linux-stable/drivers/pwm/core.c
Boris Brezillon a8c3862551 pwm: Keep PWM state in sync with hardware state
Before the introduction of pwm_args, the core was resetting the PWM
period and polarity states to the reference values (those provided
through the DT, a PWM lookup table or hardcoded in the driver).

Now that all PWM users are correctly using pwm_args to configure their
PWM device, we can safely remove the pwm_apply_args() call in pwm_get()
and of_pwm_get().

We can also get rid of the pwm_set_period() call in pwm_apply_args(),
because PWM users are now directly using pargs->period instead of
pwm_get_period(). By doing that we avoid messing with the current PWM
period.

The only remaining bit in pwm_apply_args() is the initial polarity
setting, and it should go away when all PWM users have been patched to
use the atomic API (with this API the polarity will be set along with
other PWM arguments when configuring the PWM).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17 14:47:30 +02:00

970 lines
21 KiB
C

/*
* 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->args.period = args->args[1];
if (args->args[2] & PWM_POLARITY_INVERTED)
pwm->args.polarity = PWM_POLARITY_INVERSED;
else
pwm->args.polarity = 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->args.period = 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
*
* Returns: 0 on success or a negative error code on failure.
*/
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
*
* Returns: A pointer to the chip-private data for the 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_with_polarity() - register a new PWM chip
* @chip: the PWM chip to add
* @polarity: initial polarity of PWM channels
*
* Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
* will be used. The initial polarity for all channels is specified by the
* @polarity parameter.
*
* Returns: 0 on success or a negative error code on failure.
*/
int pwmchip_add_with_polarity(struct pwm_chip *chip,
enum pwm_polarity polarity)
{
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;
pwm->polarity = polarity;
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_with_polarity);
/**
* 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. The initial polarity for all channels is normal.
*
* Returns: 0 on success or a negative error code on failure.
*/
int pwmchip_add(struct pwm_chip *chip)
{
return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
}
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.
*
* Returns: 0 on success or a negative error code on failure.
*/
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: global PWM device index
* @label: PWM device label
*
* This function is deprecated, use pwm_get() instead.
*
* Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
* failure.
*/
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: A pointer to the PWM device 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
*
* Returns: 0 on success or a negative error code on failure.
*/
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.
*
* Returns: 0 on success or a negative error code on failure.
*/
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 (pwm_is_enabled(pwm))
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
*
* Returns: 0 on success or a negative error code on failure.
*/
int pwm_enable(struct pwm_device *pwm)
{
int err = 0;
if (!pwm)
return -EINVAL;
if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
err = pwm->chip->ops->enable(pwm->chip, pwm);
if (err)
clear_bit(PWMF_ENABLED, &pwm->flags);
}
return err;
}
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.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
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 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_remove_table() - unregister PWM device consumers
* @table: array of consumers to unregister
* @num: number of consumers in table
*/
void pwm_remove_table(struct pwm_lookup *table, size_t num)
{
mutex_lock(&pwm_lookup_lock);
while (num--) {
list_del(&table->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.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
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) {
pwm = ERR_PTR(-ENODEV);
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->args.period = chosen->period;
pwm->args.polarity = 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.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
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.
*
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
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
*
* Returns: True if accessing the PWM can sleep, false otherwise.
*/
bool pwm_can_sleep(struct pwm_device *pwm)
{
return true;
}
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 (pwm_is_enabled(pwm))
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 */