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// SPDX-License-Identifier: GPL-2.0
//
// Support for generic time stamping devices on MII buses.
// Copyright (C) 2018 Richard Cochran <richardcochran@gmail.com>
//
#include <linux/mii_timestamper.h>
static LIST_HEAD(mii_timestamping_devices);
static DEFINE_MUTEX(tstamping_devices_lock);
struct mii_timestamping_desc {
struct list_head list;
struct mii_timestamping_ctrl *ctrl;
struct device *device;
};
/**
* register_mii_tstamp_controller() - registers an MII time stamping device.
*
* @device: The device to be registered.
* @ctrl: Pointer to device's control interface.
*
* Returns zero on success or non-zero on failure.
*/
int register_mii_tstamp_controller(struct device *device,
struct mii_timestamping_ctrl *ctrl)
{
struct mii_timestamping_desc *desc;
desc = kzalloc(sizeof(*desc), GFP_KERNEL);
if (!desc)
return -ENOMEM;
INIT_LIST_HEAD(&desc->list);
desc->ctrl = ctrl;
desc->device = device;
mutex_lock(&tstamping_devices_lock);
list_add_tail(&mii_timestamping_devices, &desc->list);
mutex_unlock(&tstamping_devices_lock);
return 0;
}
EXPORT_SYMBOL(register_mii_tstamp_controller);
/**
* unregister_mii_tstamp_controller() - unregisters an MII time stamping device.
*
* @device: A device previously passed to register_mii_tstamp_controller().
*/
void unregister_mii_tstamp_controller(struct device *device)
{
struct mii_timestamping_desc *desc;
struct list_head *this, *next;
mutex_lock(&tstamping_devices_lock);
list_for_each_safe(this, next, &mii_timestamping_devices) {
desc = list_entry(this, struct mii_timestamping_desc, list);
if (desc->device == device) {
list_del_init(&desc->list);
kfree(desc);
break;
}
}
mutex_unlock(&tstamping_devices_lock);
}
EXPORT_SYMBOL(unregister_mii_tstamp_controller);
/**
* register_mii_timestamper - Enables a given port of an MII time stamper.
*
* @node: The device tree node of the MII time stamp controller.
* @port: The index of the port to be enabled.
*
* Returns a valid interface on success or ERR_PTR otherwise.
*/
struct mii_timestamper *register_mii_timestamper(struct device_node *node,
unsigned int port)
{
struct mii_timestamper *mii_ts = NULL;
struct mii_timestamping_desc *desc;
struct list_head *this;
mutex_lock(&tstamping_devices_lock);
list_for_each(this, &mii_timestamping_devices) {
desc = list_entry(this, struct mii_timestamping_desc, list);
if (desc->device->of_node == node) {
mii_ts = desc->ctrl->probe_channel(desc->device, port);
if (!IS_ERR(mii_ts)) {
mii_ts->device = desc->device;
get_device(desc->device);
}
break;
}
}
mutex_unlock(&tstamping_devices_lock);
return mii_ts ? mii_ts : ERR_PTR(-EPROBE_DEFER);
}
EXPORT_SYMBOL(register_mii_timestamper);
/**
* unregister_mii_timestamper - Disables a given MII time stamper.
*
* @mii_ts: An interface obtained via register_mii_timestamper().
*
*/
void unregister_mii_timestamper(struct mii_timestamper *mii_ts)
{
struct mii_timestamping_desc *desc;
struct list_head *this;
if (!mii_ts)
return;
/* mii_timestamper statically registered by the PHY driver won't use the
* register_mii_timestamper() and thus don't have ->device set. Don't
* try to unregister these.
*/
if (!mii_ts->device)
return;
mutex_lock(&tstamping_devices_lock);
list_for_each(this, &mii_timestamping_devices) {
desc = list_entry(this, struct mii_timestamping_desc, list);
if (desc->device == mii_ts->device) {
desc->ctrl->release_channel(desc->device, mii_ts);
put_device(desc->device);
break;
}
}
mutex_unlock(&tstamping_devices_lock);
}
EXPORT_SYMBOL(unregister_mii_timestamper);
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