PowerPC 460EX AD7416 Temperature Sensor
Tirumala Reddy Marri
tmarri at amcc.com
Wed Apr 1 13:10:21 EST 2009
Did you have dts entries for IIC in device tree ? also did you have I2C enabled in "make menuconfig"
"device drivers -> i2c support --> I2C bus support -> IBM ppc 4xx On chip I2C support " selected. Then you should i2c see an entry /proc/devices . Use that major address and create a device node "mknode /dev/i2c-0 c 89 0" .
Write a user level program to access this device. Here is an example user code.
----------
cat fan.c
/* This program is an example of writing and reading an EEPROM device via
SMBus on a GE Fanuc Embedded Systems, Inc. VMIVME-7809 Single Board
Computer.
To compile this program:
gcc -O vmieep.c -o vmieep
Before running this program, log in as root, then load the following
modules using:
/sbin/modprobe i2c-core
/sbin/modprobe i2c-dev
/sbin/modprobe i2c-i801
Loading the i2c-i801 module will create /dev/i2c-0, with
permissions = CRW- --- ---. Either run the vmieep program as root,
or change the permissions to CRW- RW- RW- as shown:
chmod 666 /dev/i2c-0
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
//#include <linux/i2c.h>
//#include <linux/i2c-dev.h>
#include <sys/time.h>
/* The inline smbus function definitions may or may not be in i2c-dev.h,
depending on the Linux distribution. Comment or uncomment the following
#include as necessary. */
#include "i2c-dev.h" /* Use the file of lm_sensors */
#define EEPROM_SIZE 256 /* Adjust for actual number of bytes in EEPROM */
#define EEPROM_SMBUS_ADDR 0x90 /* Do NOT change! */
int gef_eeprom_read(int fd, unsigned char start_offset, unsigned char *buffer,
unsigned short buflen);
int gef_eeprom_write(int fd, unsigned char start_offset, unsigned char *buffer,
unsigned short buflen);
void gef_msec_delay(unsigned int msecs);
int main(int argc, char *argv[])
{
int fd; /* File descriptor initialized with open() */
int adapter_num = 0;
int status;
char filename[20]; /* Name of special device file */
int i2c_addr = EEPROM_SMBUS_ADDR; /* SMBus address of EEPROM */
unsigned short offset; /* Which byte to access in the EEPROM */
unsigned char rbuffer; /* Data read from EEPROM */
if ((argc < 3) || (argc > 4))
{
printf("Usage: fan read <addr> or fan write <addr> <data>\n");
return 0;
}
/* Open the special device file for the SMBus */
sprintf(filename, "/dev/i2c-%d", adapter_num);
fd = open(filename, O_RDWR);
if (fd < 0)
{
printf("ERROR: open(%s) failed\n", filename);
printf("errno = %d, %s\n", errno, strerror(errno));
return -1;
}
//printf("SUCCESS: open(%s) passed\n", filename);
/* Specify the EEPROM as the device we want to access.
*** IMPORTANT ***
The address is actually in the 7 LSBs, so shift
i2c_addr one bit to the right.*/
status = ioctl(fd, I2C_SLAVE, i2c_addr>>1);
if (status < 0)
{
printf("ERROR: ioctl(fd, I2C_SLAVE, 0x%02X) failed\n", i2c_addr);
printf("errno = %d, %s\n", errno, strerror(errno));
close(fd);
return -1;
}
//printf("SUCCESS: ioctl(fd, I2C_SLAVE, 0x%02X>>1) passed\n", i2c_addr);
if (strcmp(argv[1],"read") == 0)
{
offset = atoi(argv[2]);
gef_eeprom_read(fd, offset, &rbuffer, 1);
printf("Offset: %d Data: %d\n", offset, rbuffer);
}
if (strcmp(argv[1],"write") == 0)
{
offset = (unsigned char)(atoi(argv[2]));
rbuffer =(unsigned char)(atoi(argv[3]));
gef_eeprom_write(fd, offset, &rbuffer, 1);
printf("Offset: %d Data: %d\n", offset, rbuffer);
}
/* Close the special device file */
close(fd);
return 0;
}
//////////////////////////////////////////////////////////////////////////////
//
// Function name : gef_eeprom_read
//
// Description : Read buflen bytes from the EEPROM beginning at start_offset
//
// Return type : 0 for success, -1 for failure
//
// Argument : int fd : File descriptor returned by open()
// Argument : unsigned char start_offset : Read bytes starting at this
// offset in the EEPROM. The sum of buflen and
// start_offset must not exceed the maximum size in bytes
// of the EEPROM
// Argument : unsigned char *buffer : Where to store the bytes read
// from the EEPROM. The buffer must be large enough
// to store buflen bytes read from the EEPROM.
// Argument : unsigned short buflen : The size in bytes of buffer, or
// how many bytes to read from the EEPROM. The sum of
// buflen and start_offset must not exceed the maximum
// size in bytes of the EEPROM.
