_lookup_sddiv(9)

💅 _lookup_sddiv (from the Kernel API Manual) 🎀

okay bestie, buckle up, because this one is literally a tiny little helper that does one very specific job: it calculates the sigma-delta divider for a j-type DPLL. that's it. that's the whole vibe. no cap. ✨

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🌸 NAME 🌸

_lookup_sddiv — calculate the sigma delta divider for a j-type DPLL 💫

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🦋 SYNOPSIS 🦋

void _lookup_sddiv (struct clk_hw_omap *clk , u8 *sd_div , u16 m , u8 n
);

like yes, the formatting is a little cursed, it wraps onto a second line, we don't judge. 🫶

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✨ ARGUMENTS ✨

• clk — a pointer to a DPLL struct clk. this is the main character of the whole operation ngl 👑
• sd_div — the target sigma-delta divider. it's a u8 *, so it's a pointer, she writes back into you 💅
• m — the DPLL multiplier you want to set, a u16 🔢
• n — the DPLL divider you want to set, a u8 ⭐

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💖 DESCRIPTION 💖

so the actual spec tea: see 36xx TRM section 3.5.3.3.3.2 "Type B DPLL (Low-Jitter)" 📖 that's where the real lore lives, iykyk.

XXX — this code is not needed for 3430/AM35xx. the manpage literally asks the question: can it be optimized out in non-multi-OMAP builds for those chips? 🤔 so yeah, that's an open question, not a settled answer. don't come for me, I'm just the messenger 😭

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🌈 SEE ALSO 🌈

kernel file ./drivers/clk/ti/dpll3xxx.c — and oooooh the friend group is large, look at all these related functions, absolutely iconic roster fr fr:

• _omap3_noncore_dpll_lock(9)
• _omap3_noncore_dpll_bypass(9)
• _omap3_noncore_dpll_stop(9)
• _lookup_dco(9)
• omap3_noncore_dpll_ssc_program(9)
• omap3_noncore_dpll_program(9)
• omap3_dpll_recalc(9)
• omap3_noncore_dpll_enable(9)
• omap3_noncore_dpll_disable(9)
• omap3_noncore_dpll_determine_rate(9)
• omap3_noncore_dpll_set_parent(9)
• omap3_noncore_dpll_set_rate(9)
• omap3_noncore_dpll_set_rate_and_parent(9)
• omap3_dpll_autoidle_read(9)
• omap3_dpll_allow_idle(9)
• omap3_dpll_deny_idle(9)
• omap3_clkoutx2_recalc(9)
• omap3_core_dpll_save_context(9)
• omap3_core_dpll_restore_context(9)
• omap3_noncore_dpll_save_context(9)
• omap3_noncore_dpll_restore_context(9)
• omap3_dpll4_set_rate(9)
• omap3_dpll4_set_rate_and_parent(9)
• omap3_dpll5_set_rate(9)

like that's the whole clique, no gatekeeping here 🫶✨

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and that's the page, bestie! 🎀 one last cute little sign-off: this one comes from ./drivers/clk/ti and it's dated October 2026 — mark your calendars, she's a time traveler 🦋⏰💜