mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-12-24 07:01:44 +02:00
644 lines
14 KiB
C
644 lines
14 KiB
C
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/*
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* drivers/pwm/pwm.c
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*
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* Copyright (C) 2010 Bill Gatliff <bgat@billgatliff.com>
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*
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* This program is free software; you may redistribute and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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* USA
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/spinlock.h>
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#include <linux/fs.h>
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#include <linux/completion.h>
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#include <linux/workqueue.h>
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#include <linux/list.h>
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#include <linux/sched.h>
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#include <linux/slab.h> /*kcalloc, kfree since 2.6.34 */
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#include <linux/pwm/pwm.h>
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static int __pwm_create_sysfs(struct pwm_device *pwm);
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static const char *REQUEST_SYSFS = "sysfs";
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static LIST_HEAD(pwm_device_list);
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static DEFINE_MUTEX(device_list_mutex);
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static struct class pwm_class;
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static struct workqueue_struct *pwm_handler_workqueue;
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int pwm_register(struct pwm_device *pwm)
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{
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struct pwm_channel *p;
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int wchan;
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int ret;
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spin_lock_init(&pwm->list_lock);
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p = kcalloc(pwm->nchan, sizeof(*p), GFP_KERNEL);
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if (!p)
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return -ENOMEM;
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for (wchan = 0; wchan < pwm->nchan; wchan++) {
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spin_lock_init(&p[wchan].lock);
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init_completion(&p[wchan].complete);
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p[wchan].chan = wchan;
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p[wchan].pwm = pwm;
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}
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pwm->channels = p;
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mutex_lock(&device_list_mutex);
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list_add_tail(&pwm->list, &pwm_device_list);
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ret = __pwm_create_sysfs(pwm);
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if (ret) {
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mutex_unlock(&device_list_mutex);
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goto err_create_sysfs;
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}
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mutex_unlock(&device_list_mutex);
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dev_info(pwm->dev, "%d channel%s\n", pwm->nchan,
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pwm->nchan > 1 ? "s" : "");
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return 0;
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err_create_sysfs:
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kfree(p);
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return ret;
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}
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EXPORT_SYMBOL(pwm_register);
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static int __match_device(struct device *dev, void *data)
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{
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return dev_get_drvdata(dev) == data;
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}
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int pwm_unregister(struct pwm_device *pwm)
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{
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int wchan;
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struct device *dev;
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mutex_lock(&device_list_mutex);
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for (wchan = 0; wchan < pwm->nchan; wchan++) {
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if (pwm->channels[wchan].flags & BIT(FLAG_REQUESTED)) {
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mutex_unlock(&device_list_mutex);
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return -EBUSY;
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}
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}
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for (wchan = 0; wchan < pwm->nchan; wchan++) {
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dev = class_find_device(&pwm_class, NULL,
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&pwm->channels[wchan],
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__match_device);
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if (dev) {
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put_device(dev);
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device_unregister(dev);
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}
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}
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kfree(pwm->channels);
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list_del(&pwm->list);
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mutex_unlock(&device_list_mutex);
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return 0;
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}
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EXPORT_SYMBOL(pwm_unregister);
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static struct pwm_device *
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__pwm_find_device(const char *bus_id)
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{
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struct pwm_device *p;
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list_for_each_entry(p, &pwm_device_list, list) {
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if (!strcmp(bus_id, p->bus_id))
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return p;
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}
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return NULL;
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}
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static int
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__pwm_request_channel(struct pwm_channel *p,
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const char *requester)
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{
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int ret;
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if (test_and_set_bit(FLAG_REQUESTED, &p->flags))
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return -EBUSY;
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if (p->pwm->request) {
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ret = p->pwm->request(p);
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if (ret) {
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clear_bit(FLAG_REQUESTED, &p->flags);
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return ret;
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}
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}
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p->requester = requester;
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if (!strcmp(requester, REQUEST_SYSFS))
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p->pid = current->pid;
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return 0;
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}
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struct pwm_channel *
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pwm_request(const char *bus_id,
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int chan,
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const char *requester)
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{
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struct pwm_device *p;
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int ret;
