linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * drivers/base/dd.c - The core device/driver interactions.

 *

 * This file contains the (sometimes tricky) code that controls the

 * interactions between devices and drivers, which primarily includes

 * driver binding and unbinding.

 *

 * All of this code used to exist in drivers/base/bus.c, but was

 * relocated to here in the name of compartmentalization (since it wasn't

 * strictly code just for the 'struct bus_type'.

 *

 * Copyright (c) 2002-5 Patrick Mochel

 * Copyright (c) 2002-3 Open Source Development Labs

 * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>

 * Copyright (c) 2007-2009 Novell Inc.

 */

​

#include <linux/debugfs.h>

#include <linux/device.h>

#include <linux/delay.h>

#include <linux/dma-mapping.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/kthread.h>

#include <linux/wait.h>

#include <linux/async.h>

#include <linux/pm_runtime.h>

#include <linux/pinctrl/devinfo.h>

​

#include "base.h"

#include "power/power.h"

​

/*

 * Deferred Probe infrastructure.

 *

 * Sometimes driver probe order matters, but the kernel doesn't always have

 * dependency information which means some drivers will get probed before a

 * resource it depends on is available.  For example, an SDHCI driver may

 * first need a GPIO line from an i2c GPIO controller before it can be

 * initialized.  If a required resource is not available yet, a driver can

 * request probing to be deferred by returning -EPROBE_DEFER from its probe hook

 *

 * Deferred probe maintains two lists of devices, a pending list and an active

 * list.  A driver returning -EPROBE_DEFER causes the device to be added to the

 * pending list.  A successful driver probe will trigger moving all devices

 * from the pending to the active list so that the workqueue will eventually

 * retry them.

 *

 * The deferred_probe_mutex must be held any time the deferred_probe_*_list

 * of the (struct device*)->p->deferred_probe pointers are manipulated

 */

static DEFINE_MUTEX(deferred_probe_mutex);

static LIST_HEAD(deferred_probe_pending_list);

static LIST_HEAD(deferred_probe_active_list);

static atomic_t deferred_trigger_count = ATOMIC_INIT(0);

static struct dentry *deferred_devices;

static bool initcalls_done;

​

/* Save the async probe drivers' name from kernel cmdline */

#define ASYNC_DRV_NAMES_MAX_LEN 256

static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];

​