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authorBertrik Sikken <bertrik@sikken.nl>2009-07-12 10:44:02 +0000
committerBertrik Sikken <bertrik@sikken.nl>2009-07-12 10:44:02 +0000
commit61394b725bfa6ace86a293c4a98dcb44e76c2ee3 (patch)
tree2764edd73e3ec623b296f211869a21638efd2fb1 /firmware/target/arm
parent8029bee2fe175091bf1d889b5c892c67a150b0fb (diff)
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S5L8700: implement timer driver
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21801 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware/target/arm')
-rw-r--r--firmware/target/arm/s5l8700/timer-s5l8700.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/firmware/target/arm/s5l8700/timer-s5l8700.c b/firmware/target/arm/s5l8700/timer-s5l8700.c
new file mode 100644
index 0000000000..f9bef1c956
--- /dev/null
+++ b/firmware/target/arm/s5l8700/timer-s5l8700.c
@@ -0,0 +1,104 @@
+/***************************************************************************
+* __________ __ ___.
+* Open \______ \ ____ ____ | | _\_ |__ _______ ___
+* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+* \/ \/ \/ \/ \/
+* $Id$
+*
+* Copyright (C) 2008 Rafaël Carré
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License
+* as published by the Free Software Foundation; either version 2
+* of the License, or (at your option) any later version.
+*
+* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+* KIND, either express or implied.
+*
+****************************************************************************/
+
+#include "config.h"
+
+#include "inttypes.h"
+#include "s5l8700.h"
+#include "system.h"
+#include "timer.h"
+
+/* Timer driver for the S5L8700
+
+ The S5L8700 timer resolution is only 16-bit. Larger counts are done by using
+ both the clock-select and the clock prescaler to bring the count down into
+ the range of the 16-bit counter.
+
+ TODO: investigate why the timer seems to count twice as fast as expected
+*/
+
+void INT_TIMERD(void)
+{
+ /* clear interrupt */
+ TDCON = TDCON;
+
+ if (pfn_timer != NULL) {
+ pfn_timer();
+ }
+}
+
+bool timer_set(long cycles, bool start)
+{
+ static const int cs_table[] = {1, 2, 4, 6};
+ int prescale, cs;
+ long count;
+
+ /* stop and clear timer */
+ TDCMD = (1 << 1); /* TD_CLR */
+
+ /* optionally unregister any previously registered timer user */
+ if (start) {
+ if (pfn_unregister != NULL) {
+ pfn_unregister();
+ pfn_unregister = NULL;
+ }
+ }
+
+ /* scale the count down with the clock select */
+ for (cs = 0; cs < 4; cs++) {
+ count = cycles >> cs_table[cs];
+ if ((count < 65536) || (cs == 3)) {
+ break;
+ }
+ }
+
+ /* scale the count down with the prescaler */
+ prescale = 1;
+ while (count >= 65536) {
+ count >>= 1;
+ prescale <<= 1;
+ }
+
+ /* configure timer */
+ TDCON = (1 << 12) | /* TD_INT0_EN */
+ (cs << 8) | /* TS_CS */
+ (0 << 4); /* TD_MODE_SEL, 0 = interval mode */
+ TDPRE = prescale - 1;
+ TDDATA0 = count;
+ TDCMD = (1 << 0); /* TD_ENABLE */
+
+ /* enable interrupt */
+ INTMSK |= (1 << 9);
+
+ return true;
+}
+
+bool timer_start(void)
+{
+ TDCMD = (1 << 0); /* TD_ENABLE */
+ return true;
+}
+
+void timer_stop(void)
+{
+ TDCMD = (0 << 0); /* TD_ENABLE */
+}
+