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