1 /* 2 * kernel API 3 * 4 * 5 * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 20 */ 21 22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 23 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/init.h> 27 #include <linux/sched.h> 28 #include <linux/time.h> 29 #include <linux/spinlock.h> 30 #include <linux/fs.h> 31 #include <linux/pps_kernel.h> 32 #include <linux/slab.h> 33 34 /* 35 * Local functions 36 */ 37 38 static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset) 39 { 40 ts->nsec += offset->nsec; 41 while (ts->nsec >= NSEC_PER_SEC) { 42 ts->nsec -= NSEC_PER_SEC; 43 ts->sec++; 44 } 45 while (ts->nsec < 0) { 46 ts->nsec += NSEC_PER_SEC; 47 ts->sec--; 48 } 49 ts->sec += offset->sec; 50 } 51 52 /* 53 * Exported functions 54 */ 55 56 /* pps_register_source - add a PPS source in the system 57 * @info: the PPS info struct 58 * @default_params: the default PPS parameters of the new source 59 * 60 * This function is used to add a new PPS source in the system. The new 61 * source is described by info's fields and it will have, as default PPS 62 * parameters, the ones specified into default_params. 63 * 64 * The function returns, in case of success, the PPS device. Otherwise NULL. 65 */ 66 67 struct pps_device *pps_register_source(struct pps_source_info *info, 68 int default_params) 69 { 70 struct pps_device *pps; 71 int err; 72 73 /* Sanity checks */ 74 if ((info->mode & default_params) != default_params) { 75 pr_err("%s: unsupported default parameters\n", 76 info->name); 77 err = -EINVAL; 78 goto pps_register_source_exit; 79 } 80 if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 && 81 info->echo == NULL) { 82 pr_err("%s: echo function is not defined\n", 83 info->name); 84 err = -EINVAL; 85 goto pps_register_source_exit; 86 } 87 if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { 88 pr_err("%s: unspecified time format\n", 89 info->name); 90 err = -EINVAL; 91 goto pps_register_source_exit; 92 } 93 94 /* Allocate memory for the new PPS source struct */ 95 pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL); 96 if (pps == NULL) { 97 err = -ENOMEM; 98 goto pps_register_source_exit; 99 } 100 101 /* These initializations must be done before calling idr_get_new() 102 * in order to avoid reces into pps_event(). 103 */ 104 pps->params.api_version = PPS_API_VERS; 105 pps->params.mode = default_params; 106 pps->info = *info; 107 108 init_waitqueue_head(&pps->queue); 109 spin_lock_init(&pps->lock); 110 111 /* Create the char device */ 112 err = pps_register_cdev(pps); 113 if (err < 0) { 114 pr_err("%s: unable to create char device\n", 115 info->name); 116 goto kfree_pps; 117 } 118 119 dev_info(pps->dev, "new PPS source %s\n", info->name); 120 121 return pps; 122 123 kfree_pps: 124 kfree(pps); 125 126 pps_register_source_exit: 127 pr_err("%s: unable to register source\n", info->name); 128 129 return NULL; 130 } 131 EXPORT_SYMBOL(pps_register_source); 132 133 /* pps_unregister_source - remove a PPS source from the system 134 * @pps: the PPS source 135 * 136 * This function is used to remove a previously registered PPS source from 137 * the system. 138 */ 139 140 void pps_unregister_source(struct pps_device *pps) 141 { 142 pps_unregister_cdev(pps); 143 144 /* don't have to kfree(pps) here because it will be done on 145 * device destruction */ 146 } 147 EXPORT_SYMBOL(pps_unregister_source); 148 149 /* pps_event - register a PPS event into the system 150 * @pps: the PPS device 151 * @ts: the event timestamp 152 * @event: the event type 153 * @data: userdef pointer 154 * 155 * This function is used by each PPS client in order to register a new 156 * PPS event into the system (it's usually called inside an IRQ handler). 157 * 158 * If an echo function is associated with the PPS device it will be called 159 * as: 160 * pps->info.echo(pps, event, data); 161 */ 162 void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, 163 void *data) 164 { 165 unsigned long flags; 166 int captured = 0; 167 struct pps_ktime ts_real; 168 169 /* check event type */ 170 BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); 171 172 dev_dbg(pps->dev, "PPS event at %ld.%09ld\n", 173 ts->ts_real.tv_sec, ts->ts_real.tv_nsec); 174 175 timespec_to_pps_ktime(&ts_real, ts->ts_real); 176 177 spin_lock_irqsave(&pps->lock, flags); 178 179 /* Must call the echo function? */ 180 if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) 181 pps->info.echo(pps, event, data); 182 183 /* Check the event */ 184 pps->current_mode = pps->params.mode; 185 if (event & pps->params.mode & PPS_CAPTUREASSERT) { 186 /* We have to add an offset? */ 187 if (pps->params.mode & PPS_OFFSETASSERT) 188 pps_add_offset(&ts_real, 189 &pps->params.assert_off_tu); 190 191 /* Save the time stamp */ 192 pps->assert_tu = ts_real; 193 pps->assert_sequence++; 194 dev_dbg(pps->dev, "capture assert seq #%u\n", 195 pps->assert_sequence); 196 197 captured = ~0; 198 } 199 if (event & pps->params.mode & PPS_CAPTURECLEAR) { 200 /* We have to add an offset? */ 201 if (pps->params.mode & PPS_OFFSETCLEAR) 202 pps_add_offset(&ts_real, 203 &pps->params.clear_off_tu); 204 205 /* Save the time stamp */ 206 pps->clear_tu = ts_real; 207 pps->clear_sequence++; 208 dev_dbg(pps->dev, "capture clear seq #%u\n", 209 pps->clear_sequence); 210 211 captured = ~0; 212 } 213 214 /* Wake up if captured something */ 215 if (captured) { 216 pps->last_ev++; 217 wake_up_interruptible_all(&pps->queue); 218 219 kill_fasync(&pps->async_queue, SIGIO, POLL_IN); 220 } 221 222 spin_unlock_irqrestore(&pps->lock, flags); 223 } 224 EXPORT_SYMBOL(pps_event); 225