[openfirmware] [commit] r2371 - in cpu/arm: mmp2 olpc/1.75

[repository service]

Author: wmb
Date: Fri Jul 15 10:20:04 2011
New Revision: 2371
URL: http://tracker.coreboot.org/trac/openfirmware/changeset/2371

Log:
OLPC XO-1.75 - Slow down TWSI clock for accelerometer.

Modified:
   cpu/arm/mmp2/twsi.fth
   cpu/arm/olpc/1.75/accelerometer.fth

Modified: cpu/arm/mmp2/twsi.fth
==============================================================================
--- cpu/arm/mmp2/twsi.fth	Fri Jul 15 08:59:50 2011	(r2370)
+++ cpu/arm/mmp2/twsi.fth	Fri Jul 15 10:20:04 2011	(r2371)
@@ -158,6 +158,11 @@
    twsi-get
 ;
 
+d# 12,600,000 constant numerator
+: set-bus-speed  ( hz -- )  \ Useful range is currently 25,000 .. 100,000
+   child-address set-twsi-target
+   numerator swap /  h# 1ff min  h# 7e max  lcr!
+;
 : decode-unit  ( adr len -- low high )  parse-2int  ;
 : encode-unit  ( low high -- adr len )  >r <# u#s drop [char] , hold r> u#s u#>  ;
 end-package

Modified: cpu/arm/olpc/1.75/accelerometer.fth
==============================================================================
--- cpu/arm/olpc/1.75/accelerometer.fth	Fri Jul 15 08:59:50 2011	(r2370)
+++ cpu/arm/olpc/1.75/accelerometer.fth	Fri Jul 15 10:20:04 2011	(r2371)
@@ -47,6 +47,7 @@
 : delay  ( -- )  d# 30 ms  ;
 : open  ( -- flag )
    my-address my-space " set-address" $call-parent
+   d# 25,000 " set-bus-speed" $call-parent
    ['] accelerometer-on catch 0=   
 ;
 : close  ( -- )