dfll_lock(9)

💅 dfll_lock — the kernel API manual, but make it make sense

okay so bestie, welcome to dfll_lock(9) — yes that's the page name, and yes it lives in the Kernel API Manual because we're fancy like that ✨

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🌸 NAME

dfll_lock — switch from open-loop to closed-loop mode 🎀

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⭐ SYNOPSIS

int dfll_lock (struct tegra_dfll *td );

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🫶 ARGUMENTS

• td — the DFLL instance, aka the main character of this whole operation 💖

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🔥 DESCRIPTION

So here's the vibe: you're switching this thing from OPEN_LOOP state to CLOSED_LOOP state. Glow-up complete, no cap 💅

It returns 0 upon success — slay.

It returns -EINVAL if the DFLL's target rate hasn't been set yet — like bestie, you can't close the loop if you don't even know where you're going 😭

Or it returns -EPERM if the DFLL is not currently in open-loop mode — you literally cannot switch from open-loop if you're not in open-loop, that's just not the vibe 🙈

ngl, those are the only three outcomes. 0, -EINVAL, -EPERM. Memorize them, they're iconic 👑

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🌈 SEE ALSO

the whole friend group, fr fr 🧚:

• Kernel file ./drivers/clk/tegra/clk-dfll.c
• enum dfll_ctrl_mode(9)
• enum dfll_tune_range(9)
• struct dfll_rate_req(9)
• dfll_is_running(9)
• tegra_dfll_runtime_resume(9)
• tegra_dfll_runtime_suspend(9)
• dfll_tune_low(9)
• dfll_scale_dvco_rate(9)
• dfll_set_mode(9)
• dfll_i2c_set_output_enabled(9)
• dfll_pwm_set_output_enabled(9)
• dfll_set_force_output_value(9)
• dfll_set_force_output_enabled(9)
• dfll_force_output(9)
• dfll_load_i2c_lut(9)
• dfll_init_i2c_if(9)
• dfll_init_out_if(9)
• find_lut_index_for_rate(9)
• dfll_calculate_rate_request(9)
• dfll_set_frequency_request(9)
• dfll_request_rate(9)
• dfll_disable(9)
• dfll_enable(9)
• dfll_set_open_loop_config(9)
• dfll_unlock(9)
• dfll_register_clk(9)
• dfll_unregister_clk(9)
• dfll_calc_monitored_rate(9)
• dfll_read_monitor_rate(9)
• dfll_set_default_params(9)
• dfll_init_clks(9)
• dfll_init(9)
• tegra_dfll_suspend(9)
• tegra_dfll_resume(9)
• dfll_build_i2c_lut(9)
• read_dt_param(9)
• dfll_fetch_i2c_params(9)
• dfll_fetch_common_params(9)
• tegra_dfll_register(9)
• tegra_dfll_unregister(9)

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and that's the whole page bestie, go close some loops 💜

~ sourced straight from ./drivers/clk/tegra, dated October 2026, and yes this page is literally dfll_lock(9) — told you it was iconic ✨🎀🦋