blob: afc54a41df568471c6ecb7c59548b739aaea5638 [file] [log] [blame]
/*
* smbusmodule.c - Python bindings for Linux SMBus access through i2c-dev
* Copyright (C) 2005-2007 Mark M. Hoffman <mhoffman@lightlink.com>
*
* This program 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; version 2 of the License.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <Python.h>
#include "structmember.h"
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <linux/i2c-dev.h>
/*
** These are required to build this module against Linux older than 2.6.23.
*/
#ifndef I2C_SMBUS_I2C_BLOCK_BROKEN
#undef I2C_SMBUS_I2C_BLOCK_DATA
#define I2C_SMBUS_I2C_BLOCK_BROKEN 6
#define I2C_SMBUS_I2C_BLOCK_DATA 8
#endif
PyDoc_STRVAR(SMBus_module_doc,
"This module defines an object type that allows SMBus transactions\n"
"on Linux hosts. The host kernel must have I2C support, I2C device\n"
"interface support, and a bus adapter driver. All of these can be\n"
"either built-in to the kernel, or loaded from modules.\n"
"\n"
"Because the I2C device interface is opened R/W, users of this\n"
"module usually must have root permissions.\n");
typedef struct {
PyObject_HEAD
int fd; /* open file descriptor: /dev/i2c-?, or -1 */
int addr; /* current client SMBus address */
int pec; /* !0 => Packet Error Codes enabled */
} SMBus;
static PyObject *
SMBus_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
SMBus *self;
if ((self = (SMBus *)type->tp_alloc(type, 0)) == NULL)
return NULL;
self->fd = -1;
self->addr = -1;
self->pec = 0;
return (PyObject *)self;
}
PyDoc_STRVAR(SMBus_close_doc,
"close()\n\n"
"Disconnects the object from the bus.\n");
static PyObject *
SMBus_close(SMBus *self)
{
if ((self->fd != -1) && (close(self->fd) == -1)) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
self->fd = -1;
self->addr = -1;
self->pec = 0;
Py_INCREF(Py_None);
return Py_None;
}
static void
SMBus_dealloc(SMBus *self)
{
PyObject *ref = SMBus_close(self);
Py_XDECREF(ref);
self->ob_type->tp_free((PyObject *)self);
}
#define MAXPATH 16
PyDoc_STRVAR(SMBus_open_doc,
"open(bus)\n\n"
"Connects the object to the specified SMBus.\n");
static PyObject *
SMBus_open(SMBus *self, PyObject *args, PyObject *kwds)
{
int bus;
char path[MAXPATH];
static char *kwlist[] = {"bus", NULL};
if (!PyArg_ParseTupleAndKeywords(args, kwds, "i:open", kwlist, &bus))
return NULL;
if (snprintf(path, MAXPATH, "/dev/i2c-%d", bus) >= MAXPATH) {
PyErr_SetString(PyExc_OverflowError,
"Bus number is invalid.");
return NULL;
}
if ((self->fd = open(path, O_RDWR, 0)) == -1) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
static int
SMBus_init(SMBus *self, PyObject *args, PyObject *kwds)
{
int bus = -1;
static char *kwlist[] = {"bus", NULL};
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|i:__init__",
kwlist, &bus))
return -1;
if (bus >= 0) {
SMBus_open(self, args, kwds);
if (PyErr_Occurred())
return -1;
}
return 0;
}
/*
* private helper function, 0 => success, !0 => error
*/
static int
SMBus_set_addr(SMBus *self, int addr)
{
int ret = 0;
if (self->addr != addr) {
ret = ioctl(self->fd, I2C_SLAVE, addr);
self->addr = addr;
}
return ret;
}
#define SMBus_SET_ADDR(self, addr) do { \
if (SMBus_set_addr(self, addr)) { \
PyErr_SetFromErrno(PyExc_IOError); \
return NULL; \
} \
} while(0)
PyDoc_STRVAR(SMBus_write_quick_doc,
"write_quick(addr)\n\n"
"Perform SMBus Quick transaction.\n");
static PyObject *
SMBus_write_quick(SMBus *self, PyObject *args)
{
int addr;
__s32 result;
if (!PyArg_ParseTuple(args, "i:write_quick", &addr))
return NULL;
SMBus_SET_ADDR(self, addr);
if ((result = i2c_smbus_write_quick(self->fd, I2C_SMBUS_WRITE))) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
PyDoc_STRVAR(SMBus_read_byte_doc,
