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); 171