From 0eeccefbb69a71677b736d339db184bd4224d5c8 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Lothar=20Wa=C3=9Fmann?= <LW@KARO-electronics.de>
Date: Mon, 27 Aug 2012 09:17:48 +0200
Subject: [PATCH] add description of board specific environment variables

---
 README.KARO-TX53 | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/README.KARO-TX53 b/README.KARO-TX53
index 92ad39a462..2150204d91 100644
--- a/README.KARO-TX53
+++ b/README.KARO-TX53
@@ -1,5 +1,5 @@
-                             Building & Flashing U-Boot for TX53
-                             ===================================
+                                        U-Boot for TX53
+                                        ===============
 
 Building U-Boot
 ---------------
@@ -34,3 +34,32 @@ nand erase.part u-boot;nand write ${fileaddr} u-boot ${filesize}
 
 If you want to revive a bricked module, you can use one of the
 flashtools provided with the BSP to reprogram the flash.
+
+
+U-Boot Features
+---------------
+
+Environment variables:
+
+cpu_clk       <CPU freq [MHz]>
+touchpanel    {tsc2007|edt-ft5x06}
+otg_mode      [host|device|none]
+video_mode    <video mode as understood by Linux fb_find_mode() function>
+              e.g.: VGA-1:640x480MR-24@60
+baseboard     {stk5-v3|stk5-v5} selects type of baseboard
+	      'stk5-v5' setting enables CAN transceiver switch on GPIO4_21 and
+	      disables USB Host mode on USBOTG port.
+	      strings not starting in 'stk5' prevent the STK5 specific
+	      pad initialization to be done.
+splashimage   memory address of a BMP file to be displayed instead of
+	      the built-in logo. Since NAND flash is not accessible in
+	      a memory mapped fashion, U-Boot will try to load the
+	      contents of the flash partition 'logo' to the address
+	      given with 'splashimage'.
+
+Note: Some variables (like 'cpu_clk' or 'splashimage') may render the
+      board unbootable if incorrectly set. Therefore these variables
+      will not be evaluated in case the board has been reset through a
+      watchdog reset or a character is available on the serial console
+      during startup to give the user a chance to recover from this
+      situation.
-- 
2.39.2