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AP_HAL_Linux: implement function to transfer data

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This is a similar function to what we have in I2CDriver, but it can
receive a nullptr to recv or send.  It will create 2 i2c_msg structs to
send and receive data to/from the I2C slave.
This commit is contained in:
Lucas De Marchi 2015-11-12 19:43:10 -02:00
parent 2fc534d18d
commit bc2f7f2783
1 changed files with 51 additions and 2 deletions
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53
libraries/AP_HAL_Linux/I2CDevice.cpp
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@ -23,7 +23,21 @@
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <linux/i2c-dev.h>
/*
* linux/i2c-dev.h is a kernel header, but some distros rename it to
* linux/i2c-dev.h.kernel when i2c-tools is installed. The header provided by
* i2c-tools is old/broken and contains some symbols defined in
* linux/i2c.h. The i2c.h will be only included if a well-known symbol is not
* defined. This is a workaround while distros propagate the real fix like
* http://lists.opensuse.org/archive/opensuse-commit/2015-10/msg00918.html (or
* do like Archlinux that installs only the kernel header).
*/
#ifndef I2C_SMBUS_BLOCK_MAX
#include <linux/i2c.h>
#endif
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <vector>
@ -101,8 +115,43 @@ I2CDevice::~I2CDevice()
bool I2CDevice::transfer(const uint8_t *send, uint32_t send_len,
uint8_t *recv, uint32_t recv_len)
{
// TODO: implement I2C transfer
return false;
struct i2c_msg msgs[2] = { };
unsigned nmsgs = 0;
assert(_bus.fd >= 0);
if (send && send_len != 0) {
msgs[nmsgs].addr = _address;
msgs[nmsgs].flags = 0;
msgs[nmsgs].buf = const_cast<uint8_t*>(send);
msgs[nmsgs].len = send_len;
nmsgs++;
}
if (recv && recv_len != 0) {
msgs[nmsgs].addr = _address;
msgs[nmsgs].flags = I2C_M_RD;
msgs[nmsgs].buf = recv;
msgs[nmsgs].len = recv_len;
nmsgs++;
}
if (!nmsgs) {
return false;
}
struct i2c_rdwr_ioctl_data i2c_data = { };
i2c_data.msgs = msgs;
i2c_data.nmsgs = nmsgs;
int r = -EINVAL;
unsigned retries = _retries;
do {
r = ::ioctl(_bus.fd, I2C_RDWR, &i2c_data);
} while (r < 0 && retries-- > 0);
return r >= 0;
}
AP_HAL::Semaphore *I2CDevice::get_semaphore()