add SR_HWOPT_* documentation

diff --git a/libsigrok.h b/libsigrok.h
index 251a2e4d4d247cf64fa9af12699a1d08f6202a8c..9ee524d93896a8971a8a54eb2025a9ef368bd562 100644 (file)
--- a/libsigrok.h
+++ b/libsigrok.h
@@ -321,13 +321,22 @@ struct sr_hwopt {
 enum {
        SR_HWOPT_DUMMY = 0, /* Used to terminate lists. Must be 0! */
 
-       /** Some drivers cannot detect the exact model they're talking to. */
+       /** Some drivers cannot detect the exact model they're talking to
+        * (may be phased out). */
        SR_HWOPT_MODEL,
 
-       /** Specification on how to connect to a device */
+       /** Specification on how to connect to a device. In combination
+        * with SR_HWOPT_SERIALCOMM, this is a serial port in the form
+        * which makes sense to the operating system (/dev/ttyS0).
+        * Otherwise this specifies a USB device, either in the form of
+        * <bus>.<address> (decimal, e.g. 1.65) or <vendorid>.<productid>
+        * (hexadecimal, e.g. 1d6b.0001). */
        SR_HWOPT_CONN,
 
-       /** Serial communication spec: <data bits><parity><stop bit> e.g. 8n1 */
+       /** Serial communication specification, in the form:
+        *   <speed>/<data bits><parity><stop bit> e.g.9600/ 8n1
+        * This is always an optional parameter, since a driver typically
+        * knows the speed at which the device wants to communicate */
        SR_HWOPT_SERIALCOMM,
 };