move gpiochipX init out of cache c'tors

this should fix the issue with loading pyRF24 modules( downstream) when building docs. There should be negligible performance hit as most of this init stuff (`pinMode()` and `attachInterrupt()`) only takes place at user space startup. Although, devs that dynamically allocate pins (with `RF24::begin(CE, CSN)`) will see a performance cost.
nRF24 · Mar 18, 2024 · 16e19f8 · 16e19f8
1 parent d81439f
commit 16e19f8
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Showing 5 changed files with 64 additions and 50 deletions.
diff --git a/utility/RPi/interrupt.cpp b/utility/RPi/interrupt.cpp
@@ -42,24 +42,6 @@ void IrqChipCache::closeDevice()
 
 IrqChipCache::IrqChipCache()
 {
-    try {
-        openDevice();
-    }
-    catch (IRQException& exc) {
-        chip = "/dev/gpiochip0";
-        openDevice();
-    }
-
-    // cache chip info
-    memset(&info, 0, sizeof(info));
-    int ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &info);
-    if (ret < 0) {
-        std::string msg = "Could not gather info about ";
-        msg += chip;
-        throw IRQException(msg);
-        return;
-    }
-    closeDevice(); // in case other apps want to access it
 }
 
 IrqChipCache::~IrqChipCache()
@@ -102,7 +84,26 @@ int attachInterrupt(rf24_gpio_pin_t pin, int mode, void (*function)(void))
     // ensure pin is not already being used in a separate thread
     detachInterrupt(pin);
 
-    if (pin > irqChipCache.info.lines) {
+    try {
+        irqChipCache.openDevice();
+    }
+    catch (IRQException& exc) {
+        irqChipCache.chip = "/dev/gpiochip0";
+        irqChipCache.openDevice();
+    }
+
+    // get chip info
+    gpiochip_info info;
+    memset(&info, 0, sizeof(info));
+    int ret = ioctl(irqChipCache.fd, GPIO_GET_CHIPINFO_IOCTL, &info);
+    if (ret < 0) {
+        std::string msg = "[attachInterrupt] Could not gather info about ";
+        msg += irqChipCache.chip;
+        throw IRQException(msg);
+        return 0;
+    }
+
+    if (pin > info.lines) {
         std::string msg = "[attachInterrupt] pin " + std::to_string(pin) + " is not available on " + irqChipCache.chip;
         throw IRQException(msg);
         return 0;
@@ -136,8 +137,7 @@ int attachInterrupt(rf24_gpio_pin_t pin, int mode, void (*function)(void))
     }
 
     // write pin request's config
-    irqChipCache.openDevice();
-    int ret = ioctl(irqChipCache.fd, GPIO_V2_GET_LINE_IOCTL, &request);
+    ret = ioctl(irqChipCache.fd, GPIO_V2_GET_LINE_IOCTL, &request);
     if (ret < 0 || request.fd <= 0) {
         std::string msg = "[attachInterrupt] Could not get line handle from ioctl; ";
         msg += strerror(errno);

diff --git a/utility/RPi/interrupt.h b/utility/RPi/interrupt.h
@@ -4,8 +4,7 @@
 #ifndef RF24_UTILITY_RPI_INTERRUPT_H_
 #define RF24_UTILITY_RPI_INTERRUPT_H_
 
-#include <pthread.h>    // pthread_t
-#include <linux/gpio.h> // gpiochip_info
+#include <pthread.h> // pthread_t
 #include <stdexcept>
 #include "RF24_arch_config.h" // rf24_gpio_pin_t
 
@@ -33,7 +32,6 @@ struct IrqChipCache
 {
     const char* chip = RF24_LINUX_GPIO_CHIP;
     int fd = -1;
-    gpiochip_info info;
 
     /// Open the File Descriptor for the GPIO chip
     void openDevice();

diff --git a/utility/SPIDEV/gpio.cpp b/utility/SPIDEV/gpio.cpp
@@ -45,27 +45,9 @@ void GPIOChipCache::closeDevice()
 
