On 1/3/19 11:19 AM, Rob Herring wrote:

On Thu, Jan 03, 2019 at 10:53:25AM -0800, Florian Fainelli wrote:

quoted

On 1/3/19 9:41 AM, Rob Herring wrote:

quoted

On Thu, Dec 20, 2018 at 05:34:08PM -0800, Florian Fainelli wrote:

quoted

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.

pinctrl is not necessarily something I want the kernel to control, since
we have a high level scripting language without our bootloader that
makes sure pinctrl is properly configured from early boot on all the way
to the kernel, and preserved across suspend/resume states.
pinctrl-single does work, and was occasionally used. Everything else is
typically muxes that the kernel does not need to touch/see/be aware of.

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

I am afraid I can't provide that example because the sundry node is
really changing from chip to chip, and there is a gazillion of things in
there that the kernel typically does not even touch, like
pinmuxing/pinctrl, various mux selections etc. I could provide the
following example if that is what you are requesting?:


sun-top-ctrl: simple-bus@8404000 {
	compatible = "brcm,brcmstb-sun-top-ctrl", "simple-bus";
	reg = <0x8404000 0x708>;

	reset: reset-controller@318 {
		compatible = "brcm,brcmstb-reset";
		reg = <0x318 0x30>;
		#reset-cells = <1>;
	};
};

Would that be what you expect to see?
-- 
Florian

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