summaryrefslogtreecommitdiff
path: root/net/nfc
diff options
context:
space:
mode:
authorLauro Ramos Venancio <lauro.venancio@openbossa.org>2011-07-01 19:31:34 -0300
committerJohn W. Linville <linville@tuxdriver.com>2011-07-05 15:26:57 -0400
commit4d12b8b129f170d0fc3188de1e51a2a1b0f87730 (patch)
treee37bbec5da917fee80706516c56fb41fcd03a1b5 /net/nfc
parent3e256b8f8dfa309a80b5dece388d85d9a9801a29 (diff)
NFC: add nfc generic netlink interface
The NFC generic netlink interface exports the NFC control operations to the user space. Signed-off-by: Lauro Ramos Venancio <lauro.venancio@openbossa.org> Signed-off-by: Aloisio Almeida Jr <aloisio.almeida@openbossa.org> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> Reviewed-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/nfc')
-rw-r--r--net/nfc/Makefile2
-rw-r--r--net/nfc/core.c93
-rw-r--r--net/nfc/netlink.c537
-rw-r--r--net/nfc/nfc.h11
4 files changed, 640 insertions, 3 deletions
diff --git a/net/nfc/Makefile b/net/nfc/Makefile
index 28bee595868..fa6fc16246d 100644
--- a/net/nfc/Makefile
+++ b/net/nfc/Makefile
@@ -4,4 +4,4 @@
obj-$(CONFIG_NFC) += nfc.o
-nfc-objs := core.o
+nfc-objs := core.o netlink.o
diff --git a/net/nfc/core.c b/net/nfc/core.c
index 19f8035a1ba..c70f607455c 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -233,12 +233,60 @@ struct sk_buff *nfc_alloc_skb(unsigned int size, gfp_t gfp)
}
EXPORT_SYMBOL(nfc_alloc_skb);
+/**
+ * nfc_targets_found - inform that targets were found
+ *
+ * @dev: The nfc device that found the targets
+ * @targets: array of nfc targets found
+ * @ntargets: targets array size
+ *
+ * The device driver must call this function when one or many nfc targets
+ * are found. After calling this function, the device driver must stop
+ * polling for targets.
+ */
+int nfc_targets_found(struct nfc_dev *dev, struct nfc_target *targets,
+ int n_targets)
+{
+ int i;
+
+ nfc_dbg("dev_name=%s n_targets=%d", dev_name(&dev->dev), n_targets);
+
+ dev->polling = false;
+
+ for (i = 0; i < n_targets; i++)
+ targets[i].idx = dev->target_idx++;
+
+ spin_lock_bh(&dev->targets_lock);
+
+ dev->targets_generation++;
+
+ kfree(dev->targets);
+ dev->targets = kmemdup(targets, n_targets * sizeof(struct nfc_target),
+ GFP_ATOMIC);
+
+ if (!dev->targets) {
+ dev->n_targets = 0;
+ spin_unlock_bh(&dev->targets_lock);
+ return -ENOMEM;
+ }
+
+ dev->n_targets = n_targets;
+ spin_unlock_bh(&dev->targets_lock);
+
+ nfc_genl_targets_found(dev);
+
+ return 0;
+}
+EXPORT_SYMBOL(nfc_targets_found);
+
static void nfc_release(struct device *d)
{
struct nfc_dev *dev = to_nfc_dev(d);
nfc_dbg("dev_name=%s", dev_name(&dev->dev));
+ nfc_genl_data_exit(&dev->genl_data);
+ kfree(dev->targets);
kfree(dev);
}
@@ -298,6 +346,12 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
dev->ops = ops;
dev->supported_protocols = supported_protocols;
+ spin_lock_init(&dev->targets_lock);
+ nfc_genl_data_init(&dev->genl_data);
+
+ /* first generation must not be 0 */
+ dev->targets_generation = 1;
+
return dev;
}
EXPORT_SYMBOL(nfc_allocate_device);
@@ -318,7 +372,16 @@ int nfc_register_device(struct nfc_dev *dev)
rc = device_add(&dev->dev);
mutex_unlock(&nfc_devlist_mutex);
- return rc;
+ if (rc < 0)
+ return rc;
+
