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gpio.cpp
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// SPDX-License-Identifier: GPL-3.0-or-later
//
// Copyright (c) 2013-2023 plan44.ch / Lukas Zeller, Zurich, Switzerland
//
// Author: Lukas Zeller <luz@plan44.ch>
//
// This file is part of p44utils.
//
// p44utils is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// p44utils is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with p44utils. If not, see <http://www.gnu.org/licenses/>.
//
#include "gpio.hpp"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#ifdef ESP_PLATFORM
#include "driver/gpio.h"
#else
#include <fcntl.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include "gpio.h" // NS9XXX GPIO header, included in project
#endif
#include "logger.hpp"
#include "mainloop.hpp"
using namespace p44;
#ifdef ESP_PLATFORM
// MARK: - GPIO via ESP32 gpio
GpioPin::GpioPin(int aGpioNo, bool aOutput, bool aInitialState, Tristate aPull) :
gpioNo((gpio_num_t)aGpioNo),
output(aOutput),
pinState(aInitialState)
#ifndef ESP_PLATFORM
,gpioFD(-1)
#endif
{
esp_err_t ret;
// make sure pin is set to GPIO
ret = gpio_reset_pin(gpioNo);
if (ret==ESP_OK) {
// set pullup/down
ret = gpio_set_pull_mode(gpioNo, aPull==yes ? GPIO_PULLUP_ONLY : (aPull==no ? GPIO_PULLUP_PULLDOWN : GPIO_FLOATING));
}
if (ret==ESP_OK) {
// set direction
ret = gpio_set_direction(gpioNo, output ? GPIO_MODE_OUTPUT : GPIO_MODE_INPUT);
if (output && ret==ESP_OK) {
// set initial state
ret = gpio_set_level(gpioNo, pinState ? 1 : 0);
}
}
if (ret!=ESP_OK) {
LOG(LOG_ERR,"GPIO init error: %s", esp_err_to_name(ret));
gpio_reset_pin(gpioNo);
gpioNo = GPIO_NUM_NC; // signal "not connected"
}
}
GpioPin::~GpioPin()
{
// reset to default (disabled) state
gpio_reset_pin(gpioNo);
}
bool GpioPin::getState()
{
if (output) {
return pinState; // just return last set state
}
else {
// is input
if (gpioNo!=GPIO_NUM_NC) {
return gpio_get_level(gpioNo);
}
}
return false; // non-working pins always return false
}
bool GpioPin::setInputChangedHandler(InputChangedCB aInputChangedCB, bool aInverted, bool aInitialState, MLMicroSeconds aDebounceTime, MLMicroSeconds aPollInterval)
{
// TODO: implement interrupts
// for now use poll-based input change detection
return inherited::setInputChangedHandler(aInputChangedCB, aInverted, aInitialState, aDebounceTime, aPollInterval);
/*
if (aInputChangedCB==NULL) {
// release handler
MainLoop::currentMainLoop().unregisterPollHandler(gpioFD);
return inherited::setInputChangedHandler(aInputChangedCB, aInverted, aInitialState, aDebounceTime, aPollInterval);
}
// anyway, save parameters for base class
inputChangedCB = aInputChangedCB;
invertedReporting = aInverted;
currentState = aInitialState;
debounceTime = aDebounceTime;
// try to open "edge" to configure interrupt
string edgePath = string_format("%s/gpio%d/edge", GPIO_SYS_CLASS_PATH, gpioNo);
int edgeFd = open(edgePath.c_str(), O_RDWR);
if (edgeFd<0) {
LOG(LOG_DEBUG, "GPIO edge file does not exist -> GPIO %d has no edge interrupt capability", gpioNo);
// use poll-based input change detection
return inherited::setInputChangedHandler(aInputChangedCB, aInverted, aInitialState, aDebounceTime, aPollInterval);
}
// enable triggering on both edges
string s = "both";
ssize_t ret = write(edgeFd, s.c_str(), s.length());
