dt-bindings: pinctrl: Add support for Broadcom STB pin controller

The STB pin controller represents a family whose silicon instances
are found e.g. on BCM2712 SoC.

In particular, on RaspberryPi 5, there are two separate instantiations
of the same IP block which differ in the number of pins that are
associated and the pinmux functions for each of those pins. The
-aon- variant stands for 'Always On'.

Depending on the revision of the BCM2712 (CO or D0), the pin
controller instance has slight differences in the register layout.

Signed-off-by: Ivan T. Ivanov <iivanov@suse.de>
Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
[linusw: Dropped extranous label and fixed whitespace]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/brcm,bcm2712c0-pinctrl.yaml

@@ -0,0 +1,137 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/brcm,bcm2712c0-pinctrl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom STB family pin controller
+
+maintainers:
+  - Ivan T. Ivanov <iivanov@suse.de>
+  - A. della Porta <andrea.porta@suse.com>
+
+description: >
+  Broadcom's STB family of memory-mapped pin controllers.
+
+  This includes the pin controllers inside the BCM2712 SoC which
+  are instances of the STB family and has two silicon variants,
+  C0 and D0, which differs slightly in terms of registers layout.
+
+  The -aon- (Always On) variant is the same IP block but differs
+  in the number of pins that are associated and the pinmux functions
+  for each of those pins.
+
+allOf:
+  - $ref: pinctrl.yaml#
+
+properties:
+  compatible:
+    enum:
+      - brcm,bcm2712c0-pinctrl
+      - brcm,bcm2712c0-aon-pinctrl
+      - brcm,bcm2712d0-pinctrl
+      - brcm,bcm2712d0-aon-pinctrl
+
+  reg:
+    maxItems: 1
+
+patternProperties:
+  '-state$':
+    oneOf:
+      - $ref: '#/$defs/brcmstb-pinctrl-state'
+      - patternProperties:
+          '-pins$':
+            $ref: '#/$defs/brcmstb-pinctrl-state'
+        additionalProperties: false
+
+$defs:
+  brcmstb-pinctrl-state:
+    allOf:
+      - $ref: pincfg-node.yaml#
+      - $ref: pinmux-node.yaml#
+
+    description: >
+      Pin controller client devices use pin configuration subnodes (children
+      and grandchildren) for desired pin configuration.
+
+      Client device subnodes use below standard properties.
+
+    properties:
+      pins:
+        description:
+          List of gpio pins affected by the properties specified in this
+          subnode (either this or "groups" must be specified).
+        items:
+          pattern: '^((aon_)?s?gpio[0-6]?[0-9])|(emmc_(clk|cmd|dat[0-7]|ds))$'
+
+      function:
+        description:
+          Specify the alternative function to be configured for the specified
+          pins.
+        enum: [ gpio, alt1, alt2, alt3, alt4, alt5, alt6, alt7, alt8,
+                aon_cpu_standbyb, aon_fp_4sec_resetb, aon_gpclk, aon_pwm,
+                arm_jtag, aud_fs_clk0, avs_pmu_bsc, bsc_m0, bsc_m1, bsc_m2,
+                bsc_m3, clk_observe, ctl_hdmi_5v, enet0, enet0_mii, enet0_rgmii,
+                ext_sc_clk, fl0, fl1, gpclk0, gpclk1, gpclk2, hdmi_tx0_auto_i2c,
+                hdmi_tx0_bsc, hdmi_tx1_auto_i2c, hdmi_tx1_bsc, i2s_in, i2s_out,
+                ir_in, mtsif, mtsif_alt, mtsif_alt1, pdm, pkt, pm_led_out, sc0,
+                sd0, sd2, sd_card_a, sd_card_b, sd_card_c, sd_card_d, sd_card_e,
+                sd_card_f, sd_card_g, spdif_out, spi_m, spi_s, sr_edm_sense, te0,
+                te1, tsio, uart0, uart1, uart2, usb_pwr, usb_vbus, uui, vc_i2c0,
+                vc_i2c3, vc_i2c4, vc_i2c5, vc_i2csl, vc_pcm, vc_pwm0, vc_pwm1,
+                vc_spi0, vc_spi3, vc_spi4, vc_spi5, vc_uart0, vc_uart2, vc_uart3,
+                vc_uart4 ]
+
+      bias-disable: true
+      bias-pull-down: true
+      bias-pull-up: true
+
+    required:
+      - pins
+
+    if:
+      properties:
+        pins:
+          not:
+            contains:
+              pattern: "^emmc_(clk|cmd|dat[0-7]|ds)$"
+    then:
+      required:
+        - function
+    else:
+      properties:
+        function: false
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    pinctrl@7d504100 {
+        compatible = "brcm,bcm2712c0-pinctrl";
+        reg = <0x7d504100 0x30>;
+
+        bt-shutdown-default-state {
+            function = "gpio";
+            pins = "gpio29";
+        };
+
+        uarta-default-state {
+            rts-tx-pins {
+                function = "uart0";
+                pins = "gpio24", "gpio26";
+                bias-disable;
+            };
+
+            cts-rx-pins {
+                function = "uart0";
+                pins = "gpio25", "gpio27";
+                bias-pull-up;
+            };
+        };
+    };