+ rc = nfc_genl_device_added(dev);
+ if (rc)
+ nfc_dbg("The userspace won't be notified that the device %s was"
+ " added", dev_name(&dev->dev));
+
+
+ return 0;
}
EXPORT_SYMBOL(nfc_register_device);
@@ -329,6 +392,8 @@ EXPORT_SYMBOL(nfc_register_device);
*/
void nfc_unregister_device(struct nfc_dev *dev)
{
+ int rc;
+
nfc_dbg("dev_name=%s", dev_name(&dev->dev));
mutex_lock(&nfc_devlist_mutex);
@@ -341,18 +406,42 @@ void nfc_unregister_device(struct nfc_dev *dev)
device_unlock(&dev->dev);
mutex_unlock(&nfc_devlist_mutex);
+
+ rc = nfc_genl_device_removed(dev);
+ if (rc)
+ nfc_dbg("The userspace won't be notified that the device %s"
+ " was removed", dev_name(&dev->dev));
+
}
EXPORT_SYMBOL(nfc_unregister_device);
static int __init nfc_init(void)
{
+ int rc;
+
nfc_info("NFC Core ver %s", VERSION);
- return class_register(&nfc_class);
+ rc = class_register(&nfc_class);
+ if (rc)
+ return rc;
+
+ rc = nfc_genl_init();
+ if (rc)
+ goto err_genl;
+
+ /* the first generation must not be 0 */
+ nfc_devlist_generation = 1;
+
+ return 0;
+
+err_genl:
+ class_unregister(&nfc_class);
+ return rc;
}
static void __exit nfc_exit(void)
{
+ nfc_genl_exit();
class_unregister(&nfc_class);
}
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
new file mode 100644
index 00000000000..ccdff7953f7
--- /dev/null
+++ b/net/nfc/netlink.c
@@ -0,0 +1,537 @@
+/*
+ * Copyright (C) 2011 Instituto Nokia de Tecnologia
+ *
+ * Authors:
+ * Lauro Ramos Venancio <lauro.venancio@openbossa.org>
+ * Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <net/genetlink.h>
+#include <linux/nfc.h>
+#include <linux/slab.h>
+
+#include "nfc.h"
+
+static struct genl_multicast_group nfc_genl_event_mcgrp = {
+ .name = NFC_GENL_MCAST_EVENT_NAME,
+};
+
+struct genl_family nfc_genl_family = {
+ .id = GENL_ID_GENERATE,
+ .hdrsize = 0,
+ .name = NFC_GENL_NAME,
+ .version = NFC_GENL_VERSION,
+ .maxattr = NFC_ATTR_MAX,
+};
+
+static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
+ [NFC_ATTR_DEVICE_INDEX] = { .type = NLA_U32 },
+ [NFC_ATTR_DEVICE_NAME] = { .type = NLA_STRING,
+ .len = NFC_DEVICE_NAME_MAXSIZE },
+ [NFC_ATTR_PROTOCOLS] = { .type = NLA_U32 },
+};
+
+static int nfc_genl_send_target(struct sk_buff *msg, struct nfc_target *target,
+ struct netlink_callback *cb, int flags)
+{
+ void *hdr;
+
+ nfc_dbg("entry");
+
+ hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
+ &nfc_genl_family, flags, NFC_CMD_GET_TARGET);
+ if (!hdr)
+ return -EMSGSIZE;
+
+ genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
+
+ NLA_PUT_U32(msg, NFC_ATTR_TARGET_INDEX, target->idx);
+ NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS,
+ target->supported_protocols);
+ NLA_PUT_U16(msg, NFC_ATTR_TARGET_SENS_RES, target->sens_res);
+ NLA_PUT_U8(msg, NFC_ATTR_TARGET_SEL_RES, target->sel_res);
+
+ return genlmsg_end(msg, hdr);
+
+nla_put_failure:
+ genlmsg_cancel(msg, hdr);
+ return -EMSGSIZE;
+}
+
+static struct nfc_dev *__get_device_from_cb(struct netlink_callback *cb)
+{
+ struct nfc_dev *dev;
+ int rc;
+ u32 idx;
+
+ rc = nlmsg_parse(cb->nlh, GENL_HDRLEN + nfc_genl_family.hdrsize,
+ nfc_genl_family.attrbuf,
+ nfc_genl_family.maxattr,
+ nfc_genl_policy);
+ if (rc < 0)
+ return ERR_PTR(rc);
+
+ if (!nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX])
