[PATCH v2 4/8] dt-bindings: serial: Add support for selecting data transfer mode

[Viken Dadhaniya]

Data transfer mode is fixed by TrustZone (TZ), which currently restricts
developers from modifying the transfer mode from the APPS side.

Document the 'qcom,xfer-mode' properties to select the data transfer mode,
either GPI DMA (Generic Packet Interface) or non-GPI mode (PIO/CPU DMA).

UART controller can operate in one of two modes based on the
'qcom,xfer-mode' property, and the firmware is loaded accordingly.

Co-developed-by: Mukesh Kumar Savaliya <quic_msavaliy@xxxxxxxxxxx>
Signed-off-by: Mukesh Kumar Savaliya <quic_msavaliy@xxxxxxxxxxx>
Signed-off-by: Viken Dadhaniya <quic_vdadhani@xxxxxxxxxxx>
---

v1 -> v2:

- Drop 'qcom,load-firmware' property and add 'firmware-name' property in
  qup common driver.
- Update commit log.

v1 Link: https://lore.kernel.org/linux-kernel/20241204150326.1470749-4-quic_vdadhani@xxxxxxxxxxx/
---
---
 .../devicetree/bindings/serial/qcom,serial-geni-qcom.yaml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/qcom,serial-geni-qcom.yaml b/Documentation/devicetree/bindings/serial/qcom,serial-geni-qcom.yaml
index dd33794b3534..383773b32e47 100644
--- a/Documentation/devicetree/bindings/serial/qcom,serial-geni-qcom.yaml
+++ b/Documentation/devicetree/bindings/serial/qcom,serial-geni-qcom.yaml
@@ -56,6 +56,13 @@ properties:
   reg:
     maxItems: 1
 
+  qcom,xfer-mode:
+    description: Set the value to 1 for non-GPI (FIFO/CPU DMA) mode and 3 for GPI DMA mode.
+      The default mode is FIFO.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [1, 3]
+
+
 required:
   - compatible
   - clocks
@@ -82,5 +89,6 @@ examples:
         interconnects = <&qup_virt MASTER_QUP_CORE_0 0 &qup_virt SLAVE_QUP_CORE_0 0>,
                         <&gem_noc MASTER_APPSS_PROC 0 &config_noc SLAVE_QUP_0 0>;
         interconnect-names = "qup-core", "qup-config";
+        qcom,xfer-mode = <1>;
     };
 ...
-- 
2.34.1