if (ret<0) { LOG(LOG_ERR, "Cannot write to GPIO edge file %s", strerror(errno)); return false; }
close(edgeFd);
// establish a IO poll
MainLoop::currentMainLoop().registerPollHandler(gpioFD, POLLPRI, boost::bind(&GpioPin::stateChanged, this, _2));
return true;
*/
}
bool GpioPin::stateChanged(int aPollFlags)
{
bool newState = getState();
//LOG(LOG_DEBUG, "GPIO %d edge detected (poll() returned POLLPRI for value file) : new state = %d", gpioNo, newState);
inputHasChangedTo(newState);
return true; // handled
}
void GpioPin::setState(bool aState)
{
if (!output) return; // non-outputs cannot be set
if (gpioNo==GPIO_NUM_NC) return; // non-existing pins cannot be set
pinState = aState;
// - set value
gpio_set_level(gpioNo, pinState ? 1 : 0);
}
#else
// MARK: - LEDs via modern kernel support
#define GPIO_LED_CLASS_PATH "/sys/class/leds"
GpioLedPin::GpioLedPin(const char* aLedName, bool aInitialState) :
ledState(aInitialState),
ledFD(-1)
{
string name;
if (isdigit(*aLedName)) {
// old style number-only -> prefix with "led"
name = string_format("%s/led%s/brightness", GPIO_LED_CLASS_PATH, aLedName);
}
else {
// modern alphanumeric LED name -> use as-is
name = string_format("%s/%s/brightness", GPIO_LED_CLASS_PATH, aLedName);
}
ledFD = open(name.c_str(), O_RDWR);
if (ledFD<0) { LOG(LOG_ERR, "Cannot open LED brightness file %s: %s", name.c_str(), strerror(errno)); return; }
// set initial state
setState(ledState);
}
GpioLedPin::~GpioLedPin()
{
if (ledFD>0) {
close(ledFD);
}
}
bool GpioLedPin::getState()
{
return ledState; // just return last set state
}
void GpioLedPin::setState(bool aState)
{
if (ledFD<0) return; // non-existing pins cannot be set
ledState = aState;
// - set value
char buf[2];
buf[0] = ledState ? '1' : '0';
buf[1] = 0;
write(ledFD, buf, 1);
}
// MARK: - GPIO via modern kernel support
#define GPIO_SYS_CLASS_PATH "/sys/class/gpio"
GpioPin::GpioPin(int aGpioNo, bool aOutput, bool aInitialState, Tristate aPull) :
gpioNo(aGpioNo),
output(aOutput),
pinState(aInitialState),
gpioFD(-1)
{
// TODO: convert to modern character device based gpio, implement pull up/down.
int tempFd;
ssize_t ret;
string name;
string s = string_format("%d", gpioNo);
// have the kernel export the pin
name = string_format("%s/export",GPIO_SYS_CLASS_PATH);
tempFd = open(name.c_str(), O_WRONLY);
if (tempFd<0) { LOG(LOG_ERR, "Cannot open GPIO export file %s: %s", name.c_str(), strerror(errno)); return; }
ret = write(tempFd, s.c_str(), s.length());
if (ret<0) { LOG(LOG_WARNING, "Cannot write '%s' to GPIO export file %s: %s, probably already exported", s.c_str(), name.c_str(), strerror(errno)); }
close(tempFd);
// save base path
string basePath = string_format("%s/gpio%d", GPIO_SYS_CLASS_PATH, gpioNo);
// configure
name = basePath + "/direction";
tempFd = open(name.c_str(), O_RDWR);
if (tempFd<0) { LOG(LOG_ERR, "Cannot open GPIO direction file %s: %s", name.c_str(), strerror(errno)); return; }
if (output) {
// output
// - set output with initial value
s = pinState ? "high" : "low";
ret = write(tempFd, s.c_str(), s.length());
}
else {
// input
// - set input
s = "in";
ret = write(tempFd, s.c_str(), s.length());
}
if (ret<0) { LOG(LOG_WARNING, "Cannot write '%s' to GPIO direction file %s: %s", s.c_str(), name.c_str(), strerror(errno)); }
close(tempFd);
// now keep the value FD open
name = basePath + "/value";
gpioFD = open(name.c_str(), O_RDWR);