+ return ERR_PTR(-EINVAL);
+
+ idx = nla_get_u32(nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX]);
+
+ dev = nfc_get_device(idx);
+ if (!dev)
+ return ERR_PTR(-ENODEV);
+
+ return dev;
+}
+
+static int nfc_genl_dump_targets(struct sk_buff *skb,
+ struct netlink_callback *cb)
+{
+ int i = cb->args[0];
+ struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
+ int rc;
+
+ nfc_dbg("entry");
+
+ if (!dev) {
+ dev = __get_device_from_cb(cb);
+ if (IS_ERR(dev))
+ return PTR_ERR(dev);
+
+ cb->args[1] = (long) dev;
+ }
+
+ spin_lock_bh(&dev->targets_lock);
+
+ cb->seq = dev->targets_generation;
+
+ while (i < dev->n_targets) {
+ rc = nfc_genl_send_target(skb, &dev->targets[i], cb,
+ NLM_F_MULTI);
+ if (rc < 0)
+ break;
+
+ i++;
+ }
+
+ spin_unlock_bh(&dev->targets_lock);
+
+ cb->args[0] = i;
+
+ return skb->len;
+}
+
+static int nfc_genl_dump_targets_done(struct netlink_callback *cb)
+{
+ struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
+
+ nfc_dbg("entry");
+
+ if (dev)
+ nfc_put_device(dev);
+
+ return 0;
+}
+
+int nfc_genl_targets_found(struct nfc_dev *dev)
+{
+ struct sk_buff *msg;
+ void *hdr;
+
+ nfc_dbg("entry");
+
+ dev->genl_data.poll_req_pid = 0;
+
+ msg = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
+ if (!msg)
+ return -ENOMEM;
+
+ hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+ NFC_EVENT_TARGETS_FOUND);
+ if (!hdr)
+ goto free_msg;
+
+ NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+
+ genlmsg_end(msg, hdr);
+
+ return genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);
+
+nla_put_failure:
+ genlmsg_cancel(msg, hdr);
+free_msg:
+ nlmsg_free(msg);
+ return -EMSGSIZE;
+}
+
+int nfc_genl_device_added(struct nfc_dev *dev)
+{
+ struct sk_buff *msg;
+ void *hdr;
+
+ nfc_dbg("entry");
+
+ msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+ NFC_EVENT_DEVICE_ADDED);
+ if (!hdr)
+ goto free_msg;
+
+ NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
+ NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+ NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
+
+ genlmsg_end(msg, hdr);
+
+ genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
+
+ return 0;
+
+nla_put_failure:
+ genlmsg_cancel(msg, hdr);
+free_msg:
+ nlmsg_free(msg);
+ return -EMSGSIZE;
+}
+
+int nfc_genl_device_removed(struct nfc_dev *dev)
+{
+ struct sk_buff *msg;
+ void *hdr;
+
+ nfc_dbg("entry");
+
+ msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+ NFC_EVENT_DEVICE_REMOVED);
+ if (!hdr)
+ goto free_msg;
+
+ NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+
+ genlmsg_end(msg, hdr);
+
+ genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
+
+ return 0;
+
+nla_put_failure:
+ genlmsg_cancel(msg, hdr);
+free_msg:
+ nlmsg_free(msg);
+ return -EMSGSIZE;
+}
+
+static int nfc_genl_send_device(struct sk_buff *msg, struct nfc_dev *dev,
+ u32 pid, u32 seq,
+ struct netlink_callback *cb,
+ int flags)
+{
+ void *hdr;
+
+ nfc_dbg("entry");
+
+ hdr = genlmsg_put(msg, pid, seq, &nfc_genl_family, flags,
+ NFC_CMD_GET_DEVICE);
+ if (!hdr)
+ return -EMSGSIZE;
+
+ if (cb)
+ genl_dump_check_consistent(cb, hdr, &nfc_genl_family);
+
+ NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
+ NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+ NLA_PUT_U32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols);
+
+ return genlmsg_end(msg, hdr);
+
+nla_put_failure:
+ genlmsg_cancel(msg, hdr);
+ return -EMSGSIZE;
+}
+
+static int nfc_genl_dump_devices(struct sk_buff *skb,
+ struct netlink_callback *cb)
+{
+ struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
+ struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
+ bool first_call = false;
+
+ nfc_dbg("entry");
+
+ if (!iter) {
+ first_call = true;
+ iter = kmalloc(sizeof(struct class_dev_iter), GFP_KERNEL);
+ if (!iter)
+ return -ENOMEM;
+ cb->args[0] = (long) iter;
+ }
+
+ mutex_lock(&nfc_devlist_mutex);
+
+ cb->seq = nfc_devlist_generation;
+
+ if (first_call) {
+ nfc_device_iter_init(iter);
+ dev = nfc_device_iter_next(iter);
+ }
+
+ while (dev) {
+ int rc;
+
+ rc = nfc_genl_send_device(skb, dev, NETLINK_CB(cb->skb).pid,
+ cb->nlh->nlmsg_seq,
+ cb, NLM_F_MULTI);
+ if (rc < 0)
+ break;
+
+ dev = nfc_device_iter_next(iter);
+ }
+
+ mutex_unlock(&nfc_devlist_mutex);
+
+ cb->args[1] = (long) dev;
+
+ return skb->len;
+}
+
+static int nfc_genl_dump_devices_done(struct netlink_callback *cb)
+{
+ struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
+
+ nfc_dbg("entry");
+
+ nfc_device_iter_exit(iter);
+ kfree(iter);
+
+ return 0;
+}
+
+static int nfc_genl_get_device(struct sk_buff *skb, struct genl_info *info)
+{
+ struct sk_buff *msg;
+ struct nfc_dev *dev;
+ u32 idx;
+ int rc = -ENOBUFS;
+
+ nfc_dbg("entry");
+
+ if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
+ return -EINVAL;
+
+ idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+
+ dev = nfc_get_device(idx);
+ if (!dev)
+ return -ENODEV;
+
+ msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+ if (!msg) {
+ rc = -ENOMEM;
+ goto out_putdev;
+ }
+
+ rc = nfc_genl_send_device(msg, dev, info->snd_pid, info->snd_seq,
+ NULL, 0);
+ if (rc < 0)
+ goto out_free;
+
+ nfc_put_device(dev);
+
+ return genlmsg_reply(msg, info);
+
+out_free:
+ nlmsg_free(msg);
+out_putdev:
+ nfc_put_device(dev);
+ return rc;
+}
+
+static int nfc_genl_start_poll(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nfc_dev *dev;
+ int rc;
+ u32 idx;
+ u32 protocols;
+
+ nfc_dbg("entry");
+
+ if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
+ !info->attrs[NFC_ATTR_PROTOCOLS])
+ return -EINVAL;
+
+ idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+ protocols = nla_get_u32(info->attrs[NFC_ATTR_PROTOCOLS]);
+
+ dev = nfc_get_device(idx);
+ if (!dev)
+ return -ENODEV;
+
+ mutex_lock(&dev->genl_data.genl_data_mutex);
+
+ rc = nfc_start_poll(dev, protocols);
+ if (!rc)
+ dev->genl_data.poll_req_pid = info->snd_pid;
+
+ mutex_unlock(&dev->genl_data.genl_data_mutex);
+
+ nfc_put_device(dev);
+ return rc;
+}
+
+static int nfc_genl_stop_poll(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nfc_dev *dev;
+ int rc;
+ u32 idx;
+
+ nfc_dbg("entry");
+
+ if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
+ return -EINVAL;
+
+ idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+
+ dev = nfc_get_device(idx);
+ if (!dev)
+ return -ENODEV;
+
+ mutex_lock(&dev->genl_data.genl_data_mutex);
+
+ if (dev->genl_data.poll_req_pid != info->snd_pid) {
+ rc = -EBUSY;
