diff_by_scaled_ppm(9)

💅 diff_by_scaled_ppm(9)

okay so bestie, welcome to the Kernel API Manual 🫶 this one's about diff_by_scaled_ppm, and it's literally just math with extra steps. buckle up 🎀

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✨ NAME ✨

diff_by_scaled_ppm — calculate difference using scaled ppm 🌸

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✨ SYNOPSIS ✨

bool diff_by_scaled_ppm (u64 base , long scaled_ppm , u64 *diff );

like, that's the whole vibe. three args, one bool. slay 💅

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✨ ARGUMENTS ✨

• base — the base increment value you're adjusting, bestie. the starting point. the main character 👑
• scaled_ppm — the scaled parts per million you're adjusting by. yes it's scaled, don't come for me 🙈
• diff — on return, this holds the absolute value of the calculated diff. so it's an out-param, meaning it gets filled in after the call. iykyk ✨

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✨ DESCRIPTION ✨

so what it does is: calculate the difference to adjust the base increment, using scaled parts per million. that's it, that's the whole function 🦋

and here's the cute little trick — it uses mul_u64_u64_div_u64 to do the difference calculation, specifically to avoid possible overflow 🔥 no cap, that matters, because u64 math overflowing is not the vibe and would ruin everything 😭

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✨ RETURN ✨

returns true if scaled_ppm is negative, and false otherwise. literally that simple, periodt. 💀

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✨ SEE ALSO ✨

okay this list is long but every single one is here, i promise, no skipping, we don't do that here 💖

• the kernel file ./include/linux/ptp_clock_kernel.h
• struct ptp_clock_request(9)
• struct ptp_system_timestamp(9)
• struct ptp_clock_info(9)
• struct ptp_clock_event(9)
• scaled_ppm_to_ppb(9)
• adjust_by_scaled_ppm(9)
• ptp_clock_register(9)
• ptp_clock_unregister(9)
• ptp_clock_event(9)
• ptp_clock_index(9)
• ptp_clock_index_by_of_node(9)
• ptp_clock_index_by_dev(9)
• ptp_find_pin(9)
• ptp_find_pin_unlocked(9)
• ptp_schedule_worker(9)
• ptp_cancel_worker_sync(9)
• ptp_get_vclocks_index(9)
• ptp_convert_timestamp(9)

ngl ptp_clock_event(9) shows up twice in the original list and i'm keeping it twice because i don't invent or merge things. facts are facts, bestie 🧚

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alright that's the whole page!! 🌈 this absolute icon lives under ./include/linux, dated October 2026, and goes by diff_by_scaled_ppm(9) — mwah, take care of her 💜🍓