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Date:   Thu, 3 Jan 2019 13:19:15 -0600
From:   Rob Herring <robh@kernel.org>
To:     Florian Fainelli <f.fainelli@gmail.com>
Cc:     p.zabel@pengutronix.de, linux-kernel@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Brian Norris <computersforpeace@gmail.com>,
        Gregory Fong <gregory.0xf0@gmail.com>,
        "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <bcm-kernel-feedback-list@broadcom.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        "moderated list:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/2] dt-bindings: reset: Add document for Broadcom STB
 reset controller
Message-ID: <20190103191915.GB6613@bogus>
References: <20181221013409.14324-1-f.fainelli@gmail.com>
 <20181221013409.14324-2-f.fainelli@gmail.com>
 <20190103174117.GA6613@bogus>
 <2a54c2cf-5595-ade5-fb29-40e8b6d3133e@gmail.com>
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On Thu, Jan 03, 2019 at 10:53:25AM -0800, Florian Fainelli wrote:
> On 1/3/19 9:41 AM, Rob Herring wrote:
> > On Thu, Dec 20, 2018 at 05:34:08PM -0800, Florian Fainelli wrote:
> >> Add a binding document for the Broadcom STB reset controller, also known
> >> as SW_INIT-style reset controller.
> >>
> >> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> >> ---
> >>  .../devicetree/bindings/reset/brcm,reset.txt  | 27 +++++++++++++++++++
> >>  1 file changed, 27 insertions(+)
> >>  create mode 100644 Documentation/devicetree/bindings/reset/brcm,reset.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/reset/brcm,reset.txt b/Documentation/devicetree/bindings/reset/brcm,reset.txt
> >> new file mode 100644
> >> index 000000000000..6e5341b4f891
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/reset/brcm,reset.txt
> >> @@ -0,0 +1,27 @@
> >> +Broadcom STB SW_INIT-style reset controller
> >> +===========================================
> >> +
> >> +Broadcom STB SoCs have a SW_INIT-style reset controller with separate
> >> +SET/CLEAR/STATUS registers and possibly multiple banks, each of 32 bit
> >> +reset lines.
> >> +
> >> +Please also refer to reset.txt in this directory for common reset
> >> +controller binding usage.
> >> +
> >> +Required properties:
> >> +- compatible: should be brcm,brcmstb-reset
> >> +- reg: register base and length
> >> +- #reset-cells: must be set to 1
> >> +
> >> +Example:
> >> +
> >> +	reset: reset-controller@8404318 {
> >> +		compatible = "brcm,brcmstb-reset";
> >> +		reg = <0x8404318 0x30>;
> > 
> > Based on this address, should this be a sub-node of something else? Or 
> > not even a sub-node and just make the parent be a reset provider?
> 
> The reset controller is part of a larger "sundry" node which has a
> collection of functionality, from pinmux/pinctrl, reset controller,
> spare bits, chicken bits, anything the designers forgot to put somewhere
> else and decided to put there.
> 
> If there is one thing consistent though is that given a set of 32-bit
> register groups, they have a self contained functionality such that you
> can break up the larger "sundry" space into smaller sub-blocks which
> have one an only one functionality. Do you think this warrants a
> different representation in Device Tree?

With pinctrl in the mix, you're going to need sub-nodes anyways. So just 
define what this is a sub-node of.

Also, I'd prefer to have complete example for the "sundry" node and 
child nodes than partial examples spread across the tree.

Rob