Reading temperature from another Kernel modules
From: Matthias Dunda
Date: Tue Oct 26 2010 - 05:12:37 EST
Hi everybody,
I need to read out the current system temperature from inside my custom kernel module.
My system works with the jc42.c driver and I can read the temperature perfectly via the proc filesystem in user space.
How do I query the temperature from another kernel driver?
First of all I added a new function and exported the symbol
int jc42_get_temperature()
{
int temp;
// TODO get the correct temp
temp = jc42_read_value(my_local_client, JC42_REG_TEMP);
return temp;
}
EXPORT_SYMBOL(jc42_get_temperature);
BUT: how do I get the temp? Most of the internal functions require a struct device or a struct i2c_client, which - I assume - are perfectly provided by the kernel when going the way over the proc file system.
I tried to statically save such a struct during the probing process (this is the above my_local_client), but this works neither. When I use the saved struct to call jc42_read_value, I always get a temperature value which is not correct at all.
Kernel is 2.6.29.6-rt24 (yes, jc42 is originally not included there - we ported it from a newer kernel release.)
Thanks for any help!
Matthias
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