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
 18static DEFINE_IDA(soc_ida);
 19
 20static ssize_t soc_info_get(struct device *dev,
 21			    struct device_attribute *attr,
 22			    char *buf);
 23
 24struct soc_device {
 25	struct device dev;
 26	struct soc_device_attribute *attr;
 27	int soc_dev_num;
 28};
 29
 30static struct bus_type soc_bus_type = {
 31	.name  = "soc",
 32};
 33
 34static DEVICE_ATTR(machine,  S_IRUGO, soc_info_get,  NULL);
 35static DEVICE_ATTR(family,   S_IRUGO, soc_info_get,  NULL);
 36static DEVICE_ATTR(soc_id,   S_IRUGO, soc_info_get,  NULL);
 37static DEVICE_ATTR(revision, S_IRUGO, soc_info_get,  NULL);
 38
 39struct device *soc_device_to_device(struct soc_device *soc_dev)
 40{
 41	return &soc_dev->dev;
 42}
 43
 44static 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
 68static 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
 87static 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
 95static const struct attribute_group soc_attr_group = {
 96	.attrs = soc_attr,
 97	.is_visible = soc_attribute_mode,
 98};
 99
100static const struct attribute_group *soc_attr_groups[] = {
101	&soc_attr_group,
102	NULL,
103};
104
105static 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
112struct 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
142out3:
143	ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
144out2:
145	kfree(soc_dev);
146out1:
147	return ERR_PTR(ret);
148}
149
150/* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */
151void 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
158static int __init soc_bus_register(void)
159{
160	return bus_register(&soc_bus_type);
161}
162core_initcall(soc_bus_register);
163
164static void __exit soc_bus_unregister(void)
165{
166	ida_destroy(&soc_ida);
167
168	bus_unregister(&soc_bus_type);
169}
170module_exit(soc_bus_unregister);