+++ /dev/null
-/*
- * drivers/pwm/pwm.c
- *
- * Copyright (C) 2010 Bill Gatliff <bgat@billgatliff.com>
- *
- * This program is free software; you may redistribute and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * 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; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
- * USA
- */
-
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/device.h>
-#include <linux/spinlock.h>
-#include <linux/fs.h>
-#include <linux/completion.h>
-#include <linux/workqueue.h>
-#include <linux/list.h>
-#include <linux/sched.h>
-#include <linux/slab.h> /*kcalloc, kfree since 2.6.34 */
-#include <linux/pwm/pwm.h>
-
-static int __pwm_create_sysfs(struct pwm_device *pwm);
-
-static const char *REQUEST_SYSFS = "sysfs";
-static LIST_HEAD(pwm_device_list);
-static DEFINE_MUTEX(device_list_mutex);
-static struct class pwm_class;
-static struct workqueue_struct *pwm_handler_workqueue;
-
-int pwm_register(struct pwm_device *pwm)
-{
- struct pwm_channel *p;
- int wchan;
- int ret;
-
- spin_lock_init(&pwm->list_lock);
-
- p = kcalloc(pwm->nchan, sizeof(*p), GFP_KERNEL);
- if (!p)
- return -ENOMEM;
-
- for (wchan = 0; wchan < pwm->nchan; wchan++) {
- spin_lock_init(&p[wchan].lock);
- init_completion(&p[wchan].complete);
- p[wchan].chan = wchan;
- p[wchan].pwm = pwm;
- }
-
- pwm->channels = p;
-
- mutex_lock(&device_list_mutex);
-
- list_add_tail(&pwm->list, &pwm_device_list);
- ret = __pwm_create_sysfs(pwm);
- if (ret) {
- mutex_unlock(&device_list_mutex);
- goto err_create_sysfs;
- }
-
- mutex_unlock(&device_list_mutex);
-
- dev_info(pwm->dev, "%d channel%s\n", pwm->nchan,
- pwm->nchan > 1 ? "s" : "");
- return 0;
-
-err_create_sysfs:
- kfree(p);
-
- return ret;
-}
-EXPORT_SYMBOL(pwm_register);
-
-static int __match_device(struct device *dev, void *data)
-{
- return dev_get_drvdata(dev) == data;
-}
-
-int pwm_unregister(struct pwm_device *pwm)
-{
- int wchan;
- struct device *dev;
-
- mutex_lock(&device_list_mutex);
-
- for (wchan = 0; wchan < pwm->nchan; wchan++) {
- if (pwm->channels[wchan].flags & BIT(FLAG_REQUESTED)) {
- mutex_unlock(&device_list_mutex);
- return -EBUSY;
- }
- }
-
- for (wchan = 0; wchan < pwm->nchan; wchan++) {
- dev = class_find_device(&pwm_class, NULL,
- &pwm->channels[wchan],
- __match_device);
- if (dev) {
- put_device(dev);
- device_unregister(dev);
- }
- }
-
- kfree(pwm->channels);
- list_del(&pwm->list);
- mutex_unlock(&device_list_mutex);
-
- return 0;
-}
-EXPORT_SYMBOL(pwm_unregister);
-
-static struct pwm_device *
-__pwm_find_device(const char *bus_id)
-{
- struct pwm_device *p;
-
- list_for_each_entry(p, &pwm_device_list, list) {
- if (!strcmp(bus_id, p->bus_id))
- return p;
- }
- return NULL;
-}
-
-static int
-__pwm_request_channel(struct pwm_channel *p,
- const char *requester)
-{
- int ret;
-
- if (test_and_set_bit(FLAG_REQUESTED, &p->flags))
- return -EBUSY;
-
- if (p->pwm->request) {
- ret = p->pwm->request(p);
- if (ret) {
- clear_bit(FLAG_REQUESTED, &p->flags);
- return ret;
- }
- }
-
- p->requester = requester;
- if (!strcmp(requester, REQUEST_SYSFS))
- p->pid = current->pid;
-
- return 0;
-}
-
-struct pwm_channel *
-pwm_request(const char *bus_id,
- int chan,
- const char *requester)
-{
- struct pwm_device *p;
- int ret;
-
- mutex_lock(&device_list_mutex);
-
- p = __pwm_find_device(bus_id);
- if (!p || chan >= p->nchan)
- goto err_no_device;
-
- if (!try_module_get(p->owner))
- goto err_module_get_failed;
-
- ret = __pwm_request_channel(&p->channels[chan], requester);
