mirror of
https://github.com/clockworkpi/WiringPi.git
synced 2025-12-12 16:08:49 +01:00
b1dfc186ef
for kernels 4.8 onwards. Some very old stuff might break. Additional fixes for the ISR code and some tweaks here and there. I've removed the checks for some operations that might fail when using the gpiomem interface - which is now the default way of doing things - if your program segfaults, then you may need to use sudo on it.
96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
/*
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* pseudoPins.c:
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* Extend wiringPi with a number of pseudo pins which can be
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* digitally or analog written/read.
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*
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* Note:
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* Just one set of pseudo pins can exist per Raspberry Pi.
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* These pins are shared between all programs running on
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* that Raspberry Pi. The values are also persistant as
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* they live in shared RAM. This gives you a means for
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* temporary variable storing/sharing between programs,
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* or for other cunning things I've not thought of yet..
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*
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* Copyright (c) 2012-2016 Gordon Henderson
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***********************************************************************
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* This file is part of wiringPi:
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* https://projects.drogon.net/raspberry-pi/wiringpi/
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*
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* wiringPi is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* wiringPi is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with wiringPi.
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* If not, see <http://www.gnu.org/licenses/>.
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***********************************************************************
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*/
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#define SHARED_NAME "wiringPiPseudoPins"
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#define PSEUDO_PINS 64
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <wiringPi.h>
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#include "pseudoPins.h"
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static int myAnalogRead (struct wiringPiNodeStruct *node, int pin)
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{
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int *ptr = (int *)node->data0 ;
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int myPin = pin - node->pinBase ;
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return *(ptr + myPin) ;
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}
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static void myAnalogWrite (struct wiringPiNodeStruct *node, int pin, int value)
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{
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int *ptr = (int *)node->data0 ;
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int myPin = pin - node->pinBase ;
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*(ptr + myPin) = value ;
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}
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/*
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* pseudoPinsSetup:
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* Create a new wiringPi device node for the pseudoPins driver
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*********************************************************************************
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*/
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int pseudoPinsSetup (const int pinBase)
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{
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struct wiringPiNodeStruct *node ;
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void *ptr ;
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node = wiringPiNewNode (pinBase, PSEUDO_PINS) ;
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node->fd = shm_open (SHARED_NAME, O_CREAT | O_RDWR, 0666) ;
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if (node->fd < 0)
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return FALSE ;
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if (ftruncate (node->fd, PSEUDO_PINS * sizeof (int)) < 0)
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return FALSE ;
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ptr = mmap (NULL, PSEUDO_PINS * sizeof (int), PROT_READ | PROT_WRITE, MAP_SHARED, node->fd, 0) ;
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node->data0 = (unsigned int)ptr ;
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node->analogRead = myAnalogRead ;
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node->analogWrite = myAnalogWrite ;
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return TRUE ;
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}
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