drivers/hwmon/hwmon.c

   1 /*
   2  * hwmon.c - part of lm_sensors, Linux kernel modules for hardware monitoring
   3  *
   4  * This file defines the sysfs class "hwmon", for use by sensors drivers.
   5  *
   6  * Copyright (C) 2005 Mark M. Hoffman <mhoffman@lightlink.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; version 2 of the License.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17 #include <linux/err.h>
  18 #include <linux/slab.h>
  19 #include <linux/kdev_t.h>
  20 #include <linux/idr.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/gfp.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/pci.h>
  25
  26 #define HWMON_ID_PREFIX "hwmon"
  27 #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"
  28
  29 struct hwmon_device {
  30         const char *name;
  31         struct device dev;
  32 };
  33 #define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)
  34
  35 static ssize_t
  36 show_name(struct device *dev, struct device_attribute *attr, char *buf)
  37 {
  38         return sprintf(buf, "%s\n", to_hwmon_device(dev)->name);
  39 }
  40 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
  41
  42 static struct attribute *hwmon_dev_attrs[] = {
  43         &dev_attr_name.attr,
  44         NULL
  45 };
  46
  47 static umode_t hwmon_dev_name_is_visible(struct kobject *kobj,
  48                                          struct attribute *attr, int n)
  49 {
  50         struct device *dev = container_of(kobj, struct device, kobj);
  51
  52         if (to_hwmon_device(dev)->name == NULL)
  53                 return 0;
  54
  55         return attr->mode;
  56 }
  57
  58 static struct attribute_group hwmon_dev_attr_group = {
  59         .attrs          = hwmon_dev_attrs,
  60         .is_visible     = hwmon_dev_name_is_visible,
  61 };
  62
  63 static const struct attribute_group *hwmon_dev_attr_groups[] = {
  64         &hwmon_dev_attr_group,
  65         NULL
  66 };
  67
  68 static void hwmon_dev_release(struct device *dev)
  69 {
  70         kfree(to_hwmon_device(dev));
  71 }
  72
  73 static struct class hwmon_class = {
  74         .name = "hwmon",
  75         .owner = THIS_MODULE,
  76         .dev_groups = hwmon_dev_attr_groups,
  77         .dev_release = hwmon_dev_release,
  78 };
  79
  80 static DEFINE_IDA(hwmon_ida);
  81
  82 /**
  83  * hwmon_device_register_with_groups - register w/ hwmon
  84  * @dev: the parent device
  85  * @name: hwmon name attribute
  86  * @drvdata: driver data to attach to created device
  87  * @groups: List of attribute groups to create
  88  *
  89  * hwmon_device_unregister() must be called when the device is no
  90  * longer needed.
  91  *
  92  * Returns the pointer to the new device.
  93  */
  94 struct device *
  95 hwmon_device_register_with_groups(struct device *dev, const char *name,
  96                                   void *drvdata,
  97                                   const struct attribute_group **groups)
  98 {
  99         struct hwmon_device *hwdev;
 100         int err, id;
 101
 102         id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
 103         if (id < 0)
 104                 return ERR_PTR(id);
 105
 106         hwdev = kzalloc(sizeof(*hwdev), GFP_KERNEL);
 107         if (hwdev == NULL) {
 108                 err = -ENOMEM;
 109                 goto ida_remove;
 110         }
 111
 112         hwdev->name = name;
 113         hwdev->dev.class = &hwmon_class;
 114         hwdev->dev.parent = dev;
 115         hwdev->dev.groups = groups;
 116         hwdev->dev.of_node = dev ? dev->of_node : NULL;
 117         dev_set_drvdata(&hwdev->dev, drvdata);
 118         dev_set_name(&hwdev->dev, HWMON_ID_FORMAT, id);
 119         err = device_register(&hwdev->dev);
 120         if (err)
 121                 goto free;
 122
 123         return &hwdev->dev;
 124
 125 free:
 126         kfree(hwdev);
 127 ida_remove:
 128         ida_simple_remove(&hwmon_ida, id);
 129         return ERR_PTR(err);
 130 }
 131 EXPORT_SYMBOL_GPL(hwmon_device_register_with_groups);
 132
 133 /**
 134  * hwmon_device_register - register w/ hwmon
 135  * @dev: the device to register
 136  *
 137  * hwmon_device_unregister() must be called when the device is no
 138  * longer needed.
 139  *
 140  * Returns the pointer to the new device.
