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[v10,01/10] dt-bindings: serial: Added secondary clock for RZ/T2H RSCI

Message ID 20250523142417.2840797-2-thierry.bultel.yh@bp.renesas.com
State New
Headers show
Series [v10,01/10] dt-bindings: serial: Added secondary clock for RZ/T2H RSCI | expand

Commit Message

Thierry Bultel May 23, 2025, 2:24 p.m. UTC
At boot, the default clock is the PCLKM core clock (synchronous
clock, which is enabled by the bootloader).
For different baudrates, the asynchronous clock input must be used.
Clock selection is made by an internal register of RCSI.

Add the optional "sck", external clock input.

Also remove the unneeded serial0 alias from the dts example.

Signed-off-by: Thierry Bultel <thierry.bultel.yh@bp.renesas.com>
---
Changes v9->v10:
 - mention sck in description
 - no maxItems on clock-names
 - fixed the #include dependency in dts example
Changes v8->v9:
 - typo in description
 - named clocks 'operational' and 'bus', and added optional 'sck' clock
 - uses value of 2nd core clock in example to break the dependency on cpg patch
---
 .../bindings/serial/renesas,rsci.yaml           | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)
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Patch

diff --git a/Documentation/devicetree/bindings/serial/renesas,rsci.yaml b/Documentation/devicetree/bindings/serial/renesas,rsci.yaml
index ea879db5f485..1bf255407df0 100644
--- a/Documentation/devicetree/bindings/serial/renesas,rsci.yaml
+++ b/Documentation/devicetree/bindings/serial/renesas,rsci.yaml
@@ -35,10 +35,15 @@  properties:
       - const: tei
 
   clocks:
-    maxItems: 1
+    minItems: 2
+    maxItems: 3
 
   clock-names:
-    const: fck # UART functional clock
+    minItems: 2
+    items:
+      - const: operation
+      - const: bus
+      - const: sck # optional external clock input
 
   power-domains:
     maxItems: 1
@@ -60,10 +65,6 @@  examples:
     #include <dt-bindings/interrupt-controller/arm-gic.h>
     #include <dt-bindings/clock/renesas-cpg-mssr.h>
 
-    aliases {
-        serial0 = &sci0;
-    };
-
     sci0: serial@80005000 {
         compatible = "renesas,r9a09g077-rsci";
         reg = <0x80005000 0x400>;
@@ -72,7 +73,7 @@  examples:
                      <GIC_SPI 592 IRQ_TYPE_EDGE_RISING>,
                      <GIC_SPI 593 IRQ_TYPE_LEVEL_HIGH>;
         interrupt-names = "eri", "rxi", "txi", "tei";
-        clocks = <&cpg CPG_MOD 108>;
-        clock-names = "fck";
+        clocks = <&cpg CPG_MOD 8>, <&cpg CPG_CORE 13>;
+        clock-names = "operation", "bus";
         power-domains = <&cpg>;
     };