drivers/iio/inkern.c

   1 /* The industrial I/O core in kernel channel mapping
   2  *
   3  * Copyright (c) 2011 Jonathan Cameron
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  */
   9 #include <linux/err.h>
  10 #include <linux/export.h>
  11 #include <linux/slab.h>
  12 #include <linux/mutex.h>
  13
  14 #include <linux/iio/iio.h>
  15 #include "iio_core.h"
  16 #include <linux/iio/machine.h>
  17 #include <linux/iio/driver.h>
  18 #include <linux/iio/consumer.h>
  19
  20 struct iio_map_internal {
  21         struct iio_dev *indio_dev;
  22         struct iio_map *map;
  23         struct list_head l;
  24 };
  25
  26 static LIST_HEAD(iio_map_list);
  27 static DEFINE_MUTEX(iio_map_list_lock);
  28
  29 int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
  30 {
  31         int i = 0, ret = 0;
  32         struct iio_map_internal *mapi;
  33
  34         if (maps == NULL)
  35                 return 0;
  36
  37         mutex_lock(&iio_map_list_lock);
  38         while (maps[i].consumer_dev_name != NULL) {
  39                 mapi = kzalloc(sizeof(*mapi), GFP_KERNEL);
  40                 if (mapi == NULL) {
  41                         ret = -ENOMEM;
  42                         goto error_ret;
  43                 }
  44                 mapi->map = &maps[i];
  45                 mapi->indio_dev = indio_dev;
  46                 list_add(&mapi->l, &iio_map_list);
  47                 i++;
  48         }
  49 error_ret:
  50         mutex_unlock(&iio_map_list_lock);
  51
  52         return ret;
  53 }
  54 EXPORT_SYMBOL_GPL(iio_map_array_register);
  55
  56
  57 /* Assumes the exact same array (e.g. memory locations)
  58  * used at unregistration as used at registration rather than
  59  * more complex checking of contents.
  60  */
  61 int iio_map_array_unregister(struct iio_dev *indio_dev,
  62                              struct iio_map *maps)
  63 {
  64         int i = 0, ret = 0;
  65         bool found_it;
  66         struct iio_map_internal *mapi;
  67
  68         if (maps == NULL)
  69                 return 0;
  70
  71         mutex_lock(&iio_map_list_lock);
  72         while (maps[i].consumer_dev_name != NULL) {
  73                 found_it = false;
  74                 list_for_each_entry(mapi, &iio_map_list, l)
  75                         if (&maps[i] == mapi->map) {
  76                                 list_del(&mapi->l);
  77                                 kfree(mapi);
  78                                 found_it = true;
  79                                 break;
  80                         }
  81                 if (found_it == false) {
  82                         ret = -ENODEV;
  83                         goto error_ret;
  84                 }
  85                 i++;
  86         }
  87 error_ret:
  88         mutex_unlock(&iio_map_list_lock);
  89
  90         return ret;
  91 }
  92 EXPORT_SYMBOL_GPL(iio_map_array_unregister);
  93
  94 static const struct iio_chan_spec
  95 *iio_chan_spec_from_name(const struct iio_dev *indio_dev, const char *name)
  96 {
  97         int i;
  98         const struct iio_chan_spec *chan = NULL;
  99
 100         for (i = 0; i < indio_dev->num_channels; i++)
 101                 if (indio_dev->channels[i].datasheet_name &&
 102                     strcmp(name, indio_dev->channels[i].datasheet_name) == 0) {
 103                         chan = &indio_dev->channels[i];
 104                         break;
 105                 }
 106         return chan;
 107 }
 108
 109
 110 struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
 111 {
 112         struct iio_map_internal *c_i = NULL, *c = NULL;
 113         struct iio_channel *channel;
 114
 115         if (name == NULL && channel_name == NULL)
 116                 return ERR_PTR(-ENODEV);
 117
 118         /* first find matching entry the channel map */
 119         mutex_lock(&iio_map_list_lock);
 120         list_for_each_entry(c_i, &iio_map_list, l) {
 121                 if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
 122                     (channel_name &&
 123                      strcmp(channel_name, c_i->map->consumer_channel) != 0))
 124                         continue;
 125                 c = c_i;
 126                 iio_device_get(c->indio_dev);
 127                 break;
 128         }
 129         mutex_unlock(&iio_map_list_lock);
 130         if (c == NULL)
 131                 return ERR_PTR(-ENODEV);
 132
 133         channel = kmalloc(sizeof(*channel), GFP_KERNEL);
 134         if (channel == NULL)
 135                 return ERR_PTR(-ENOMEM);
 136
 137         channel->indio_dev = c->indio_dev;
 138
 139         if (c->map->adc_channel_label)
 140                 channel->channel =
 141                         iio_chan_spec_from_name(channel->indio_dev,
 142                                                 c->map->adc_channel_label);
 143
 144         return channel;
