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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2021 Aidan MacDonald
*
* 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 "pwm-x1000.h"
#include "clk-x1000.h"
#include "gpio-x1000.h"
#include "system.h"
#include "kernel.h"
#include "x1000/tcu.h"
struct pwm_gpio_data {
int port;
unsigned pin;
int func;
};
struct pwm_state {
int period_ns;
int duty_ns;
int full_ticks;
int half_ticks;
int prescaler;
};
static const struct pwm_gpio_data pwm_gpios[] = {
{GPIO_C, 1 << 25, GPIO_DEVICE(0)},
{GPIO_C, 1 << 26, GPIO_DEVICE(1)},
{GPIO_C, 1 << 27, GPIO_DEVICE(1)},
{GPIO_B, 1 << 6, GPIO_DEVICE(2)},
{GPIO_C, 1 << 24, GPIO_DEVICE(0)},
};
static struct pwm_state pwm_state[] = {
{-1, -1, -1, -1, -1},
{-1, -1, -1, -1, -1},
{-1, -1, -1, -1, -1},
{-1, -1, -1, -1, -1},
{-1, -1, -1, -1, -1},
};
void pwm_init(int chn)
{
/* clear cached state */
struct pwm_state* st = &pwm_state[chn];
st->period_ns = -1;
st->duty_ns = -1;
st->full_ticks = -1;
st->prescaler = -1;
st->prescaler = -1;
/* clear GPIO and disable timer */
const struct pwm_gpio_data* pg = &pwm_gpios[chn];
gpio_config(pg->port, pg->pin, GPIO_OUTPUT(0));
jz_clr(TCU_STOP, 1 << chn);
jz_clr(TCU_ENABLE, 1 << chn);
jz_set(TCU_STOP, 1 << chn);
}
void pwm_set_period(int chn, int period_ns, int duty_ns)
{
struct pwm_state* st = &pwm_state[chn];
unsigned long long tmp;
int full_ticks = st->full_ticks;
int half_ticks = st->half_ticks;
int prescaler = st->prescaler;
if(period_ns != st->period_ns) {
/* calculate full tick period and prescaler */
tmp = clk_get(X1000_CLK_PCLK) / 1000000;
tmp *= period_ns;
tmp /= 1000;
prescaler = 0;
while(tmp > 0xffff && prescaler < 5) {
tmp /= 4;
prescaler += 1;
}
full_ticks = (tmp > 0xffff) ? 0xffff : tmp;
st->period_ns = period_ns;
}
if(duty_ns != st->duty_ns) {
/* calculate half tick value */
tmp = full_ticks;
tmp *= duty_ns;
tmp /= period_ns;
half_ticks = (tmp > 0xffff) ? 0xffff : tmp;
if(half_ticks >= full_ticks)
half_ticks = full_ticks - 1;
st->duty_ns = duty_ns;
}
/* need to clear STOP bit to access timer unit registers */
int was_stopped = !!(jz_read(TCU_STOP) & (1 << chn));
if(was_stopped)
jz_clr(TCU_STOP, 1 << chn);
/* check if timer is currently running */
int was_enabled = !!(jz_read(TCU_ENABLE) & (1 << chn));
int enabled = was_enabled;
if(prescaler != st->prescaler) {
/* must disable timer to change these settings */
if(was_enabled) {
jz_clr(TCU_ENABLE, 1 << chn);
enabled = 0;
}
jz_overwritef(TCU_CTRL(chn), SHUTDOWN_V(GRACEFUL), INIT_LVL(0),
PWM_EN(1), PRESCALE(prescaler), SOURCE_V(PCLK));
REG_TCU_COUNT(chn) = 0;
st->prescaler = prescaler;
}
if(full_ticks != st->full_ticks || half_ticks != st->half_ticks) {
if(enabled) {
/* avoid changing PWM settings in the middle of a cycle,
* because for some reason, that is supposed to be "bad" */
jz_clr(TCU_FLAG, 1 << chn);
while((REG_TCU_FLAG & (1 << chn)) == 0);
}
/* these can be changed while the timer is running */
REG_TCU_CMP_FULL(chn) = full_ticks;
REG_TCU_CMP_HALF(chn) = full_ticks - half_ticks;
st->full_ticks = full_ticks;
st->half_ticks = half_ticks;
}
/* restore the enable/stop state */
if(was_enabled && !enabled)
jz_set(TCU_ENABLE, 1 << chn);
if(was_stopped)
jz_set(TCU_STOP, 1 << chn);
}
void pwm_enable(int chn)
{
/* Start timer */
jz_clr(TCU_STOP, 1 << chn);
jz_set(TCU_ENABLE, 1 << chn);
/* Configure GPIO function */
const struct pwm_gpio_data* pg = &pwm_gpios[chn];
gpio_config(pg->port, pg->pin, pg->func);
}
void pwm_disable(int chn)
{
/* Set GPIO to output 0 */
const struct pwm_gpio_data* pg = &pwm_gpios[chn];
gpio_config(pg->port, pg->pin, GPIO_OUTPUT(0));
/* Stop timer */
jz_clr(TCU_ENABLE, 1 << chn);
jz_set(TCU_STOP, 1 << chn);
}
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