[PATCH v2 5/6] arm64: dts: imx8mp-evk: add board-level mux for CAN2 and MICFIL

[Frank Li]

The board integrates an on-board mux to route shared signals to either
CAN2 or PDM (MICFIL). The mux is controlled by a GPIO.

Add a pinctrl-based multiplexer node to describe this routing and ensure
proper probe ordering of the dependent devices.

Previously, MICFIL operation implicitly depended on the default level of
PCA6416 GPIO3. After adding the pinctrl-multiplexer, make the dependency
explicit.

Signed-off-by: Frank Li <Frank.Li at nxp.com>
---
change in v2
- update commit message to show why need update PDM MICIFL.
---
 arch/arm64/boot/dts/freescale/imx8mp-evk.dts | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
index b256be710ea1281465f5cecc7a3b979f2c068e43..1341ee27239fd41a26117adc9023524ce50420a7 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mp-evk.dts
@@ -50,6 +50,25 @@ status {
 		};
 	};
 
+	can_mux: mux-controller-0 {
+		compatible = "gpio-mux";
+		#mux-control-cells = <0>;
+		#mux-state-cells = <1>;
+		mux-gpios = <&pca6416 3 GPIO_ACTIVE_HIGH>;
+	};
+
+	can_mux_pinctrl: pinctrl-gpiomux {
+		compatible = "pinctrl-multiplexer";
+
+		can_fun: can-grp {
+			mux-states = <&can_mux 1>;
+		};
+
+		pdm_fun: pdm-grp {
+			mux-states = <&can_mux 0>;
+		};
+	};
+
 	memory at 40000000 {
 		device_type = "memory";
 		reg = <0x0 0x40000000 0 0xc0000000>,
@@ -446,7 +465,7 @@ &flexcan1 {
 
 &flexcan2 {
 	pinctrl-names = "default";
-	pinctrl-0 = <&pinctrl_flexcan2>;
+	pinctrl-0 = <&pinctrl_flexcan2>, <&can_fun>;
 	phys = <&flexcan_phy 1>;
 	status = "disabled";/* can2 pin conflict with pdm */
 };
@@ -712,7 +731,7 @@ &lcdif3 {
 &micfil {
 	#sound-dai-cells = <0>;
 	pinctrl-names = "default";
-	pinctrl-0 = <&pinctrl_pdm>;
+	pinctrl-0 = <&pinctrl_pdm>, <&pdm_fun>;
 	assigned-clocks = <&clk IMX8MP_CLK_PDM>;
 	assigned-clock-parents = <&clk IMX8MP_AUDIO_PLL1_OUT>;
 	assigned-clock-rates = <196608000>;

-- 
2.43.0