"read_byte(addr) -> result\n\n"
"Perform SMBus Read Byte transaction.\n");
static PyObject *
SMBus_read_byte(SMBus *self, PyObject *args)
{
int addr;
__s32 result;
if (!PyArg_ParseTuple(args, "i:read_byte", &addr))
return NULL;
SMBus_SET_ADDR(self, addr);
if ((result = i2c_smbus_read_byte(self->fd)) == -1) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
return Py_BuildValue("l", (long)result);
}
PyDoc_STRVAR(SMBus_write_byte_doc,
"write_byte(addr, val)\n\n"
"Perform SMBus Write Byte transaction.\n");
static PyObject *
SMBus_write_byte(SMBus *self, PyObject *args)
{
int addr, val;
__s32 result;
if (!PyArg_ParseTuple(args, "ii:write_byte", &addr, &val))
return NULL;
SMBus_SET_ADDR(self, addr);
if ((result = i2c_smbus_write_byte(self->fd, (__u8)val)) == -1) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
PyDoc_STRVAR(SMBus_read_byte_data_doc,
"read_byte_data(addr, cmd) -> result\n\n"
"Perform SMBus Read Byte Data transaction.\n");
static PyObject *
SMBus_read_byte_data(SMBus *self, PyObject *args)
{
int addr, cmd;
__s32 result;
if (!PyArg_ParseTuple(args, "ii:read_byte_data", &addr, &cmd))
return NULL;
SMBus_SET_ADDR(self, addr);
if ((result = i2c_smbus_read_byte_data(self->fd, (__u8)cmd)) == -1) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
return Py_BuildValue("l", (long)result);
}
PyDoc_STRVAR(SMBus_write_byte_data_doc,
"write_byte_data(addr, cmd, val)\n\n"
"Perform SMBus Write Byte Data transaction.\n");
static PyObject *
SMBus_write_byte_data(SMBus *self, PyObject *args)
{
int addr, cmd, val;
__s32 result;
if (!PyArg_ParseTuple(args, "iii:write_byte_data", &addr, &cmd, &val))
return NULL;
SMBus_SET_ADDR(self, addr);
if ((result = i2c_smbus_write_byte_data(self->fd,
(__u8)cmd, (__u8)val)) == -1) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
PyDoc_STRVAR(SMBus_read_word_data_doc,
"read_word_data(addr, cmd) -> result\n\n"
"Perform SMBus Read Word Data transaction.\n");
static PyObject *
SMBus_read_word_data(SMBus *self, PyObject *args)
{
int addr, cmd;
__s32 result;
if (!PyArg_ParseTuple(args, "ii:read_word_data", &addr, &cmd))
return NULL;
SMBus_SET_ADDR(self, addr);
if ((result = i2c_smbus_read_word_data(self->fd, (__u8)cmd)) == -1) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
return Py_BuildValue("l", (long)result);
}
PyDoc_STRVAR(SMBus_write_word_data_doc,
"write_word_data(addr, cmd, val)\n\n"
"Perform SMBus Write Word Data transaction.\n");
static PyObject *
SMBus_write_word_data(SMBus *self, PyObject *args)
{
int addr, cmd, val;
__s32 result;
if (!PyArg_ParseTuple(args, "iii:write_word_data", &addr, &cmd, &val))
return NULL;
SMBus_SET_ADDR(self, addr);
if ((result = i2c_smbus_write_word_data(self->fd,
(__u8)cmd, (__u16)val)) == -1) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
PyDoc_STRVAR(SMBus_process_call_doc,
"process_call(addr, cmd, val)\n\n"
"Perform SMBus Process Call transaction.\n");
static PyObject *
SMBus_process_call(SMBus *self, PyObject *args)
{
int addr, cmd, val;
__s32 result;
if (!PyArg_ParseTuple(args, "iii:process_call", &addr, &cmd, &val))
return NULL;
SMBus_SET_ADDR(self, addr);
if ((result = i2c_smbus_process_call(self->fd,
(__u8)cmd, (__u16)val)) == -1) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
/*
* private helper function; returns a new list of integers
*/
static PyObject *
SMBus_buf_to_list(__u8 const *buf, int len)
{
PyObject *list = PyList_New(len);
int ii;
if (list == NULL)
return NULL;
for (ii = 0; ii < len; ii++) {
PyObject *val = Py_BuildValue("l", (long)buf[ii]);
PyList_SET_ITEM(list, ii, val);
}
return list;
}
PyDoc_STRVAR(SMBus_read_block_data_doc,
"read_block_data(addr, cmd) -> results\n\n"
