variants/linux: make lora_gpiochip configurable, refresh docs

platformio.ini

@@ -124,7 +124,7 @@ lib_deps = ${arduino_base.lib_deps}
 [linux_base]
 platform =
   # renovate: datasource=git-tags depName=ardulinux packageName=https://github.com/l5yth/ardulinux
-  git+https://github.com/l5yth/ardulinux.git#v0.2.1
+  git+https://github.com/l5yth/ardulinux.git#v0.2.2
 framework = arduino
 board = linux
 board_level = extra

variants/linux/LinuxBoard.cpp

@@ -69,22 +69,22 @@ void LinuxBoard::begin() {
 
   int failures = 0;
   if (config.lora_nss_pin != RADIOLIB_NC) {
-    failures += initGPIOPin(config.lora_nss_pin, "gpiochip0", config.lora_nss_pin);
+    failures += initGPIOPin(config.lora_nss_pin, config.lora_gpiochip, config.lora_nss_pin);
   }
   if (config.lora_busy_pin != RADIOLIB_NC) {
-    failures += initGPIOPin(config.lora_busy_pin, "gpiochip0", config.lora_busy_pin);
+    failures += initGPIOPin(config.lora_busy_pin, config.lora_gpiochip, config.lora_busy_pin);
   }
   if (config.lora_irq_pin != RADIOLIB_NC) {
-    failures += initGPIOPin(config.lora_irq_pin, "gpiochip0", config.lora_irq_pin);
+    failures += initGPIOPin(config.lora_irq_pin, config.lora_gpiochip, config.lora_irq_pin);
   }
   if (config.lora_reset_pin != RADIOLIB_NC) {
-    failures += initGPIOPin(config.lora_reset_pin, "gpiochip0", config.lora_reset_pin);
+    failures += initGPIOPin(config.lora_reset_pin, config.lora_gpiochip, config.lora_reset_pin);
   }
   if (config.lora_rxen_pin != RADIOLIB_NC) {
-    failures += initGPIOPin(config.lora_rxen_pin, "gpiochip0", config.lora_rxen_pin);
+    failures += initGPIOPin(config.lora_rxen_pin, config.lora_gpiochip, config.lora_rxen_pin);
   }
   if (config.lora_txen_pin != RADIOLIB_NC) {
-    failures += initGPIOPin(config.lora_txen_pin, "gpiochip0", config.lora_txen_pin);
+    failures += initGPIOPin(config.lora_txen_pin, config.lora_gpiochip, config.lora_txen_pin);
   }
 
   if (failures > 0) {
@@ -149,6 +149,7 @@ int LinuxConfig::load(const char *filename) {
     }
 
     if (strcmp(key, "spidev") == 0)         spidev = safe_copy(value, 32);
+    else if (strcmp(key, "lora_gpiochip") == 0) lora_gpiochip = safe_copy(value, 32);
     else if (strcmp(key, "lora_freq") == 0) lora_freq = atof(value);
     else if (strcmp(key, "lora_bw") == 0)   lora_bw = atof(value);
     else if (strcmp(key, "lora_sf") == 0)   lora_sf = (uint8_t)atoi(value);

variants/linux/LinuxBoard.h

@@ -31,6 +31,7 @@ class LinuxConfig {
   bool rx_boosted_gain = true;
 
   char* spidev = "/dev/spidev0.0";
+  char* lora_gpiochip = "gpiochip0";
 
   float lora_tcxo = 1.8f;
 

variants/linux/README.md

@@ -20,14 +20,14 @@ sudo pacman -S pkgconf libgpiod i2c-tools bluez-libs libuv
 sudo apt install pkg-config libgpiod-dev libi2c-dev libbluetooth-dev libuv1-dev
 ```
 
-> On DietPi the base image does not include `pkg-config`; without it the build
-> silently falls back to simulated GPIO/I2C even when `libgpiod-dev` is
-> installed, and the resulting `meshcored` won't talk to the radio.
-
 The ArduLinux platform always links `bluetooth`, `uv`, `pthread`, and
 `stdc++fs`; `gpiod`/`i2c` are added automatically when libgpiod is detected via
-`pkg-config`. Missing `bluez-libs`/`libbluetooth-dev` shows up as a `cannot
-find -lbluetooth` link error.
+`pkg-config`. If `pkg-config` is missing (e.g. on DietPi, which does not ship
+it in the base image), libgpiod goes undetected and the build falls back to
+simulated GPIO/I2C — the resulting `meshcored` will refuse to start with a
+`FATAL: meshcored was built without libgpiod support` message pointing back at
+the missing dep. Missing `bluez-libs`/`libbluetooth-dev` shows up at link time
+as `cannot find -lbluetooth`.
 
 You also need **PlatformIO Core** (`pio`) to build:
 
@@ -85,6 +85,7 @@ Key settings:
 | Key | Default | Notes |
 |-----|---------|-------|
 | `spidev` | `/dev/spidev0.0` | SPI device node |
+| `lora_gpiochip` | `gpiochip0` | Name of the `/dev/gpiochip*` device (or kernel label). `gpiochip0` is correct for Pi 3/4/Zero 2W; Pi 5 may need `gpiochip4` or `pinctrl-rp1` depending on kernel |
 | `lora_irq_pin` | (none) | GPIO line number for IRQ |
 | `lora_reset_pin` | (none) | GPIO line number for RESET |
 | `lora_nss_pin` | (none) | GPIO line number for NSS/CS (if not handled by the SPI driver) |

variants/linux/meshcored.ini

@@ -17,6 +17,7 @@ lora_reset_pin = 13
 #lora_txen_pin
 
 spidev = /dev/spidev0.0
+# lora_gpiochip = gpiochip0   # Pi 3/4/Zero 2W default; Pi 5 may need gpiochip4 or pinctrl-rp1
 lora_freq = 869.618
 lora_bw = 62.5
 lora_sf = 8

variants/linux/meshcored.ini.pow-sx1262

@@ -3,6 +3,7 @@
 
 # Hardware config (read on every startup):
 spidev = /dev/spidev0.0
+# lora_gpiochip = gpiochip0   # Pi 3/4/Zero 2W default; Pi 5 may need gpiochip4 or pinctrl-rp1
 lora_irq_pin = 22
 lora_reset_pin = 13
 # lora_nss_pin - SS is handled by the SPI driver; not needed

variants/linux/meshcored.ini.waveshare

@@ -3,6 +3,7 @@
 
 # Hardware config (read on every startup):
 spidev = /dev/spidev0.0
+# lora_gpiochip = gpiochip0   # Pi 3/4/Zero 2W default; Pi 5 may need gpiochip4 or pinctrl-rp1
 lora_irq_pin = 16
 lora_reset_pin = 18
 lora_nss_pin = 21