STRUCT LPG_CHANNEL(9)

💖 struct lpg_channel(9) 💖

okay so bestie, we're in the Kernel API Manual today and the star of the show is struct lpg_channel(9) — literally just per channel data. one struct, one channel, all the vibes. let's get into it 🫶

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✨ NAME ✨

struct lpg_channel — per channel data. that's it, that's the whole name. short, sweet, iconic 👑

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🌈 SYNOPSIS 🌈

struct lpg_channel {
    struct lpg *lpg;
    u32 base;
    unsigned int triled_mask;
    unsigned int lut_mask;
    unsigned int subtype;
    u32 sdam_offset;
    bool in_use;
    int color;
    u32 dtest_line;
    u32 dtest_value;
    u16 pwm_value;
    bool enabled;
    u64 period;
    unsigned int clk_sel;
    unsigned int pre_div_sel;
    unsigned int pre_div_exp;
    unsigned int pwm_resolution_sel;
    bool ramp_enabled;
    bool ramp_ping_pong;
    bool ramp_oneshot;
    bool ramp_reverse;
    unsigned short ramp_tick_ms;
    unsigned long ramp_lo_pause_ms;
    unsigned long ramp_hi_pause_ms;
    unsigned int pattern_lo_idx;
    unsigned int pattern_hi_idx;
 };

no cap, that's a lot of fields, but every single one is doing its job 💅

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🎀 Members 🎀

now the good part — meet the cast, one field at a time. everyone gets a moment to shine ✨

• lpg — reference to parent lpg. the main character it reports to 💖
• base — base address of the PWM channel. the address, the whole address, nothing but the address 🏠
• triled_mask — mask in TRILED to enable this channel. it's the enable button, but make it a bitmask 🔥
• lut_mask — mask in LUT to start pattern generator for this channel. starts the pattern generator, lowkey a hype-man 🎉
• subtype — PMIC hardware block subtype. hardware lore, iykyk 🧚
• sdam_offset — channel offset in LPG SDAM. where it sits in the SDAM neighbourhood 📍
• in_use — channel is exposed to LED framework. true means the LED framework has claimed it, so hands off 🙈
• color — color of the LED attached to this channel. the aesthetic, fr 🌈
• dtest_line — DTEST line for output, or 0 if disabled. zero means nope, disabled, we're not doing that 💀
• dtest_value — DTEST line configuration. the settings for that DTEST line ⚙️
• pwm_value — duty (in microseconds) of the generated pulses, overridden by LUT. yes unit is microseconds, and yes LUT can just take over 😤
• enabled — output enabled? the question mark is load-bearing, bestie 💅
• period — period (in nanoseconds) of the generated pulses. nanoseconds!! so tiny, so precise ⏱️
• clk_sel — reference clock frequency selector. picks which reference clock frequency we're on 🕰️
• pre_div_sel — divider selector of the reference clock. divider, but the selector one 🎚️
• pre_div_exp — exponential divider of the reference clock. now it's exponential, she's fancy 👑
• pwm_resolution_sel — pwm resolution selector. how much resolution do we want? yes 💜
• ramp_enabled — duty cycle is driven by iterating over lookup table. the LUT is driving, buckle up 🚗
• ramp_ping_pong — reverse through pattern, rather than wrapping to start. ping pong!! going back instead of loop-de-loop 🏓
• ramp_oneshot — perform only a single pass over the pattern. one pass, no encore, periodt ✋
• ramp_reverse — iterate over pattern backwards. back, back, back it up 🔙
• ramp_tick_ms — length (in milliseconds) of one step in the pattern. one step = this many ms 🐾
• ramp_lo_pause_ms — pause (in milliseconds) before iterating over pattern. the pre-game pause 🧘
• ramp_hi_pause_ms — pause (in milliseconds) after iterating over pattern. the post-game pause 🛬
• pattern_lo_idx — start index of associated pattern. start here bestie 🟢
• pattern_hi_idx — last index of associated pattern. and stop here 🔴

heads up: pwm_value is in microseconds and period is in nanoseconds — do not mix them up, that's a vibe check you will fail 😭

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🦋 SEE ALSO 🦋

Kernel file ./drivers/leds/rgb/leds-qcom-lpg.c — plus these certified besties: struct lpg_led(9), struct lpg(9), struct lpg_channel_data(9), struct lpg_data(9) ✨

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and that's the page!! huge shoutout to ./drivers/leds/rgb for the source and October 2026 for the date — slay, go read the other structs, ily, bye 💖🎀🫶