From 7f747c53fc4afa9a25eeb3ca290b4fed4690ca3f Mon Sep 17 00:00:00 2001
From: "Sunip K. Mukherjee" <sunipkmukherjee@gmail.com>
Date: Sun, 4 Jul 2021 16:03:07 -0400
Subject: [PATCH] overlays: Add overlay for Si446x Transceiver SPI

See: https://github.com/raspberrypi/linux/pull/4430

Signed-off-by: Sunip K. Mukherjee <sunipkmukherjee@gmail.com>
---
 arch/arm/boot/dts/overlays/Makefile           |  1 +
 arch/arm/boot/dts/overlays/README             | 10 ++++
 .../boot/dts/overlays/si446x-spi0-overlay.dts | 53 +++++++++++++++++++
 3 files changed, 64 insertions(+)
 create mode 100644 arch/arm/boot/dts/overlays/si446x-spi0-overlay.dts

--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -176,6 +176,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	seeed-can-fd-hat-v1.dtbo \
 	seeed-can-fd-hat-v2.dtbo \
 	sh1106-spi.dtbo \
+	si446x-spi0.dtbo \
 	smi.dtbo \
 	smi-dev.dtbo \
 	smi-nand.dtbo \
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -2733,6 +2733,16 @@ Params: speed                   SPI bus
         height                  Display height (32 or 64; default 64)
 
 
+Name:   si446x-spi0
+Info:   Overlay for Si446x UHF Transceiver via SPI using si446x driver.
+        The driver is currently out-of-tree at
+        https://github.com/sunipkmukherjee/silabs.git
+Load:   dtoverlay=si446x-spi0,<param>=<val>
+Params: speed                   SPI bus speed (default 4000000)
+        int_pin                 GPIO pin for interrupts (default 17)
+        reset_pin               GPIO pin for RESET (default 27)
+
+
 Name:   smi
 Info:   Enables the Secondary Memory Interface peripheral. Uses GPIOs 2-25!
 Load:   dtoverlay=smi
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/si446x-spi0-overlay.dts
@@ -0,0 +1,53 @@
+// Overlay for the SiLabs Si446X Controller - SPI0
+// Default Interrupt Pin: 17
+// Default SDN Pin: 27
+/dts-v1/;
+/plugin/;
+
+   / {
+    compatible = "brcm,bcm2835";
+
+    fragment@0 {
+        target = <&spi0>;
+        __overlay__ {
+            // needed to avoid dtc warning
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            status = "okay";
+
+            uhf0: si446x@0{
+                compatible = "silabs,si446x";
+                reg = <0>; // CE0
+                pinctrl-names = "default";
+                pinctrl-0 = <&uhf0_pins>;
+                interrupt-parent = <&gpio>;
+                interrupts = <17 0x2>; // falling edge
+                spi-max-frequency = <4000000>;
+                sdn_pin = <27>;
+                irq_pin = <17>;
+                status = "okay";
+            };
+        };
+    };
+
+    fragment@1 {
+        target = <&gpio>;
+        __overlay__ {
+            uhf0_pins: uhf0_pins {
+                brcm,pins = <17 27>;
+                brcm,function = <0 1>; // in, out
+                brcm,pull = <2 0>; // high, none
+            };
+        };
+    };
+
+    __overrides__ {
+        int_pin = <&uhf0>, "interrupts:0",
+                  <&uhf0>, "irq_pin:0",
+                  <&uhf0_pins>, "brcm,pins:0";
+        reset_pin = <&uhf0>, "sdn_pin:0",
+                    <&uhf0_pins>, "brcm,pins:4";
+        speed   = <&uhf0>, "spi-max-frequency:0";
+    };
+};