[PATCH v2] arm64: dts: Added syscon-reboot node for FSL's LS2085A SoC

[PATCH v2] arm64: dts: Added syscon-reboot node for FSL's LS2085A SoC

[J. German Rivera]

Added sys-reboot node to the FSL's LS2085A SoC DT to leverage
the ARM-generic reboot mechanism for this SoC. This mechanism
is enabled through CONFIG_POWER_RESET_SYSCON.

Signed-off-by: J. German Rivera <German.Rivera@freescale.com>
---
CHANGE HISTORY

Changes in v2:
- Address comment form Stuart Yoder:
  * Removed "@<address>" from reboot node

 arch/arm64/boot/dts/freescale/fsl-ls2085a.dtsi | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls2085a.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls2085a.dtsi
index e281ceb..8fb3646 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls2085a.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-ls2085a.dtsi
@@ -131,6 +131,18 @@
 		interrupts = <1 9 0x4>;
 	};

+	rst_ccsr: rstccsr at 1E60000 {
+	        compatible = "syscon";
+		reg = <0x0 0x1E60000 0x0 0x10000>;
+	};
+
+	reboot {
+		compatible ="syscon-reboot";
+		regmap = <&rst_ccsr>;
+		offset = <0x0>;
+		mask = <0x2>;
+	};
+
 	timer {
 		compatible = "arm,armv8-timer";
 		interrupts = <1 13 0x8>, /* Physical Secure PPI, active-low */
--
2.3.3

[PATCH v2] arm64: dts: Added syscon-reboot node for FSL's LS2085A SoC

[Arnd Bergmann]

On Wednesday 28 October 2015 16:09:44 J. German Rivera wrote:
> +       rst_ccsr: rstccsr at 1E60000 {
> +               compatible = "syscon";
> +               reg = <0x0 0x1E60000 0x0 0x10000>;
> +       };
> +
> 

What does 'rstccsr' stand for? Is this by chance a reset controller?

If so, we probably want a real driver for it rather than just a
syscon.

	Arnd

[PATCH v2] arm64: dts: Added syscon-reboot node for FSL's LS2085A SoC

[Stuart Yoder]

> -----Original Message-----
> From: Arnd Bergmann [mailto:arnd at arndb.de]
> Sent: Thursday, October 29, 2015 4:49 PM
> To: linux-arm-kernel at lists.infradead.org
> Cc: Rivera Jose-B46482; robh+dt at kernel.org; mark.rutland at arm.com; devicetree at vger.kernel.org; linux-
> kernel at vger.kernel.org; Sharma Bhupesh-B45370; Li Yang-Leo-R58472; Yoder Stuart-B08248
> Subject: Re: [PATCH v2] arm64: dts: Added syscon-reboot node for FSL's LS2085A SoC
> 
> On Wednesday 28 October 2015 16:09:44 J. German Rivera wrote:
> > +       rst_ccsr: rstccsr at 1E60000 {
> > +               compatible = "syscon";
> > +               reg = <0x0 0x1E60000 0x0 0x10000>;
> > +       };
> > +
> >
> 
> What does 'rstccsr' stand for? Is this by chance a reset controller?

It is a region of some miscellaneous registers, some related to reset.
 
> If so, we probably want a real driver for it rather than just a
> syscon.

There is not other stuff in this region that to be exposed,
and so we really don't need a real driver.

My suggestion is to perhaps make that more explicit in the proposed
device tree node, by making the reg size "4" and naming it
as per the register name

       rstcr: rstcr at 1E60000 {
               compatible = "syscon";
               reg = <0x0 0x1E60000 0x0 0x4>;
       };

The intent is really just to expose a single reset register
and use syscon-reboot until PSCI is available.

Thanks,
Stuart

[PATCH v2] arm64: dts: Added syscon-reboot node for FSL's LS2085A SoC

[Arnd Bergmann]

On Friday 30 October 2015 16:34:26 Stuart Yoder wrote:
> My suggestion is to perhaps make that more explicit in the proposed
> device tree node, by making the reg size "4" and naming it
> as per the register name
> 
>        rstcr: rstcr at 1E60000 {
>                compatible = "syscon";
>                reg = <0x0 0x1E60000 0x0 0x4>;
>        };
> 
> The intent is really just to expose a single reset register
> and use syscon-reboot until PSCI is available.

I would rather see a more specific compatible string here that describes
the actual name, e.g.

	compatible = "fsl,ls2085a-rstcr", "syscon";

this way we have the option of making it a real driver later on by matching
on the specific string, but using the fallback syscon string otherwise.

BTW, please change the address to lowercase letters in both the node name and
the reg property. I would also change the name to 'syscon' instead of 'rstcr',
making that

	rstcr: syscon at 1e60000 {
		...
	};

	Arnd