//
int gef_eeprom_read(int fd, unsigned char start_offset, unsigned char *buffer,
unsigned short buflen)
{
int offset, index;
int data;
for (index=0, offset=start_offset; index<buflen &&
offset<EEPROM_SIZE; index++, offset++)
{
data = i2c_smbus_read_byte_data(fd, offset);
if (data == -1)
{
printf("ERROR: i2c_smbus_read_byte_data(fd, 0x%02X) failed\n",
offset);
printf("errno = %d, %s\n", errno, strerror(errno));
return -1;
}
buffer[index] = (unsigned char) (data);
}
return 0;
}
//////////////////////////////////////////////////////////////////////////////
//
// Function name : gef_eeprom_write
//
// Description : Write buflen bytes to the EEPROM beginning at start_offset
//
// Return type : 0 for success, -1 for failure
//
// Argument : int fd : File descriptor returned by open()
// Argument : unsigned char start_offset : Write bytes starting at this
// offset in the EEPROM. The sum of buflen and
// start_offset must not exceed the maximum size in bytes
// of the EEPROM
// Argument : unsigned char *buffer : Where to get the bytes to write
// to the EEPROM.
// Argument : unsigned short buflen : The size in bytes of buffer.
// The sum of buflen and start_offset must not exceed the
// maximum size in bytes of the EEPROM.
//
int gef_eeprom_write(int fd, unsigned char start_offset, unsigned char *buffer,
unsigned short buflen)
{
int offset, index;
int status;
for (index=0, offset=start_offset; index<buflen &&
offset<EEPROM_SIZE; index++, offset++)
{
status = i2c_smbus_write_byte_data(fd, offset, buffer[index]);
if (status < 0)
{
printf("ERROR: i2c_smbus_write_byte_data(fd, 0x%02X, 0x%02X) failed\n",
offset, buffer[index]);
printf("errno = %d, %s\n", errno, strerror(errno));
return -1;
}
/* Delay while the byte write completes */
gef_msec_delay(10);
}
return 0;
}
//////////////////////////////////////////////////////////////////////////////
//
// Function name : gef_msec_delay
//
// Description : Delay for a number of milliseconds before returning
//
// Return type : void
//
// Argument : unsigned int msecs : The number of milliseconds to delay
//
void gef_msec_delay(unsigned int msecs)
{
struct timeval s_current, s_start;
struct timezone tz;
unsigned int current, start;
/* Get initial time */
gettimeofday(&s_start, &tz);
start = s_start.tv_sec*1000000 + s_start.tv_usec;
/* Loop until msecs time have elapsed */
do
{
gettimeofday(&s_current, &tz);
current = s_current.tv_sec*1000000 + s_current.tv_usec;
} while ((current-start) < (msecs*1000));
}
-------------
________________________________
From: linuxppc-dev-bounces+tmarri=amcc.com at ozlabs.org on behalf of Henry Bausley
Sent: Tue 3/31/2009 5:41 PM
To: linuxppc-dev at ozlabs.org
Subject: PowerPC 460EX AD7416 Temperature Sensor
Does anyone know if the I2C temperature sensor is functioning on the AMCC
460EX?
When I do a cat /proc/ad7416 I get the following crash.
Unable to handle kernel paging request for data at address 0x00000000
Faulting instruction address: 0xc02cbe28
Oops: Kernel access of bad area, sig: 11 [#1]
PowerPC 44x Platform
NIP: c02cbe28 LR: c023cec8 CTR: c023d314
REGS: ef107d90 TRAP: 0300 Not tainted (2.6.28.7)
MSR: 00029000 <EE,ME> CR: 88000444 XER: 00000000
DEAR: 00000000, ESR: 00000000
TASK = ef8590c0[2611] 'cat' THREAD: ef106000
GPR00: 00000000 ef107e40 ef8590c0 00000000 ef107e9c 00000000 00000c00
ef107e98
GPR08: 00000000 c0330000 ffffffff c0330000 48000448 1001cb7c 100042bc
100df49c
GPR16: 00000002 00000400 c032f014 c032efe4 ef107e9c ef107e98 bfffffff
efb43a00
GPR24: ef61d000 00000000 ef107f20 ef107e98 00000c00 c0400000 00001000
efb43a00
NIP [c02cbe28] mutex_lock+0x0/0x1c
LR [c023cec8] ad7416_read_temp+0x24/0x80
Call Trace:
[ef107e40] [00000400] 0x400 (unreliable)
[ef107e70] [c023d334] i2c_ad7416_read_proc+0x20/0x70
[ef107e90] [c00e8018] proc_file_read+0x108/0x334
[ef107ee0] [c00e2d3c] proc_reg_read+0x4c/0x70
[ef107ef0] [c00a54e8] vfs_read+0xb4/0x16c
[ef107f10] [c00a58e0] sys_read+0x4c/0x90
[ef107f40] [c000ea88] ret_from_syscall+0x0/0x3c
Instruction dump:
90010014 38000001 90030000 85230004 7f891800 419e000c 80690008 4bd50779
80010014 38210010 7c0803a6 4e800020 <7c001828> 3000ffff 7c00192d 40a2fff4
---[ end trace 774db769c3754abe ]---
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