mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-30 02:29:01 +00:00
f07e572f64
bcm2708: boot tested on RPi B+ v1.2 bcm2709: boot tested on RPi 3B v1.2 and RPi 4B v1.1 4G bcm2710: boot tested on RPi 3B v1.2 bcm2711: boot tested on RPi 4B v1.1 4G Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
200 lines
6.2 KiB
Diff
200 lines
6.2 KiB
Diff
From 296cff78df285c99a52760cbcd896abc37820e06 Mon Sep 17 00:00:00 2001
|
|
From: Thomas Preston <thomas.preston@codethink.co.uk>
|
|
Date: Thu, 13 Aug 2020 01:38:35 +0100
|
|
Subject: [PATCH] dt/overlays: Add PiFace Digital Device Tree Overlay
|
|
|
|
The PiFace Digital is a convenient breakout board for the Microchip
|
|
mcp23s17 SPI GPIO port expander.
|
|
|
|
The first eight GPIOs 0..7 (bank A) are connected to eight output
|
|
terminals and LEDs, plus two relays on the first two outputs. These
|
|
output loads are active-high.
|
|
|
|
The next eight GPIOs 8..15 (bank B) are connected to eight input
|
|
terminals with four on-board switches connecting them to ground. Inputs
|
|
devices are therefore expected to bridge terminals to ground, so the
|
|
mcp23s17 pullups are activated for GPIO bank B.
|
|
|
|
Signed-off-by: Thomas Preston <thomas.preston@codethink.co.uk>
|
|
---
|
|
arch/arm/boot/dts/overlays/Makefile | 1 +
|
|
arch/arm/boot/dts/overlays/README | 8 +
|
|
.../dts/overlays/pifacedigital-overlay.dts | 144 ++++++++++++++++++
|
|
3 files changed, 153 insertions(+)
|
|
create mode 100644 arch/arm/boot/dts/overlays/pifacedigital-overlay.dts
|
|
|
|
--- a/arch/arm/boot/dts/overlays/Makefile
|
|
+++ b/arch/arm/boot/dts/overlays/Makefile
|
|
@@ -121,6 +121,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
|
|
papirus.dtbo \
|
|
pca953x.dtbo \
|
|
pibell.dtbo \
|
|
+ pifacedigital.dtbo \
|
|
piglow.dtbo \
|
|
piscreen.dtbo \
|
|
piscreen2r.dtbo \
|
|
--- a/arch/arm/boot/dts/overlays/README
|
|
+++ b/arch/arm/boot/dts/overlays/README
|
|
@@ -1949,6 +1949,14 @@ Params: alsaname Set the
|
|
"PiBell")
|
|
|
|
|
|
+Name: pifacedigital
|
|
+Info: Configures the PiFace Digital mcp23s17 GPIO port expander.
|
|
+Load: dtoverlay=pifacedigital,<param>=<val>
|
|
+Params: spi-present-mask 8-bit integer, bitmap indicating MCP23S17 SPI0
|
|
+ CS0 address. PiFace Digital supports addresses
|
|
+ 0-3, which can be configured with JP1 and JP2.
|
|
+
|
|
+
|
|
Name: piglow
|
|
Info: Configures the PiGlow by pimoroni.com
|
|
Load: dtoverlay=piglow
|
|
--- /dev/null
|
|
+++ b/arch/arm/boot/dts/overlays/pifacedigital-overlay.dts
|
|
@@ -0,0 +1,144 @@
|
|
+// SPDX-License-Identifier: GPL-2.0-only
|
|
+/*
|
|
+ * PiFace Digital, Device Tree Overlay.
|
|
+ * Copyright (C) 2020 Thomas Preston <thomas.preston@codethink.co.uk>
|
|
+ *
|
|
+ * The PiFace Digital is a convenient breakout board for the Microchip mcp23s17
|
|
+ * SPI GPIO port expander.
|
|
+ *
|
|
+ * The first eight GPIOs 0..7 (bank A) are connected to eight output terminals
|
|
+ * and LEDs, plus two relays on the first two outputs. These output loads are
|
|
+ * active-high.
|
|
+ *
|
|
+ * The next eight GPIOs 8..15 (bank B) are connected to eight input terminals
|
|
+ * with four on-board switches connecting them to ground. Inputs devices are
|
|
+ * therefore expected to bridge terminals to ground, so the mcp23s17 pullups are
|
|
+ * activated for GPIO bank B.
|
|
+ *
|
|
+ * On PiFace Digital, the mcp23s17 is connected to the Raspberry Pi's SPI0 CS0
|
|
+ * bus. Each SPI bus supports up to eight addressable child devices. The PiFace
|
|
+ * Digital only supports addresses 0-4, which can be configured by jumpers JP1
|
|
+ * and JP2.
