On 5/31/23 21:37, Krzysztof Kozlowski wrote:
On 24/05/2023 05:30, Marek Vasut wrote:
On 5/18/23 16:26, Krzysztof Kozlowski wrote:
On 17/05/2023 17:25, Marek Vasut wrote:
Add trivial bindings for driver which permits exposing syscon backed
register to userspace. This is useful e.g. to expose U-Boot boot
counter on various platforms where the boot counter is stored in
random volatile register, like STM32MP15xx TAMP_BKPxR register.
Signed-off-by: Marek Vasut <marex@xxxxxxx>
---
Cc: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx>
Cc: Conor Dooley <conor+dt@xxxxxxxxxx>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx>
Cc: Marek Vasut <marex@xxxxxxx>
Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: kernel@xxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
---
V2: Use generic syscon supernode
---
.../bindings/nvmem/nvmem-syscon.yaml | 39 +++++++++++++++++++
1 file changed, 39 insertions(+)
create mode 100644 Documentation/devicetree/bindings/nvmem/nvmem-syscon.yaml
diff --git a/Documentation/devicetree/bindings/nvmem/nvmem-syscon.yaml b/Documentation/devicetree/bindings/nvmem/nvmem-syscon.yaml
new file mode 100644
index 0000000000000..7c1173a1a6218
--- /dev/null
+++ b/Documentation/devicetree/bindings/nvmem/nvmem-syscon.yaml
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/nvmem/nvmem-syscon.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic syscon backed nvmem
+
+maintainers:
+ - Marek Vasut <marex@xxxxxxx>
+
+allOf:
+ - $ref: "nvmem.yaml#"
Usual comment: drop quotes. We removed them everywhere, so you based
your work on some old tree.
+
+properties:
+ compatible:
+ enum:
+ - nvmem-syscon
+
+ reg:
+ maxItems: 1
Rob's questions are not solved.
Can you reiterate this one ? I likely missed it.
You did not solve the case of more than one register. This isn't an odd
case.
So why not just extend the bindings to support
reg = <0x14c 0x4>, <0x180 0x10>, ... ;
this kind of stuff ?
The nvmem.yaml schema expects here to
allow children. This should not be created per-register, but per entire
block of registers.
This thing works the other way around, I have a syscon register block
already, and I want to expose subset of it to userspace as read/write
accessible file to expose bootcounter available in that register (so I
can read it and reset it from user application).
And this makes it too limited. I would expect one device exposing
multiple blocks or registers, just like all nvmem providers are doing.
What would be the real-world use case of that ?
