u-boot/arch/arm/cpu/armv7/s5p-common/pwm.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

170 lines
3.5 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2011 Samsung Electronics
*
* Donghwa Lee <dh09.lee@samsung.com>
*/
#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_SEC 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 frequency;
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_SEC || duty_ns > NS_IN_SEC || period_ns == 0)
return -ERANGE;
if (duty_ns > period_ns)
return -EINVAL;
frequency = NS_IN_SEC / period_ns;
/* Check to see if we are changing the clock rate of the PWM */
tin_rate = pwm_calc_tin(pwm_id, frequency);
tin_ns = NS_IN_SEC / tin_rate;
tcnt = period_ns / tin_ns;
/* Note, counters count down */
tcmp = duty_ns / tin_ns;
tcmp = tcnt - tcmp;
/* 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;
}