if (gpioFD<0) { LOG(LOG_ERR, "Cannot open GPIO value file %s: %s", name.c_str(), strerror(errno)); return; }
}
GpioPin::~GpioPin()
{
if (gpioFD>0) {
MainLoop::currentMainLoop().unregisterPollHandler(gpioFD);
close(gpioFD);
}
}
bool GpioPin::getState()
{
if (output)
return pinState; // just return last set state
else {
// is input
if (gpioFD<0)
return false; // non-working pins always return false
else {
// read from input
char buf[2];
lseek(gpioFD, 0, SEEK_SET);
if (read(gpioFD, buf, 1)>0) {
return buf[0]!='0';
}
}
}
return false;
}
bool GpioPin::setInputChangedHandler(InputChangedCB aInputChangedCB, bool aInverted, bool aInitialState, MLMicroSeconds aDebounceTime, MLMicroSeconds aPollInterval)
{
if (aInputChangedCB==NULL) {
// release handler
MainLoop::currentMainLoop().unregisterPollHandler(gpioFD);
return inherited::setInputChangedHandler(aInputChangedCB, aInverted, aInitialState, aDebounceTime, aPollInterval);
}
// anyway, save parameters for base class
inputChangedCB = aInputChangedCB;
invertedReporting = aInverted;
currentState = aInitialState;
debounceTime = aDebounceTime;
// try to open "edge" to configure interrupt
string edgePath = string_format("%s/gpio%d/edge", GPIO_SYS_CLASS_PATH, gpioNo);
int edgeFd = open(edgePath.c_str(), O_RDWR);
if (edgeFd<0) {
LOG(LOG_DEBUG, "GPIO edge file does not exist -> GPIO %d has no edge interrupt capability", gpioNo);
// use poll-based input change detection
return inherited::setInputChangedHandler(aInputChangedCB, aInverted, aInitialState, aDebounceTime, aPollInterval);
}
// enable triggering on both edges
string s = "both";
ssize_t ret = write(edgeFd, s.c_str(), s.length());
if (ret<0) { LOG(LOG_ERR, "Cannot write to GPIO edge file %s", strerror(errno)); return false; }
close(edgeFd);
// establish a IO poll
MainLoop::currentMainLoop().registerPollHandler(gpioFD, POLLPRI, boost::bind(&GpioPin::stateChanged, this, _2));
return true;
}
bool GpioPin::stateChanged(int aPollFlags)
{
bool newState = getState();
//LOG(LOG_DEBUG, "GPIO %d edge detected (poll() returned POLLPRI for value file) : new state = %d", gpioNo, newState);
inputHasChangedTo(newState);
return true; // handled
}
void GpioPin::setState(bool aState)
{
if (!output) return; // non-outputs cannot be set
if (gpioFD<0) return; // non-existing pins cannot be set
pinState = aState;
// - set value
char buf[2];
buf[0] = pinState ? '1' : '0';
buf[1] = 0;
write(gpioFD, buf, 1);
}
// Sysfs Interface for Userspace (OPTIONAL)
// ========================================
// Platforms which use the "gpiolib" implementors framework may choose to
// configure a sysfs user interface to GPIOs. This is different from the
// debugfs interface, since it provides control over GPIO direction and
// value instead of just showing a gpio state summary. Plus, it could be
// present on production systems without debugging support.
//
// Given appropriate hardware documentation for the system, userspace could
// know for example that GPIO #23 controls the write protect line used to
// protect boot loader segments in flash memory. System upgrade procedures
// may need to temporarily remove that protection, first importing a GPIO,
// then changing its output state, then updating the code before re-enabling
// the write protection. In normal use, GPIO #23 would never be touched,
// and the kernel would have no need to know about it.
