[RFC PATCH] spi: dt-bindings: ti,qspi: convert to dtschema

[Kousik Sanagavarapu <five231003@xxxxxxxxx>]

Convert txt binding of TI's qspi controller (found on their omap SoCs) to
dtschema to allow for validation.

It is however to be noted that it is not a one-to-one conversion, in the
sense that the original txt binding needed to be updated, but these
changes are included in the dtschema and are mentioned below.

The changes, w.r.t. the original txt binding, are:

- Introduce "clocks" and "clock-names" which was never mentioned.
- Reflect that "ti,hwmods" is deprecated and is not a "required"
  property anymore.
- Introduce "num-cs" which allows for setting the number of chip
  selects.

Signed-off-by: Kousik Sanagavarapu <five231003@xxxxxxxxx>
---
I'm a bit iffy about this one as I guess the original txt binding failed
to cover some things about the properties.  I added the properties based
on their use in the *.dtsi files when I grepped for the compatible string

        arch/arm/boot/dts/ti/omap/dra7.dtsi
        arch/arm/boot/dts/ti/omap/am4372.dtsi

I also looked at the probe function in the driver for it, which can be
found at

        drivers/spi/spi-ti-qspi.c

 .../devicetree/bindings/spi/ti,qspi.yaml      | 94 +++++++++++++++++++
 .../devicetree/bindings/spi/ti_qspi.txt       | 53 -----------
 2 files changed, 94 insertions(+), 53 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/ti,qspi.yaml
 delete mode 100644 Documentation/devicetree/bindings/spi/ti_qspi.txt

diff --git a/Documentation/devicetree/bindings/spi/ti,qspi.yaml b/Documentation/devicetree/bindings/spi/ti,qspi.yaml
new file mode 100644
index 000000000000..77cabd7158f5
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/ti,qspi.yaml
@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/ti,qspi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TI QSPI controller
+
+maintainers:
+  - Kousik Sanagavarapu <five231003@xxxxxxxxx>
+
+allOf:
+  - $ref: spi-controller.yaml#
+
+properties:
+  compatible:
+    enum:
+      - ti,am4372-qspi
+      - ti,dra7xxx-qspi
+
+  reg:
+    items:
+      - description: base registers
+      - description: mapped memory
+
+  reg-names:
+    items:
+      - const: qspi_base
+      - const: qspi_mmap
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: fck
+
+  interrupts:
+    maxItems: 1
+
+  num-cs:
+    maxItems: 1
+
+  ti,hwmods:
+    description:
+      Name of the hwmod associated to the QSPI.  This is for legacy
+      platforms only.
+    $ref: /schemas/types.yaml#/definitions/string
+    deprecated: true
+
+  syscon-chipselects:
+    description:
+      Handle to system control region contains QSPI chipselect register
+      and offset of that register.
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      items:
+        - description: phandle to system control register
+        - description: register offset
+
+  spi-max-frequency:
+    description: Maximum SPI clocking speed of the controller in Hz.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - clock-names
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/dra7.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    qspi: spi@0 {
+        compatible = "ti,dra7xxx-qspi";
+        reg = <0x4b300000 0x100>,
+              <0x5c000000 0x4000000>;
+        reg-names = "qspi_base", "qspi_mmap";
+        syscon-chipselects = <&scm_conf 0x558>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        clocks = <&l4per2_clkctrl DRA7_L4PER2_QSPI_CLKCTRL 25>;
+        clock-names = "fck";
+        num-cs = <4>;
+        spi-max-frequency = <48000000>;
+        interrupts = <GIC_SPI 343 IRQ_TYPE_LEVEL_HIGH>;
+    };
+...
diff --git a/Documentation/devicetree/bindings/spi/ti_qspi.txt b/Documentation/devicetree/bindings/spi/ti_qspi.txt
deleted file mode 100644
index 47b184bce414..000000000000
--- a/Documentation/devicetree/bindings/spi/ti_qspi.txt
+++ /dev/null
@@ -1,53 +0,0 @@
-TI QSPI controller.
-
-Required properties:
-- compatible : should be "ti,dra7xxx-qspi" or "ti,am4372-qspi".
-- reg: Should contain QSPI registers location and length.
-- reg-names: Should contain the resource reg names.
-	- qspi_base: Qspi configuration register Address space
-	- qspi_mmap: Memory mapped Address space
-	- (optional) qspi_ctrlmod: Control module Address space
-- interrupts: should contain the qspi interrupt number.
-- #address-cells, #size-cells : Must be present if the device has sub-nodes
-- ti,hwmods: Name of the hwmod associated to the QSPI
-
-Recommended properties:
-- spi-max-frequency: Definition as per
-                     Documentation/devicetree/bindings/spi/spi-bus.txt
-
-Optional properties:
-- syscon-chipselects: Handle to system control region contains QSPI
-		      chipselect register and offset of that register.
-
-NOTE: TI QSPI controller requires different pinmux and IODelay
-parameters for Mode-0 and Mode-3 operations, which needs to be set up by
-the bootloader (U-Boot). Default configuration only supports Mode-0
-operation. Hence, "spi-cpol" and "spi-cpha" DT properties cannot be
-specified in the slave nodes of TI QSPI controller without appropriate
-modification to bootloader.
-
-Example:
-
-For am4372:
-qspi: qspi@47900000 {
-	compatible = "ti,am4372-qspi";
-	reg = <0x47900000 0x100>, <0x30000000 0x4000000>;
-	reg-names = "qspi_base", "qspi_mmap";
-	#address-cells = <1>;
-	#size-cells = <0>;
-	spi-max-frequency = <25000000>;
-	ti,hwmods = "qspi";
-};
-
-For dra7xx:
-qspi: qspi@4b300000 {
-	compatible = "ti,dra7xxx-qspi";
-	reg = <0x4b300000 0x100>,
-	      <0x5c000000 0x4000000>,
-	reg-names = "qspi_base", "qspi_mmap";
-	syscon-chipselects = <&scm_conf 0x558>;
-	#address-cells = <1>;
-	#size-cells = <0>;
-	spi-max-frequency = <48000000>;
-	ti,hwmods = "qspi";
-};
-- 
2.45.0.rc1.8.ge326e52010