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/timex.h> 30 #include <linux/spinlock.h> 31 #include <linux/fs.h> 32 #include <linux/pps_kernel.h> 33 #include <linux/slab.h> 34 35 #include "kc.h" 36 37 /* 38 * Local functions 39 */ 40 41 static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset) 42 { 43 ts->nsec += offset->nsec; 44 while (ts->nsec >= NSEC_PER_SEC) { 45 ts->nsec -= NSEC_PER_SEC; 46 ts->sec++; 47 } 48 while (ts->nsec < 0) { 49 ts->nsec += NSEC_PER_SEC; 50 ts->sec--; 51 } 52 ts->sec += offset->sec; 53 } 54 55 /* 56 * Exported functions 57 */ 58 59 /* pps_register_source - add a PPS source in the system 60 * @info: the PPS info struct 61 * @default_params: the default PPS parameters of the new source 62 * 63 * This function is used to add a new PPS source in the system. The new 64 * source is described by info's fields and it will have, as default PPS 65 * parameters, the ones specified into default_params. 66 * 67 * The function returns, in case of success, the PPS device. Otherwise NULL. 68 */ 69 70 struct pps_device *pps_register_source(struct pps_source_info *info, 71 int default_params) 72 { 73 struct pps_device *pps; 74 int err; 75 76 /* Sanity checks */ 77 if ((info->mode & default_params) != default_params) { 78 pr_err("%s: unsupported default parameters\n", 79 info->name); 80 err = -EINVAL; 81 goto pps_register_source_exit; 82 } 83 if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 && 84 info->echo == NULL) { 85 pr_err("%s: echo function is not defined\n", 86 info->name); 87 err = -EINVAL; 88 goto pps_register_source_exit; 89 } 90 if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { 91 pr_err("%s: unspecified time format\n", 92 info->name); 93 err = -EINVAL; 94 goto pps_register_source_exit; 95 } 96 97 /* Allocate memory for the new PPS source struct */ 98 pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL); 99 if (pps == NULL) { 100 err = -ENOMEM; 101 goto pps_register_source_exit; 102 } 103 104 /* These initializations must be done before calling idr_get_new() 105 * in order to avoid reces into pps_event(). 106 */ 107 pps->params.api_version = PPS_API_VERS; 108 pps->params.mode = default_params; 109 pps->info = *info; 110 111 init_waitqueue_head(&pps->queue); 112 spin_lock_init(&pps->lock); 113 114 /* Create the char device */ 115 err = pps_register_cdev(pps); 116 if (err < 0) { 117 pr_err("%s: unable to create char device\n", 118 info->name); 119 goto kfree_pps; 120 } 121 122 dev_info(pps->dev, "new PPS source %s\n", info->name); 123 124 return pps; 125 126 kfree_pps: 127 kfree(pps); 128 129 pps_register_source_exit: 130 pr_err("%s: unable to register source\n", info->name); 131 132 return NULL; 133 } 134 EXPORT_SYMBOL(pps_register_source); 135 136 /* pps_unregister_source - remove a PPS source from the system 137 * @pps: the PPS source 138 * 139 * This function is used to remove a previously registered PPS source from 140 * the system. 141 */ 142 143 void pps_unregister_source(struct pps_device *pps) 144 { 145 pps_kc_remove(pps); 146 pps_unregister_cdev(pps); 147 148 /* don't have to kfree(pps) here because it will be done on 149 * device destruction */ 150 } 151 EXPORT_SYMBOL(pps_unregister_source); 152 153 /* pps_event - register a PPS event into the system 154 * @pps: the PPS device 155 * @ts: the event timestamp 156 * @event: the event type 157 * @data: userdef pointer 158 * 159 * This function is used by each PPS client in order to register a new 160 * PPS event into the system (it's usually called inside an IRQ handler). 161 * 162 * If an echo function is associated with the PPS device it will be called 163 * as: 164 * pps->info.echo(pps, event, data); 165 */ 166 void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, 167 void *data) 168 { 169 unsigned long flags; 170 int captured = 0; 171 struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 }; 172 173 /* check event type */ 174 BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); 175 176 dev_dbg(pps->dev, "PPS event at %ld.%09ld\n", 177 ts->ts_real.tv_sec, ts->ts_real.tv_nsec); 178 179 timespec_to_pps_ktime(&ts_real, ts->ts_real); 180 181 spin_lock_irqsave(&pps->lock, flags); 182 183 /* Must call the echo function? */ 184 if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) 185 pps->info.echo(pps, event, data); 186 187 /* Check the event */ 188 pps->current_mode = pps->params.mode; 189 if (event & pps->params.mode & PPS_CAPTUREASSERT) { 190 /* We have to add an offset? */ 191 if (pps->params.mode & PPS_OFFSETASSERT) 192 pps_add_offset(&ts_real, 193 &pps->params.assert_off_tu); 194 195 /* Save the time stamp */ 196 pps->assert_tu = ts_real; 197 pps->assert_sequence++; 198 dev_dbg(pps->dev, "capture assert seq #%u\n", 199 pps->assert_sequence); 200 201 captured = ~0; 202 } 203 if (event & pps->params.mode & PPS_CAPTURECLEAR) { 204 /* We have to add an offset? */ 205 if (pps->params.mode & PPS_OFFSETCLEAR) 206 pps_add_offset(&ts_real, 207 &pps->params.clear_off_tu); 208 209 /* Save the time stamp */ 210 pps->clear_tu = ts_real; 211 pps->clear_sequence++; 212 dev_dbg(pps->dev, "capture clear seq #%u\n", 213 pps->clear_sequence); 214 215 captured = ~0; 216 } 217 218 pps_kc_event(pps, ts, event); 219 220 /* Wake up if captured something */ 221 if (captured) { 222 pps->last_ev++; 223 wake_up_interruptible_all(&pps->queue); 224 225 kill_fasync(&pps->async_queue, SIGIO, POLL_IN); 226 } 227 228 spin_unlock_irqrestore(&pps->lock, flags); 229 } 230 EXPORT_SYMBOL(pps_event); 231