//
// Again depending on appropriate hardware documentation, on some systems
// userspace GPIO can be used to determine system configuration data that
// standard kernels won't know about. And for some tasks, simple userspace
// GPIO drivers could be all that the system really needs.
//
// Note that standard kernel drivers exist for common "LEDs and Buttons"
// GPIO tasks: "leds-gpio" and "gpio_keys", respectively. Use those
// instead of talking directly to the GPIOs; they integrate with kernel
// frameworks better than your userspace code could.
//
//
// Paths in Sysfs
// --------------
// There are three kinds of entry in /sys/class/gpio:
//
// - Control interfaces used to get userspace control over GPIOs;
//
// - GPIOs themselves; and
//
// - GPIO controllers ("gpio_chip" instances).
//
// That's in addition to standard files including the "device" symlink.
//
// The control interfaces are write-only:
//
// /sys/class/gpio/
//
// "export" ... Userspace may ask the kernel to export control of
// a GPIO to userspace by writing its number to this file.
//
// Example: "echo 19 > export" will create a "gpio19" node
// for GPIO #19, if that's not requested by kernel code.
//
// "unexport" ... Reverses the effect of exporting to userspace.
//
// Example: "echo 19 > unexport" will remove a "gpio19"
// node exported using the "export" file.
//
// GPIO signals have paths like /sys/class/gpio/gpio42/ (for GPIO #42)
// and have the following read/write attributes:
//
// /sys/class/gpio/gpioN/
//
// "direction" ... reads as either "in" or "out". This value may
// normally be written. Writing as "out" defaults to
// initializing the value as low. To ensure glitch free
// operation, values "low" and "high" may be written to
// configure the GPIO as an output with that initial value.
//
// Note that this attribute *will not exist* if the kernel
// doesn't support changing the direction of a GPIO, or
// it was exported by kernel code that didn't explicitly
// allow userspace to reconfigure this GPIO's direction.
//
// "value" ... reads as either 0 (low) or 1 (high). If the GPIO
// is configured as an output, this value may be written;
// any nonzero value is treated as high.
//
// If the pin can be configured as interrupt-generating interrupt
// and if it has been configured to generate interrupts (see the
// description of "edge"), you can poll(2) on that file and
// poll(2) will return whenever the interrupt was triggered. If
// you use poll(2), set the events POLLPRI and POLLERR. If you
// use select(2), set the file descriptor in exceptfds. After
// poll(2) returns, either lseek(2) to the beginning of the sysfs
// file and read the new value or close the file and re-open it
// to read the value.
//
// "edge" ... reads as either "none", "rising", "falling", or
// "both". Write these strings to select the signal edge(s)
// that will make poll(2) on the "value" file return.
//
// This file exists only if the pin can be configured as an
// interrupt generating input pin.
//
// "active_low" ... reads as either 0 (false) or 1 (true). Write
// any nonzero value to invert the value attribute both
// for reading and writing. Existing and subsequent
// poll(2) support configuration via the edge attribute
// for "rising" and "falling" edges will follow this
// setting.
//
// GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the
// controller implementing GPIOs starting at #42) and have the following
// read-only attributes:
//
// /sys/class/gpio/gpiochipN/
//
// "base" ... same as N, the first GPIO managed by this chip
//
// "label" ... provided for diagnostics (not always unique)
//
// "ngpio" ... how many GPIOs this manges (N to N + ngpio - 1)
//
// Board documentation should in most cases cover what GPIOs are used for
// what purposes. However, those numbers are not always stable; GPIOs on
// a daughtercard might be different depending on the base board being used,
// or other cards in the stack. In such cases, you may need to use the
// gpiochip nodes (possibly in conjunction with schematics) to determine
// the correct GPIO number to use for a given signal.
