/*
* 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>
#include <dt-bindings/pwm/pwm.h>
#define MAX_PWMS 1024
static DEFINE_MUTEX(pwm_lookup_lock);
static LIST_HEAD(pwm_lookup_list);
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 struct pwm_chip *pwmchip_find_by_name(const char *name)
{
struct pwm_chip *chip;
if (!name)
return NULL;
mutex_lock(&pwm_lock);
list_for_each_entry(chip, &pwm_chips, list) {
const char *chip_name = dev_name(chip->dev);
if (chip_name && strcmp(chip_name, name) == 0) {
mutex_unlock(&pwm_lock);
return chip;
}
}
mutex_unlock(&pwm_lock);
return 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;
}
struct pwm_device *
of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
if (pc->of_pwm_n_cells < 3)
return ERR_PTR(-EINVAL);
if (args->args[0] >= pc->npwm)
return ERR_PTR(-EINVAL);
pwm = pwm_request_from_chip(pc, args->args[0], NULL);
if (IS_ERR(pwm))
return pwm;
pwm_set_period(pwm, args->args[1]);
if (args->args[2] & PWM_POLARITY_INVERTED)
pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
else
pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
static struct pwm_device *
of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
if (pc->of_pwm_n_cells < 2)
return ERR_PTR(-EINVAL);
if (args->args[0] >= pc->npwm)
return ERR_PTR(-EINVAL);
pwm = pwm_request_from_chip(pc, args->args[0], NULL);
if (IS_ERR(pwm))
return pwm;
pwm_set_period(pwm, args->args[1]);
return pwm;
}
static void of_pwmchip_add(struct pwm_chip *chip)
{
if (!chip->dev || !chip->dev->of_node)
return;
if (!chip->of_xlate) {
chip->of_xlate = of_pwm_simple_xlate;
chip->of_pwm_n_cells = 2;
}
of_node_get(chip->dev->of_node);
}
static void of_pwmchip_remove(struct pwm_chip *chip)
{
if (chip->dev)
of_node_put(chip->dev->of_node);
}
/**
* 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;
}
EXPORT_SYMBOL_GPL(pwm_set_chip_data);
/**
* 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;
}
EXPORT_SYMBOL_GPL(pwm_get_chip_data);
/**
* 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 || !chip->npwm)
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;
if (IS_ENABLED(CONFIG_OF))
of_pwmchip_add(chip);
pwmchip_sysfs_export(chip);
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);
if (IS_ENABLED(CONFIG_OF))
of_pwmchip_remove(chip);
free_pwms(chip);
pwmchip_sysfs_unexport(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
*
* This function is deprecated, use pwm_get() instead.
*/
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
*
* This function is deprecated, use pwm_put() instead.
*/
void pwm_free(struct pwm_device *pwm)
{
pwm_put(pwm);
}
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)
{
int err;
if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
return -EINVAL;
err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
if (err)
return err;
pwm->duty_cycle = duty_ns;
pwm->period = period_ns;
return 0;
}
EXPORT_SYMBOL_GPL(pwm_config);
/**
* pwm_set_polarity() - configure the polarity of a PWM signal
* @pwm: PWM device
* @polarity: new polarity of the PWM signal
*
* Note that the polarity cannot be configured while the PWM device is enabled
*/
int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
{
int err;
if (!pwm || !pwm->chip->ops)
return -EINVAL;
if (!pwm->chip->ops->set_polarity)
return -ENOSYS;
if (test_bit(PWMF_ENABLED, &pwm->flags))
return -EBUSY;
err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
if (err)
return err;
pwm->polarity = polarity;
return 0;
}
EXPORT_SYMBOL_GPL(pwm_set_polarity);
/**
* 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);
static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
{
struct pwm_chip *chip;
mutex_lock(&pwm_lock);
list_for_each_entry(chip, &pwm_chips, list)
if (chip->dev && chip->dev->of_node == np) {
mutex_unlock(&pwm_lock);
return chip;
}
mutex_unlock(&pwm_lock);
return ERR_PTR(-EPROBE_DEFER);
}
/**
* of_pwm_get() - request a PWM via the PWM framework
* @np: device node to get the PWM from
* @con_id: consumer name
*
* Returns the PWM device parsed from the phandle and index specified in the
* "pwms" property of a device tree node or a negative error-code on failure.
* Values parsed from the device tree are stored in the returned PWM device
* object.
*
* If con_id is NULL, the first PWM device listed in the "pwms" property will
* be requested. Otherwise the "pwm-names" property is used to do a reverse
* lookup of the PWM index. This also means that the "pwm-names" property
* becomes mandatory for devices that look up the PWM device via the con_id
* parameter.
*/
struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
{
struct pwm_device *pwm = NULL;
struct of_phandle_args args;
struct pwm_chip *pc;
int index = 0;
int err;
if (con_id) {
index = of_property_match_string(np, "pwm-names", con_id);
if (index < 0)
return ERR_PTR(index);
}
err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
&args);
if (err) {
pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
return ERR_PTR(err);
}
pc = of_node_to_pwmchip(args.np);
if (IS_ERR(pc)) {
pr_debug("%s(): PWM chip not found\n", __func__);
pwm = ERR_CAST(pc);
goto put;
}
if (args.args_count != pc->of_pwm_n_cells) {
pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
args.np->full_name);
pwm = ERR_PTR(-EINVAL);
goto put;
}
pwm = pc->of_xlate(pc, &args);
if (IS_ERR(pwm))
goto put;
/*
* If a consumer name was not given, try to look it up from the
* "pwm-names" property if it exists. Otherwise use the name of
* the user device node.