 141  */
 142 struct device *hwmon_device_register(struct device *dev)
 143 {
 144         return hwmon_device_register_with_groups(dev, NULL, NULL, NULL);
 145 }
 146 EXPORT_SYMBOL_GPL(hwmon_device_register);
 147
 148 /**
 149  * hwmon_device_unregister - removes the previously registered class device
 150  *
 151  * @dev: the class device to destroy
 152  */
 153 void hwmon_device_unregister(struct device *dev)
 154 {
 155         int id;
 156
 157         if (likely(sscanf(dev_name(dev), HWMON_ID_FORMAT, &id) == 1)) {
 158                 device_unregister(dev);
 159                 ida_simple_remove(&hwmon_ida, id);
 160         } else
 161                 dev_dbg(dev->parent,
 162                         "hwmon_device_unregister() failed: bad class ID!\n");
 163 }
 164 EXPORT_SYMBOL_GPL(hwmon_device_unregister);
 165
 166 static void devm_hwmon_release(struct device *dev, void *res)
 167 {
 168         struct device *hwdev = *(struct device **)res;
 169
 170         hwmon_device_unregister(hwdev);
 171 }
 172
 173 /**
 174  * devm_hwmon_device_register_with_groups - register w/ hwmon
 175  * @dev: the parent device
 176  * @name: hwmon name attribute
 177  * @drvdata: driver data to attach to created device
 178  * @groups: List of attribute groups to create
 179  *
 180  * Returns the pointer to the new device. The new device is automatically
 181  * unregistered with the parent device.
 182  */
 183 struct device *
 184 devm_hwmon_device_register_with_groups(struct device *dev, const char *name,
 185                                        void *drvdata,
 186                                        const struct attribute_group **groups)
 187 {
 188         struct device **ptr, *hwdev;
 189
 190         if (!dev)
 191                 return ERR_PTR(-EINVAL);
 192
 193         ptr = devres_alloc(devm_hwmon_release, sizeof(*ptr), GFP_KERNEL);
 194         if (!ptr)
 195                 return ERR_PTR(-ENOMEM);
 196
 197         hwdev = hwmon_device_register_with_groups(dev, name, drvdata, groups);
 198         if (IS_ERR(hwdev))
 199                 goto error;
 200
 201         *ptr = hwdev;
 202         devres_add(dev, ptr);
 203         return hwdev;
 204
 205 error:
 206         devres_free(ptr);
 207         return hwdev;
 208 }
 209 EXPORT_SYMBOL_GPL(devm_hwmon_device_register_with_groups);
 210
 211 static int devm_hwmon_match(struct device *dev, void *res, void *data)
 212 {
 213         struct device **hwdev = res;
 214
 215         return *hwdev == data;
 216 }
 217
 218 /**
 219  * devm_hwmon_device_unregister - removes a previously registered hwmon device
 220  *
 221  * @dev: the parent device of the device to unregister
 222  */
 223 void devm_hwmon_device_unregister(struct device *dev)
 224 {
 225         WARN_ON(devres_release(dev, devm_hwmon_release, devm_hwmon_match, dev));
 226 }
 227 EXPORT_SYMBOL_GPL(devm_hwmon_device_unregister);
 228
 229 static void __init hwmon_pci_quirks(void)
 230 {
 231 #if defined CONFIG_X86 && defined CONFIG_PCI
 232         struct pci_dev *sb;
 233         u16 base;
 234         u8 enable;
 235
 236         /* Open access to 0x295-0x296 on MSI MS-7031 */
 237         sb = pci_get_device(PCI_VENDOR_ID_ATI, 0x436c, NULL);
 238         if (sb) {
 239                 if (sb->subsystem_vendor == 0x1462 &&   /* MSI */
 240                     sb->subsystem_device == 0x0031) {   /* MS-7031 */
 241                         pci_read_config_byte(sb, 0x48, &enable);
 242                         pci_read_config_word(sb, 0x64, &base);
 243
 244                         if (base == 0 && !(enable & BIT(2))) {
 245                                 dev_info(&sb->dev,
 246                                          "Opening wide generic port at 0x295\n");
 247                                 pci_write_config_word(sb, 0x64, 0x295);
 248                                 pci_write_config_byte(sb, 0x48,
 249                                                       enable | BIT(2));
 250                         }
 251                 }
 252                 pci_dev_put(sb);
 253         }
 254 #endif
 255 }
 256
 257 static int __init hwmon_init(void)
 258 {
 259         int err;
 260
 261         hwmon_pci_quirks();
 262
 263         err = class_register(&hwmon_class);
 264         if (err) {
 265                 pr_err("couldn't register hwmon sysfs class\n");
 266                 return err;
 267         }
 268         return 0;
 269 }
 270
 271 static void __exit hwmon_exit(void)
 272 {
 273         class_unregister(&hwmon_class);
 274 }
 275
 276 subsys_initcall(hwmon_init);
 277 module_exit(hwmon_exit);
 278
 279 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 280 MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
 281 MODULE_LICENSE("GPL");
 282