 145 }
 146 EXPORT_SYMBOL_GPL(iio_channel_get);
 147
 148 void iio_channel_release(struct iio_channel *channel)
 149 {
 150         iio_device_put(channel->indio_dev);
 151         kfree(channel);
 152 }
 153 EXPORT_SYMBOL_GPL(iio_channel_release);
 154
 155 struct iio_channel *iio_channel_get_all(const char *name)
 156 {
 157         struct iio_channel *chans;
 158         struct iio_map_internal *c = NULL;
 159         int nummaps = 0;
 160         int mapind = 0;
 161         int i, ret;
 162
 163         if (name == NULL)
 164                 return ERR_PTR(-EINVAL);
 165
 166         mutex_lock(&iio_map_list_lock);
 167         /* first count the matching maps */
 168         list_for_each_entry(c, &iio_map_list, l)
 169                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 170                         continue;
 171                 else
 172                         nummaps++;
 173
 174         if (nummaps == 0) {
 175                 ret = -ENODEV;
 176                 goto error_ret;
 177         }
 178
 179         /* NULL terminated array to save passing size */
 180         chans = kzalloc(sizeof(*chans)*(nummaps + 1), GFP_KERNEL);
 181         if (chans == NULL) {
 182                 ret = -ENOMEM;
 183                 goto error_ret;
 184         }
 185
 186         /* for each map fill in the chans element */
 187         list_for_each_entry(c, &iio_map_list, l) {
 188                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 189                         continue;
 190                 chans[mapind].indio_dev = c->indio_dev;
 191                 chans[mapind].channel =
 192                         iio_chan_spec_from_name(chans[mapind].indio_dev,
 193                                                 c->map->adc_channel_label);
 194                 if (chans[mapind].channel == NULL) {
 195                         ret = -EINVAL;
 196                         goto error_free_chans;
 197                 }
 198                 iio_device_get(chans[mapind].indio_dev);
 199                 mapind++;
 200         }
 201         if (mapind == 0) {
 202                 ret = -ENODEV;
 203                 goto error_free_chans;
 204         }
 205         mutex_unlock(&iio_map_list_lock);
 206
 207         return chans;
 208
 209 error_free_chans:
 210         for (i = 0; i < nummaps; i++)
 211                 iio_device_put(chans[i].indio_dev);
 212         kfree(chans);
 213 error_ret:
 214         mutex_unlock(&iio_map_list_lock);
 215
 216         return ERR_PTR(ret);
 217 }
 218 EXPORT_SYMBOL_GPL(iio_channel_get_all);
 219
 220 void iio_channel_release_all(struct iio_channel *channels)
 221 {
 222         struct iio_channel *chan = &channels[0];
 223
 224         while (chan->indio_dev) {
 225                 iio_device_put(chan->indio_dev);
 226                 chan++;
 227         }
 228         kfree(channels);
 229 }
 230 EXPORT_SYMBOL_GPL(iio_channel_release_all);
 231
 232 int iio_read_channel_raw(struct iio_channel *chan, int *val)
 233 {
 234         int val2, ret;
 235
 236         mutex_lock(&chan->indio_dev->info_exist_lock);
 237         if (chan->indio_dev->info == NULL) {
 238                 ret = -ENODEV;
 239                 goto err_unlock;
 240         }
 241
 242         ret = chan->indio_dev->info->read_raw(chan->indio_dev, chan->channel,
 243                                               val, &val2, 0);
 244 err_unlock:
 245         mutex_unlock(&chan->indio_dev->info_exist_lock);
 246
 247         return ret;
 248 }
 249 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 250
 251 int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
 252 {
 253         int ret;
 254
 255         mutex_lock(&chan->indio_dev->info_exist_lock);
 256         if (chan->indio_dev->info == NULL) {
 257                 ret = -ENODEV;
 258                 goto err_unlock;
 259         }
 260
 261         ret = chan->indio_dev->info->read_raw(chan->indio_dev,
 262                                               chan->channel,
 263                                               val, val2,
 264                                               IIO_CHAN_INFO_SCALE);
 265 err_unlock:
 266         mutex_unlock(&chan->indio_dev->info_exist_lock);
 267
 268         return ret;
 269 }
 270 EXPORT_SYMBOL_GPL(iio_read_channel_scale);
 271
 272 int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
 273 {
 274         int ret = 0;
 275         /* Need to verify underlying driver has not gone away */
 276
 277         mutex_lock(&chan->indio_dev->info_exist_lock);
 278         if (chan->indio_dev->info == NULL) {
 279                 ret = -ENODEV;
 280                 goto err_unlock;
 281         }
 282
 283         *type = chan->channel->type;
 284 err_unlock:
 285         mutex_unlock(&chan->indio_dev->info_exist_lock);
 286
 287         return ret;
 288 }
 289 EXPORT_SYMBOL_GPL(iio_get_channel_type);