pwm_set_relative_duty_cycle(9)

💅 pwm_set_relative_duty_cycle(9) — the Kernel API Manual page, bestie edition

okay so picture this: you're deep in the kernel, you've got a PWM thing, and you want to say "gimme 50%" instead of doing nanosecond math in your head at 2am. That's literally this function. It's called pwm_set_relative_duty_cycle, and it's from the Kernel API Manual, and it's here to save your whole night. 🫶

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✨ NAME ✨

pwm_set_relative_duty_cycle — sets a relative duty cycle value. that's it, that's the vibe. no absolute, no nanosecond nonsense on your end. 💅

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🦋 SYNOPSIS 🦋

int pwm_set_relative_duty_cycle (struct pwm_state *state , unsigned int
duty_cycle , unsigned int scale );

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🎀 ARGUMENTS 🎀

• state — the PWM state you're filling in. she's the canvas, you're the artist ✨
• duty_cycle — the relative duty cycle value. yes, the relative one, like a percentage-ish number, not nanoseconds 🌸
• scale — the scale your duty_cycle is expressed in. so if you're thinking in hundredths, this is your 100. context is everything, bestie 🧚

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💖 DESCRIPTION 💖

okay so what she does: this function converts a relative duty cycle into an absolute one — expressed in nanoseconds — and puts that result straight into state->duty_cycle. no cap. she does the conversion so you don't have to. 👑

so like, for example, if you want to configure a 50% duty cycle, you call:

pwm_init_state(pwm, state); pwm_set_relative_duty_cycle(state, 50, 100);
pwm_apply_might_sleep(pwm, state);

see how clean that reads? 50 out of 100, and the rest is handled. iconic. ate. 🍓

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🔥 RETURN 🔥

• 0 — success, we love to see it 💜
• -EINVAL — the bad-ending timeline 😭. you get this if duty_cycle and/or scale are inconsistent, which specifically means scale == 0 or duty_cycle > scale. so don't divide by zero and don't go over 100%, bestie, it's giving chaos 💀

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🌈 SEE ALSO 🌈

all the siblings, neighbors, and lore-adjacent icons of the kernel PWM-verse, plus the kernel file they live in: ./include/linux/pwm.h 📁

• enum pwm_polarity(9)
• struct pwm_args(9)
• struct pwm_waveform(9)
• struct pwm_device(9)
• pwm_get_state(9)
• pwm_init_state(9)
• pwm_get_relative_duty_cycle(9)
• struct pwm_capture(9)
• struct pwm_ops(9)
• struct pwm_chip(9)
• pwmchip_supports_waveform(9)
• pwm_config(9)
• pwm_enable(9)
• pwm_disable(9)
• pwm_might_sleep(9)

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k bye, go set some duty cycles 💅✨ this page lives in ./include/linux and is dated October 2026 — mwah, stay slaying, and remember: relative in, nanoseconds out, no cap 🎀💖