i'd need to obtain a pointer to a particular device registered in linux. Briefly, this device represents a mii_bus
object. The problem is that this device seems doesn't belong to a bus (its dev->bus
is NULL
) so i can't use for example the function bus_for_each_dev
. The device is however registered by the Open Firmware layer and i can see the relative of_device
(which is the parent of the device i'm interested in) in /sys/bus/of_platform
. My device is also registered in a class
so i can find it in /sys/class/mdio_bus
. Now the questions:
It's possible to obtain the pointer using the pointer to the of_device
that is the parent of the device we want?
How can i get a pointer to an already instantiated class by using only the name?If it was possible i could iterate over the devices of that class.
Any other advice would be very useful! Thank you all.
I found the way. I explain it briefly, maybe it could be useful. The method we could use is device_find_child
. The method takes as third parameter a pointer to a function that implements the comparison logic. If the function returns not zero when called with a particular device as first parameter, device_find_child
will return that pointer.
#include <linux/device.h>
#include <linux/of_platform.h>
static int custom_match_dev(struct device *dev, void *data)
{
/* this function implements the comaparison logic. Return not zero if device
pointed by dev is the device you are searching for.
*/
}
static struct device *find_dev()
{
struct device *ofdev = bus_find_device_by_name(&of_platform_bus_type,
NULL, "OF_device_name");
if (ofdev)
{
/* of device is the parent of device we are interested in */
struct device *real_dev = device_find_child(ofdev,
NULL, /* passed in the second param to custom_match_dev */
custom_match_dev);
if (real_dev)
return real_dev;
}
return NULL;
}
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