- if (ret)
- goto err_request_failed;
-
- mutex_unlock(&device_list_mutex);
- return &p->channels[chan];
-
-err_request_failed:
- module_put(p->owner);
-err_module_get_failed:
-err_no_device:
- mutex_unlock(&device_list_mutex);
- return NULL;
-}
-EXPORT_SYMBOL(pwm_request);
-
-void pwm_free(struct pwm_channel *p)
-{
- mutex_lock(&device_list_mutex);
-
- if (!test_and_clear_bit(FLAG_REQUESTED, &p->flags))
- goto done;
-
- pwm_stop(p);
- pwm_unsynchronize(p, NULL);
- pwm_set_handler(p, NULL, NULL);
-
- if (p->pwm->free)
- p->pwm->free(p);
- module_put(p->pwm->owner);
-done:
- mutex_unlock(&device_list_mutex);
-}
-EXPORT_SYMBOL(pwm_free);
-
-unsigned long pwm_ns_to_ticks(struct pwm_channel *p,
- unsigned long nsecs)
-{
- unsigned long long ticks;
-
- ticks = nsecs;
- ticks *= p->tick_hz;
- do_div(ticks, 1000000000);
- return ticks;
-}
-EXPORT_SYMBOL(pwm_ns_to_ticks);
-
-unsigned long pwm_ticks_to_ns(struct pwm_channel *p,
- unsigned long ticks)
-{
- unsigned long long ns;
-
- if (!p->tick_hz)
- return 0;
-
- ns = ticks;
- ns *= 1000000000UL;
- do_div(ns, p->tick_hz);
- return ns;
-}
-EXPORT_SYMBOL(pwm_ticks_to_ns);
-
-static void
-pwm_config_ns_to_ticks(struct pwm_channel *p,
- struct pwm_channel_config *c)
-{
- if (c->config_mask & PWM_CONFIG_PERIOD_NS) {
- c->period_ticks = pwm_ns_to_ticks(p, c->period_ns);
- c->config_mask &= ~PWM_CONFIG_PERIOD_NS;
- c->config_mask |= PWM_CONFIG_PERIOD_TICKS;
- }
-
- if (c->config_mask & PWM_CONFIG_DUTY_NS) {
- c->duty_ticks = pwm_ns_to_ticks(p, c->duty_ns);
- c->config_mask &= ~PWM_CONFIG_DUTY_NS;
- c->config_mask |= PWM_CONFIG_DUTY_TICKS;
- }
-}
-
-static void
-pwm_config_percent_to_ticks(struct pwm_channel *p,
- struct pwm_channel_config *c)
-{
- if (c->config_mask & PWM_CONFIG_DUTY_PERCENT) {
- if (c->config_mask & PWM_CONFIG_PERIOD_TICKS)
- c->duty_ticks = c->period_ticks;
- else
- c->duty_ticks = p->period_ticks;
-
- c->duty_ticks *= c->duty_percent;
- c->duty_ticks /= 100;
- c->config_mask &= ~PWM_CONFIG_DUTY_PERCENT;
- c->config_mask |= PWM_CONFIG_DUTY_TICKS;
- }
-}
-
-int pwm_config_nosleep(struct pwm_channel *p,
- struct pwm_channel_config *c)
-{
- if (!p->pwm->config_nosleep)
- return -EINVAL;
-
- pwm_config_ns_to_ticks(p, c);
- pwm_config_percent_to_ticks(p, c);
-
- return p->pwm->config_nosleep(p, c);
-}
-EXPORT_SYMBOL(pwm_config_nosleep);
-
-int pwm_config(struct pwm_channel *p,
- struct pwm_channel_config *c)
-{
- int ret = 0;
-
- if (unlikely(!p->pwm->config))
- return -EINVAL;
-
- pwm_config_ns_to_ticks(p, c);
- pwm_config_percent_to_ticks(p, c);
-
- switch (c->config_mask & (PWM_CONFIG_PERIOD_TICKS
- | PWM_CONFIG_DUTY_TICKS)) {
- case PWM_CONFIG_PERIOD_TICKS:
- if (p->duty_ticks > c->period_ticks) {
- ret = -EINVAL;
- goto err;
- }
- break;
- case PWM_CONFIG_DUTY_TICKS:
- if (p->period_ticks < c->duty_ticks) {
- ret = -EINVAL;
- goto err;
- }
- break;
- case PWM_CONFIG_DUTY_TICKS | PWM_CONFIG_PERIOD_TICKS:
- if (c->duty_ticks > c->period_ticks) {
- ret = -EINVAL;
- goto err;
- }
- break;
- default:
- break;
- }
-
-err:
- dev_dbg(p->pwm->dev, "%s: config_mask %d period_ticks %lu duty_ticks %lu"
- " polarity %d duty_ns %lu period_ns %lu duty_percent %d\n",
- __func__, c->config_mask, c->period_ticks, c->duty_ticks,
- c->polarity, c->duty_ns, c->period_ns, c->duty_percent);
-
- if (ret)
- return ret;
- return p->pwm->config(p, c);
-}
-EXPORT_SYMBOL(pwm_config);
-
-int pwm_set_period_ns(struct pwm_channel *p,
- unsigned long period_ns)
-{
- struct pwm_channel_config c = {