//
//
// Exporting from Kernel code
// --------------------------
// Kernel code can explicitly manage exports of GPIOs which have already been
// requested using gpio_request():
//
// /* export the GPIO to userspace */
// int gpio_export(unsigned gpio, bool direction_may_change);
//
// /* reverse gpio_export() */
// void gpio_unexport();
//
// /* create a sysfs link to an exported GPIO node */
// int gpio_export_link(struct device *dev, const char *name,
// unsigned gpio)
//
// /* change the polarity of a GPIO node in sysfs */
// int gpio_sysfs_set_active_low(unsigned gpio, int value);
//
// After a kernel driver requests a GPIO, it may only be made available in
// the sysfs interface by gpio_export(). The driver can control whether the
// signal direction may change. This helps drivers prevent userspace code
// from accidentally clobbering important system state.
//
// This explicit exporting can help with debugging (by making some kinds
// of experiments easier), or can provide an always-there interface that's
// suitable for documenting as part of a board support package.
//
// After the GPIO has been exported, gpio_export_link() allows creating
// symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can
// use this to provide the interface under their own device in sysfs with
// a descriptive name.
//
// Drivers can use gpio_sysfs_set_active_low() to hide GPIO line polarity
// differences between boards from user space. This only affects the
// sysfs interface. Polarity change can be done both before and after
// gpio_export(), and previously enabled poll(2) support for either
// rising or falling edge will be reconfigured to follow this setting.
// MARK: - GPIO for NS9xxx (Digi ME 9210 LX)
GpioNS9XXXPin::GpioNS9XXXPin(const char* aGpioName, bool aOutput, bool aInitialState) :
gpioFD(-1),
pinState(false)
{
// save params
output = aOutput;
name = aGpioName;
pinState = aInitialState; // set even for inputs
int ret_val;
// open device
string gpiopath(GPION9XXX_DEVICES_BASEPATH);
gpiopath.append(name);
gpioFD = open(gpiopath.c_str(), O_RDWR);
if (gpioFD<0) {
LOG(LOG_ERR, "Cannot open GPIO device %s: %s", name.c_str(), strerror(errno));
return;
}
// configure
if (output) {
// output
if ((ret_val = ioctl(gpioFD, GPIO_CONFIG_AS_OUT)) < 0) {
LOG(LOG_ERR, "GPIO_CONFIG_AS_OUT failed for %s: %s", name.c_str(), strerror(errno));
return;
}
// set state immediately
setState(pinState);
}
else {
// input
if ((ret_val = ioctl(gpioFD, GPIO_CONFIG_AS_INP)) < 0) {
LOG(LOG_ERR, "GPIO_CONFIG_AS_INP failed for %s: %s", name.c_str(), strerror(errno));
return;
}
}
}
GpioNS9XXXPin::~GpioNS9XXXPin()
{
if (gpioFD>0) {
close(gpioFD);
}
}
bool GpioNS9XXXPin::getState()
{
if (output)
return pinState; // just return last set state
if (gpioFD<0)
return false; // non-working pins always return false
else {
// read from input
int inval;
#ifndef __APPLE__
int ret_val;
if ((ret_val = ioctl(gpioFD, GPIO_READ_PIN_VAL, &inval)) < 0) {
LOG(LOG_ERR, "GPIO_READ_PIN_VAL failed for %s: %s", name.c_str(), strerror(errno));
return false;
}
#else
DBGLOG(LOG_ERR, "ioctl(gpioFD, GPIO_READ_PIN_VAL, &dummy)");
inval = 0;
#endif
return (bool)inval;
}
}
void GpioNS9XXXPin::setState(bool aState)
{
if (!output) return; // non-outputs cannot be set
if (gpioFD<0) return; // non-existing pins cannot be set
pinState = aState;
// - set value
int setval = pinState;
#ifndef __APPLE__
int ret_val;
if ((ret_val = ioctl(gpioFD, GPIO_WRITE_PIN_VAL, &setval)) < 0) {
LOG(LOG_ERR, "GPIO_WRITE_PIN_VAL failed for %s: %s", name.c_str(), strerror(errno));
return;
}
#else
DBGLOG(LOG_ERR, "ioctl(gpioFD, GPIO_WRITE_PIN_VAL, %d)", setval);
#endif
}
#endif // !ESP_PLATFORM