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/*
* Copyright (C) 2011 Samsung Electronics
*
* Donghwa Lee <dh09.lee@samsung.com>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <errno.h>
#include <pwm.h>
#include <asm/io.h>
#include <asm/arch/pwm.h>
#include <asm/arch/clk.h>
int pwm_enable(int pwm_id)
{
const struct s5p_timer *pwm =
(struct s5p_timer *)samsung_get_base_timer();
unsigned long tcon;
tcon = readl(&pwm->tcon);
tcon |= TCON_START(pwm_id);
writel(tcon, &pwm->tcon);
return 0;
}
void pwm_disable(int pwm_id)
{
const struct s5p_timer *pwm =
(struct s5p_timer *)samsung_get_base_timer();
unsigned long tcon;
tcon = readl(&pwm->tcon);
tcon &= ~TCON_START(pwm_id);
writel(tcon, &pwm->tcon);
}
static unsigned long pwm_calc_tin(int pwm_id, unsigned long freq)
{
unsigned long tin_parent_rate;
unsigned int div;
tin_parent_rate = get_pwm_clk();
for (div = 2; div <= 16; div *= 2) {
if ((tin_parent_rate / (div << 16)) < freq)
return tin_parent_rate / div;
}
return tin_parent_rate / 16;
}
#define NS_IN_HZ (1000000000UL)
int pwm_config(int pwm_id, int duty_ns, int period_ns)
{
const struct s5p_timer *pwm =
(struct s5p_timer *)samsung_get_base_timer();
unsigned int offset;
unsigned long tin_rate;
unsigned long tin_ns;
unsigned long period;
unsigned long tcon;
unsigned long tcnt;
unsigned long tcmp;
/*
* We currently avoid using 64bit arithmetic by using the
* fact that anything faster than 1GHz is easily representable
* by 32bits.
*/
if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
return -ERANGE;
if (duty_ns > period_ns)
return -EINVAL;
period = NS_IN_HZ / period_ns;
/* Check to see if we are changing the clock rate of the PWM */
tin_rate = pwm_calc_tin(pwm_id, period);
tin_ns = NS_IN_HZ / tin_rate;
tcnt = period_ns / tin_ns;
/* Note, counters count down */
tcmp = duty_ns / tin_ns;
tcmp = tcnt - tcmp;
/*
* the pwm hw only checks the compare register after a decrement,
* so the pin never toggles if tcmp = tcnt
*/
if (tcmp == tcnt)
tcmp--;
if (tcmp < 0)
tcmp = 0;
/* Update the PWM register block. */
offset = pwm_id * 3;
if (pwm_id < 4) {
writel(tcnt, &pwm->tcntb0 + offset);
writel(tcmp, &pwm->tcmpb0 + offset);
}
tcon = readl(&pwm->tcon);
tcon |= TCON_UPDATE(pwm_id);
if (pwm_id < 4)
tcon |= TCON_AUTO_RELOAD(pwm_id);
else
tcon |= TCON4_AUTO_RELOAD;
writel(tcon, &pwm->tcon);
tcon &= ~TCON_UPDATE(pwm_id);
writel(tcon, &pwm->tcon);
return 0;
}
int pwm_init(int pwm_id, int div, int invert)
{
u32 val;
const struct s5p_timer *pwm =
(struct s5p_timer *)samsung_get_base_timer();
unsigned long ticks_per_period;
unsigned int offset, prescaler;
/*
* Timer Freq(HZ) =
* PWM_CLK / { (prescaler_value + 1) * (divider_value) }
*/
val = readl(&pwm->tcfg0);
if (pwm_id < 2) {
prescaler = PRESCALER_0;
val &= ~0xff;
val |= (prescaler & 0xff);
} else {
prescaler = PRESCALER_1;
val &= ~(0xff << 8);
val |= (prescaler & 0xff) << 8;
}
writel(val, &pwm->tcfg0);
val = readl(&pwm->tcfg1);
val &= ~(0xf << MUX_DIV_SHIFT(pwm_id));
val |= (div & 0xf) << MUX_DIV_SHIFT(pwm_id);
writel(val, &pwm->tcfg1);
if (pwm_id == 4) {
/*
* TODO(sjg): Use this as a countdown timer for now. We count
* down from the maximum value to 0, then reset.
*/
ticks_per_period = -1UL;
} else {
const unsigned long pwm_hz = 1000;
unsigned long timer_rate_hz = get_pwm_clk() /
((prescaler + 1) * (1 << div));
ticks_per_period = timer_rate_hz / pwm_hz;
}
/* set count value */
offset = pwm_id * 3;
writel(ticks_per_period, &pwm->tcntb0 + offset);
val = readl(&pwm->tcon) & ~(0xf << TCON_OFFSET(pwm_id));
if (invert && (pwm_id < 4))
val |= TCON_INVERTER(pwm_id);
writel(val, &pwm->tcon);
pwm_enable(pwm_id);
return 0;
}
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