- .config_mask = PWM_CONFIG_PERIOD_TICKS,
- .period_ticks = pwm_ns_to_ticks(p, period_ns),
- };
-
- return pwm_config(p, &c);
-}
-EXPORT_SYMBOL(pwm_set_period_ns);
-
-unsigned long pwm_get_period_ns(struct pwm_channel *p)
-{
- return pwm_ticks_to_ns(p, p->period_ticks);
-}
-EXPORT_SYMBOL(pwm_get_period_ns);
-
-int pwm_set_duty_ns(struct pwm_channel *p,
- unsigned long duty_ns)
-{
- struct pwm_channel_config c = {
- .config_mask = PWM_CONFIG_DUTY_TICKS,
- .duty_ticks = pwm_ns_to_ticks(p, duty_ns),
- };
- return pwm_config(p, &c);
-}
-EXPORT_SYMBOL(pwm_set_duty_ns);
-
-unsigned long pwm_get_duty_ns(struct pwm_channel *p)
-{
- return pwm_ticks_to_ns(p, p->duty_ticks);
-}
-EXPORT_SYMBOL(pwm_get_duty_ns);
-
-int pwm_set_duty_percent(struct pwm_channel *p,
- int percent)
-{
- struct pwm_channel_config c = {
- .config_mask = PWM_CONFIG_DUTY_PERCENT,
- .duty_percent = percent,
- };
- return pwm_config(p, &c);
-}
-EXPORT_SYMBOL(pwm_set_duty_percent);
-
-int pwm_set_polarity(struct pwm_channel *p,
- int active_high)
-{
- struct pwm_channel_config c = {
- .config_mask = PWM_CONFIG_POLARITY,
- .polarity = active_high,
- };
- return pwm_config(p, &c);
-}
-EXPORT_SYMBOL(pwm_set_polarity);
-
-int pwm_start(struct pwm_channel *p)
-{
- struct pwm_channel_config c = {
- .config_mask = PWM_CONFIG_START,
- };
- return pwm_config(p, &c);
-}
-EXPORT_SYMBOL(pwm_start);
-
-int pwm_stop(struct pwm_channel *p)
-{
- struct pwm_channel_config c = {
- .config_mask = PWM_CONFIG_STOP,
- };
- return pwm_config(p, &c);
-}
-EXPORT_SYMBOL(pwm_stop);
-
-int pwm_synchronize(struct pwm_channel *p,
- struct pwm_channel *to_p)
-{
- if (p->pwm != to_p->pwm) {
- /* TODO: support cross-device synchronization */
- return -EINVAL;
- }
-
- if (!p->pwm->synchronize)
- return -EINVAL;
-
- return p->pwm->synchronize(p, to_p);
-}
-EXPORT_SYMBOL(pwm_synchronize);
-
-int pwm_unsynchronize(struct pwm_channel *p,
- struct pwm_channel *from_p)
-{
- if (from_p && (p->pwm != from_p->pwm)) {
- /* TODO: support cross-device synchronization */
- return -EINVAL;
- }
-
- if (!p->pwm->unsynchronize)
- return -EINVAL;
-
- return p->pwm->unsynchronize(p, from_p);
-}
-EXPORT_SYMBOL(pwm_unsynchronize);
-
-static void pwm_handler(struct work_struct *w)
-{
- struct pwm_channel *p = container_of(w, struct pwm_channel,
- handler_work);
- if (p->handler && p->handler(p, p->handler_data))
- pwm_stop(p);
-}
-
-static void __pwm_callback(struct pwm_channel *p)
-{
- queue_work(pwm_handler_workqueue, &p->handler_work);
- dev_dbg(p->pwm->dev, "handler %p scheduled with data %p\n",
- p->handler, p->handler_data);
-}
-
-int pwm_set_handler(struct pwm_channel *p,
- pwm_handler_t handler,
- void *data)
-{
- if (p->pwm->set_callback) {
- p->handler_data = data;
- p->handler = handler;
- INIT_WORK(&p->handler_work, pwm_handler);
- return p->pwm->set_callback(p, handler ? __pwm_callback : NULL);
- }
- return -EINVAL;
-}
-EXPORT_SYMBOL(pwm_set_handler);
-
-static ssize_t pwm_run_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t len)
-{
- struct pwm_channel *p = dev_get_drvdata(dev);
- if (sysfs_streq(buf, "1"))
- pwm_start(p);
- else if (sysfs_streq(buf, "0"))
- pwm_stop(p);
- return len;
-}
-static DEVICE_ATTR(run, 0200, NULL, pwm_run_store);
-
-static ssize_t pwm_duty_ns_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
-{
- struct pwm_channel *p = dev_get_drvdata(dev);
- return sprintf(buf, "%lu\n", pwm_get_duty_ns(p));
-}
-
-static ssize_t pwm_duty_ns_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t len)
