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d94ba80ebb
This patch adds an infrastructure for hardware clocks that implement IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a registration method to particular hardware clock drivers. Each clock is presented as a standard POSIX clock. The ancillary clock features are exposed in two different ways, via the sysfs and by a character device. Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: John Stultz <john.stultz@linaro.org>
231 lines
5.8 KiB
C
231 lines
5.8 KiB
C
/*
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* PTP 1588 clock support - sysfs interface.
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*
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* Copyright (C) 2010 OMICRON electronics GmbH
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU 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., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/capability.h>
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#include "ptp_private.h"
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static ssize_t clock_name_show(struct device *dev,
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struct device_attribute *attr, char *page)
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{
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struct ptp_clock *ptp = dev_get_drvdata(dev);
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return snprintf(page, PAGE_SIZE-1, "%s\n", ptp->info->name);
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}
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#define PTP_SHOW_INT(name) \
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static ssize_t name##_show(struct device *dev, \
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struct device_attribute *attr, char *page) \
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{ \
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struct ptp_clock *ptp = dev_get_drvdata(dev); \
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return snprintf(page, PAGE_SIZE-1, "%d\n", ptp->info->name); \
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}
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PTP_SHOW_INT(max_adj);
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PTP_SHOW_INT(n_alarm);
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PTP_SHOW_INT(n_ext_ts);
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PTP_SHOW_INT(n_per_out);
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PTP_SHOW_INT(pps);
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#define PTP_RO_ATTR(_var, _name) { \
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.attr = { .name = __stringify(_name), .mode = 0444 }, \
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.show = _var##_show, \
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}
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struct device_attribute ptp_dev_attrs[] = {
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PTP_RO_ATTR(clock_name, clock_name),
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PTP_RO_ATTR(max_adj, max_adjustment),
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PTP_RO_ATTR(n_alarm, n_alarms),
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PTP_RO_ATTR(n_ext_ts, n_external_timestamps),
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PTP_RO_ATTR(n_per_out, n_periodic_outputs),
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PTP_RO_ATTR(pps, pps_available),
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__ATTR_NULL,
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};
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static ssize_t extts_enable_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct ptp_clock *ptp = dev_get_drvdata(dev);
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struct ptp_clock_info *ops = ptp->info;
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struct ptp_clock_request req = { .type = PTP_CLK_REQ_EXTTS };
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int cnt, enable;
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int err = -EINVAL;
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cnt = sscanf(buf, "%u %d", &req.extts.index, &enable);
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if (cnt != 2)
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goto out;
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if (req.extts.index >= ops->n_ext_ts)
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goto out;
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err = ops->enable(ops, &req, enable ? 1 : 0);
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if (err)
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goto out;
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return count;
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out:
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return err;
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}
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static ssize_t extts_fifo_show(struct device *dev,
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struct device_attribute *attr, char *page)
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{
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struct ptp_clock *ptp = dev_get_drvdata(dev);
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struct timestamp_event_queue *queue = &ptp->tsevq;
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struct ptp_extts_event event;
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unsigned long flags;
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size_t qcnt;
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int cnt = 0;
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memset(&event, 0, sizeof(event));
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if (mutex_lock_interruptible(&ptp->tsevq_mux))
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return -ERESTARTSYS;
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spin_lock_irqsave(&queue->lock, flags);
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qcnt = queue_cnt(queue);
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if (qcnt) {
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event = queue->buf[queue->head];
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queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
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}
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spin_unlock_irqrestore(&queue->lock, flags);
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if (!qcnt)
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goto out;
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cnt = snprintf(page, PAGE_SIZE, "%u %lld %u\n",
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event.index, event.t.sec, event.t.nsec);
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out:
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mutex_unlock(&ptp->tsevq_mux);
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return cnt;
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}
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static ssize_t period_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct ptp_clock *ptp = dev_get_drvdata(dev);
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struct ptp_clock_info *ops = ptp->info;
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struct ptp_clock_request req = { .type = PTP_CLK_REQ_PEROUT };
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int cnt, enable, err = -EINVAL;
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cnt = sscanf(buf, "%u %lld %u %lld %u", &req.perout.index,
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&req.perout.start.sec, &req.perout.start.nsec,
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&req.perout.period.sec, &req.perout.period.nsec);
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if (cnt != 5)
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goto out;
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if (req.perout.index >= ops->n_per_out)
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goto out;
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enable = req.perout.period.sec || req.perout.period.nsec;
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err = ops->enable(ops, &req, enable);
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if (err)
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goto out;
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return count;
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out:
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return err;
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}
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static ssize_t pps_enable_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct ptp_clock *ptp = dev_get_drvdata(dev);
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struct ptp_clock_info *ops = ptp->info;
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struct ptp_clock_request req = { .type = PTP_CLK_REQ_PPS };
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int cnt, enable;
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int err = -EINVAL;
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if (!capable(CAP_SYS_TIME))
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return -EPERM;
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cnt = sscanf(buf, "%d", &enable);
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if (cnt != 1)
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goto out;
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err = ops->enable(ops, &req, enable ? 1 : 0);
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if (err)
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goto out;
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return count;
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out:
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return err;
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}
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static DEVICE_ATTR(extts_enable, 0220, NULL, extts_enable_store);
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static DEVICE_ATTR(fifo, 0444, extts_fifo_show, NULL);
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static DEVICE_ATTR(period, 0220, NULL, period_store);
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static DEVICE_ATTR(pps_enable, 0220, NULL, pps_enable_store);
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int ptp_cleanup_sysfs(struct ptp_clock *ptp)
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{
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struct device *dev = ptp->dev;
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struct ptp_clock_info *info = ptp->info;
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if (info->n_ext_ts) {
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device_remove_file(dev, &dev_attr_extts_enable);
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device_remove_file(dev, &dev_attr_fifo);
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}
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if (info->n_per_out)
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device_remove_file(dev, &dev_attr_period);
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if (info->pps)
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device_remove_file(dev, &dev_attr_pps_enable);
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return 0;
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}
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int ptp_populate_sysfs(struct ptp_clock *ptp)
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{
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struct device *dev = ptp->dev;
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struct ptp_clock_info *info = ptp->info;
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int err;
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if (info->n_ext_ts) {
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err = device_create_file(dev, &dev_attr_extts_enable);
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if (err)
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goto out1;
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err = device_create_file(dev, &dev_attr_fifo);
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if (err)
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goto out2;
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}
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if (info->n_per_out) {
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err = device_create_file(dev, &dev_attr_period);
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if (err)
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goto out3;
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}
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if (info->pps) {
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err = device_create_file(dev, &dev_attr_pps_enable);
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if (err)
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goto out4;
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}
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return 0;
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out4:
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if (info->n_per_out)
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device_remove_file(dev, &dev_attr_period);
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out3:
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if (info->n_ext_ts)
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device_remove_file(dev, &dev_attr_fifo);
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out2:
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if (info->n_ext_ts)
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device_remove_file(dev, &dev_attr_extts_enable);
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out1:
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return err;
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}
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