Re: [PATCH RESEND v2] mfd: syscon: add child device support

From: Flora Fu
Date: Mon Dec 15 2014 - 20:59:35 EST


Hi,

The patch set is used to implement reset controller in
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-November/299141.html

Tested-by: Flora Fu <flora.fu@xxxxxxxxxxxx>

Thanks,
Flora

On Mon, 2014-12-15 at 09:58 +0000, Lee Jones wrote:
> On Mon, 15 Dec 2014, Philipp Zabel wrote:
> > Am Montag, den 01.12.2014, 17:25 +0100 schrieb Philipp Zabel:
> > > For devices which have a complete register for themselves, it is possible to
> > > place them next to the syscon device with overlapping reg ranges. The same is
> > > not possible for devices which only occupy bitfields in registers shared with
> > > other users.
> > > For devices that are completely controlled by bitfields in the syscon address
> > > range, such as multiplexers or voltage regulators, allow to put child devices
> > > into the syscon device node.
> >
> > What is the status of this patch?
> > Is this ok to be applied after the merge window closes?
> >
> > For reference, these are the previous threads:
> > https://lkml.org/lkml/2014/5/27/422
> > https://lkml.org/lkml/2014/11/3/134
>
> As this is such an important driver I need more Acks for users/testers
> and senior reviewers before applying.
>
> > > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> > > ---
> > > Changes since v1:
> > > - Reworded binding documentation to allow #size-cells = <1>, which is useful
> > > for syscon children that are controlled through a (possibly shared) register
> > > range.
> > > ---
> > > Documentation/devicetree/bindings/mfd/syscon.txt | 13 +++++++++++++
> > > drivers/mfd/syscon.c | 3 +++
> > > 2 files changed, 16 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
> > > index fe8150b..0c6b497 100644
> > > --- a/Documentation/devicetree/bindings/mfd/syscon.txt
> > > +++ b/Documentation/devicetree/bindings/mfd/syscon.txt
> > > @@ -9,12 +9,25 @@ using a specific compatible value), interrogate the node (or associated
> > > OS driver) to determine the location of the registers, and access the
> > > registers directly.
> > >
> > > +Optionally, devices that are controlled exclusively through syscon registers,
> > > +or even bitfields in shared syscon registers, can also be added as child nodes
> > > +to the syscon device node. These devices can implicitly assume their parent
> > > +node is a syscon provider without referencing it explicitly via phandle.
> > > +In this case, the syscon node should have #address-cells = <1> and
> > > +#size-cells = <0> or <1> and no ranges property.
> > > +
> > > Required properties:
> > > - compatible: Should contain "syscon".
> > > - reg: the register region can be accessed from syscon
> > >
> > > +Optional properties:
> > > +- #address-cells: Should be 1.
> > > +- #size-cells: Should be 0 or 1.
> > > +
> > > Examples:
> > > gpr: iomuxc-gpr@020e0000 {
> > > + #address-cells = <1>;
> > > + #size-cells = <0>;
> > > compatible = "fsl,imx6q-iomuxc-gpr", "syscon";
> > > reg = <0x020e0000 0x38>;
> > > };
> > > diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> > > index ca15878..38da178 100644
> > > --- a/drivers/mfd/syscon.c
> > > +++ b/drivers/mfd/syscon.c
> > > @@ -155,6 +155,9 @@ static int syscon_probe(struct platform_device *pdev)
> > >
> > > dev_dbg(dev, "regmap %pR registered\n", res);
> > >
> > > + if (!of_device_is_compatible(pdev->dev.of_node, "simple-bus"))
> > > + of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
> > > +
> > > return 0;
> > > }
> > >
> >
> >
>


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