dt-bindings: sc16is7xx: Add property to change GPIO function

commit 4cf478d upstream.

Some variants in this series of UART controllers have GPIO pins that
are shared between GPIO and modem control lines.

The pin mux mode (GPIO or modem control lines) can be set for each
ports (channels) supported by the variant.

This adds a property to the device tree to set the GPIO pin mux to
modem control lines on selected ports if needed.

Cc: stable@vger.kernel.org # 6.1.x
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Lech Perczak <lech.perczak@camlingroup.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230807214556.540627-4-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/nxp,sc16is7xx.txt

@@ -23,6 +23,9 @@ Optional properties:
     1 = active low.
 - irda-mode-ports: An array that lists the indices of the port that
 		   should operate in IrDA mode.
+- nxp,modem-control-line-ports: An array that lists the indices of the port that
+				should have shared GPIO lines configured as
+				modem control lines.
 
 Example:
         sc16is750: sc16is750@51 {
@@ -35,6 +38,26 @@ Example:
                 #gpio-cells = <2>;
         };
 
+	sc16is752: sc16is752@53 {
+		compatible = "nxp,sc16is752";
+		reg = <0x53>;
+		clocks = <&clk20m>;
+		interrupt-parent = <&gpio3>;
+		interrupts = <7 IRQ_TYPE_EDGE_FALLING>;
+		nxp,modem-control-line-ports = <1>; /* Port 1 as modem control lines */
+		gpio-controller; /* Port 0 as GPIOs */
+		#gpio-cells = <2>;
+	};
+
+	sc16is752: sc16is752@54 {
+		compatible = "nxp,sc16is752";
+		reg = <0x54>;
+		clocks = <&clk20m>;
+		interrupt-parent = <&gpio3>;
+		interrupts = <7 IRQ_TYPE_EDGE_FALLING>;
+		nxp,modem-control-line-ports = <0 1>; /* Ports 0 and 1 as modem control lines */
+	};
+
 * spi as bus
 
 Required properties:
@@ -59,6 +82,9 @@ Optional properties:
     1 = active low.
 - irda-mode-ports: An array that lists the indices of the port that
 		   should operate in IrDA mode.
+- nxp,modem-control-line-ports: An array that lists the indices of the port that
+				should have shared GPIO lines configured as
+				modem control lines.
 
 Example:
 	sc16is750: sc16is750@0 {
@@ -70,3 +96,23 @@ Example:
 		gpio-controller;
 		#gpio-cells = <2>;
 	};
+
+	sc16is752: sc16is752@1 {
+		compatible = "nxp,sc16is752";
+		reg = <1>;
+		clocks = <&clk20m>;
+		interrupt-parent = <&gpio3>;
+		interrupts = <7 IRQ_TYPE_EDGE_FALLING>;
+		nxp,modem-control-line-ports = <1>; /* Port 1 as modem control lines */
+		gpio-controller; /* Port 0 as GPIOs */
+		#gpio-cells = <2>;
+	};
+
+	sc16is752: sc16is752@2 {
+		compatible = "nxp,sc16is752";
+		reg = <2>;
+		clocks = <&clk20m>;
+		interrupt-parent = <&gpio3>;
+		interrupts = <7 IRQ_TYPE_EDGE_FALLING>;
+		nxp,modem-control-line-ports = <0 1>; /* Ports 0 and 1 as modem control lines */
+	};