PERIOD             21 drivers/gpu/drm/i915/i915_pmu.c #define PERIOD max_t(u64, 10000, NSEC_PER_SEC / FREQUENCY)
PERIOD            316 drivers/gpu/drm/radeon/sumod.h #       define PERIOD(x)                                ((x) << 8)
PERIOD             21 drivers/pwm/pwm-bcm2835.c #define PERIOD(x)		(((x) * 0x10) + 0x10)