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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright © 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 "system.h"
#include "kernel.h"
#include "panic.h"
#include "timer.h"
#if INCREASED_SCROLLWHEEL_POLLING
#include "button-target.h"
/* The scrollwheel is polled every 5 ms (the tick tasks only every 10) */
static int poll_scrollwheel = 0;
static inline void do_scrollwheel(void)
{
if (!poll_scrollwheel)
call_tick_tasks(); /* Run through the list of tick tasks
* (that includes reading the scrollwheel) */
else
{
if (!button_hold())
get_scrollwheel(); /* Read the scrollwheel */
}
poll_scrollwheel ^= 1;
}
#else
static inline void do_scrollwheel(void)
{
call_tick_tasks(); /* Run through the list of tick tasks */
}
#endif
#if defined(SANSA_C200V2)
#include "backlight-target.h"
static int timer2_cycles_per_tick = 0;
static int timer2_cycles_pwmon = 0;
static int timer2_cycles_pwmoff = 0;
static int timer2_pwm_state = 0;
static int timer2_pwm_on = 0;
void _set_timer2_pwm_ratio(int ratio)
{
int cycles = timer2_cycles_per_tick;
/*
* Rather arbitrary limits, but since the CPU
* needs some to time in the interrupt handler
* there sure is some limit.
* More specifically, if the cycles needed to do
* the pwm handling are more than the reloaded counter needs
* to reach 0 again it will reload to the old value most
* likely leading to a (slight) slowdown in tick rate.
*/
if (ratio < 10) {
/*
* Permanent off, reduce interrupt rate to save power
*/
TIMER2_BGLOAD = cycles;
timer2_pwm_on = 0;
_backlight_pwm(0);
return;
}
if (ratio > 990) {
/*
* Permanent on, reduce interrupt rate to save power
*/
TIMER2_BGLOAD = cycles;
timer2_pwm_on = 0;
_backlight_pwm(1);
return;
}
timer2_cycles_pwmon = cycles*ratio/1000;
timer2_cycles_pwmoff = cycles*(1000-ratio)/1000;
if (timer2_pwm_on == 0) {
timer2_pwm_state = 0;
timer2_pwm_on = 1;
TIMER2_BGLOAD = timer2_cycles_pwmoff;
}
}
static void set_timer2_cycles_per_tick(int cycles)
{
timer2_cycles_per_tick = cycles;
}
static inline void do_sw_pwm(void)
{
if (!timer2_pwm_on) {
do_scrollwheel(); /* Handle scrollwheel and tick tasks */
return;
}
timer2_pwm_state ^= 1;
if (timer2_pwm_state) {
TIMER2_BGLOAD = timer2_cycles_pwmoff;
_backlight_pwm(1);
/*
* Always do scrollwheel and tick tasks during the longer cycle for safety,
* since the short cycle can be quite short.
* (minimum: 1us if ratio is 10 or 990 or 0.5us with scrollwheel,
* or just about 6000 clock cycles at 60MHz)
*/
if (timer2_cycles_pwmon > timer2_cycles_pwmoff)
do_scrollwheel(); /* Handle scrollwheel and tick tasks */
} else {
TIMER2_BGLOAD = timer2_cycles_pwmon;
_backlight_pwm(0);
if (!(timer2_cycles_pwmon > timer2_cycles_pwmoff))
do_scrollwheel(); /* Handle scrollwheel and tick tasks */
}
}
#else
static inline void do_sw_pwm(void)
{
do_scrollwheel(); /* Handle scrollwheel and tick tasks */
}
static void set_timer2_cycles_per_tick(int cycles)
{
(void)cycles;
}
#endif
void INT_TIMER2(void)
{
/*
* Timer is stacked as follows:
* Lowest layer: Software PWM (if configured)
* Alternates timer2 reload value to implement
* software pwm at 100Hz (no scrollwheel)
* or 200Hz (scrollwheel) with variable pulse width 1% to 99%
* Middle layer: Scrollwheel handling (if configured, 200Hz)
* Alternate between polling scrollwheel and running tick
* tasks (includes scrollwheel polling).
* Top layer: Run tick tasks at 100Hz
*/
do_sw_pwm();
TIMER2_INTCLR = 0; /* clear interrupt */
}
void tick_start(unsigned int interval_in_ms)
{
int cycles = KERNEL_TIMER_FREQ / 1000 * interval_in_ms;
bitset32(&CGU_PERI, CGU_TIMER2_CLOCK_ENABLE); /* enable peripheral */
VIC_INT_ENABLE = INTERRUPT_TIMER2; /* enable interrupt */
set_timer2_cycles_per_tick(cycles);
TIMER2_LOAD = TIMER2_BGLOAD = cycles; /* timer period */
/* /!\ bit 4 (reserved) must not be modified
* periodic mode, interrupt enabled, no prescale, 32 bits counter */
TIMER2_CONTROL = (TIMER2_CONTROL & (1<<4)) |
TIMER_ENABLE |
TIMER_PERIODIC |
TIMER_INT_ENABLE |
TIMER_32_BIT;
}
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