governor_powersave.c 1.3 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * linux/drivers/devfreq/governor_powersave.c
  4. *
  5. * Copyright (C) 2011 Samsung Electronics
  6. * MyungJoo Ham <myungjoo.ham@samsung.com>
  7. */
  8. #include <linux/devfreq.h>
  9. #include <linux/module.h>
  10. #include "governor.h"
  11. static int devfreq_powersave_func(struct devfreq *df,
  12. unsigned long *freq)
  13. {
  14. /*
  15. * target callback should be able to get ceiling value as
  16. * said in devfreq.h
  17. */
  18. *freq = DEVFREQ_MIN_FREQ;
  19. return 0;
  20. }
  21. static int devfreq_powersave_handler(struct devfreq *devfreq,
  22. unsigned int event, void *data)
  23. {
  24. int ret = 0;
  25. if (event == DEVFREQ_GOV_START) {
  26. mutex_lock(&devfreq->lock);
  27. ret = update_devfreq(devfreq);
  28. mutex_unlock(&devfreq->lock);
  29. }
  30. return ret;
  31. }
  32. static struct devfreq_governor devfreq_powersave = {
  33. .name = DEVFREQ_GOV_POWERSAVE,
  34. .get_target_freq = devfreq_powersave_func,
  35. .event_handler = devfreq_powersave_handler,
  36. };
  37. static int __init devfreq_powersave_init(void)
  38. {
  39. return devfreq_add_governor(&devfreq_powersave);
  40. }
  41. subsys_initcall(devfreq_powersave_init);
  42. static void __exit devfreq_powersave_exit(void)
  43. {
  44. int ret;
  45. ret = devfreq_remove_governor(&devfreq_powersave);
  46. if (ret)
  47. pr_err("%s: failed remove governor %d\n", __func__, ret);
  48. return;
  49. }
  50. module_exit(devfreq_powersave_exit);
  51. MODULE_LICENSE("GPL");