|
|
+ *
|
|
+ * You can tell the driver about these jumper configurations with the
|
|
+ * spi-present-mask bitmask:
|
|
+ *
|
|
+ * | JP1 | JP2 | dtoverlay line in /boot/config.txt |
|
|
+ * | --- | --- | ------------------------------------------ |
|
|
+ * | 0 | 0 | dtoverlay=pifacedigital |
|
|
+ * | 0 | 0 | dtoverlay=pifacedigital:spi-present-mask=1 |
|
|
+ * | 0 | 1 | dtoverlay=pifacedigital:spi-present-mask=2 |
|
|
+ * | 1 | 0 | dtoverlay=pifacedigital:spi-present-mask=4 |
|
|
+ * | 1 | 1 | dtoverlay=pifacedigital:spi-present-mask=8 |
|
|
+ *
|
|
+ * # Example
|
|
+ * Set the dtoverlay config in /boot/config.txt and power off the Raspberry Pi:
|
|
+ *
|
|
+ * $ grep pifacedigital /boot/config.txt
|
|
+ * dtoverlay=pifacedigital
|
|
+ * $ sudo systemctl poweroff
|
|
+ *
|
|
+ * Attach the PiFace Digital and power on the Raspberry Pi.
|
|
+ * Then use the libgpiod tools to query the device:
|
|
+ *
|
|
+ * $ sudo apt install gpiod
|
|
+ * $ gpiodetect | grep mcp23s17
|
|
+ * gpiochip2 [mcp23s17.0] (16 lines)
|
|
+ *
|
|
+ * Set GPIO outputs 0, 2 and 5:
|
|
+ *
|
|
+ * $ gpioset gpiochip2 0=1 2=1 5=1
|
|
+ *
|
|
+ * Get GPIO status (input GPIO 8..15 are high, because they are active-low):
|
|
+ *
|
|
+ * $ gpioget gpiochip2 {8..15}
|
|
+ * 1 1 1 1 1 1 1 1
|
|
+ *
|
|
+ * And even monitor interrupts:
|
|
+ *
|
|
+ * $ gpiomon gpiochip2 {8..15}
|
|
+ * event: FALLING EDGE offset: 11 timestamp: [1597361662.926741667]
|
|
+ * event: RISING EDGE offset: 11 timestamp: [1597361663.062555051]
|
|
+ *
|
|
+ */
|
|
+
|
|
+/dts-v1/;
|
|
+/plugin/;
|
|
+
|
|
+/ {
|
|
+ compatible = "brcm,bcm2835";
|
|
+
|
|
+ /* Disable exposing /dev/spidev0.0 */
|
|
+ fragment@0 {
|
|
+ target = <&spidev0>;
|
|
+ __overlay__ {
|
|
+ status = "disabled";
|
|
+ };
|
|
+ };
|
|
+
|
|
+ /* Add the PiFace Digital device node to the spi0.0 device. */
|
|
+ fragment@1 {
|
|
+ target = <&spi0>;
|
|
+ __overlay__ {
|
|
+ status = "okay";
|
|
+ #address-cells = <1>;
|
|
+ #size-cells = <0>;
|
|
+
|
|
+ pfdigital: pifacedigital@0 {
|
|
+ compatible = "microchip,mcp23s17";
|
|
+ reg = <0>;
|
|
+
|
|
+ /* Set devices present with 8-bit mask. */
|
|
+ microchip,spi-present-mask = <0x01>;
|
|
+ spi-max-frequency = <500000>;
|
|
+
|
|
+ gpio-controller;
|
|
+ #gpio-cells = <2>;
|
|
+
|
|
+ /* This device can pass through interrupts. */
|
|
+ interrupt-controller;
|
|
+ #interrupt-cells = <2>;
|
|
+
|
|
+ /* INTB is connected to GPIO 25.
|
|
+ * 0x8 active-low level-sensitive
|
|
+ */
|
|
+ interrupts = <25 0x8>;
|
|
+ interrupt-parent = <&gpio>;
|
|
+
|
|
+ /* Configure pull-ups on bank B GPIOs */
|
|
+ pinctrl-0 = <&pfdigital_irq &pfdigital_pullups>;
|
|
+ pinctrl-names = "default";
|
|
+ pfdigital_pullups: pinmux {
|
|
+ pins =
|
|
+ "gpio8",
|
|
+ "gpio9",
|
|
+ "gpio10",
|
|
+ "gpio11",
|
|
+ "gpio12",
|
|
+ "gpio13",
|
|
+ "gpio14",
|
|
+ "gpio15";
|
|
+ bias-pull-up;
|
|
+ };
|
|
+ };
|
|
+ };
|
|
+ };
|
|
+
|
|
+ /* PiFace Digital mcp23s17 INTB pin is connected to GPIO 25. The INTB
|
|
+ * pin is configured active-low (0 on interrupt), so expect to see
|
|
+ * FALLING_EDGE when inputs are bridged to ground (switch is pressed).
|
|
+ */
|
|
+ fragment@3 {
|
|
+ target = <&gpio>;
|
|
+ __overlay__ {
|
|
+ pfdigital_irq: pifacedigital_irq {
|
|
+ brcm,pins = <25>;
|
|
+ brcm,function = <0>; /* input */
|
|
+ };
|
|
+ };
|
|
+ };
|
|
+
|
|
+ __overrides__ {
|
|
+ spi-present-mask = <&pfdigital>, "microchip,spi-present-mask:0";
|
|
+ };
|
|
+};
|