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/*
* Generic pwmlib implementation
*
* Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
* Copyright (C) 2011-2012 Avionic Design GmbH
*
* 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 <linux/module.h>
#include <linux/pwm.h>
#include <linux/radix-tree.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#define MAX_PWMS 1024
static DEFINE_MUTEX(pwm_lock);
static LIST_HEAD(pwm_chips);
static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
static RADIX_TREE(pwm_tree, GFP_KERNEL);
static struct pwm_device *pwm_to_device(unsigned int pwm)
{
return radix_tree_lookup(&pwm_tree, pwm);
}
static int alloc_pwms(int pwm, unsigned int count)
{
unsigned int from = 0;
unsigned int start;
if (pwm >= MAX_PWMS)
return -EINVAL;
if (pwm >= 0)
from = pwm;
start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
count, 0);
if (pwm >= 0 && start != pwm)
return -EEXIST;
if (start + count > MAX_PWMS)
return -ENOSPC;
return start;
}
static void free_pwms(struct pwm_chip *chip)
{
unsigned int i;
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
radix_tree_delete(&pwm_tree, pwm->pwm);
}
bitmap_clear(allocated_pwms, chip->base, chip->npwm);
kfree(chip->pwms);
chip->pwms = NULL;
}
static int pwm_device_request(struct pwm_device *pwm, const char *label)
{
int err;
if (test_bit(PWMF_REQUESTED, &pwm->flags))
return -EBUSY;
if (!try_module_get(pwm->chip->ops->owner))
return -ENODEV;
if (pwm->chip->ops->request) {
err = pwm->chip->ops->request(pwm->chip, pwm);
if (err) {
module_put(pwm->chip->ops->owner);
return err;
}
}
set_bit(PWMF_REQUESTED, &pwm->flags);
pwm->label = label;
return 0;
}
/**
* pwm_set_chip_data() - set private chip data for a PWM
* @pwm: PWM device
* @data: pointer to chip-specific data
*/
int pwm_set_chip_data(struct pwm_device *pwm, void *data)
{
if (!pwm)
return -EINVAL;
pwm->chip_data = data;
return 0;
}
/**
* pwm_get_chip_data() - get private chip data for a PWM
* @pwm: PWM device
*/
void *pwm_get_chip_data(struct pwm_device *pwm)
{
return pwm ? pwm->chip_data : NULL;
}
/**
* pwmchip_add() - register a new PWM chip
* @chip: the PWM chip to add
*
* Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
* will be used.
*/
int pwmchip_add(struct pwm_chip *chip)
{
struct pwm_device *pwm;
unsigned int i;
int ret;
if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
!chip->ops->enable || !chip->ops->disable)
return -EINVAL;
mutex_lock(&pwm_lock);
ret = alloc_pwms(chip->base, chip->npwm);
if (ret < 0)
goto out;
chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
if (!chip->pwms) {
ret = -ENOMEM;
goto out;
}
chip->base = ret;
for (i = 0; i < chip->npwm; i++) {
pwm = &chip->pwms[i];
pwm->chip = chip;
pwm->pwm = chip->base + i;
pwm->hwpwm = i;
radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
}
bitmap_set(allocated_pwms, chip->base, chip->npwm);
INIT_LIST_HEAD(&chip->list);
list_add(&chip->list, &pwm_chips);
ret = 0;
out:
mutex_unlock(&pwm_lock);
return ret;
}
EXPORT_SYMBOL_GPL(pwmchip_add);
/**
* pwmchip_remove() - remove a PWM chip
* @chip: the PWM chip to remove
*
* Removes a PWM chip. This function may return busy if the PWM chip provides
* a PWM device that is still requested.
*/
int pwmchip_remove(struct pwm_chip *chip)
{
unsigned int i;
int ret = 0;
mutex_lock(&pwm_lock);
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
ret = -EBUSY;
goto out;
}
}
list_del_init(&chip->list);
free_pwms(chip);
out:
mutex_unlock(&pwm_lock);
return ret;
}
EXPORT_SYMBOL_GPL(pwmchip_remove);
/**
* pwm_request() - request a PWM device
* @pwm_id: global PWM device index
* @label: PWM device label
*/
struct pwm_device *pwm_request(int pwm, const char *label)
{
struct pwm_device *dev;
int err;
if (pwm < 0 || pwm >= MAX_PWMS)
return ERR_PTR(-EINVAL);
mutex_lock(&pwm_lock);
dev = pwm_to_device(pwm);
if (!dev) {
dev = ERR_PTR(-EPROBE_DEFER);
goto out;
}
err = pwm_device_request(dev, label);
if (err < 0)
dev = ERR_PTR(err);
out:
mutex_unlock(&pwm_lock);
return dev;
}
EXPORT_SYMBOL_GPL(pwm_request);
/**
* pwm_request_from_chip() - request a PWM device relative to a PWM chip
* @chip: PWM chip
* @index: per-chip index of the PWM to request
* @label: a literal description string of this PWM
*
* Returns the PWM at the given index of the given PWM chip. A negative error
* code is returned if the index is not valid for the specified PWM chip or
* if the PWM device cannot be requested.