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mutex_lock(&device_list_mutex);
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p = __pwm_find_device(bus_id);
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if (!p || chan >= p->nchan)
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goto err_no_device;
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if (!try_module_get(p->owner))
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goto err_module_get_failed;
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ret = __pwm_request_channel(&p->channels[chan], requester);
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if (ret)
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goto err_request_failed;
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mutex_unlock(&device_list_mutex);
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return &p->channels[chan];
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err_request_failed:
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module_put(p->owner);
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err_module_get_failed:
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err_no_device:
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mutex_unlock(&device_list_mutex);
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return NULL;
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}
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EXPORT_SYMBOL(pwm_request);
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void pwm_free(struct pwm_channel *p)
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{
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mutex_lock(&device_list_mutex);
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if (!test_and_clear_bit(FLAG_REQUESTED, &p->flags))
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goto done;
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pwm_stop(p);
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pwm_unsynchronize(p, NULL);
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pwm_set_handler(p, NULL, NULL);
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if (p->pwm->free)
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p->pwm->free(p);
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module_put(p->pwm->owner);
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done:
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mutex_unlock(&device_list_mutex);
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}
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EXPORT_SYMBOL(pwm_free);
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unsigned long pwm_ns_to_ticks(struct pwm_channel *p,
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unsigned long nsecs)
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{
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unsigned long long ticks;
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ticks = nsecs;
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ticks *= p->tick_hz;
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do_div(ticks, 1000000000);
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return ticks;
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}
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EXPORT_SYMBOL(pwm_ns_to_ticks);
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unsigned long pwm_ticks_to_ns(struct pwm_channel *p,
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unsigned long ticks)
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{
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unsigned long long ns;
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if (!p->tick_hz)
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return 0;
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ns = ticks;
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ns *= 1000000000UL;
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do_div(ns, p->tick_hz);
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return ns;
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}
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EXPORT_SYMBOL(pwm_ticks_to_ns);
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static void
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pwm_config_ns_to_ticks(struct pwm_channel *p,
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struct pwm_channel_config *c)
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{
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if (c->config_mask & PWM_CONFIG_PERIOD_NS) {
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c->period_ticks = pwm_ns_to_ticks(p, c->period_ns);
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c->config_mask &= ~PWM_CONFIG_PERIOD_NS;
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c->config_mask |= PWM_CONFIG_PERIOD_TICKS;
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}
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if (c->config_mask & PWM_CONFIG_DUTY_NS) {
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c->duty_ticks = pwm_ns_to_ticks(p, c->duty_ns);
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c->config_mask &= ~PWM_CONFIG_DUTY_NS;
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c->config_mask |= PWM_CONFIG_DUTY_TICKS;
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}
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}
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static void
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pwm_config_percent_to_ticks(struct pwm_channel *p,
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struct pwm_channel_config *c)
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{
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if (c->config_mask & PWM_CONFIG_DUTY_PERCENT) {
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if (c->config_mask & PWM_CONFIG_PERIOD_TICKS)
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c->duty_ticks = c->period_ticks;
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else
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c->duty_ticks = p->period_ticks;
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c->duty_ticks *= c->duty_percent;
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c->duty_ticks /= 100;
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c->config_mask &= ~PWM_CONFIG_DUTY_PERCENT;
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c->config_mask |= PWM_CONFIG_DUTY_TICKS;
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}
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}
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int pwm_config_nosleep(struct pwm_channel *p,
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struct pwm_channel_config *c)
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{
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if (!p->pwm->config_nosleep)
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return -EINVAL;
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pwm_config_ns_to_ticks(p, c);
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pwm_config_percent_to_ticks(p, c);
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return p->pwm->config_nosleep(p, c);
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}
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EXPORT_SYMBOL(pwm_config_nosleep);
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int pwm_config(struct pwm_channel *p,
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struct pwm_channel_config *c)
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{
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int ret = 0;
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if (unlikely(!p->pwm->config))
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return -EINVAL;
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pwm_config_ns_to_ticks(p, c);
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pwm_config_percent_to_ticks(p, c);
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switch (c->config_mask & (PWM_CONFIG_PERIOD_TICKS
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| PWM_CONFIG_DUTY_TICKS)) {
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case PWM_CONFIG_PERIOD_TICKS:
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if (p->duty_ticks > c->period_ticks) {
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ret = -EINVAL;
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goto err;
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}
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break;
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case PWM_CONFIG_DUTY_TICKS:
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if (p->period_ticks < c->duty_ticks) {
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ret = -EINVAL;
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goto err;
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}
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break;
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case PWM_CONFIG_DUTY_TICKS | PWM_CONFIG_PERIOD_TICKS:
