plugins: add README explaining plugin relationships

plugins/README.txt

@@ -0,0 +1,155 @@
+
+The following list shows the relationship among the different plugins provided
+by default by ModemManager. For each of the plugin types, the list of modem
+objects created by the plugin is given.
+
+ * Altair:
+   ** MMBroadbandModemAltairLte
+
+ * Anydata:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemAnydata
+
+ * Cinterion:
+   ** MMBroadbandModemQmiCinterion
+   ** MMBroadbandModemCinterion
+
+ * Dell:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemFoxconnT77w968    (from the Foxconn utils)
+   ** MMBroadbandModemMbimXmm           (from the XMM utils)
+   ** MMBroadbandModemMbim              (generic)
+   ** MMBroadbandModemNovatel           (from the Novatel utils)
+   ** MMBroadbandModemSierra            (from the Sierra Legacy utils)
+   ** MMBroadbandModemTelit             (from the Telit utils)
+   ** MMBroadbandModemXmm               (from the XMM utils)
+   ** MMBroadbandModem                  (generic)
+
+ * D-Link:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModem                  (generic)
+
+ * Fibocom:
+   ** MMBroadbandModemMbimXmm           (from the XMM utils)
+   ** MMBroadbandModemMbim              (generic)
+   ** MMBroadbandModemXmm               (from the XMM utils)
+   ** MMBroadbandModem                  (generic)
+
+ * Foxconn:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemFoxconnT77w968
+   ** MMBroadbandModemMbim              (generic)
+   ** MMBroadbandModem                  (generic)
+
+ * Generic:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemMbim              (generic)
+   ** MMBroadbandModem                  (generic)
+
+ * Haier:
+   ** MMBroadbandModem                  (generic)
+
+ * Huawei:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemMbim              (generic)
+   ** MMBroadbandModemHuawei
+
+ * Icera (no explicit plugin):
+   ** MMBroadbandModemIcera
+
+ * Iridium:
+   ** MMBroadbandModemIridium
+
+ * Linktop:
+   ** MMBroadbandModemLinktop
+
+ * Longcheer:
+   ** MMBroadbandModemLongcheer
+
+ * MBM:
+   ** MMBroadbandModemMbim              (generic)
+   ** MMBroadbandModemMbm
+
+ * Motorola:
+   ** MMBroadbandModemMotorola
+
+ * Mtk:
+   ** MMBroadbandModemMtk
+
+ * Nokia:
+   ** MMBroadbandModemNokia
+
+ * Nokia Icera:
+   ** MMBroadbandModemIcera             (from the Icera utils)
+
+ * Novatel:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemNovatel
+
+ * Novatel LTE:
+   ** MMBroadbandModemNovatelLte
+
+ * Option:
+   ** MMBroadbandModemOption
+
+ * Option HSO:
+   ** MMBroadbandModemHso
+
+ * Pantech:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemPantech
+
+ * Quectel:
+   ** MMBroadbandModemQmiQuectel
+   ** MMBroadbandModemQuectel
+
+ * Samsung:
+   ** MMBroadbandModemSamsung           (subclassed from the Icera utils)
+
+ * Sierra Legacy:
+   ** MMBroadbandModemSierraIcera       (subclassed from the Icera utils)
+   ** MMBroadbandModemSierra
+
+ * Sierra:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemMbim              (generic)
+   ** MMBroadbandModem                  (generic)
+
+ * Simtech:
+   ** MMBroadbandModemQmiSimtech
+   ** MMBroadbandModemSimtech
+
+ * Telit:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemMbimTelit
+   ** MMBroadbandModemTelit
+
+ * Thuraya
+   ** MMBroadbandModemThuraya
+
+ * TP-Link:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModem                  (generic)
+
+ * u-blox:
+   ** MMBroadbandModemUblox
+
+ * via:
+   ** MMBroadbandModemVia
+
+ * wavecom:
+   ** MMBroadbandModemWavecom
+
+ * x22x:
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemX22x
+
+ * XMM (no explicit plugin):
+   ** MMBroadbandModemMbimXmm
+   ** MMBroadbandModemXmm
+
+ * ZTE
+   ** MMBroadbandModemQmi               (generic)
+   ** MMBroadbandModemMbim              (generic)
+   ** MMBroadbandModemZteIcera          (subclassed from the Icera utils)
+   ** MMBroadbandModemZte