*/
struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
unsigned int index,
const char *label)
{
struct pwm_device *pwm;
int err;
if (!chip || index >= chip->npwm)
return ERR_PTR(-EINVAL);
mutex_lock(&pwm_lock);
pwm = &chip->pwms[index];
err = pwm_device_request(pwm, label);
if (err < 0)
pwm = ERR_PTR(err);
mutex_unlock(&pwm_lock);
return pwm;
}
EXPORT_SYMBOL_GPL(pwm_request_from_chip);
/**
* pwm_free() - free a PWM device
* @pwm: PWM device
*/
void pwm_free(struct pwm_device *pwm)
{
mutex_lock(&pwm_lock);
if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
pr_warning("PWM device already freed\n");
goto out;
}
if (pwm->chip->ops->free)
pwm->chip->ops->free(pwm->chip, pwm);
pwm->label = NULL;
module_put(pwm->chip->ops->owner);
out:
mutex_unlock(&pwm_lock);
}
EXPORT_SYMBOL_GPL(pwm_free);
/**
* pwm_config() - change a PWM device configuration
* @pwm: PWM device
* @duty_ns: "on" time (in nanoseconds)
* @period_ns: duration (in nanoseconds) of one cycle
*/
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
if (!pwm || period_ns == 0 || duty_ns > period_ns)
return -EINVAL;
return pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
}
EXPORT_SYMBOL_GPL(pwm_config);
/**
* pwm_enable() - start a PWM output toggling
* @pwm: PWM device
*/
int pwm_enable(struct pwm_device *pwm)
{
if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
return pwm->chip->ops->enable(pwm->chip, pwm);
return pwm ? 0 : -EINVAL;
}
EXPORT_SYMBOL_GPL(pwm_enable);
/**
* pwm_disable() - stop a PWM output toggling
* @pwm: PWM device
*/
void pwm_disable(struct pwm_device *pwm)
{
if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
pwm->chip->ops->disable(pwm->chip, pwm);
}
EXPORT_SYMBOL_GPL(pwm_disable);
#ifdef CONFIG_DEBUG_FS
static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
{
unsigned int i;
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
if (test_bit(PWMF_REQUESTED, &pwm->flags))
seq_printf(s, " requested");
if (test_bit(PWMF_ENABLED, &pwm->flags))
seq_printf(s, " enabled");
seq_printf(s, "\n");
}
}
static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
{
mutex_lock(&pwm_lock);
s->private = "";
return seq_list_start(&pwm_chips, *pos);
}
static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
s->private = "\n";
return seq_list_next(v, &pwm_chips, pos);
}
static void pwm_seq_stop(struct seq_file *s, void *v)
{
mutex_unlock(&pwm_lock);
}
static int pwm_seq_show(struct seq_file *s, void *v)
{
struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
chip->dev->bus ? chip->dev->bus->name : "no-bus",
dev_name(chip->dev), chip->npwm,
(chip->npwm != 1) ? "s" : "");
if (chip->ops->dbg_show)
chip->ops->dbg_show(chip, s);
else
pwm_dbg_show(chip, s);
return 0;
}
static const struct seq_operations pwm_seq_ops = {
.start = pwm_seq_start,
.next = pwm_seq_next,
.stop = pwm_seq_stop,
.show = pwm_seq_show,
};
static int pwm_seq_open(struct inode *inode, struct file *file)
{
return seq_open(file, &pwm_seq_ops);
}
static const struct file_operations pwm_debugfs_ops = {
.owner = THIS_MODULE,
.open = pwm_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init pwm_debugfs_init(void)
{
debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
&pwm_debugfs_ops);
return 0;
}
subsys_initcall(pwm_debugfs_init);
#endif /* CONFIG_DEBUG_FS */