Le Thu, 29 Jul 2021 15:19:19 -0600,
Rob Herring [off-list ref] a écrit :

On Fri, Jul 23, 2021 at 03:52:39PM +0200, Clément Léger wrote:

quoted

This patch adds documentation for the "syscon-smc" compatible which
describes a syscon using a SMC regmap instead of a MMIO one. This
allows accessing system controllers that are set as secure by using
SMC handled by the secure monitor.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
---
 .../devicetree/bindings/mfd/syscon-smc.yaml   | 57
+++++++++++++++++++ 1 file changed, 57 insertions(+)
 create mode 100644
Documentation/devicetree/bindings/mfd/syscon-smc.yaml

diff --git a/Documentation/devicetree/bindings/mfd/syscon-smc.yaml

b/Documentation/devicetree/bindings/mfd/syscon-smc.yaml new file
mode 100644 index 000000000000..6ce1392c5e7f

--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/syscon-smc.yaml

@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/syscon-smc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: System Controller Registers R/W via SMC Device Tree Bindings
+
+description: |
+  System controller SMC node represents a register region

containing a set
+  of miscellaneous registers accessed through a secure monitor.
+  The typical use-case is the same as the syscon one but when
running with a
+  secure monitor.
+
+maintainers:
+  - Lee Jones [off-list ref]
+
+properties:
+  compatible:
+    anyOf:
+      - items:
+          - enum:
+              - atmel,sama5d2-sfr
+
+          - const: syscon-smc  

I regret having 'syscon' as a compatible, so nak on a 2nd flavor of
it. It's only purpose is a hint to Linux to automagically create a
regmap for you.

Indeed.

All you need is the specific compatible, atmel,sama5d2-sfr, and you
can imply the rest of this from it. That's assuming the conclusion is
a register read/write interface on SMC is a good idea, but I don't
think it is.

Ok noted, I'll try to find something else to implement that.

Clément

Rob