Difference between revisions of "ADC overo 2.6.39+"
m (→Using the ADC's: fix formatting) |
m (→Python) |
||
| Line 30: | Line 30: | ||
=== Python === | === Python === | ||
| − | import os | + | import os |
| − | + | import sys | |
| − | import sys | + | import subprocess |
| − | + | cmd1 = "cat /sys/class/hwmon/hwmon1/device/in7_input" | |
| − | import subprocess | + | process = subprocess.Popen(cmd1, stdout=subprocess.PIPE , shell=True) |
| − | + | os.waitpid(process.pid, 0)[1] | |
| − | cmd1 = "cat /sys/class/hwmon/hwmon1/device/in7_input" | + | udata = process.stdout.read().strip() |
| − | + | print udata | |
| − | process = subprocess.Popen(cmd1, stdout=subprocess.PIPE , shell=True) | + | |
| − | + | ||
| − | os.waitpid(process.pid, 0)[1] | + | |
| − | + | ||
| − | udata = process.stdout.read().strip() | + | |
| − | + | ||
| − | print udata | + | |
'''In console (in interactive mode)''' | '''In console (in interactive mode)''' | ||
| − | python | + | python |
| − | + | Python 2.6.6 (r266:84292, Sep 1 2011, 13:08:10) | |
| − | Python 2.6.6 (r266:84292, Sep 1 2011, 13:08:10) | + | [GCC 4.3.3] on linux2 |
| − | + | >>> import os | |
| − | [GCC 4.3.3] on linux2 | + | >>> import sys |
| − | + | >>> import subprocess | |
| − | >>> import os | + | >>> cmd1 = "cat /sys/class/hwmon/hwmon1/device/in7_input" |
| − | + | >>> process = subprocess.Popen(cmd1, stdout=subprocess.PIPE , shell=True) | |
| − | >>> import sys | + | >>> os.waitpid(process.pid, 0)[1] |
| − | + | 0 | |
| − | >>> import subprocess | + | >>> udata = process.stdout.read().strip() |
| − | + | >>> print udata | |
| − | >>> cmd1 = "cat /sys/class/hwmon/hwmon1/device/in7_input" | + | 1388 |
| − | + | >>> | |
| − | >>> process = subprocess.Popen(cmd1, stdout=subprocess.PIPE , shell=True) | + | |
| − | + | ||
| − | >>> os.waitpid(process.pid, 0)[1] | + | |
| − | + | ||
==Using sysfs from c and fopen and fread== | ==Using sysfs from c and fopen and fread== | ||
Latest revision as of 23:11, 20 September 2011
Contents
Using the ADC's
From posts in the mailing list by Steve Sakoman and others
In linux-omap3-2.6.39 and 3.0 and above
The madc driver is now upstream and in the process it moved to the hwmon subsystem. It is now even easier to access using the /sys/class interface:
root@omap3-multi:~# ls /sys/class/hwmon/hwmon1/device/ curr10_input in11_input in3_input in7_input power driver in12_input in4_input in8_input subsystem hwmon in15_input in5_input in9_input temp1_input in0_input in2_input in6_input modalias uevent
root@omap3-multi:~# cat /sys/class/hwmon/hwmon1/device/temp1_input 56
root@omap3-multi:~# cat /sys/class/hwmon/hwmon1/device/curr10_input -750
ADC's via a system call
a quick and very nasty way to access them is by a system call
C
system("cat /sys/class/hwmon/hwmon1/device/in7_input");
Python
os.system("cat /sys/class/hwmon/hwmon1/device/in7_input")
Python
import os import sys import subprocess cmd1 = "cat /sys/class/hwmon/hwmon1/device/in7_input" process = subprocess.Popen(cmd1, stdout=subprocess.PIPE , shell=True) os.waitpid(process.pid, 0)[1] udata = process.stdout.read().strip() print udata
In console (in interactive mode)
python Python 2.6.6 (r266:84292, Sep 1 2011, 13:08:10) [GCC 4.3.3] on linux2 >>> import os >>> import sys >>> import subprocess >>> cmd1 = "cat /sys/class/hwmon/hwmon1/device/in7_input" >>> process = subprocess.Popen(cmd1, stdout=subprocess.PIPE , shell=True) >>> os.waitpid(process.pid, 0)[1] 0 >>> udata = process.stdout.read().strip() >>> print udata 1388 >>>
Using sysfs from c and fopen and fread
A much useful way to access the adc's is using fopen and fread.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
FILE *fp;
int main(void)
{
char read_value[4];
char adcVal2[6];
if (( fp = fopen("/sys/class/hwmon/hwmon1/device/in2_input", "r")) == NULL)
{
printf("Can not open hwmon1 \n");
exit(1);
}
rewind(fp);
fread(&read_value, sizeof(char), 1 , fp);
strcpy(adcVal2 , read_value);
fclose(fp);
printf("\nADC 2 value = %s \n",adcVal2);
return 0;
}
Building your own kernel
When building your own kernel Make sure your defconfig has CONFIG_TWL4030_MADC and CONFIG_SENSORS_TWL4030_MADC and make sure your rootfs has the module.
Link to kernel docs for Kernel driver twl4030-madc http://www.sakoman.com/cgi-bin/gitweb.cgi?p=linux-omap-2.6.git;a=blob;f=Documentation/hwmon/twl4030-madc-hwmon;h=ef7984317cecb29eca6ef23a30c21d920e66ef31;hb=refs/heads/omap-2.6.39-pm
