linux/drivers/acpi/platform_profile.c
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   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
  12static struct platform_profile_handler *cur_profile;
  13static DEFINE_MUTEX(profile_lock);
  14
  15static 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};
  23static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
  24
  25static 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
  52static 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
  80static 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
 115static DEVICE_ATTR_RO(platform_profile_choices);
 116static DEVICE_ATTR_RW(platform_profile);
 117
 118static struct attribute *platform_profile_attrs[] = {
 119        &dev_attr_platform_profile_choices.attr,
 120        &dev_attr_platform_profile.attr,
 121        NULL
 122};
 123
 124static const struct attribute_group platform_profile_group = {
 125        .attrs = platform_profile_attrs
 126};
 127
 128void platform_profile_notify(void)
 129{
 130        if (!cur_profile)
 131                return;
 132        sysfs_notify(acpi_kobj, NULL, "platform_profile");
 133}
 134EXPORT_SYMBOL_GPL(platform_profile_notify);
 135
 136int 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}
 164EXPORT_SYMBOL_GPL(platform_profile_register);
 165
 166int 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}
 175EXPORT_SYMBOL_GPL(platform_profile_remove);
 176
 177MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
 178MODULE_LICENSE("GPL");
 179