-{
- unsigned long duty_ns;
- struct pwm_channel *p = dev_get_drvdata(dev);
-
- if (1 == sscanf(buf, "%lu", &duty_ns))
- pwm_set_duty_ns(p, duty_ns);
- return len;
-}
-static DEVICE_ATTR(duty_ns, 0644, pwm_duty_ns_show, pwm_duty_ns_store);
-
-static ssize_t pwm_period_ns_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
-{
- struct pwm_channel *p = dev_get_drvdata(dev);
- return sprintf(buf, "%lu\n", pwm_get_period_ns(p));
-}
-
-static ssize_t pwm_period_ns_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t len)
-{
- unsigned long period_ns;
- struct pwm_channel *p = dev_get_drvdata(dev);
-
- if (1 == sscanf(buf, "%lu", &period_ns))
- pwm_set_period_ns(p, period_ns);
- return len;
-}
-static DEVICE_ATTR(period_ns, 0644, pwm_period_ns_show, pwm_period_ns_store);
-
-static ssize_t pwm_polarity_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
-{
- struct pwm_channel *p = dev_get_drvdata(dev);
- return sprintf(buf, "%d\n", p->active_high ? 1 : 0);
-}
-
-static ssize_t pwm_polarity_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t len)
-{
- int polarity;
- struct pwm_channel *p = dev_get_drvdata(dev);
-
- if (1 == sscanf(buf, "%d", &polarity))
- pwm_set_polarity(p, polarity);
- return len;
-}
-static DEVICE_ATTR(polarity, 0644, pwm_polarity_show, pwm_polarity_store);
-
-static ssize_t pwm_request_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
-{
- struct pwm_channel *p = dev_get_drvdata(dev);
- mutex_lock(&device_list_mutex);
- __pwm_request_channel(p, REQUEST_SYSFS);
- mutex_unlock(&device_list_mutex);
-
- if (p->pid)
- return sprintf(buf, "%s %d\n", p->requester, p->pid);
- else
- return sprintf(buf, "%s\n", p->requester);
-}
-
-static ssize_t pwm_request_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t len)
-{
- struct pwm_channel *p = dev_get_drvdata(dev);
- pwm_free(p);
- return len;
-}
-static DEVICE_ATTR(request, 0644, pwm_request_show, pwm_request_store);
-
-static const struct attribute *pwm_attrs[] =
-{
- &dev_attr_run.attr,
- &dev_attr_polarity.attr,
- &dev_attr_duty_ns.attr,
- &dev_attr_period_ns.attr,
- &dev_attr_request.attr,
- NULL,
-};
-
-static const struct attribute_group pwm_device_attr_group = {
- .attrs = (struct attribute **)pwm_attrs,
-};
-
-static int __pwm_create_sysfs(struct pwm_device *pwm)
-{
- int ret = 0;
- struct device *dev;
- int wchan;
-
- for (wchan = 0; wchan < pwm->nchan; wchan++) {
- dev = device_create(&pwm_class, pwm->dev, MKDEV(0, 0),
- pwm->channels + wchan,
- "%s:%d", pwm->bus_id, wchan);
- if (!dev)
- goto err_dev_create;
- ret = sysfs_create_group(&dev->kobj, &pwm_device_attr_group);
- if (ret)
- goto err_dev_create;
- }
-
- return ret;
-
-err_dev_create:
- for (wchan = 0; wchan < pwm->nchan; wchan++) {
- dev = class_find_device(&pwm_class, NULL,
- &pwm->channels[wchan],
- __match_device);
- if (dev) {
- put_device(dev);
- device_unregister(dev);
- }
- }
-
- return ret;
-}
-
-static struct class_attribute pwm_class_attrs[] = {
- __ATTR_NULL,
-};
-
-static struct class pwm_class = {
- .name = "pwm",
- .owner = THIS_MODULE,
-
- .class_attrs = pwm_class_attrs,
-};
-
-static int __init pwm_init(void)
-{
- int ret;
-
- /* TODO: how to deal with devices that register very early? */
- pr_err("%s\n", __func__);
- ret = class_register(&pwm_class);
- if (ret < 0)
- return ret;
-
- pwm_handler_workqueue = create_workqueue("pwmd");
-
- return 0;
-}
-postcore_initcall(pwm_init);
projects / openwrt / svn-archive / archive.git / blobdiff