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.
178 lines
4.3 KiB
C
178 lines
4.3 KiB
C
/*
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* piFace.:
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* Copyright (c) 2012-2016 Gordon Henderson
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*
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* This file to interface with the PiFace peripheral device which
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* has an MCP23S17 GPIO device connected via the SPI bus.
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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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#include <stdio.h>
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#include <stdint.h>
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#include <wiringPi.h>
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#include <wiringPiSPI.h>
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#include "../wiringPi/mcp23x0817.h"
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#include "piFace.h"
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#define PIFACE_SPEED 4000000
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#define PIFACE_DEVNO 0
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/*
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* writeByte:
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* Write a byte to a register on the MCP23S17 on the SPI bus.
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*********************************************************************************
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*/
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static void writeByte (uint8_t reg, uint8_t data)
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{
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uint8_t spiData [4] ;
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spiData [0] = CMD_WRITE ;
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spiData [1] = reg ;
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spiData [2] = data ;
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wiringPiSPIDataRW (PIFACE_DEVNO, spiData, 3) ;
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}
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/*
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* readByte:
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* Read a byte from a register on the MCP23S17 on the SPI bus.
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*********************************************************************************
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*/
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static uint8_t readByte (uint8_t reg)
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{
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uint8_t spiData [4] ;
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spiData [0] = CMD_READ ;
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spiData [1] = reg ;
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wiringPiSPIDataRW (PIFACE_DEVNO, spiData, 3) ;
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return spiData [2] ;
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}
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/*
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* myDigitalWrite:
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* Perform the digitalWrite function on the PiFace board
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*********************************************************************************
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*/
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void myDigitalWrite (struct wiringPiNodeStruct *node, int pin, int value)
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{
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uint8_t mask, old ;
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pin -= node->pinBase ;
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mask = 1 << pin ;
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old = readByte (MCP23x17_GPIOA) ;
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if (value == 0)
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old &= (~mask) ;
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else
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old |= mask ;
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writeByte (MCP23x17_GPIOA, old) ;
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}
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/*
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* myDigitalRead:
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* Perform the digitalRead function on the PiFace board
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*********************************************************************************
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*/
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int myDigitalRead (struct wiringPiNodeStruct *node, int pin)
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{
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uint8_t mask, reg ;
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mask = 1 << ((pin - node->pinBase) & 7) ;
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if (pin < 8)
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reg = MCP23x17_GPIOB ; // Input regsiter
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else
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reg = MCP23x17_OLATA ; // Output latch regsiter
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if ((readByte (reg) & mask) != 0)
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return HIGH ;
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else
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return LOW ;
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}
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/*
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* myPullUpDnControl:
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* Perform the pullUpDnControl function on the PiFace board
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*********************************************************************************
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*/
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void myPullUpDnControl (struct wiringPiNodeStruct *node, int pin, int pud)
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{
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uint8_t mask, old ;
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mask = 1 << (pin - node->pinBase) ;
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old = readByte (MCP23x17_GPPUB) ;
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if (pud == 0)
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old &= (~mask) ;
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else
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old |= mask ;
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writeByte (MCP23x17_GPPUB, old) ;
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}
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/*
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* piFaceSetup
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* Setup the SPI interface and initialise the MCP23S17 chip
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* We create one node with 16 pins - each if the first 8 pins being read
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* and write - although the operations actually go to different
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* hardware ports. The top 8 let you read the state of the output register.
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*********************************************************************************
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*/
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int piFaceSetup (const int pinBase)
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{
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int x ;
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struct wiringPiNodeStruct *node ;
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if ((x = wiringPiSPISetup (PIFACE_DEVNO, PIFACE_SPEED)) < 0)
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return x ;
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// Setup the MCP23S17
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writeByte (MCP23x17_IOCON, IOCON_INIT) ;
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writeByte (MCP23x17_IODIRA, 0x00) ; // Port A -> Outputs
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writeByte (MCP23x17_IODIRB, 0xFF) ; // Port B -> Inputs
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node = wiringPiNewNode (pinBase, 16) ;
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node->digitalRead = myDigitalRead ;
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node->digitalWrite = myDigitalWrite ;
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node->pullUpDnControl = myPullUpDnControl ;
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return 0 ;
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}
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