"Perform SMBus Read Block Data transaction.\n");
static PyObject *
SMBus_read_block_data(SMBus *self, PyObject *args)
{
int addr, cmd;
union i2c_smbus_data data;
if (!PyArg_ParseTuple(args, "ii:read_block_data", &addr, &cmd))
return NULL;
SMBus_SET_ADDR(self, addr);
/* save a bit of code by calling the access function directly */
if (i2c_smbus_access(self->fd, I2C_SMBUS_READ, (__u8)cmd,
I2C_SMBUS_BLOCK_DATA, &data)) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
/* first byte of the block contains (remaining) data length */
return SMBus_buf_to_list(&data.block[1], data.block[0]);
}
/*
* private helper function: convert an integer list to union i2c_smbus_data
*/
static int
SMBus_list_to_data(PyObject *list, union i2c_smbus_data *data)
{
static char *msg = "Third argument must be a list of at least one, "
"but not more than 32 integers";
int ii, len;
if (!PyList_Check(list)) {
PyErr_SetString(PyExc_TypeError, msg);
return 0; /* fail */
}
if ((len = PyList_GET_SIZE(list)) > 32) {
PyErr_SetString(PyExc_OverflowError, msg);
return 0; /* fail */
}
/* first byte is the length */
data->block[0] = (__u8)len;
for (ii = 0; ii < len; ii++) {
PyObject *val = PyList_GET_ITEM(list, ii);
if (!PyInt_Check(val)) {
PyErr_SetString(PyExc_TypeError, msg);
return 0; /* fail */
}
data->block[ii+1] = (__u8)PyInt_AS_LONG(val);
}
return 1; /* success */
}
PyDoc_STRVAR(SMBus_write_block_data_doc,
"write_block_data(addr, cmd, [vals])\n\n"
"Perform SMBus Write Block Data transaction.\n");
static PyObject *
SMBus_write_block_data(SMBus *self, PyObject *args)
{
int addr, cmd;
union i2c_smbus_data data;
if (!PyArg_ParseTuple(args, "iiO&:write_block_data", &addr, &cmd,
SMBus_list_to_data, &data))
return NULL;
SMBus_SET_ADDR(self, addr);
/* save a bit of code by calling the access function directly */
if (i2c_smbus_access(self->fd, I2C_SMBUS_WRITE, (__u8)cmd,
I2C_SMBUS_BLOCK_DATA, &data)) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
PyDoc_STRVAR(SMBus_block_process_call_doc,
"block_process_call(addr, cmd, [vals]) -> results\n\n"
"Perform SMBus Block Process Call transaction.\n");
static PyObject *
SMBus_block_process_call(SMBus *self, PyObject *args)
{
int addr, cmd;
union i2c_smbus_data data;
if (!PyArg_ParseTuple(args, "iiO&:block_process_call", &addr, &cmd,
SMBus_list_to_data, &data))
return NULL;
SMBus_SET_ADDR(self, addr);
/* save a bit of code by calling the access function directly */
if (i2c_smbus_access(self->fd, I2C_SMBUS_WRITE, (__u8)cmd,
I2C_SMBUS_BLOCK_PROC_CALL, &data)) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
/* first byte of the block contains (remaining) data length */
return SMBus_buf_to_list(&data.block[1], data.block[0]);
}
PyDoc_STRVAR(SMBus_read_i2c_block_data_doc,
"read_i2c_block_data(addr, cmd, len=32) -> results\n\n"
"Perform I2C Block Read transaction.\n");
static PyObject *
SMBus_read_i2c_block_data(SMBus *self, PyObject *args)
{
int addr, cmd, len=32;
union i2c_smbus_data data;
if (!PyArg_ParseTuple(args, "ii|i:read_i2c_block_data", &addr, &cmd,
&len))
return NULL;
SMBus_SET_ADDR(self, addr);
data.block[0] = len;
/* save a bit of code by calling the access function directly */
if (i2c_smbus_access(self->fd, I2C_SMBUS_READ, (__u8)cmd,
len == 32 ? I2C_SMBUS_I2C_BLOCK_BROKEN:
I2C_SMBUS_I2C_BLOCK_DATA, &data)) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
/* first byte of the block contains (remaining) data length */
return SMBus_buf_to_list(&data.block[1], data.block[0]);
}
PyDoc_STRVAR(SMBus_write_i2c_block_data_doc,
"write_i2c_block_data(addr, cmd, [vals])\n\n"
"Perform I2C Block Write transaction.\n");
static PyObject *
SMBus_write_i2c_block_data(SMBus *self, PyObject *args)
{
int addr, cmd;
