = <0x44>;
> > gpio-controller;
> > #gpio-cells = <2>;
> > interrupt-parent = <&portb>;
> > interrupts = <23 IRQ_TYPE_NONE>;
> > interrupt-controller;
> > #interrupt-cells = <2>;
> > };
> >
> > The common pattern looks like the devlink can't cope with suppliers from
> > child dt node.
>
> fw_devlink doesn't have any problem dealing with child devices being
> suppliers. The problem with your case is that the
> drivers/gpio/gpio-dwapb.c driver directly parses the child nodes and
> never creates struct devices for them. If you have a node with
> compatible string, fw_devlink expects you to create and probe a struct
> device for it. So change your driver to add the child devices as
> devices instead of just parsing the node directly and doing stuff with
> it.
>
> Either that, or stop putting "compatible" string in a node if you
> don't plan to actually treat it as a device -- but that's too late for
> this driver (it needs to be backward compatible). So change the driver
> to add of_platform_populate() and write a driver that probes
> "snps,dw-apb-gpio-port".
>
Thanks for the information. The "snps,dw-apb-gpio-port" is never used,
so I just sent out a series to remove it.
Thanks
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next prev parent reply other threads:[~2020-10-15 4:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-14 11:12 fw_devlink on will break all snps,dw-apb-gpio users Jisheng Zhang
2020-10-14 17:29 ` Saravana Kannan
2020-10-15 4:02 ` Jisheng Zhang [this message]
2020-10-15 5:04 ` Saravana Kannan
2020-10-15 8:14 ` Jisheng Zhang
2020-10-15 8:48 ` Saravana Kannan
2020-10-15 9:52 ` Jisheng Zhang
2020-10-15 14:08 ` Robin Murphy
2020-10-16 3:39 ` Jisheng Zhang
2020-10-17 0:44 ` Saravana Kannan
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