+ goto out;
+ }
+
+ rc = nfc_stop_poll(dev);
+ dev->genl_data.poll_req_pid = 0;
+
+out:
+ mutex_unlock(&dev->genl_data.genl_data_mutex);
+ nfc_put_device(dev);
+ return rc;
+}
+
+static struct genl_ops nfc_genl_ops[] = {
+ {
+ .cmd = NFC_CMD_GET_DEVICE,
+ .doit = nfc_genl_get_device,
+ .dumpit = nfc_genl_dump_devices,
+ .done = nfc_genl_dump_devices_done,
+ .policy = nfc_genl_policy,
+ },
+ {
+ .cmd = NFC_CMD_START_POLL,
+ .doit = nfc_genl_start_poll,
+ .policy = nfc_genl_policy,
+ },
+ {
+ .cmd = NFC_CMD_STOP_POLL,
+ .doit = nfc_genl_stop_poll,
+ .policy = nfc_genl_policy,
+ },
+ {
+ .cmd = NFC_CMD_GET_TARGET,
+ .dumpit = nfc_genl_dump_targets,
+ .done = nfc_genl_dump_targets_done,
+ .policy = nfc_genl_policy,
+ },
+};
+
+static int nfc_genl_rcv_nl_event(struct notifier_block *this,
+ unsigned long event, void *ptr)
+{
+ struct netlink_notify *n = ptr;
+ struct class_dev_iter iter;
+ struct nfc_dev *dev;
+
+ if (event != NETLINK_URELEASE || n->protocol != NETLINK_GENERIC)
+ goto out;
+
+ nfc_dbg("NETLINK_URELEASE event from id %d", n->pid);
+
+ nfc_device_iter_init(&iter);
+ dev = nfc_device_iter_next(&iter);
+
+ while (dev) {
+ mutex_lock(&dev->genl_data.genl_data_mutex);
+ if (dev->genl_data.poll_req_pid == n->pid) {
+ nfc_stop_poll(dev);
+ dev->genl_data.poll_req_pid = 0;
+ }
+ mutex_unlock(&dev->genl_data.genl_data_mutex);
+ dev = nfc_device_iter_next(&iter);
+ }
+
+ nfc_device_iter_exit(&iter);
+
+out:
+ return NOTIFY_DONE;
+}
+
+void nfc_genl_data_init(struct nfc_genl_data *genl_data)
+{
+ genl_data->poll_req_pid = 0;
+ mutex_init(&genl_data->genl_data_mutex);
+}
+
+void nfc_genl_data_exit(struct nfc_genl_data *genl_data)
+{
+ mutex_destroy(&genl_data->genl_data_mutex);
+}
+
+static struct notifier_block nl_notifier = {
+ .notifier_call = nfc_genl_rcv_nl_event,
+};
+
+/**
+ * nfc_genl_init() - Initialize netlink interface
+ *
+ * This initialization function registers the nfc netlink family.
+ */
+int __init nfc_genl_init(void)
+{
+ int rc;
+
+ rc = genl_register_family_with_ops(&nfc_genl_family, nfc_genl_ops,
+ ARRAY_SIZE(nfc_genl_ops));
+ if (rc)
+ return rc;
+
+ rc = genl_register_mc_group(&nfc_genl_family, &nfc_genl_event_mcgrp);
+
+ netlink_register_notifier(&nl_notifier);
+
+ return rc;
+}
+
+/**
+ * nfc_genl_exit() - Deinitialize netlink interface
+ *
+ * This exit function unregisters the nfc netlink family.
+ */
+void nfc_genl_exit(void)
+{
+ netlink_unregister_notifier(&nl_notifier);
+ genl_unregister_family(&nfc_genl_family);
+}
diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h
index 55f83f86fe2..2b31e808e6f 100644
--- a/net/nfc/nfc.h
+++ b/net/nfc/nfc.h
@@ -36,6 +36,17 @@ int nfc_printk(const char *level, const char *fmt, ...);
extern int nfc_devlist_generation;
extern struct mutex nfc_devlist_mutex;
+int __init nfc_genl_init(void);
+void nfc_genl_exit(void);
+
+void nfc_genl_data_init(struct nfc_genl_data *genl_data);
+void nfc_genl_data_exit(struct nfc_genl_data *genl_data);
+
+int nfc_genl_targets_found(struct nfc_dev *dev);
+
+int nfc_genl_device_added(struct nfc_dev *dev);
+int nfc_genl_device_removed(struct nfc_dev *dev);
+
struct nfc_dev *nfc_get_device(unsigned idx);
static inline void nfc_put_device(struct nfc_dev *dev)