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
soc_device_to_device(struct soc_device * soc_dev)39 struct device *soc_device_to_device(struct soc_device *soc_dev)
40 {
41 return &soc_dev->dev;
42 }
43
soc_attribute_mode(struct kobject * kobj,struct attribute * attr,int index)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
soc_info_get(struct device * dev,struct device_attribute * attr,char * buf)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
soc_release(struct device * dev)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
soc_device_register(struct soc_device_attribute * soc_dev_attr)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 EXPORT_SYMBOL_GPL(soc_device_register);
150
151 /* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */
soc_device_unregister(struct soc_device * soc_dev)152 void soc_device_unregister(struct soc_device *soc_dev)
153 {
154 ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
155
156 device_unregister(&soc_dev->dev);
157 }
158 EXPORT_SYMBOL_GPL(soc_device_unregister);
159
soc_bus_register(void)160 static int __init soc_bus_register(void)
161 {
162 return bus_register(&soc_bus_type);
163 }
164 core_initcall(soc_bus_register);
165
soc_bus_unregister(void)166 static void __exit soc_bus_unregister(void)
167 {
168 ida_destroy(&soc_ida);
169
170 bus_unregister(&soc_bus_type);
171 }
172 module_exit(soc_bus_unregister);
173