From f7dce91bb84cdefe69eba8be24462c5eef4503f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Mon, 9 Dec 2019 19:45:03 +0100
Subject: [PATCH] usb_cables: minor, add doc

---
 usb_cables.h | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/usb_cables.h b/usb_cables.h
index 29c5367..6e7bea9 100644
--- a/usb_cables.h
+++ b/usb_cables.h
@@ -18,14 +18,15 @@
  *  @date 2019
  */
 
+/** the USB pin type */
 enum usb_pin_type_t {
-	USB_PIN_TYPE_UNKNOWN,
-	USB_PIN_TYPE_GROUND,
-	USB_PIN_TYPE_POWER,
-	USB_PIN_TYPE_SHIELD,
-	USB_PIN_TYPE_DIFFERENTIAL,
-	USB_PIN_TYPE_IDENTIFICATION,
-	USB_PIN_TYPE_OTHER,
+	USB_PIN_TYPE_UNDEFINED, /*< the default type, undefined */
+	USB_PIN_TYPE_GROUND, /*< ground (including ground drain) */
+	USB_PIN_TYPE_POWER, /*< power (VBUS) */
+	USB_PIN_TYPE_SHIELD, /*< shield */
+	USB_PIN_TYPE_DIFFERENTIAL, /*< differential data pairs (D+/-, SSTX+/-, SSRX+/-) */
+	USB_PIN_TYPE_IDENTIFICATION, /*< pin to identify type (often connected to power or ground through resistor) */
+	USB_PIN_TYPE_OTHER, /*< any other type */
 };
 
 /** the type of connection between two pins