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/*
* Generic pwmlib implementation
*
* Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
*
* 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, 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; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <common.h>
#include <errno.h>
#include <malloc.h>
#include <pwm.h>
#include <linux/list.h>
struct pwm_device {
struct pwm_chip *chip;
unsigned long flags;
#define FLAG_REQUESTED 0
#define FLAG_ENABLED 1
struct list_head node;
};
static LIST_HEAD(pwm_list);
static struct pwm_device *_find_pwm(const char *devname)
{
struct pwm_device *pwm;
list_for_each_entry(pwm, &pwm_list, node) {
if (!strcmp(pwm->chip->devname, devname))
return pwm;
}
return NULL;
}
/**
* pwmchip_add() - register a new pwm
* @chip: the pwm
*
* register a new pwm. pwm->devname must be initialized, usually
* from dev_name(dev) from the hardware driver.
*/
int pwmchip_add(struct pwm_chip *chip)
{
struct pwm_device *pwm;
int ret = 0;
if (_find_pwm(chip->devname))
return -EBUSY;
pwm = xzalloc(sizeof(*pwm));
pwm->chip = chip;
list_add_tail(&pwm->node, &pwm_list);
return ret;
}
EXPORT_SYMBOL_GPL(pwmchip_add);
/**
* pwmchip_remove() - remove a pwm
* @chip: the pwm
*
* remove a pwm. This function may return busy if the pwm is still requested.
*/
int pwmchip_remove(struct pwm_chip *chip)
{
struct pwm_device *pwm;
pwm = _find_pwm(chip->devname);
if (!pwm)
return -ENOENT;
if (test_bit(FLAG_REQUESTED, &pwm->flags))
return -EBUSY;
list_del(&pwm->node);
kfree(pwm);
return 0;
}
EXPORT_SYMBOL_GPL(pwmchip_remove);
/*
* pwm_request - request a PWM device
*/
struct pwm_device *pwm_request(const char *devname)
{
struct pwm_device *pwm;
int ret;
pwm = _find_pwm(devname);
if (!pwm)
return NULL;
if (test_bit(FLAG_REQUESTED, &pwm->flags))
return NULL;
if (pwm->chip->ops->request) {
ret = pwm->chip->ops->request(pwm->chip);
if (ret)
return NULL;
}
set_bit(FLAG_REQUESTED, &pwm->flags);
return pwm;
}
EXPORT_SYMBOL_GPL(pwm_request);
/*
* pwm_free - free a PWM device
*/
void pwm_free(struct pwm_device *pwm)
{
if (!test_and_clear_bit(FLAG_REQUESTED, &pwm->flags))
return;
}
EXPORT_SYMBOL_GPL(pwm_free);
/*
* pwm_config - change a PWM device configuration
*/
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
return pwm->chip->ops->config(pwm->chip, duty_ns, period_ns);
}
EXPORT_SYMBOL_GPL(pwm_config);
/*
* pwm_enable - start a PWM output toggling
*/
int pwm_enable(struct pwm_device *pwm)
{
if (!test_and_set_bit(FLAG_ENABLED, &pwm->flags))
return pwm->chip->ops->enable(pwm->chip);
return 0;
}
EXPORT_SYMBOL_GPL(pwm_enable);
/*
* pwm_disable - stop a PWM output toggling
*/
void pwm_disable(struct pwm_device *pwm)
{
if (test_and_clear_bit(FLAG_ENABLED, &pwm->flags))
pwm->chip->ops->disable(pwm->chip);
}
EXPORT_SYMBOL_GPL(pwm_disable);
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