staging: nvec: Add is_event() and size() functions for nvec_msg

Add functions nvec_msg_is_event() and nvec_msg_size() which
do just what the say: tell whether the message is an event,
and getting the size of the message.

Signed-off-by: Julian Andres Klode <jak@jak-linux.org>
Acked-by: Marc Dietrich <marvin24@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
index 17f5abf..8e97e2d 100644 (file)
--- a/drivers/staging/nvec/nvec.c
+++ b/drivers/staging/nvec/nvec.c
@@ -114,6 +114,37 @@ static void nvec_msg_free(struct nvec_chip *nvec, struct nvec_msg *msg)
        atomic_set(&msg->used, 0);
 }
 
+/**
+ * nvec_msg_is_event - Return %true if @msg is an event
+ * @msg: A message
+ */
+static bool nvec_msg_is_event(struct nvec_msg *msg)
+{
+       return msg->data[0] >> 7;
+}
+
+/**
+ * nvec_msg_size - Get the size of a message
+ * @msg: The message to get the size for
+ *
+ * This only works for received messages, not for outgoing messages.
+ */
+static size_t nvec_msg_size(struct nvec_msg *msg)
+{
+       bool is_event = nvec_msg_is_event(msg);
+       int event_length = (msg->data[0] & 0x60) >> 5;
+
+       /* for variable size, payload size in byte 1 + count (1) + cmd (1) */
+       if (!is_event || event_length == NVEC_VAR_SIZE)
+               return (msg->pos || msg->size) ? (msg->data[1] + 2) : 0;
+       else if (event_length == NVEC_2BYTES)
+               return 2;
+       else if (event_length == NVEC_3BYTES)
+               return 3;
+       else
+               return 0;
+}
+
 static void nvec_gpio_set_value(struct nvec_chip *nvec, int value)
 {
        dev_dbg(nvec->dev, "GPIO changed from %u to %u\n",