Harald Geyer
0a38c18f00
* Move OS specific code to new files i2c.h and i2c.c * As side effect a likely bug (linux only code) in the existing driver has been fixed. Compile tested on Debian/i386 and OpenWRT/arm. Signed-off-by: Harald Geyer <harald@ccbib.org>
121 lines
2.3 KiB
C
121 lines
2.3 KiB
C
/** \file server/drivers/i2c.c
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* OS agnostic functions to access i2c devices.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <fcntl.h>
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#include <stdlib.h>
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#include <strings.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#ifdef HAVE_DEV_IICBUS_IIC_H
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#include <dev/iicbus/iic.h>
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#else /* HAVE_LINUX_I2C_DEV_H */
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#include <linux/i2c-dev.h>
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/* I2C_SLAVE is missing in linux/i2c-dev.h from kernel headers of 2.4.x kernels
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*/
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#ifndef I2C_SLAVE
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#define I2C_SLAVE 0x0703 /* ioctl to change slave address */
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#endif
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#endif
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#define I2C_DEFAULT_DEVICE "/dev/i2c-0"
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/** data to access an i2c slave */
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typedef struct {
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int fd; /**< file descriptor of the i2c device */
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#ifdef HAVE_DEV_IICBUS_IIC_H
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unsigned int slave; /**< slave address */
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#endif
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} I2CHandle;
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/**
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* setup connection to i2c slave
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* \param device device file of the i2c bus
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* \param addr use this slave address
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* \retval NULL Error
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* \retval Pointer to handle of the connection
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*/
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I2CHandle *i2c_open(const char *device, unsigned int addr)
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{
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I2CHandle *h;
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#ifdef HAVE_DEV_IICBUS_IIC_H
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struct iiccmd cmd;
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bzero(&cmd, sizeof(cmd));
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#endif
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h = malloc(sizeof(*h));
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if(!h)
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return NULL;
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h->fd = open(device, O_RDWR);
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if(h->fd < 0)
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goto free;
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#ifdef HAVE_DEV_IICBUS_IIC_H
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cmd.slave = h->slave = addr << 1;
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cmd.last = 0;
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cmd.count = 0;
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if (ioctl(h->fd, I2CRSTCARD, &cmd) < 0)
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goto close;
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if (ioctl(h->fd, I2CSTART, &cmd) < 0)
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goto close;
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#else /* HAVE_LINUX_I2C_DEV_H */
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if (ioctl(h->fd, I2C_SLAVE, addr) < 0) {
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goto close;
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}
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#endif
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return h;
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close:
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close(h->fd);
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free:
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free(h);
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return NULL;
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}
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/**
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* close connection to i2c slave
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*/
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void i2c_close(I2CHandle *h)
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{
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#ifdef HAVE_DEV_IICBUS_IIC_H
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ioctl(h->fd, I2CSTOP);
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#endif
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close(h->fd);
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free(h);
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}
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/**
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* write data to an i2c slave
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* \param h Handle of i2c slave
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* \param buf Buffer to send to the device
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* \param count Number of bytes to write
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* \retval >=0 Success.
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* \retval <0 Error.
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*/
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int i2c_write(I2CHandle *h, void *buf, unsigned int count)
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{
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#ifdef HAVE_DEV_IICBUS_IIC_H
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struct iiccmd cmd;
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bzero(&cmd, sizeof(cmd));
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cmd.slave = h->slave;
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cmd.last = 1;
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cmd.count = count;
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cmd.buf = buf;
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return ioctl(h->fd, I2CWRITE, &cmd);
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#else /* HAVE_LINUX_I2C_DEV_H */
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if (write(h->fd, buf, count) != count)
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return -1;
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return 0;
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#endif
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}
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