[PATCH v2 1/8] dt-bindings: pinctrl: Add thead,th1520-pinctrl bindings

[Drew Fustini <dfustini@xxxxxxxxxxxxxxx>]

From: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>

Add bindings for the pin controllers on the T-Head TH1520 RISC-V SoC.

Tested-by: Thomas Bonnefille <thomas.bonnefille@xxxxxxxxxxx>
Signed-off-by: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
[dfustini: add thead,pad-group to select the pin controller instance]
Signed-off-by: Drew Fustini <dfustini@xxxxxxxxxxxxxxx>
---
 .../bindings/pinctrl/thead,th1520-pinctrl.yaml     | 176 +++++++++++++++++++++
 MAINTAINERS                                        |   1 +
 2 files changed, 177 insertions(+)

diff --git a/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
new file mode 100644
index 000000000000..21f86740a63d
--- /dev/null
+++ b/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
@@ -0,0 +1,176 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/thead,th1520-pinctrl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-Head TH1520 SoC pin controller
+
+maintainers:
+  - Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
+
+description: |
+  Pinmux and pinconf controller in the T-Head TH1520 RISC-V SoC.
+
+  The TH1520 has 3 groups of pads each controlled from different memory ranges.
+  Confusingly the memory ranges are named
+    PADCTRL_AOSYS  -> PAD Group 1
+    PADCTRL1_APSYS -> PAD Group 2
+    PADCTRL0_APSYS -> PAD Group 3
+
+  Each pad can be muxed individually to up to 6 different functions. For most
+  pads only a few of those 6 configurations are valid though, and a few pads in
+  group 1 does not support muxing at all.
+
+  Pinconf is fairly regular except for a few pads in group 1 that either can't
+  be configured or has some special functions. The rest have configurable drive
+  strength, input enable, schmitt trigger, slew rate, pull-up and pull-down in
+  addition to a special strong pull up.
+
+  Certain pads in group 1 can be muxed to AUDIO_PA0 - AUDIO_PA30 functions and
+  are then meant to be used by the audio co-processor. Each such pad can then
+  be further muxed to either audio GPIO or one of 4 functions such as UART, I2C
+  and I2S. If the audio pad is muxed to one of the 4 functions then pinconf is
+  also configured in different registers. All of this is done from a different
+  AUDIO_IOCTRL memory range and is left to the audio co-processor for now.
+
+properties:
+  compatible:
+    enum:
+      - thead,th1520-pinctrl
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  thead,pad-group:
+    description: |
+      Select the pad group that is associated with the pin controller instance.
+
+        Base Address   Name           Group
+        0xFF_FFF4_A000 PADCTRL_AOSYS  1
+        0xFF_E7F3_C000 PADCTRL1_APSYS 2
+        0xFF_EC00_7000 PADCTRL0_APSYS 3
+
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [1, 2, 3]
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+patternProperties:
+  '-[0-9]+$':
+    type: object
+    additionalProperties: false
+
+    patternProperties:
+      '-pins$':
+        type: object
+        allOf:
+          - $ref: /schemas/pinctrl/pincfg-node.yaml#
+          - $ref: /schemas/pinctrl/pinmux-node.yaml#
+
+        additionalProperties: false
+
+        description:
+          A pinctrl node should contain at least one subnode describing one
+          or more pads and their associated pinmux and pinconf settings.
+
+        properties:
+          pins:
+            description: List of pads that properties in the node apply to.
+
+          function:
+            enum: [ gpio, pwm, uart, ir, i2c, spi, qspi, sdio, audio, i2s,
+                    gmac0, gmac1, dpu0, dpu1, isp, hdmi, bootsel, debug,
+                    clock, jtag, iso7816, efuse, reset ]
+            description: The mux function to select for the given pins.
+
+          bias-disable: true
+
+          bias-pull-up:
+            oneOf:
+              - type: boolean
+                description: Enable the regular 48kOhm pull-up
+              - enum: [ 2100, 48000 ]
+                description: Enable the strong 2.1kOhm pull-up or regular 48kOhm pull-up
+
+          bias-pull-down:
+            oneOf:
+              - type: boolean
+              - const: 44000
+            description: Enable the regular 44kOhm pull-down
+
+          drive-strength:
+            enum: [ 1, 2, 3, 5, 7, 8, 10, 12, 13, 15, 16, 18, 20, 21, 23, 25 ]
+            description: Drive strength in mA
+
+          input-enable: true
+
+          input-disable: true
+
+          input-schmitt-enable: true
+
+          input-schmitt-disable: true
+
+          slew-rate:
+            maximum: 1
+
+        required:
+          - pins
+
+additionalProperties: false
+
+examples:
+  - |
+    padctrl0_apsys: pinctrl@ec007000 {
+        compatible = "thead,th1520-pinctrl";
+        reg = <0xec007000 0x1000>;
+        clocks = <&apb_clk>;
+        thead,pad-group = <3>;
+
+        uart0_pins: uart0-0 {
+            tx-pins {
+                pins = "UART0_TXD";
+                function = "uart";
+                bias-disable;
+                drive-strength = <3>;
+                input-disable;
+                input-schmitt-disable;
+                slew-rate = <0>;
+            };
+
+            rx-pins {
+                pins = "UART0_RXD";
+                function = "uart";
+                bias-disable;
+                drive-strength = <1>;
+                input-enable;
+                input-schmitt-enable;
+                slew-rate = <0>;
+            };
+        };
+    };
+
+    padctrl1_apsys: pinctrl@e7f3c000 {
+        compatible = "thead,th1520-pinctrl";
+        reg = <0xe7f3c000 0x1000>;
+        clocks = <&apb_clk>;
+        thead,pad-group = <2>;
+
+        i2c5_pins: i2c5-0 {
+            i2c-pins {
+                pins = "QSPI1_CSN0",    /* I2C5_SCL */
+                       "QSPI1_D0_MOSI"; /* I2C5_SDA */
+                function = "i2c";
+                bias-pull-up = <2100>;
+                drive-strength = <7>;
+                input-enable;
+                input-schmitt-enable;
+                slew-rate = <0>;
+            };
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 878dcd23b331..a73953c0f080 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19700,6 +19700,7 @@ L:	linux-riscv@xxxxxxxxxxxxxxxxxxx
 S:	Maintained
 T:	git https://github.com/pdp7/linux.git
 F:	Documentation/devicetree/bindings/clock/thead,th1520-clk-ap.yaml
+F:	Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
 F:	arch/riscv/boot/dts/thead/
 F:	drivers/clk/thead/clk-th1520-ap.c
 F:	include/dt-bindings/clock/thead,th1520-clk-ap.h

-- 
2.34.1