dt-bindings: pinctrl: rp1: Describe groups for RP1 pin controller

The DT binding for RP1 pin controller currently lacks the group
definitions.

Add groups enumeration to the schema.

Signed-off-by: Andrea della Porta <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Link: https://lore.kernel.org/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

Documentation/devicetree/bindings/pinctrl/raspberrypi,rp1-gpio.yaml

···
       pins:
         description:
           List of gpio pins affected by the properties specified in this
-          subnode.
+          subnode (either this or "groups" must be specified).
         items:
           pattern: '^gpio([0-9]|[1-4][0-9]|5[0-3])$'
+
+      groups:
+        description:
+          List of groups affected by the properties specified in this
+          subnode (either this or "pins" must be specified).
+        items:
+          anyOf:
+            - pattern: '^gpio([0-9]|[1-4][0-9]|5[0-3])$'
+            - enum: [ uart0, uart0_ctrl, uart1, uart1_ctrl, uart2, uart2_ctrl,
+                      uart3, uart3_ctrl, uart4, uart4_ctrl, uart5_0,
+                      uart5_0_ctrl, uart5_1, uart5_1_ctrl, uart5_2,
+                      uart5_2_ctrl, uart5_3,
+                      sd0, sd1,
+                      i2s0, i2s0_dual, i2s0_quad, i2s1, i2s1_dual, i2s1_quad,
+                      i2s2_0, i2s2_0_dual, i2s2_1, i2s2_1_dual,
+                      i2c4_0, i2c4_1, i2c4_2, i2c4_3, i2c6_0, i2c6_1, i2c5_0,
+                      i2c5_1, i2c5_2, i2c5_3, i2c0_0, i2c0_1, i2c1_0, i2c1_1,
+                      i2c2_0, i2c2_1, i2c3_0, i2c3_1, i2c3_2,
+                      dpi_16bit, dpi_16bit_cpadhi, dpi_16bit_pad666,
+                      dpi_18bit, dpi_18bit_cpadhi, dpi_24bit,
+                      spi0, spi0_quad, spi1, spi2, spi3, spi4, spi5, spi6_0,
+                      spi6_1, spi7_0, spi7_1, spi8_0, spi8_1,
+                      aaud_0, aaud_1, aaud_2, aaud_3, aaud_4,
+                      vbus0_0, vbus0_1, vbus1, vbus2, vbus3,
+                      mic_0, mic_1, mic_2, mic_3,
+                      ir ]
 
       function:
         enum: [ alt0, alt1, alt2, alt3, alt4, gpio, alt6, alt7, alt8, none,
···
         enum: [ 0, 1 ]
       drive-strength:
         enum: [ 2, 4, 8, 12 ]
+
+    required:
+      - function
+
+    oneOf:
+      - required: [ groups ]
+      - required: [ pins ]
 
     additionalProperties: false