Thank you anish for the reply, the code is I pasted below.
[code-starts]
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/sysdev.h>
#include <linux/major.h>
#include <asm/uaccess.h>
#include <linux/slab.h>
#include <linux/cdev.h>
#include <linux/kdev_t.h>
static char *gvar = "BeHonest";
// Store and Show functions......
static ssize_t attr1_store(struct class *cls, struct class_attribute *attr, const char *buf, size_t count);
static ssize_t attr1_show(struct class *cls, struct class_attribute *attr, char *buf);
static struct class_attribute pwm_class_attrs[] = {
__ATTR(attr1, S_IRUGO | S_IWUSR , attr1_show, attr1_store),
__ATTR_NULL
};
static struct class pwm_class =
{
.name = "dev_jes",
.owner = THIS_MODULE,
.class_attrs = pwm_class_attrs
};
static int hello_init(void)
{
class_register(&pwm_class);
printk("In hello_init function \n");
return 0;
}
static ssize_t attr1_show(struct class *cls, struct class_attribute *attr, char *buf)
{
printk("In attr1_show function\n");
return sprintf(buf, "%s\n", gvar);
}
static ssize_t attr1_store(struct class *cls, struct class_attribute *attr, const char *buf, size_t count)
{
printk("the string is : %s\n",buf);
printk("In attr1_store function\n");
return 1;
//return sprintf(gvar, "%s\n", buf); --- If I put this line I am getting ERROR :(
}
static void hello_exit(void)
{
class_unregister(&pwm_class);
printk("In hello_exit function \n");
}
module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jeshwanth");
MODULE_DESCRIPTION("Learning sysfs");
[code-ends]
echo "jeshu" > /sys/class/dev_jes/attr1
And If I pass the command to atttribute I got result below in dmesg.
[ 3435.613057] the string is : jeshu
[ 3435.613061]
[ 3435.613066] In attr1_store function
[ 3435.613072] the string is : eshu
[ 3435.613074]
[ 3435.613078] In attr1_store function
[ 3435.613083] the string is : shu
[ 3435.613085]
[ 3435.613088] In attr1_store function
[ 3435.613093] the string is : hu
[ 3435.613095]
[ 3435.613098] In attr1_store function
[ 3435.613103] the string is : u
[ 3435.613105]
[ 3435.613108] In attr1_store function
[ 3435.613113] the string is :
[ 3435.613115]
[ 3435.613118] In attr1_store function
So please help me how to read the attribute in store function.. Thanks :)
On Tue, Jun 19, 2012 at 4:02 PM, anish singh <anish198519851985@xxxxxxxxx> wrote:
On Tue, Jun 19, 2012 at 3:14 PM, jeshwanth Kumar N KWhy don't you post your code?As that will really help and moreover as
<jeshkumar555@xxxxxxxxx> wrote:
> Hello all
>
> I am new to sysfs interface ans I read about in mochel's documentation. And
> doing some experiements on it. Let's come to Tue problem, in my module I
> have a global variable type char* myglobal and it s static, I am putting
> that value in my one and only class attribute using show function. But for
> the same if I a user put some value in to the using echo or something, the
> attribute value is not changing. And one more thing s after I passed the
> value to the attribute my system not shutting down :( . Please help me how
> to read values.
this is your code
you won't be breakign any law set by your company.
>> _______________________________________________
> // in store function I am doing this:
> Myglobal = bus;
>
> Sent from my HTC
>
>
>
>
> Kernelnewbies mailing list
> Kernelnewbies@xxxxxxxxxxxxxxxxx
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
--
Regards
Jeshwanth Kumar N K
+91-7411483498
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