drivers/base/soc.c

   1 /*
   2  * Copyright (C) ST-Ericsson SA 2011
   3  *
   4  * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
   5  * License terms:  GNU General Public License (GPL), version 2
   6  */
   7
   8 #include <linux/sysfs.h>
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/stat.h>
  12 #include <linux/slab.h>
  13 #include <linux/idr.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/sys_soc.h>
  16 #include <linux/err.h>
  17
  18 static DEFINE_IDA(soc_ida);
  19
  20 static ssize_t soc_info_get(struct device *dev,
  21                             struct device_attribute *attr,
  22                             char *buf);
  23
  24 struct soc_device {
  25         struct device dev;
  26         struct soc_device_attribute *attr;
  27         int soc_dev_num;
  28 };
  29
  30 static struct bus_type soc_bus_type = {
  31         .name  = "soc",
  32 };
  33
  34 static DEVICE_ATTR(machine,  S_IRUGO, soc_info_get,  NULL);
  35 static DEVICE_ATTR(family,   S_IRUGO, soc_info_get,  NULL);
  36 static DEVICE_ATTR(soc_id,   S_IRUGO, soc_info_get,  NULL);
  37 static DEVICE_ATTR(revision, S_IRUGO, soc_info_get,  NULL);
  38
  39 struct device *soc_device_to_device(struct soc_device *soc_dev)
  40 {
  41         return &soc_dev->dev;
  42 }
  43
  44 static umode_t soc_attribute_mode(struct kobject *kobj,
  45                                 struct attribute *attr,
  46                                 int index)
  47 {
  48         struct device *dev = container_of(kobj, struct device, kobj);
  49         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  50
  51         if ((attr == &dev_attr_machine.attr)
  52             && (soc_dev->attr->machine != NULL))
  53                 return attr->mode;
  54         if ((attr == &dev_attr_family.attr)
  55             && (soc_dev->attr->family != NULL))
  56                 return attr->mode;
  57         if ((attr == &dev_attr_revision.attr)
  58             && (soc_dev->attr->revision != NULL))
  59                 return attr->mode;
  60         if ((attr == &dev_attr_soc_id.attr)
  61             && (soc_dev->attr->soc_id != NULL))
  62                 return attr->mode;
  63
  64         /* Unknown or unfilled attribute. */
  65         return 0;
  66 }
  67
  68 static ssize_t soc_info_get(struct device *dev,
  69                             struct device_attribute *attr,
  70                             char *buf)
  71 {
  72         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
  73
  74         if (attr == &dev_attr_machine)
  75                 return sprintf(buf, "%s\n", soc_dev->attr->machine);
  76         if (attr == &dev_attr_family)
  77                 return sprintf(buf, "%s\n", soc_dev->attr->family);
  78         if (attr == &dev_attr_revision)
  79                 return sprintf(buf, "%s\n", soc_dev->attr->revision);
  80         if (attr == &dev_attr_soc_id)
  81                 return sprintf(buf, "%s\n", soc_dev->attr->soc_id);
  82
  83         return -EINVAL;
  84
  85 }
  86
  87 static struct attribute *soc_attr[] = {
  88         &dev_attr_machine.attr,
  89         &dev_attr_family.attr,
  90         &dev_attr_soc_id.attr,
  91         &dev_attr_revision.attr,
  92         NULL,
  93 };
  94
  95 static const struct attribute_group soc_attr_group = {
  96         .attrs = soc_attr,
  97         .is_visible = soc_attribute_mode,
  98 };
  99
 100 static const struct attribute_group *soc_attr_groups[] = {
 101         &soc_attr_group,
 102         NULL,
 103 };
 104
 105 static void soc_release(struct device *dev)
 106 {
 107         struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 108
 109         kfree(soc_dev);
 110 }
 111
 112 struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
 113 {
 114         struct soc_device *soc_dev;
 115         int ret;
 116
 117         soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
 118         if (!soc_dev) {
 119                 ret = -ENOMEM;
 120                 goto out1;
 121         }
 122
 123         /* Fetch a unique (reclaimable) SOC ID. */
 124         ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
 125         if (ret < 0)
 126                 goto out2;
 127         soc_dev->soc_dev_num = ret;
 128
 129         soc_dev->attr = soc_dev_attr;
 130         soc_dev->dev.bus = &soc_bus_type;
 131         soc_dev->dev.groups = soc_attr_groups;
 132         soc_dev->dev.release = soc_release;
 133
 134         dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
 135
 136         ret = device_register(&soc_dev->dev);
 137         if (ret)
 138                 goto out3;
 139
 140         return soc_dev;
 141
 142 out3:
 143         ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
 144 out2:
 145         kfree(soc_dev);
 146 out1:
 147         return ERR_PTR(ret);
 148 }
 149
 150 /* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */
 151 void soc_device_unregister(struct soc_device *soc_dev)
 152 {
 153         ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
 154
 155         device_unregister(&soc_dev->dev);
 156 }
 157
 158 static int __init soc_bus_register(void)
 159 {
 160         return bus_register(&soc_bus_type);
 161 }
 162 core_initcall(soc_bus_register);
 163
 164 static void __exit soc_bus_unregister(void)
 165 {
 166         ida_destroy(&soc_ida);
 167
 168         bus_unregister(&soc_bus_type);
 169 }
 170 module_exit(soc_bus_unregister);