diff options
Diffstat (limited to 'drivers/pps/kapi.c')
| -rw-r--r-- | drivers/pps/kapi.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c new file mode 100644 index 000000000..d9d566f70 --- /dev/null +++ b/drivers/pps/kapi.c @@ -0,0 +1,223 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * kernel API + * + * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/time.h> +#include <linux/timex.h> +#include <linux/spinlock.h> +#include <linux/fs.h> +#include <linux/pps_kernel.h> +#include <linux/slab.h> + +#include "kc.h" + +/* + * Local functions + */ + +static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset) +{ + ts->nsec += offset->nsec; + while (ts->nsec >= NSEC_PER_SEC) { + ts->nsec -= NSEC_PER_SEC; + ts->sec++; + } + while (ts->nsec < 0) { + ts->nsec += NSEC_PER_SEC; + ts->sec--; + } + ts->sec += offset->sec; +} + +static void pps_echo_client_default(struct pps_device *pps, int event, + void *data) +{ + dev_info(pps->dev, "echo %s %s\n", + event & PPS_CAPTUREASSERT ? "assert" : "", + event & PPS_CAPTURECLEAR ? "clear" : ""); +} + +/* + * Exported functions + */ + +/* pps_register_source - add a PPS source in the system + * @info: the PPS info struct + * @default_params: the default PPS parameters of the new source + * + * This function is used to add a new PPS source in the system. The new + * source is described by info's fields and it will have, as default PPS + * parameters, the ones specified into default_params. + * + * The function returns, in case of success, the PPS device. Otherwise + * ERR_PTR(errno). + */ + +struct pps_device *pps_register_source(struct pps_source_info *info, + int default_params) +{ + struct pps_device *pps; + int err; + + /* Sanity checks */ + if ((info->mode & default_params) != default_params) { + pr_err("%s: unsupported default parameters\n", + info->name); + err = -EINVAL; + goto pps_register_source_exit; + } + if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { + pr_err("%s: unspecified time format\n", + info->name); + err = -EINVAL; + goto pps_register_source_exit; + } + + /* Allocate memory for the new PPS source struct */ + pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL); + if (pps == NULL) { + err = -ENOMEM; + goto pps_register_source_exit; + } + + /* These initializations must be done before calling idr_alloc() + * in order to avoid reces into pps_event(). + */ + pps->params.api_version = PPS_API_VERS; + pps->params.mode = default_params; + pps->info = *info; + + /* check for default echo function */ + if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) && + pps->info.echo == NULL) + pps->info.echo = pps_echo_client_default; + + init_waitqueue_head(&pps->queue); + spin_lock_init(&pps->lock); + + /* Create the char device */ + err = pps_register_cdev(pps); + if (err < 0) { + pr_err("%s: unable to create char device\n", + info->name); + goto kfree_pps; + } + + dev_info(pps->dev, "new PPS source %s\n", info->name); + + return pps; + +kfree_pps: + kfree(pps); + +pps_register_source_exit: + pr_err("%s: unable to register source\n", info->name); + + return ERR_PTR(err); +} +EXPORT_SYMBOL(pps_register_source); + +/* pps_unregister_source - remove a PPS source from the system + * @pps: the PPS source + * + * This function is used to remove a previously registered PPS source from + * the system. + */ + +void pps_unregister_source(struct pps_device *pps) +{ + pps_kc_remove(pps); + pps_unregister_cdev(pps); + + /* don't have to kfree(pps) here because it will be done on + * device destruction */ +} +EXPORT_SYMBOL(pps_unregister_source); + +/* pps_event - register a PPS event into the system + * @pps: the PPS device + * @ts: the event timestamp + * @event: the event type + * @data: userdef pointer + * + * This function is used by each PPS client in order to register a new + * PPS event into the system (it's usually called inside an IRQ handler). + * + * If an echo function is associated with the PPS device it will be called + * as: + * pps->info.echo(pps, event, data); + */ +void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, + void *data) +{ + unsigned long flags; + int captured = 0; + struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 }; + + /* check event type */ + BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); + + dev_dbg(pps->dev, "PPS event at %lld.%09ld\n", + (s64)ts->ts_real.tv_sec, ts->ts_real.tv_nsec); + + timespec_to_pps_ktime(&ts_real, ts->ts_real); + + spin_lock_irqsave(&pps->lock, flags); + + /* Must call the echo function? */ + if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) + pps->info.echo(pps, event, data); + + /* Check the event */ + pps->current_mode = pps->params.mode; + if (event & pps->params.mode & PPS_CAPTUREASSERT) { + /* We have to add an offset? */ + if (pps->params.mode & PPS_OFFSETASSERT) + pps_add_offset(&ts_real, + &pps->params.assert_off_tu); + + /* Save the time stamp */ + pps->assert_tu = ts_real; + pps->assert_sequence++; + dev_dbg(pps->dev, "capture assert seq #%u\n", + pps->assert_sequence); + + captured = ~0; + } + if (event & pps->params.mode & PPS_CAPTURECLEAR) { + /* We have to add an offset? */ + if (pps->params.mode & PPS_OFFSETCLEAR) + pps_add_offset(&ts_real, + &pps->params.clear_off_tu); + + /* Save the time stamp */ + pps->clear_tu = ts_real; + pps->clear_sequence++; + dev_dbg(pps->dev, "capture clear seq #%u\n", + pps->clear_sequence); + + captured = ~0; + } + + pps_kc_event(pps, ts, event); + + /* Wake up if captured something */ + if (captured) { + pps->last_ev++; + wake_up_interruptible_all(&pps->queue); + + kill_fasync(&pps->async_queue, SIGIO, POLL_IN); + } + + spin_unlock_irqrestore(&pps->lock, flags); +} +EXPORT_SYMBOL(pps_event); |