drivers/acpi/platform_profile.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 /* Platform profile sysfs interface */
   4
   5 #include <linux/acpi.h>
   6 #include <linux/bits.h>
   7 #include <linux/init.h>
   8 #include <linux/mutex.h>
   9 #include <linux/platform_profile.h>
  10 #include <linux/sysfs.h>
  11
  12 static struct platform_profile_handler *cur_profile;
  13 static DEFINE_MUTEX(profile_lock);
  14
  15 static const char * const profile_names[] = {
  16         [PLATFORM_PROFILE_LOW_POWER] = "low-power",
  17         [PLATFORM_PROFILE_COOL] = "cool",
  18         [PLATFORM_PROFILE_QUIET] = "quiet",
  19         [PLATFORM_PROFILE_BALANCED] = "balanced",
  20         [PLATFORM_PROFILE_PERFORMANCE] = "performance",
  21 };
  22 static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
  23
  24 static ssize_t platform_profile_choices_show(struct device *dev,
  25                                         struct device_attribute *attr,
  26                                         char *buf)
  27 {
  28         int len = 0;
  29         int err, i;
  30
  31         err = mutex_lock_interruptible(&profile_lock);
  32         if (err)
  33                 return err;
  34
  35         if (!cur_profile) {
  36                 mutex_unlock(&profile_lock);
  37                 return -ENODEV;
  38         }
  39
  40         for_each_set_bit(i, cur_profile->choices, PLATFORM_PROFILE_LAST) {
  41                 if (len == 0)
  42                         len += sysfs_emit_at(buf, len, "%s", profile_names[i]);
  43                 else
  44                         len += sysfs_emit_at(buf, len, " %s", profile_names[i]);
  45         }
  46         len += sysfs_emit_at(buf, len, "\n");
  47         mutex_unlock(&profile_lock);
  48         return len;
  49 }
  50
  51 static ssize_t platform_profile_show(struct device *dev,
  52                                         struct device_attribute *attr,
  53                                         char *buf)
  54 {
  55         enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED;
  56         int err;
  57
  58         err = mutex_lock_interruptible(&profile_lock);
  59         if (err)
  60                 return err;
  61
  62         if (!cur_profile) {
  63                 mutex_unlock(&profile_lock);
  64                 return -ENODEV;
  65         }
  66
  67         err = cur_profile->profile_get(cur_profile, &profile);
  68         mutex_unlock(&profile_lock);
  69         if (err)
  70                 return err;
  71
  72         /* Check that profile is valid index */
  73         if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
  74                 return -EIO;
  75
  76         return sysfs_emit(buf, "%s\n", profile_names[profile]);
  77 }
  78
  79 static ssize_t platform_profile_store(struct device *dev,
  80                             struct device_attribute *attr,
  81                             const char *buf, size_t count)
  82 {
  83         int err, i;
  84
  85         err = mutex_lock_interruptible(&profile_lock);
  86         if (err)
  87                 return err;
  88
  89         if (!cur_profile) {
  90                 mutex_unlock(&profile_lock);
  91                 return -ENODEV;
  92         }
  93
  94         /* Scan for a matching profile */
  95         i = sysfs_match_string(profile_names, buf);
  96         if (i < 0) {
  97                 mutex_unlock(&profile_lock);
  98                 return -EINVAL;
  99         }
 100
 101         /* Check that platform supports this profile choice */
 102         if (!test_bit(i, cur_profile->choices)) {
 103                 mutex_unlock(&profile_lock);
 104                 return -EOPNOTSUPP;
 105         }
 106
 107         err = cur_profile->profile_set(cur_profile, i);
 108         mutex_unlock(&profile_lock);
 109         if (err)
 110                 return err;
 111         return count;
 112 }
 113
 114 static DEVICE_ATTR_RO(platform_profile_choices);
 115 static DEVICE_ATTR_RW(platform_profile);
 116
 117 static struct attribute *platform_profile_attrs[] = {
 118         &dev_attr_platform_profile_choices.attr,
 119         &dev_attr_platform_profile.attr,
 120         NULL
 121 };
 122
 123 static const struct attribute_group platform_profile_group = {
 124         .attrs = platform_profile_attrs
 125 };
 126
 127 void platform_profile_notify(void)
 128 {
 129         if (!cur_profile)
 130                 return;
 131         sysfs_notify(acpi_kobj, NULL, "platform_profile");
 132 }
 133 EXPORT_SYMBOL_GPL(platform_profile_notify);
 134
 135 int platform_profile_register(struct platform_profile_handler *pprof)
 136 {
 137         int err;
 138
 139         mutex_lock(&profile_lock);
 140         /* We can only have one active profile */
 141         if (cur_profile) {
 142                 mutex_unlock(&profile_lock);
 143                 return -EEXIST;
 144         }
 145
 146         /* Sanity check the profile handler field are set */
 147         if (!pprof || bitmap_empty(pprof->choices, PLATFORM_PROFILE_LAST) ||
 148                 !pprof->profile_set || !pprof->profile_get) {
 149                 mutex_unlock(&profile_lock);
 150                 return -EINVAL;
 151         }
 152
 153         err = sysfs_create_group(acpi_kobj, &platform_profile_group);
 154         if (err) {
 155                 mutex_unlock(&profile_lock);
 156                 return err;
 157         }
 158
 159         cur_profile = pprof;
 160         mutex_unlock(&profile_lock);
 161         return 0;
 162 }
 163 EXPORT_SYMBOL_GPL(platform_profile_register);
 164
 165 int platform_profile_remove(void)
 166 {
 167         mutex_lock(&profile_lock);
 168         if (!cur_profile) {
 169                 mutex_unlock(&profile_lock);
 170                 return -ENODEV;
 171         }
 172
 173         sysfs_remove_group(acpi_kobj, &platform_profile_group);
 174         cur_profile = NULL;
 175         mutex_unlock(&profile_lock);
 176         return 0;
 177 }
 178 EXPORT_SYMBOL_GPL(platform_profile_remove);
 179
 180 MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
 181 MODULE_LICENSE("GPL");