@@ -89,6 +89,7 @@
* @NFC_CMD_ACTIVATE_TARGET: Request NFC controller to reactivate target.
* @NFC_CMD_VENDOR: Vendor specific command, to be implemented directly
* from the driver in order to support hardware specific operations.
+ * @NFC_CMD_DEACTIVATE_TARGET: Request NFC controller to deactivate target.
*/
enum nfc_commands {
NFC_CMD_UNSPEC,
@@ -121,6 +122,7 @@ enum nfc_commands {
NFC_CMD_SE_IO,
NFC_CMD_ACTIVATE_TARGET,
NFC_CMD_VENDOR,
+ NFC_CMD_DEACTIVATE_TARGET,
/* private: internal use only */
__NFC_CMD_AFTER_LAST
};
@@ -926,6 +926,30 @@ static int nfc_genl_activate_target(struct sk_buff *skb, struct genl_info *info)
return rc;
}
+static int nfc_genl_deactivate_target(struct sk_buff *skb,
+ struct genl_info *info)
+{
+ struct nfc_dev *dev;
+ u32 device_idx, target_idx;
+ int rc;
+
+ if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
+ return -EINVAL;
+
+ device_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+
+ dev = nfc_get_device(device_idx);
+ if (!dev)
+ return -ENODEV;
+
+ target_idx = nla_get_u32(info->attrs[NFC_ATTR_TARGET_INDEX]);
+
+ rc = nfc_deactivate_target(dev, target_idx, NFC_TARGET_MODE_SLEEP);
+
+ nfc_put_device(dev);
+ return rc;
+}
+
static int nfc_genl_dep_link_up(struct sk_buff *skb, struct genl_info *info)
{
struct nfc_dev *dev;
@@ -1749,6 +1773,11 @@ static const struct genl_ops nfc_genl_ops[] = {
.doit = nfc_genl_vendor_cmd,
.policy = nfc_genl_policy,
},
+ {
+ .cmd = NFC_CMD_DEACTIVATE_TARGET,
+ .doit = nfc_genl_deactivate_target,
+ .policy = nfc_genl_policy,
+ },
};
static struct genl_family nfc_genl_family __ro_after_init = {
Once an NFC target (i.e., a tag) is found, it remains active until there is a failure reading or writing it (often caused by the target moving out of range). While the target is active, the NFC adapter and antenna must remain powered. This wastes power when the target remains in range but the client application no longer cares whether it is there or not. To mitigate this, add a new netlink command that allows userspace to deactivate an active target. When issued, this command will cause the NFC subsystem to act as though the target was moved out of range. Once the command has been executed, the client application can power off the NFC adapter to reduce power consumption. Signed-off-by: Mark Greer <mgreer@animalcreek.com> --- I'm not really sure what the correct argument for the mode parameter of digital_activate_target() is. I do not have any NCI controllers to test with. --- include/uapi/linux/nfc.h | 2 ++ net/nfc/netlink.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+)