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         if (!err)
 110                 sysfs_notify(acpi_kobj, NULL, "platform_profile");
 111
 112         mutex_unlock(&profile_lock);
 113         if (err)
 114                 return err;
 115         return count;
 116 }
 117
 118 static DEVICE_ATTR_RO(platform_profile_choices);
 119 static DEVICE_ATTR_RW(platform_profile);
 120
 121 static struct attribute *platform_profile_attrs[] = {
 122         &dev_attr_platform_profile_choices.attr,
 123         &dev_attr_platform_profile.attr,
 124         NULL
 125 };
 126
 127 static const struct attribute_group platform_profile_group = {
 128         .attrs = platform_profile_attrs
 129 };
 130
 131 void platform_profile_notify(void)
 132 {
 133         if (!cur_profile)
 134                 return;
 135         sysfs_notify(acpi_kobj, NULL, "platform_profile");
 136 }
 137 EXPORT_SYMBOL_GPL(platform_profile_notify);
 138
 139 int platform_profile_register(struct platform_profile_handler *pprof)
 140 {
 141         int err;
 142
 143         mutex_lock(&profile_lock);
 144         /* We can only have one active profile */
 145         if (cur_profile) {
 146                 mutex_unlock(&profile_lock);
 147                 return -EEXIST;
 148         }
 149
 150         /* Sanity check the profile handler field are set */
 151         if (!pprof || bitmap_empty(pprof->choices, PLATFORM_PROFILE_LAST) ||
 152                 !pprof->profile_set || !pprof->profile_get) {
 153                 mutex_unlock(&profile_lock);
 154                 return -EINVAL;
 155         }
 156
 157         err = sysfs_create_group(acpi_kobj, &platform_profile_group);
 158         if (err) {
 159                 mutex_unlock(&profile_lock);
 160                 return err;
 161         }
 162
 163         cur_profile = pprof;
 164         mutex_unlock(&profile_lock);
 165         return 0;
 166 }
 167 EXPORT_SYMBOL_GPL(platform_profile_register);
 168
 169 int platform_profile_remove(void)
 170 {
 171         sysfs_remove_group(acpi_kobj, &platform_profile_group);
 172
 173         mutex_lock(&profile_lock);
 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");