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![Arvind Yadav](/assets/img/avatar_default.png)
Never directly free @dev after calling device_register(), even if it returned an error! Always use put_device() to give up the reference initialized. Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
258 lines
6.2 KiB
C
258 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) ST-Ericsson SA 2011
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*
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* Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
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*/
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#include <linux/sysfs.h>
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#include <linux/init.h>
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#include <linux/stat.h>
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#include <linux/slab.h>
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#include <linux/idr.h>
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#include <linux/spinlock.h>
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#include <linux/sys_soc.h>
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#include <linux/err.h>
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#include <linux/glob.h>
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static DEFINE_IDA(soc_ida);
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static ssize_t soc_info_get(struct device *dev,
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struct device_attribute *attr,
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char *buf);
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struct soc_device {
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struct device dev;
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struct soc_device_attribute *attr;
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int soc_dev_num;
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};
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static struct bus_type soc_bus_type = {
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.name = "soc",
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};
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static DEVICE_ATTR(machine, S_IRUGO, soc_info_get, NULL);
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static DEVICE_ATTR(family, S_IRUGO, soc_info_get, NULL);
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static DEVICE_ATTR(soc_id, S_IRUGO, soc_info_get, NULL);
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static DEVICE_ATTR(revision, S_IRUGO, soc_info_get, NULL);
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struct device *soc_device_to_device(struct soc_device *soc_dev)
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{
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return &soc_dev->dev;
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}
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static umode_t soc_attribute_mode(struct kobject *kobj,
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struct attribute *attr,
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int index)
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{
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struct device *dev = container_of(kobj, struct device, kobj);
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struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
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if ((attr == &dev_attr_machine.attr)
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&& (soc_dev->attr->machine != NULL))
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return attr->mode;
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if ((attr == &dev_attr_family.attr)
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&& (soc_dev->attr->family != NULL))
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return attr->mode;
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if ((attr == &dev_attr_revision.attr)
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&& (soc_dev->attr->revision != NULL))
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return attr->mode;
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if ((attr == &dev_attr_soc_id.attr)
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&& (soc_dev->attr->soc_id != NULL))
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return attr->mode;
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/* Unknown or unfilled attribute. */
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return 0;
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}
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static ssize_t soc_info_get(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
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if (attr == &dev_attr_machine)
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return sprintf(buf, "%s\n", soc_dev->attr->machine);
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if (attr == &dev_attr_family)
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return sprintf(buf, "%s\n", soc_dev->attr->family);
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if (attr == &dev_attr_revision)
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return sprintf(buf, "%s\n", soc_dev->attr->revision);
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if (attr == &dev_attr_soc_id)
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return sprintf(buf, "%s\n", soc_dev->attr->soc_id);
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return -EINVAL;
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}
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static struct attribute *soc_attr[] = {
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&dev_attr_machine.attr,
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&dev_attr_family.attr,
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&dev_attr_soc_id.attr,
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&dev_attr_revision.attr,
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NULL,
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};
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static const struct attribute_group soc_attr_group = {
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.attrs = soc_attr,
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.is_visible = soc_attribute_mode,
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};
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static const struct attribute_group *soc_attr_groups[] = {
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&soc_attr_group,
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NULL,
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};
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static void soc_release(struct device *dev)
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{
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struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
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kfree(soc_dev);
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}
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static struct soc_device_attribute *early_soc_dev_attr;
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struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
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{
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struct soc_device *soc_dev;
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int ret;
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if (!soc_bus_type.p) {
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if (early_soc_dev_attr)
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return ERR_PTR(-EBUSY);
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early_soc_dev_attr = soc_dev_attr;
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return NULL;
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}
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soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
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if (!soc_dev) {
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ret = -ENOMEM;
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goto out1;
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}
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/* Fetch a unique (reclaimable) SOC ID. */
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ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
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if (ret < 0)
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goto out2;
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soc_dev->soc_dev_num = ret;
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soc_dev->attr = soc_dev_attr;
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soc_dev->dev.bus = &soc_bus_type;
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soc_dev->dev.groups = soc_attr_groups;
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soc_dev->dev.release = soc_release;
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dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
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ret = device_register(&soc_dev->dev);
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if (ret)
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goto out3;
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return soc_dev;
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out3:
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ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
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put_device(&soc_dev->dev);
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soc_dev = NULL;
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out2:
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kfree(soc_dev);
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out1:
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return ERR_PTR(ret);
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}
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/* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */
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void soc_device_unregister(struct soc_device *soc_dev)
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{
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ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
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device_unregister(&soc_dev->dev);
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early_soc_dev_attr = NULL;
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}
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static int __init soc_bus_register(void)
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{
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int ret;
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ret = bus_register(&soc_bus_type);
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if (ret)
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return ret;
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if (early_soc_dev_attr)
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return PTR_ERR(soc_device_register(early_soc_dev_attr));
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return 0;
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}
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core_initcall(soc_bus_register);
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static int soc_device_match_attr(const struct soc_device_attribute *attr,
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const struct soc_device_attribute *match)
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{
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if (match->machine &&
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(!attr->machine || !glob_match(match->machine, attr->machine)))
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return 0;
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if (match->family &&
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(!attr->family || !glob_match(match->family, attr->family)))
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return 0;
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if (match->revision &&
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(!attr->revision || !glob_match(match->revision, attr->revision)))
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return 0;
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if (match->soc_id &&
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(!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
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return 0;
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return 1;
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}
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static int soc_device_match_one(struct device *dev, void *arg)
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{
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struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
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return soc_device_match_attr(soc_dev->attr, arg);
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}
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/*
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* soc_device_match - identify the SoC in the machine
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* @matches: zero-terminated array of possible matches
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*
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* returns the first matching entry of the argument array, or NULL
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* if none of them match.
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*
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* This function is meant as a helper in place of of_match_node()
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* in cases where either no device tree is available or the information
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* in a device node is insufficient to identify a particular variant
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* by its compatible strings or other properties. For new devices,
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* the DT binding should always provide unique compatible strings
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* that allow the use of of_match_node() instead.
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*
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* The calling function can use the .data entry of the
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* soc_device_attribute to pass a structure or function pointer for
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* each entry.
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*/
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const struct soc_device_attribute *soc_device_match(
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const struct soc_device_attribute *matches)
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{
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int ret = 0;
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if (!matches)
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return NULL;
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while (!ret) {
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if (!(matches->machine || matches->family ||
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matches->revision || matches->soc_id))
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break;
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ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
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soc_device_match_one);
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if (ret < 0 && early_soc_dev_attr)
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ret = soc_device_match_attr(early_soc_dev_attr,
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matches);
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if (ret < 0)
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return NULL;
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if (!ret)
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matches++;
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else
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return matches;
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}
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return NULL;
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}
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EXPORT_SYMBOL_GPL(soc_device_match);
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