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 #include <linux/string.h>
  26
  27 #define HWMON_ID_PREFIX "hwmon"
  28 #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"
  29
  30 struct hwmon_device {
  31         const char *name;
  32         struct device dev;
  33 };
  34 #define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)
  35
  36 static ssize_t
  37 show_name(struct device *dev, struct device_attribute *attr, char *buf)
  38 {
  39         return sprintf(buf, "%s\n", to_hwmon_device(dev)->name);
  40 }
  41 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
  42
  43 static struct attribute *hwmon_dev_attrs[] = {
  44         &dev_attr_name.attr,
  45         NULL
  46 };
  47
  48 static umode_t hwmon_dev_name_is_visible(struct kobject *kobj,
  49                                          struct attribute *attr, int n)
  50 {
  51         struct device *dev = container_of(kobj, struct device, kobj);
  52
  53         if (to_hwmon_device(dev)->name == NULL)
  54                 return 0;
  55
  56         return attr->mode;
  57 }
  58
  59 static struct attribute_group hwmon_dev_attr_group = {
  60         .attrs          = hwmon_dev_attrs,
  61         .is_visible     = hwmon_dev_name_is_visible,
  62 };
  63
  64 static const struct attribute_group *hwmon_dev_attr_groups[] = {
  65         &hwmon_dev_attr_group,
  66         NULL
  67 };
  68
  69 static void hwmon_dev_release(struct device *dev)
  70 {
  71         kfree(to_hwmon_device(dev));
  72 }
  73
  74 static struct class hwmon_class = {
  75         .name = "hwmon",
  76         .owner = THIS_MODULE,
  77         .dev_groups = hwmon_dev_attr_groups,
  78         .dev_release = hwmon_dev_release,
  79 };
  80
  81 static DEFINE_IDA(hwmon_ida);
  82
  83 /**
  84  * hwmon_device_register_with_groups - register w/ hwmon
  85  * @dev: the parent device
  86  * @name: hwmon name attribute
  87  * @drvdata: driver data to attach to created device
  88  * @groups: List of attribute groups to create
  89  *
  90  * hwmon_device_unregister() must be called when the device is no
  91  * longer needed.
  92  *
  93  * Returns the pointer to the new device.
  94  */
  95 struct device *
  96 hwmon_device_register_with_groups(struct device *dev, const char *name,
  97                                   void *drvdata,
  98                                   const struct attribute_group **groups)
  99 {
 100         struct hwmon_device *hwdev;
 101         int err, id;
 102
 103         /* Do not accept invalid characters in hwmon name attribute */
 104         if (name && (!strlen(name) || strpbrk(name, "-* \t\n")))
 105                 return ERR_PTR(-EINVAL);
 106
 107         id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
 108         if (id < 0)
 109                 return ERR_PTR(id);
 110
 111         hwdev = kzalloc(sizeof(*hwdev), GFP_KERNEL);
 112         if (hwdev == NULL) {
 113                 err = -ENOMEM;
 114                 goto ida_remove;
 115         }
 116
 117         hwdev->name = name;
 118         hwdev->dev.class = &hwmon_class;
 119         hwdev->dev.parent = dev;
 120         hwdev->dev.groups = groups;
 121         hwdev->dev.of_node = dev ? dev->of_node : NULL;
 122         dev_set_drvdata(&hwdev->dev, drvdata);
 123         dev_set_name(&hwdev->dev, HWMON_ID_FORMAT, id);
 124         err = device_register(&hwdev->dev);
 125         if (err)
 126                 goto free;
 127
 128         return &hwdev->dev;
 129
 130 free:
 131         kfree(hwdev);
 132 ida_remove:
 133         ida_simple_remove(&hwmon_ida, id);
 134         return ERR_PTR(err);
 135 }
 136 EXPORT_SYMBOL_GPL(hwmon_device_register_with_groups);
 137
 138 /**
 139  * hwmon_device_register - register w/ hwmon
 140  * @dev: the device to register
 141  *
 142  * hwmon_device_unregister() must be called when the device is no
 143  * longer needed.
 144  *
 145  * Returns the pointer to the new device.
