drivers: pinctrl: added slew-rate setting for the sy1xx soc

With this commit we have the option to set the pad slew-rates
for all available pins on the soc.

Signed-off-by: Sven Ginka <s.ginka@sensry.de>

Author: tswaehn

dts/bindings/pinctrl/sensry,sy1xx-pinctrl.yaml

@@ -74,3 +74,19 @@ child-binding:
       description: |
         Pin mux selection. See the SOC level pinctrl header
         for a defined list of these options.
+
+    slew-rate:
+      type: int
+      enum:
+        - 0 # 2pF
+        - 1 # 4pF
+        - 2 # 8pF
+        - 3 # 16pF
+      default: 0
+      description: |
+        Selects the output drive strength. Choices represent approximate capacitive load.
+        The default corresponds to the reset value of the register field.
+        - 0.. 2pF, Weakest drive
+        - 1.. 4pF, Low drive
+        - 2.. 8pF, Medium drive
+        - 3.. 16pF, Strongest drive

soc/sensry/ganymed/sy1xx/common/pinctrl_soc.h

@@ -45,6 +45,7 @@ typedef struct {
 		(SY1XX_PULL_UP_ENABLE * DT_PROP(node, bias_pull_up)) << SY1XX_PAD_PULL_UP_OFFS |   \
 		(SY1XX_PULL_DOWN_ENABLE * DT_PROP(node, bias_pull_down))                           \
 			<< SY1XX_PAD_PULL_DOWN_OFFS |                                              \
+		(DT_PROP(node, slew_rate) << SY1XX_PAD_DRIVE_OFFS) |                               \
 		(SY1XX_TRISTATE_ENABLE * DT_PROP(node, bias_high_impedance))                       \
 			<< SY1XX_PAD_TRISTATE_OFFS |                                               \
 		(SY1XX_OUTPUT_ENABLE & (1 - DT_PROP(node, input_enable))) << SY1XX_PAD_DIR_OFFS    \