Re: [PATCH 02/10] dt-bindings: net: can: grcan: Convert GRCAN CAN controllers binding from txt to YAML
From: Arun Muthusamy
Date: Mon Nov 24 2025 - 04:38:03 EST
Hi Krzysztof,
Thank you for your thorough review and insightful questions. I’d like to
clarify a few points regarding the DT binding and get your guidance.
Node name vs. compatible matching:
SPARC systems do not use DTS files; the device tree is generated by the
PROM. On LEON (SPARC32), AMBA Plug & Play information creates the DT
properties, and drivers historically match devices based on node names.
For DTS-based systems such as NOEL, this patch series adds
compatible-string matching. To reflect this, I updated the $nodename
pattern to support LEON-style node names:
properties:
$nodename:
pattern: "^(GAISLER_GRCAN|01_03d|GAISLER_GRHCAN|01_034)$"
I’d appreciate any suggestions on the preferred way to describe this
dual matching approach: node name for PROM-based LEON, compatible string
for DTS-based NOEL.
Freq and Clocks:
The driver needs to support both LEON and NOEL platforms:
LEON: relies on the freq property
NOEL: uses a standard clocks binding
Because of this dual approach, the freq property is no longer required
in the DTS binding itself.
It is only relevant for LEON/PROM-based systems and is handled
internally by the driver
Systemid:
The driver now reads systemid directly from /ambapp0, so the property no
longer needs to be defined in the DTS. The previous documentation was
outdated and should have been updated after commit:
1e93ed26acf0 ("can: grcan: grcan_probe(): fix broken system id check for
errata workaround needs")
Thanks,
--
BR,
Arun Muthusamy
Software Engineer
Frontgrade Gaisler
T : +46 (0) 700 558 528
arun.muthusamy@xxxxxxxxxxx
Frontgrade Gaisler AB, Kungsgatan 12, SE-411 19 GÖTEBORG, Sweden.
+46 (0) 31 775 8650, www.gaisler.com
On 18.11.2025 12:01, Krzysztof Kozlowski wrote:
On 18/11/2025 10:21, Arun Muthusamy wrote:
Migrate device tree bindings for Gaisler GRCAN, GRHCAN
and GRCANFD CAN controllers from a text format to YAML format.
- Add properties such as `compatible`, `reg`, `interrupts`
Odd indentation. Please write readable commit msgs.
Also:
1. Why? You need to explain why you are changing binding during
conversion.
2. Reg was already there, so I don't understand why you need to add it.
and `clocks` for the CAN controllers.
- Removal of the old `grcan.txt` file as its contents have
been fully migrated to the YAML file.
Drop, that's not relevant.
- YAML file includes examples of device tree bindings for
the CAN controllers
Drop, not relevant. Please look at git history how commits are written.
Signed-off-by: Arun Muthusamy <arun.muthusamy@xxxxxxxxxxx>
---
.../bindings/net/can/gaisler,grcan.yaml | 85
+++++++++++++++++++
.../devicetree/bindings/net/can/grcan.txt | 28 ------
2 files changed, 85 insertions(+), 28 deletions(-)
create mode 100644
Documentation/devicetree/bindings/net/can/gaisler,grcan.yaml
delete mode 100644
Documentation/devicetree/bindings/net/can/grcan.txt
diff --git
a/Documentation/devicetree/bindings/net/can/gaisler,grcan.yaml
b/Documentation/devicetree/bindings/net/can/gaisler,grcan.yaml
new file mode 100644
index 000000000000..521bdd89f130
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/can/gaisler,grcan.yaml
@@ -0,0 +1,85 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/can/gaisler,grcan.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title:
+ Aeroflex Gaisler GRCAN, GRHCAN and GRCANFD CAN controllers.
+
+description: |
+ GRCAN, GRCANFD, GRHCAN controllers are available in the GRLIB VHDL
IP core
+ library.
+
+ For further information look in the documentation for the GRLIB IP
library:
+ https://download.gaisler.com/products/GRLIB/doc/grip.pdf
+
+maintainers:
+ - Arun Muthusamy <arun.muthusamy@xxxxxxxxxxx>
+ - Andreas Larsson <andreas@xxxxxxxxxxx>
+
+allOf:
+ - $ref: can-controller.yaml#
+
+properties:
+ compatible:
+ enum:
+ - gaisler,grcan
+ - gaisler,grcanfd
Blank line
+ name:
+ description: |
Do not need '|' unless you need to preserve formatting.
+ Fallback on node name matching for systems that don't provide
compatible.
+ enum:
+ - GAISLER_GRCAN
+ - 01_03d
+ - GAISLER_GRHCAN
+ - "01_034"
This does not really work. Are you really defining here "name"
property?
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ clocks:
+ maxItems: 1
+
+ freq:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ Frequency of the external oscillator clock in Hz (the frequency
of the
+ amba bus in the ordinary case).
+ This property should be used by systems that utilize the common
clock
+ framework is not supported.
Missing systemid. Your commit msg must explain any changes done to the
binding during conversion.
+
+unevaluatedProperties: false
This goes after required block.
+
+required:
compatible as well
+ - reg
+ - interrupts
Where is freq? It was required in the old binding. Again, you need to
explain the changes.
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/irq.h>
+ can@ff400000 {
+ compatible = "gaisler,grcanfd";
+ clocks = <&sysclock>;
+ reg = <0xff400000 0x400>;
+ interrupt-parent = <&plic0>;
+ interrupts = <6>;
+ };
One example is enough
+ - |
+ #include <dt-bindings/interrupt-controller/irq.h>
+ can@ff400000 {
+ compatible = "gaisler,grcan";
+ clocks = <&sysclock>;
+ reg = <0xff400000 0x400>;
+ interrupt-parent = <&plic0>;
+ interrupts = <6>;
+ };
+ - |
+ GAISLER_GRCAN@ff840000 {
Especially no such examples. Please read DTS coding style.
+ reg = <0xff840000 0x400>;
+ freq = <50000000>;
+ interrupts = <16>;
+ };
diff --git a/Documentation/devicetree/bindings/net/can/grcan.txt
b/Documentation/devicetree/bindings/net/can/grcan.txt
deleted file mode 100644
index 34ef3498f887..000000000000
--- a/Documentation/devicetree/bindings/net/can/grcan.txt
+++ /dev/null
@@ -1,28 +0,0 @@
Best regards,
Krzysztof