 146  */
 147 struct device *hwmon_device_register(struct device *dev)
 148 {
 149         return hwmon_device_register_with_groups(dev, NULL, NULL, NULL);
 150 }
 151 EXPORT_SYMBOL_GPL(hwmon_device_register);
 152
 153 /**
 154  * hwmon_device_unregister - removes the previously registered class device
 155  *
 156  * @dev: the class device to destroy
 157  */
 158 void hwmon_device_unregister(struct device *dev)
 159 {
 160         int id;
 161
 162         if (likely(sscanf(dev_name(dev), HWMON_ID_FORMAT, &id) == 1)) {
 163                 device_unregister(dev);
 164                 ida_simple_remove(&hwmon_ida, id);
 165         } else
 166                 dev_dbg(dev->parent,
 167                         "hwmon_device_unregister() failed: bad class ID!\n");
 168 }
 169 EXPORT_SYMBOL_GPL(hwmon_device_unregister);
 170
 171 static void devm_hwmon_release(struct device *dev, void *res)
 172 {
 173         struct device *hwdev = *(struct device **)res;
 174
 175         hwmon_device_unregister(hwdev);
 176 }
 177
 178 /**
 179  * devm_hwmon_device_register_with_groups - register w/ hwmon
 180  * @dev: the parent device
 181  * @name: hwmon name attribute
 182  * @drvdata: driver data to attach to created device
 183  * @groups: List of attribute groups to create
 184  *
 185  * Returns the pointer to the new device. The new device is automatically
 186  * unregistered with the parent device.
 187  */
 188 struct device *
 189 devm_hwmon_device_register_with_groups(struct device *dev, const char *name,
 190                                        void *drvdata,
 191                                        const struct attribute_group **groups)
 192 {
 193         struct device **ptr, *hwdev;
 194
 195         if (!dev)
 196                 return ERR_PTR(-EINVAL);
 197
 198         ptr = devres_alloc(devm_hwmon_release, sizeof(*ptr), GFP_KERNEL);
 199         if (!ptr)
 200                 return ERR_PTR(-ENOMEM);
 201
 202         hwdev = hwmon_device_register_with_groups(dev, name, drvdata, groups);
 203         if (IS_ERR(hwdev))
 204                 goto error;
 205
 206         *ptr = hwdev;
 207         devres_add(dev, ptr);
 208         return hwdev;
 209
 210 error:
 211         devres_free(ptr);
 212         return hwdev;
 213 }
 214 EXPORT_SYMBOL_GPL(devm_hwmon_device_register_with_groups);
 215
 216 static int devm_hwmon_match(struct device *dev, void *res, void *data)
 217 {
 218         struct device **hwdev = res;
 219
 220         return *hwdev == data;
 221 }
 222
 223 /**
 224  * devm_hwmon_device_unregister - removes a previously registered hwmon device
 225  *
 226  * @dev: the parent device of the device to unregister
 227  */
 228 void devm_hwmon_device_unregister(struct device *dev)
 229 {
 230         WARN_ON(devres_release(dev, devm_hwmon_release, devm_hwmon_match, dev));
 231 }
 232 EXPORT_SYMBOL_GPL(devm_hwmon_device_unregister);
 233
 234 static void __init hwmon_pci_quirks(void)
 235 {
 236 #if defined CONFIG_X86 && defined CONFIG_PCI
 237         struct pci_dev *sb;
 238         u16 base;
 239         u8 enable;
 240
 241         /* Open access to 0x295-0x296 on MSI MS-7031 */
 242         sb = pci_get_device(PCI_VENDOR_ID_ATI, 0x436c, NULL);
 243         if (sb) {
 244                 if (sb->subsystem_vendor == 0x1462 &&   /* MSI */
 245                     sb->subsystem_device == 0x0031) {   /* MS-7031 */
 246                         pci_read_config_byte(sb, 0x48, &enable);
 247                         pci_read_config_word(sb, 0x64, &base);
 248
 249                         if (base == 0 && !(enable & BIT(2))) {
 250                                 dev_info(&sb->dev,
 251                                          "Opening wide generic port at 0x295\n");
 252                                 pci_write_config_word(sb, 0x64, 0x295);
 253                                 pci_write_config_byte(sb, 0x48,
 254                                                       enable | BIT(2));
 255                         }
 256                 }
 257                 pci_dev_put(sb);
 258         }
 259 #endif
 260 }
 261
 262 static int __init hwmon_init(void)
 263 {
 264         int err;
 265
 266         hwmon_pci_quirks();
 267
 268         err = class_register(&hwmon_class);
 269         if (err) {
 270                 pr_err("couldn't register hwmon sysfs class\n");
 271                 return err;
 272         }
 273         return 0;
 274 }
 275
 276 static void __exit hwmon_exit(void)
 277 {
 278         class_unregister(&hwmon_class);
 279 }
 280
 281 subsys_initcall(hwmon_init);
 282 module_exit(hwmon_exit);
 283
 284 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 285 MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
 286 MODULE_LICENSE("GPL");
 287