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 an of_device structure has a matching
  14  * of_match structure
  15  * @ids: array of of device match structures to search in
  16  * @dev: the of device structure to match against
  17  *
  18  * Used by a driver to check whether an of_device present in the
  19  * system is in its list of supported devices.
  20  */
  21 const struct of_device_id *of_match_device(const struct of_device_id *matches,
  22                                         const struct of_device *dev)
  23 {
  24         if (!dev->node)
  25                 return NULL;
  26         return of_match_node(matches, dev->node);
  27 }
  28 EXPORT_SYMBOL(of_match_device);
  29
  30 struct of_device *of_dev_get(struct of_device *dev)
  31 {
  32         struct device *tmp;
  33
  34         if (!dev)
  35                 return NULL;
  36         tmp = get_device(&dev->dev);
  37         if (tmp)
  38                 return to_of_device(tmp);
  39         else
  40                 return NULL;
  41 }
  42 EXPORT_SYMBOL(of_dev_get);
  43
  44 void of_dev_put(struct of_device *dev)
  45 {
  46         if (dev)
  47                 put_device(&dev->dev);
  48 }
  49 EXPORT_SYMBOL(of_dev_put);
  50
  51 static ssize_t devspec_show(struct device *dev,
  52                                 struct device_attribute *attr, char *buf)
  53 {
  54         struct of_device *ofdev;
  55
  56         ofdev = to_of_device(dev);
  57         return sprintf(buf, "%s\n", ofdev->node->full_name);
  58 }
  59
  60 static ssize_t modalias_show(struct device *dev,
  61                                 struct device_attribute *attr, char *buf)
  62 {
  63         struct of_device *ofdev = to_of_device(dev);
  64         ssize_t len = 0;
  65
  66         len = of_device_get_modalias(ofdev, buf, PAGE_SIZE - 2);
  67         buf[len] = '\n';
  68         buf[len+1] = 0;
  69         return len+1;
  70 }
  71
  72 struct device_attribute of_platform_device_attrs[] = {
  73         __ATTR_RO(devspec),
  74         __ATTR_RO(modalias),
  75         __ATTR_NULL
  76 };
  77
  78 /**
  79  * of_release_dev - free an of device structure when all users of it are finished.
  80  * @dev: device that's been disconnected
  81  *
  82  * Will be called only by the device core when all users of this of device are
  83  * done.
  84  */
  85 void of_release_dev(struct device *dev)
  86 {
  87         struct of_device *ofdev;
  88
  89         ofdev = to_of_device(dev);
  90         of_node_put(ofdev->node);
  91         kfree(ofdev);
  92 }
  93 EXPORT_SYMBOL(of_release_dev);
  94
  95 int of_device_register(struct of_device *ofdev)
  96 {
  97         BUG_ON(ofdev->node == NULL);
  98         return device_register(&ofdev->dev);
  99 }
 100 EXPORT_SYMBOL(of_device_register);
 101
 102 void of_device_unregister(struct of_device *ofdev)
 103 {
 104         device_unregister(&ofdev->dev);
 105 }
 106 EXPORT_SYMBOL(of_device_unregister);
 107
 108 ssize_t of_device_get_modalias(struct of_device *ofdev,
 109                                 char *str, ssize_t len)
 110 {
 111         const char *compat;
 112         int cplen, i;
 113         ssize_t tsize, csize, repend;
 114
 115         /* Name & Type */
 116         csize = snprintf(str, len, "of:N%sT%s",
 117                                 ofdev->node->name, ofdev->node->type);
 118
 119         /* Get compatible property if any */
 120         compat = of_get_property(ofdev->node, "compatible", &cplen);
 121         if (!compat)
 122                 return csize;
 123
 124         /* Find true end (we tolerate multiple \0 at the end */
 125         for (i = (cplen - 1); i >= 0 && !compat[i]; i--)
 126                 cplen--;
 127         if (!cplen)
 128                 return csize;
 129         cplen++;
 130
 131         /* Check space (need cplen+1 chars including final \0) */
 132         tsize = csize + cplen;
 133         repend = tsize;
 134
 135         if (csize >= len)               /* @ the limit, all is already filled */
 136                 return tsize;
 137
 138         if (tsize >= len) {             /* limit compat list */
 139                 cplen = len - csize - 1;
 140                 repend = len;
 141         }
 142
 143         /* Copy and do char replacement */
 144         memcpy(&str[csize + 1], compat, cplen);
 145         for (i = csize; i < repend; i++) {
 146                 char c = str[i];
 147                 if (c == '\0')
 148                         str[i] = 'C';
 149                 else if (c == ' ')
 150                         str[i] = '_';
 151         }
 152
 153         return tsize;
 154 }