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if (c->duty_ticks > c->period_ticks) {
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ret = -EINVAL;
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goto err;
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}
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break;
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default:
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break;
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}
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err:
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dev_dbg(p->pwm->dev, "%s: config_mask %d period_ticks %lu duty_ticks %lu"
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" polarity %d duty_ns %lu period_ns %lu duty_percent %d\n",
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__func__, c->config_mask, c->period_ticks, c->duty_ticks,
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c->polarity, c->duty_ns, c->period_ns, c->duty_percent);
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if (ret)
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return ret;
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return p->pwm->config(p, c);
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}
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EXPORT_SYMBOL(pwm_config);
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int pwm_set_period_ns(struct pwm_channel *p,
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unsigned long period_ns)
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{
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struct pwm_channel_config c = {
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.config_mask = PWM_CONFIG_PERIOD_TICKS,
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.period_ticks = pwm_ns_to_ticks(p, period_ns),
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};
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return pwm_config(p, &c);
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}
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EXPORT_SYMBOL(pwm_set_period_ns);
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unsigned long pwm_get_period_ns(struct pwm_channel *p)
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{
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return pwm_ticks_to_ns(p, p->period_ticks);
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}
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EXPORT_SYMBOL(pwm_get_period_ns);
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int pwm_set_duty_ns(struct pwm_channel *p,
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unsigned long duty_ns)
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{
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struct pwm_channel_config c = {
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.config_mask = PWM_CONFIG_DUTY_TICKS,
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.duty_ticks = pwm_ns_to_ticks(p, duty_ns),
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};
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return pwm_config(p, &c);
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}
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EXPORT_SYMBOL(pwm_set_duty_ns);
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unsigned long pwm_get_duty_ns(struct pwm_channel *p)
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{
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return pwm_ticks_to_ns(p, p->duty_ticks);
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}
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EXPORT_SYMBOL(pwm_get_duty_ns);
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int pwm_set_duty_percent(struct pwm_channel *p,
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int percent)
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{
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struct pwm_channel_config c = {
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.config_mask = PWM_CONFIG_DUTY_PERCENT,
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.duty_percent = percent,
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};
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return pwm_config(p, &c);
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}
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EXPORT_SYMBOL(pwm_set_duty_percent);
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int pwm_set_polarity(struct pwm_channel *p,
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int active_high)
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{
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struct pwm_channel_config c = {
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.config_mask = PWM_CONFIG_POLARITY,
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.polarity = active_high,
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};
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return pwm_config(p, &c);
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}
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EXPORT_SYMBOL(pwm_set_polarity);
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int pwm_start(struct pwm_channel *p)
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{
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struct pwm_channel_config c = {
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.config_mask = PWM_CONFIG_START,
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};
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return pwm_config(p, &c);
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}
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EXPORT_SYMBOL(pwm_start);
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int pwm_stop(struct pwm_channel *p)
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{
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struct pwm_channel_config c = {
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.config_mask = PWM_CONFIG_STOP,
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};
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return pwm_config(p, &c);
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}
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EXPORT_SYMBOL(pwm_stop);
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int pwm_synchronize(struct pwm_channel *p,
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struct pwm_channel *to_p)
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{
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if (p->pwm != to_p->pwm) {
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/* TODO: support cross-device synchronization */
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return -EINVAL;
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}
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if (!p->pwm->synchronize)
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return -EINVAL;
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return p->pwm->synchronize(p, to_p);
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}
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EXPORT_SYMBOL(pwm_synchronize);
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int pwm_unsynchronize(struct pwm_channel *p,
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struct pwm_channel *from_p)
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{
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if (from_p && (p->pwm != from_p->pwm)) {
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/* TODO: support cross-device synchronization */
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return -EINVAL;
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}
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if (!p->pwm->unsynchronize)
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return -EINVAL;
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return p->pwm->unsynchronize(p, from_p);
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}
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EXPORT_SYMBOL(pwm_unsynchronize);
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static void pwm_handler(struct work_struct *w)
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{
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struct pwm_channel *p = container_of(w, struct pwm_channel,
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handler_work);
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if (p->handler && p->handler(p, p->handler_data))
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pwm_stop(p);
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}
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static void __pwm_callback(struct pwm_channel *p)
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{
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queue_work(pwm_handler_workqueue, &p->handler_work);
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||
|
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);
|