drivers/of/device.c

   1 #include <linux/string.h>
   2 #include <linux/kernel.h>
   3 #include <linux/of.h>
   4 #include <linux/of_device.h>
   5 #include <linux/init.h>
   6 #include <linux/module.h>
   7 #include <linux/mod_devicetable.h>
   8 #include <linux/slab.h>
   9
  10 #include <asm/errno.h>
  11
  12 /**
  13  * of_match_device - Tell if a struct device matches an of_device_id list
  14  * @ids: array of of device match structures to search in
  15  * @dev: the of device structure to match against
  16  *
  17  * Used by a driver to check whether an platform_device present in the
  18  * system is in its list of supported devices.
  19  */
  20 const struct of_device_id *of_match_device(const struct of_device_id *matches,
  21                                            const struct device *dev)
  22 {
  23         if ((!matches) || (!dev->of_node))
  24                 return NULL;
  25         return of_match_node(matches, dev->of_node);
  26 }
  27 EXPORT_SYMBOL(of_match_device);
  28
  29 struct platform_device *of_dev_get(struct platform_device *dev)
  30 {
  31         struct device *tmp;
  32
  33         if (!dev)
  34                 return NULL;
  35         tmp = get_device(&dev->dev);
  36         if (tmp)
  37                 return to_platform_device(tmp);
  38         else
  39                 return NULL;
  40 }
  41 EXPORT_SYMBOL(of_dev_get);
  42
  43 void of_dev_put(struct platform_device *dev)
  44 {
  45         if (dev)
  46                 put_device(&dev->dev);
  47 }
  48 EXPORT_SYMBOL(of_dev_put);
  49
  50 static ssize_t devspec_show(struct device *dev,
  51                                 struct device_attribute *attr, char *buf)
  52 {
  53         struct platform_device *ofdev;
  54
  55         ofdev = to_platform_device(dev);
  56         return sprintf(buf, "%s\n", ofdev->dev.of_node->full_name);
  57 }
  58
  59 static ssize_t name_show(struct device *dev,
  60                                 struct device_attribute *attr, char *buf)
  61 {
  62         struct platform_device *ofdev;
  63
  64         ofdev = to_platform_device(dev);
  65         return sprintf(buf, "%s\n", ofdev->dev.of_node->name);
  66 }
  67
  68 static ssize_t modalias_show(struct device *dev,
  69                                 struct device_attribute *attr, char *buf)
  70 {
  71         ssize_t len = of_device_get_modalias(dev, buf, PAGE_SIZE - 2);
  72         buf[len] = '\n';
  73         buf[len+1] = 0;
  74         return len+1;
  75 }
  76
  77 struct device_attribute of_platform_device_attrs[] = {
  78         __ATTR_RO(devspec),
  79         __ATTR_RO(name),
  80         __ATTR_RO(modalias),
  81         __ATTR_NULL
  82 };
  83
  84 /**
  85  * of_release_dev - free an of device structure when all users of it are finished.
  86  * @dev: device that's been disconnected
  87  *
  88  * Will be called only by the device core when all users of this of device are
  89  * done.
  90  */
  91 void of_release_dev(struct device *dev)
  92 {
  93         struct platform_device *ofdev;
  94
  95         ofdev = to_platform_device(dev);
  96         of_node_put(ofdev->dev.of_node);
  97         kfree(ofdev);
  98 }
  99 EXPORT_SYMBOL(of_release_dev);
 100
 101 int of_device_register(struct platform_device *ofdev)
 102 {
 103         BUG_ON(ofdev->dev.of_node == NULL);
 104
 105         device_initialize(&ofdev->dev);
 106
 107         /* name and id have to be set so that the platform bus doesn't get
 108          * confused on matching */
 109         ofdev->name = dev_name(&ofdev->dev);
 110         ofdev->id = -1;
 111
 112         /* device_add will assume that this device is on the same node as
 113          * the parent. If there is no parent defined, set the node
 114          * explicitly */
 115         if (!ofdev->dev.parent)
 116                 set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
 117
 118         return device_add(&ofdev->dev);
 119 }
 120 EXPORT_SYMBOL(of_device_register);
 121
 122 void of_device_unregister(struct platform_device *ofdev)
 123 {
 124         device_unregister(&ofdev->dev);
 125 }
 126 EXPORT_SYMBOL(of_device_unregister);
 127
 128 ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len)
 129 {
 130         const char *compat;
 131         int cplen, i;
 132         ssize_t tsize, csize, repend;
 133
 134         /* Name & Type */
 135         csize = snprintf(str, len, "of:N%sT%s", dev->of_node->name,
 136                          dev->of_node->type);
 137
 138         /* Get compatible property if any */
 139         compat = of_get_property(dev->of_node, "compatible", &cplen);
 140         if (!compat)
 141                 return csize;
 142
 143         /* Find true end (we tolerate multiple \0 at the end */
 144         for (i = (cplen - 1); i >= 0 && !compat[i]; i--)
 145                 cplen--;
 146         if (!cplen)
 147                 return csize;
 148         cplen++;
 149
 150         /* Check space (need cplen+1 chars including final \0) */
 151         tsize = csize + cplen;
 152         repend = tsize;
 153
 154         if (csize >= len)               /* @ the limit, all is already filled */
 155                 return tsize;
 156
 157         if (tsize >= len) {             /* limit compat list */
 158                 cplen = len - csize - 1;
 159                 repend = len;
 160         }
 161
 162         /* Copy and do char replacement */
 163         memcpy(&str[csize + 1], compat, cplen);
 164         for (i = csize; i < repend; i++) {
 165                 char c = str[i];
 166                 if (c == '\0')
 167                         str[i] = 'C';
 168                 else if (c == ' ')
 169                         str[i] = '_';
 170         }
 171
 172         return tsize;
 173 }
 174
 175 /**
 176  * of_device_uevent - Display OF related uevent information
 177  */
 178 int of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 179 {
 180         const char *compat;
 181         int seen = 0, cplen, sl;
 182
 183         if ((!dev) || (!dev->of_node))
 184                 return -ENODEV;
 185
 186         if (add_uevent_var(env, "OF_NAME=%s", dev->of_node->name))
 187                 return -ENOMEM;
 188
 189         if (add_uevent_var(env, "OF_TYPE=%s", dev->of_node->type))
 190                 return -ENOMEM;
 191
 192         /* Since the compatible field can contain pretty much anything
 193          * it's not really legal to split it out with commas. We split it
 194          * up using a number of environment variables instead. */
 195
 196         compat = of_get_property(dev->of_node, "compatible", &cplen);
 197         while (compat && *compat && cplen > 0) {
 198                 if (add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat))
 199                         return -ENOMEM;
 200
 201                 sl = strlen(compat) + 1;
 202                 compat += sl;
 203                 cplen -= sl;
 204                 seen++;
 205         }
 206
 207         if (add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen))
 208                 return -ENOMEM;
 209
 210         /* modalias is trickier, we add it in 2 steps */
 211         if (add_uevent_var(env, "MODALIAS="))
 212                 return -ENOMEM;
 213
 214         sl = of_device_get_modalias(dev, &env->buf[env->buflen-1],
 215                                     sizeof(env->buf) - env->buflen);
 216         if (sl >= (sizeof(env->buf) - env->buflen))
 217                 return -ENOMEM;
 218         env->buflen += sl;
 219
 220         return 0;
 221 }