[PATCH v3 2/8] dt-bindings: can: renesas,rcar-canfd: Document RZ/G3S SoC

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>

The CAN FD controller found on the Renesas RZ/G3S SoC is largely compatible
with the variant present on the RZ/G3E SoC. The main differences are:
- the RZ/G3S provides only two CAN FD channels
- the RZ/G3S supports only CAN FD operation; the Channel n CAN FD
  Configuration Register does not implement the bits used to select
  classical CAN-only mode (bit 30) or CAN FD-only mode (bit 28);
  consequently, bit 31 (CAN FD Frame Distinction Enable) of the same
  register is also not implemented
- some bits in several registers (mainly reserved or status bits) are
  read-write on the RZ/G3S but read-only on the RZ/G3E; their behavior is
  otherwise identical: the bits read back as 0 on both SoCs and software
  is allowed to write only 0 to them on the RZ/G3S
- the RZ/G3S provides 256 acceptance filters, compared to 768 on the
  RZ/G3E
- the RZ/G3S can use PCLK clock as the CAN FD clock source through an
  internal clock divider, while also supporting an external CAN FD clock
  source

Since:
- the SoC clock generator provides to the CAN IP only the peripheral and
  the RAM clocks
- when sourced from the peripheral clock, the CAN-FD clock is obtained
  inside the IP itself by dividing the peripheral clock
- the assigned-clocks and assigned-clock-rates properties are specific to
  the CAN-FD clock
the assigned-clocks and assigned-clock-rates properties were dropped from
the required properties list of the Renesas RZ/G3S SoC.

Add documentation for the Renesas RZ/G3S SoC.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
---

Changes in v3:
- updated the patch description to reflect RZ/G3S has 256 acceptance
  filters and RZ/G3E has 768 acceptance filters
- kept compatibles alphanumerically sorted

Changes in v2:
- forbid renesas,no-can-fd and renesas,fd-only since the IP supports
  only CAN-FD; for this didn't collect Biju's tag

 .../bindings/net/can/renesas,rcar-canfd.yaml  | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
index b9d9dd7a7967..bbaaef8f4282 100644
--- a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
+++ b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
@@ -13,6 +13,7 @@ properties:
   compatible:
     oneOf:
       - enum:
+          - renesas,r9a08g045-canfd        # RZ/G3S
           - renesas,r9a09g047-canfd        # RZ/G3E
           - renesas,r9a09g077-canfd        # RZ/T2H
 
@@ -185,8 +186,6 @@ required:
   - clocks
   - clock-names
   - power-domains
-  - assigned-clocks
-  - assigned-clock-rates
   - channel0
   - channel1
 
@@ -198,6 +197,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - renesas,r9a08g045-canfd
               - renesas,rzg2l-canfd
     then:
       properties:
@@ -266,6 +266,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - renesas,r9a08g045-canfd
               - renesas,r9a09g077-canfd
               - renesas,rcar-gen3-canfd
               - renesas,rzg2l-canfd
@@ -330,6 +331,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - renesas,r9a08g045-canfd
               - renesas,r9a09g047-canfd
               - renesas,rzg2l-canfd
     then:
@@ -350,6 +352,20 @@ allOf:
       properties:
         reset-names: false
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: renesas,r9a08g045-canfd
+    then:
+      properties:
+        renesas,no-can-fd: false
+        renesas,fd-only: false
+    else:
+      required:
+        - assigned-clocks
+        - assigned-clock-rates
+
 unevaluatedProperties: false
 
 examples:
-- 
2.43.0