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