union i2c_smbus_data data;
if (!PyArg_ParseTuple(args, "iiO&:write_i2c_block_data", &addr, &cmd,
SMBus_list_to_data, &data))
return NULL;
SMBus_SET_ADDR(self, addr);
/* save a bit of code by calling the access function directly */
if (i2c_smbus_access(self->fd, I2C_SMBUS_WRITE, (__u8)cmd,
I2C_SMBUS_I2C_BLOCK_BROKEN, &data)) {
PyErr_SetFromErrno(PyExc_IOError);
return NULL;
}
Py_INCREF(Py_None);
return Py_None;
}
PyDoc_STRVAR(SMBus_type_doc,
"SMBus([bus]) -> SMBus\n\n"
"Return a new SMBus object that is (optionally) connected to the\n"
"specified I2C device interface.\n");
static PyMethodDef SMBus_methods[] = {
{"open", (PyCFunction)SMBus_open, METH_VARARGS | METH_KEYWORDS,
SMBus_open_doc},
{"close", (PyCFunction)SMBus_close, METH_NOARGS,
SMBus_close_doc},
{"write_quick", (PyCFunction)SMBus_write_quick, METH_VARARGS,
SMBus_write_quick_doc},
{"read_byte", (PyCFunction)SMBus_read_byte, METH_VARARGS,
SMBus_read_byte_doc},
{"write_byte", (PyCFunction)SMBus_write_byte, METH_VARARGS,
SMBus_write_byte_doc},
{"read_byte_data", (PyCFunction)SMBus_read_byte_data, METH_VARARGS,
SMBus_read_byte_data_doc},
{"write_byte_data", (PyCFunction)SMBus_write_byte_data, METH_VARARGS,
SMBus_write_byte_data_doc},
{"read_word_data", (PyCFunction)SMBus_read_word_data, METH_VARARGS,
SMBus_read_word_data_doc},
{"write_word_data", (PyCFunction)SMBus_write_word_data, METH_VARARGS,
SMBus_write_word_data_doc},
{"process_call", (PyCFunction)SMBus_process_call, METH_VARARGS,
SMBus_process_call_doc},
{"read_block_data", (PyCFunction)SMBus_read_block_data, METH_VARARGS,
SMBus_read_block_data_doc},
{"write_block_data", (PyCFunction)SMBus_write_block_data, METH_VARARGS,
SMBus_write_block_data_doc},
{"block_process_call", (PyCFunction)SMBus_block_process_call,
METH_VARARGS, SMBus_block_process_call_doc},
{"read_i2c_block_data", (PyCFunction)SMBus_read_i2c_block_data,
METH_VARARGS, SMBus_read_i2c_block_data_doc},
{"write_i2c_block_data", (PyCFunction)SMBus_write_i2c_block_data,
METH_VARARGS, SMBus_write_i2c_block_data_doc},
{NULL},
};
static PyObject *
SMBus_get_pec(SMBus *self, void *closure)
{
PyObject *result = self->pec ? Py_True : Py_False;
Py_INCREF(result);
return result;
}
static int
SMBus_set_pec(SMBus *self, PyObject *val, void *closure)
{
int pec;
pec = PyObject_IsTrue(val);
if (val == NULL) {
PyErr_SetString(PyExc_TypeError,
"Cannot delete attribute");
return -1;
}
else if (pec == -1) {
PyErr_SetString(PyExc_TypeError,
"The pec attribute must be a boolean.");
return -1;
}
if (self->pec != pec) {
if (ioctl(self->fd, I2C_PEC, pec)) {
PyErr_SetFromErrno(PyExc_IOError);
return -1;
}
self->pec = pec;
}
return 0;
}
static PyGetSetDef SMBus_getset[] = {
{"pec", (getter)SMBus_get_pec, (setter)SMBus_set_pec,
"True if Packet Error Codes (PEC) are enabled"},
{NULL},
};
static PyTypeObject SMBus_type = {
PyObject_HEAD_INIT(NULL)
0, /* ob_size */
"SMBus", /* tp_name */
sizeof(SMBus), /* tp_basicsize */
0, /* tp_itemsize */
(destructor)SMBus_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT, /* tp_flags */
SMBus_type_doc, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
SMBus_methods, /* tp_methods */
0, /* tp_members */
SMBus_getset, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
(initproc)SMBus_init, /* tp_init */
0, /* tp_alloc */
SMBus_new, /* tp_new */
};
static PyMethodDef SMBus_module_methods[] = {
{NULL}
};
#ifndef PyMODINIT_FUNC /* declarations for DLL import/export */
#define PyMODINIT_FUNC void
#endif
PyMODINIT_FUNC
initsmbus(void)
{
PyObject* m;
if (PyType_Ready(&SMBus_type) < 0)
return;
m = Py_InitModule3("smbus", SMBus_module_methods, SMBus_module_doc);
Py_INCREF(&SMBus_type);
PyModule_AddObject(m, "SMBus", (PyObject *)&SMBus_type);
}