Add dev_pm_qos notifies to devfreq core in order to support frequency
limits via the dev_pm_qos_add_request.

Unlike the rest of devfreq the dev_pm_qos frequency is measured in Khz,
this is consistent with current dev_pm_qos usage for cpufreq and
allows frequencies above 2Ghz (pm_qos expresses limits as s32).

Like with cpufreq the handling of min_freq/max_freq is moved to the dev_pm_qos
mechanism and this decreases the precision of the sysfs entries.

Signed-off-by: Leonard Crestez <redacted>

---

Changes since v2:
 * Handle sysfs via dev_pm_qos (in separate patch)
 * Add locking to {min,max}_freq_show
 * Fix checkpatch issues (long lines etc)
Link to v2: https://patchwork.kernel.org/patch/11084279/

Changes since v1:
 * Add doxygen comments for min_nb/max_nb
 * Remove notifiers on error/cleanup paths. Keep gotos simple by relying on
dev_pm_qos_remove_notifier ignoring notifiers which were not added.
Link to v1: https://patchwork.kernel.org/patch/11078475/

Leonard Crestez (2):
  PM / devfreq: Add dev_pm_qos support
  PM / devfreq: Use dev_pm_qos for sysfs min/max_freq

 drivers/devfreq/devfreq.c | 170 +++++++++++++++++++++++++++-----------
 include/linux/devfreq.h   |  14 +++-
 2 files changed, 131 insertions(+), 53 deletions(-)

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2.17.1