MIPS: JZ4740: Add PWM support
Add support for the PWM part of the timer unit on a JZ4740 SoC. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/1468/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Lars-Peter Clausen
Ralf Baechle
parent
68fcfe7f82
commit
eda0347bf8
1 changed files with 177 additions and 0 deletions
177
arch/mips/jz4740/pwm.c
Normal file
177
arch/mips/jz4740/pwm.c
Normal file
|
|
@ -0,0 +1,177 @@
|
|||
/*
|
||||
* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
|
||||
* JZ4740 platform PWM support
|
||||
*
|
||||
* 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.
|
||||
*
|
||||
* 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.,
|
||||
* 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*
|
||||
*/
|
||||
|
||||
#include <linux/kernel.h>
|
||||
|
||||
#include <linux/clk.h>
|
||||
#include <linux/err.h>
|
||||
#include <linux/pwm.h>
|
||||
#include <linux/gpio.h>
|
||||
|
||||
#include <asm/mach-jz4740/gpio.h>
|
||||
#include "timer.h"
|
||||
|
||||
static struct clk *jz4740_pwm_clk;
|
||||
|
||||
DEFINE_MUTEX(jz4740_pwm_mutex);
|
||||
|
||||
struct pwm_device {
|
||||
unsigned int id;
|
||||
unsigned int gpio;
|
||||
bool used;
|
||||
};
|
||||
|
||||
static struct pwm_device jz4740_pwm_list[] = {
|
||||
{ 2, JZ_GPIO_PWM2, false },
|
||||
{ 3, JZ_GPIO_PWM3, false },
|
||||
{ 4, JZ_GPIO_PWM4, false },
|
||||
{ 5, JZ_GPIO_PWM5, false },
|
||||
{ 6, JZ_GPIO_PWM6, false },
|
||||
{ 7, JZ_GPIO_PWM7, false },
|
||||
};
|
||||
|
||||
struct pwm_device *pwm_request(int id, const char *label)
|
||||
{
|
||||
int ret = 0;
|
||||
struct pwm_device *pwm;
|
||||
|
||||
if (id < 2 || id > 7 || !jz4740_pwm_clk)
|
||||
return ERR_PTR(-ENODEV);
|
||||
|
||||
mutex_lock(&jz4740_pwm_mutex);
|
||||
|
||||
pwm = &jz4740_pwm_list[id - 2];
|
||||
if (pwm->used)
|
||||
ret = -EBUSY;
|
||||
else
|
||||
pwm->used = true;
|
||||
|
||||
mutex_unlock(&jz4740_pwm_mutex);
|
||||
|
||||
if (ret)
|
||||
return ERR_PTR(ret);
|
||||
|
||||
ret = gpio_request(pwm->gpio, label);
|
||||
|
||||
if (ret) {
|
||||
printk(KERN_ERR "Failed to request pwm gpio: %d\n", ret);
|
||||
pwm->used = false;
|
||||
return ERR_PTR(ret);
|
||||
}
|
||||
|
||||
jz_gpio_set_function(pwm->gpio, JZ_GPIO_FUNC_PWM);
|
||||
|
||||
jz4740_timer_start(id);
|
||||
|
||||
return pwm;
|
||||
}
|
||||
|
||||
void pwm_free(struct pwm_device *pwm)
|
||||
{
|
||||
pwm_disable(pwm);
|
||||
jz4740_timer_set_ctrl(pwm->id, 0);
|
||||
|
||||
jz_gpio_set_function(pwm->gpio, JZ_GPIO_FUNC_NONE);
|
||||
gpio_free(pwm->gpio);
|
||||
|
||||
jz4740_timer_stop(pwm->id);
|
||||
|
||||
pwm->used = false;
|
||||
}
|
||||
|
||||
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
|
||||
{
|
||||
unsigned long long tmp;
|
||||
unsigned long period, duty;
|
||||
unsigned int prescaler = 0;
|
||||
unsigned int id = pwm->id;
|
||||
uint16_t ctrl;
|
||||
bool is_enabled;
|
||||
|
||||
if (duty_ns < 0 || duty_ns > period_ns)
|
||||
return -EINVAL;
|
||||
|
||||
tmp = (unsigned long long)clk_get_rate(jz4740_pwm_clk) * period_ns;
|
||||
do_div(tmp, 1000000000);
|
||||
period = tmp;
|
||||
|
||||
while (period > 0xffff && prescaler < 6) {
|
||||
period >>= 2;
|
||||
++prescaler;
|
||||
}
|
||||
|
||||
if (prescaler == 6)
|
||||
return -EINVAL;
|
||||
|
||||
tmp = (unsigned long long)period * duty_ns;
|
||||
do_div(tmp, period_ns);
|
||||
duty = period - tmp;
|
||||
|
||||
if (duty >= period)
|
||||
duty = period - 1;
|
||||
|
||||
is_enabled = jz4740_timer_is_enabled(id);
|
||||
if (is_enabled)
|
||||
pwm_disable(pwm);
|
||||
|
||||
jz4740_timer_set_count(id, 0);
|
||||
jz4740_timer_set_duty(id, duty);
|
||||
jz4740_timer_set_period(id, period);
|
||||
|
||||
ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT |
|
||||
JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;
|
||||
|
||||
jz4740_timer_set_ctrl(id, ctrl);
|
||||
|
||||
if (is_enabled)
|
||||
pwm_enable(pwm);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
int pwm_enable(struct pwm_device *pwm)
|
||||
{
|
||||
uint32_t ctrl = jz4740_timer_get_ctrl(pwm->id);
|
||||
|
||||
ctrl |= JZ_TIMER_CTRL_PWM_ENABLE;
|
||||
jz4740_timer_set_ctrl(pwm->id, ctrl);
|
||||
jz4740_timer_enable(pwm->id);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
void pwm_disable(struct pwm_device *pwm)
|
||||
{
|
||||
uint32_t ctrl = jz4740_timer_get_ctrl(pwm->id);
|
||||
|
||||
ctrl &= ~JZ_TIMER_CTRL_PWM_ENABLE;
|
||||
jz4740_timer_disable(pwm->id);
|
||||
jz4740_timer_set_ctrl(pwm->id, ctrl);
|
||||
}
|
||||
|
||||
static int __init jz4740_pwm_init(void)
|
||||
{
|
||||
int ret = 0;
|
||||
|
||||
jz4740_pwm_clk = clk_get(NULL, "ext");
|
||||
|
||||
if (IS_ERR(jz4740_pwm_clk)) {
|
||||
ret = PTR_ERR(jz4740_pwm_clk);
|
||||
jz4740_pwm_clk = NULL;
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
subsys_initcall(jz4740_pwm_init);
|
||||
Loading…
Reference in a new issue