*/
if (!con_id) {
err = of_property_read_string_index(np, "pwm-names", index,
&con_id);
if (err < 0)
con_id = np->name;
}
pwm->label = con_id;
put:
of_node_put(args.np);
return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_get);
/**
* pwm_add_table() - register PWM device consumers
* @table: array of consumers to register
* @num: number of consumers in table
*/
void __init pwm_add_table(struct pwm_lookup *table, size_t num)
{
mutex_lock(&pwm_lookup_lock);
while (num--) {
list_add_tail(&table->list, &pwm_lookup_list);
table++;
}
mutex_unlock(&pwm_lookup_lock);
}
/**
* pwm_get() - look up and request a PWM device
* @dev: device for PWM consumer
* @con_id: consumer name
*
* Lookup is first attempted using DT. If the device was not instantiated from
* a device tree, a PWM chip and a relative index is looked up via a table
* supplied by board setup code (see pwm_add_table()).
*
* Once a PWM chip has been found the specified PWM device will be requested
* and is ready to be used.
*/
struct pwm_device *pwm_get(struct device *dev, const char *con_id)
{
struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
const char *dev_id = dev ? dev_name(dev) : NULL;
struct pwm_chip *chip = NULL;
unsigned int best = 0;
struct pwm_lookup *p, *chosen = NULL;
unsigned int match;
/* look up via DT first */
if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
return of_pwm_get(dev->of_node, con_id);
/*
* We look up the provider in the static table typically provided by
* board setup code. We first try to lookup the consumer device by
* name. If the consumer device was passed in as NULL or if no match
* was found, we try to find the consumer by directly looking it up
* by name.
*
* If a match is found, the provider PWM chip is looked up by name
* and a PWM device is requested using the PWM device per-chip index.
*
* The lookup algorithm was shamelessly taken from the clock
* framework:
*
* We do slightly fuzzy matching here:
* An entry with a NULL ID is assumed to be a wildcard.
* If an entry has a device ID, it must match
* If an entry has a connection ID, it must match
* Then we take the most specific entry - with the following order
* of precedence: dev+con > dev only > con only.
*/
mutex_lock(&pwm_lookup_lock);
list_for_each_entry(p, &pwm_lookup_list, list) {
match = 0;
if (p->dev_id) {
if (!dev_id || strcmp(p->dev_id, dev_id))
continue;
match += 2;
}
if (p->con_id) {
if (!con_id || strcmp(p->con_id, con_id))
continue;
match += 1;
}
if (match > best) {
chosen = p;
if (match != 3)
best = match;
else
break;
}
}
if (!chosen)
goto out;
chip = pwmchip_find_by_name(chosen->provider);
if (!chip)
goto out;
pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
if (IS_ERR(pwm))
goto out;
pwm_set_period(pwm, chosen->period);
pwm_set_polarity(pwm, chosen->polarity);
out:
mutex_unlock(&pwm_lookup_lock);
return pwm;
}
EXPORT_SYMBOL_GPL(pwm_get);
/**
* pwm_put() - release a PWM device
* @pwm: PWM device
*/
void pwm_put(struct pwm_device *pwm)
{
if (!pwm)
return;
mutex_lock(&pwm_lock);
if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
pr_warn("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_put);
static void devm_pwm_release(struct device *dev, void *res)
{
pwm_put(*(struct pwm_device **)res);
}
/**
* devm_pwm_get() - resource managed pwm_get()
* @dev: device for PWM consumer
* @con_id: consumer name
*
* This function performs like pwm_get() but the acquired PWM device will
* automatically be released on driver detach.
*/
struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
{
struct pwm_device **ptr, *pwm;
ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
pwm = pwm_get(dev, con_id);
if (!IS_ERR(pwm)) {
*ptr = pwm;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return pwm;
}
EXPORT_SYMBOL_GPL(devm_pwm_get);
/**
* devm_of_pwm_get() - resource managed of_pwm_get()
* @dev: device for PWM consumer
* @np: device node to get the PWM from
* @con_id: consumer name
*
* This function performs like of_pwm_get() but the acquired PWM device will
* automatically be released on driver detach.
*/
struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
const char *con_id)
{
struct pwm_device **ptr, *pwm;
ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
pwm = of_pwm_get(np, con_id);
if (!IS_ERR(pwm)) {
*ptr = pwm;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return pwm;
}
EXPORT_SYMBOL_GPL(devm_of_pwm_get);
static int devm_pwm_match(struct device *dev, void *res, void *data)
{
struct pwm_device **p = res;
if (WARN_ON(!p || !*p))
return 0;
return *p == data;
}
/**
* devm_pwm_put() - resource managed pwm_put()
* @dev: device for PWM consumer
* @pwm: PWM device
*
* Release a PWM previously allocated using devm_pwm_get(). Calling this
* function is usually not needed because devm-allocated resources are
* automatically released on driver detach.
*/
void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
{
WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
}
EXPORT_SYMBOL_GPL(devm_pwm_put);
/**
* pwm_can_sleep() - report whether PWM access will sleep
* @pwm: PWM device
*
* It returns true if accessing the PWM can sleep, false otherwise.
*/
bool pwm_can_sleep(struct pwm_device *pwm)
{
return pwm->chip->can_sleep;
}
EXPORT_SYMBOL_GPL(pwm_can_sleep);
#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_puts(s, " requested");
if (test_bit(PWMF_ENABLED, &pwm->flags))
seq_puts(s, " enabled");
seq_puts(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 */