 GPIOChipCache::GPIOChipCache()
 {
-    try {
-        openDevice();
-    }
-    catch (GPIOException& exc) {
-        chip = "/dev/gpiochip0";
-        openDevice();
-    }
     request.num_lines = 1;
     strcpy(request.consumer, "RF24 lib");
     data.mask = 1ULL; // only change value for specified pin
-
-    // cache chip info
-    memset(&info, 0, sizeof(info));
-    int ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &info);
-    if (ret < 0) {
-        std::string msg = "Could not gather info about ";
-        msg += chip;
-        throw GPIOException(msg);
-        return;
-    }
-    closeDevice(); // in case other apps want to access it
 }
 
 GPIOChipCache::~GPIOChipCache()
@@ -91,7 +73,26 @@ GPIO::~GPIO()
 
 void GPIO::open(rf24_gpio_pin_t port, int DDR)
 {
-    if (port > gpioCache.info.lines) {
+    try {
+        gpioCache.openDevice();
+    }
+    catch (GPIOException& exc) {
+        gpioCache.chip = "/dev/gpiochip0";
+        gpioCache.openDevice();
+    }
+
+    // get chip info
+    gpiochip_info info;
+    memset(&info, 0, sizeof(info));
+    int ret = ioctl(gpioCache.fd, GPIO_GET_CHIPINFO_IOCTL, &info);
+    if (ret < 0) {
+        std::string msg = "Could not gather info about ";
+        msg += gpioCache.chip;
+        throw GPIOException(msg);
+        return;
+    }
+
+    if (port > info.lines) {
         std::string msg = "pin number " + std::to_string(port) + " not available for " + gpioCache.chip;
         throw GPIOException(msg);
         return;
@@ -107,8 +108,6 @@ void GPIO::open(rf24_gpio_pin_t port, int DDR)
         request.fd = pin->second;
     }
 
-    gpioCache.openDevice();
-    int ret;
     if (request.fd <= 0) {
         ret = ioctl(gpioCache.fd, GPIO_V2_GET_LINE_IOCTL, &request);
         if (ret == -1 || request.fd <= 0) {

diff --git a/utility/SPIDEV/gpio.h b/utility/SPIDEV/gpio.h
@@ -44,7 +44,6 @@ struct GPIOChipCache
 {
     const char* chip = RF24_LINUX_GPIO_CHIP;
     int fd = -1;
-    gpiochip_info info;
 
     /// Open the File Descriptor for the GPIO chip
     void openDevice();

diff --git a/utility/SPIDEV/interrupt.cpp b/utility/SPIDEV/interrupt.cpp
@@ -10,7 +10,7 @@
 #include <pthread.h>
 #include <map>
 #include "interrupt.h"
-#include "gpio.h" // GPIOChipCache
+#include "gpio.h" // GPIOChipCache, GPIOException
 
 #ifdef __cplusplus
 extern "C" {
@@ -64,7 +64,26 @@ int attachInterrupt(rf24_gpio_pin_t pin, int mode, void (*function)(void))
     detachInterrupt(pin);
     GPIO::close(pin);
 
-    if (pin > irqChipCache.info.lines) {
+    try {
+        irqChipCache.openDevice();
+    }
+    catch (GPIOException& exc) {
+        irqChipCache.chip = "/dev/gpiochip0";
+        irqChipCache.openDevice();
+    }
+
+    // get chip info
+    gpiochip_info info;
+    memset(&info, 0, sizeof(info));
+    int ret = ioctl(irqChipCache.fd, GPIO_GET_CHIPINFO_IOCTL, &info);
+    if (ret < 0) {
+        std::string msg = "[attachInterrupt] Could not gather info about ";
+        msg += irqChipCache.chip;
+        throw IRQException(msg);
+        return 0;
+    }
+
+    if (pin > info.lines) {
         std::string msg = "[attachInterrupt] pin " + std::to_string(pin) + " is not available on " + irqChipCache.chip;
         throw IRQException(msg);
         return 0;
@@ -98,8 +117,7 @@ int attachInterrupt(rf24_gpio_pin_t pin, int mode, void (*function)(void))
     }
 
     // write pin request's config
-    irqChipCache.openDevice();
-    int ret = ioctl(irqChipCache.fd, GPIO_V2_GET_LINE_IOCTL, &request);
+    ret = ioctl(irqChipCache.fd, GPIO_V2_GET_LINE_IOCTL, &request);
     if (ret < 0 || request.fd <= 0) {
         std::string msg = "[attachInterrupt] Could not get line handle from ioctl; ";
         msg += strerror(errno);