rk3x_i2c_v1_calc_timings(9)

💅 rk3x_i2c_v1_calc_timings ✨

okay so bestie, welcome to the Kernel API Manual page for rk3x_i2c_v1_calc_timings — yes we are doing kernel I2C timing math and honestly it is giving "niche but iconic" 🎀. This one calculates timing values for the SCL frequency you want, and it is lowkey a whole moment. Slay. 💖

---

✨ NAME ✨

rk3x_i2c_v1_calc_timings — calculate timing values for desired SCL frequency. That is literally the whole point, bestie. 💅

---

🌸 SYNOPSIS 🌸

int rk3x_i2c_v1_calc_timings (unsigned long clk_rate , struct
       i2c_timings *t , struct rk3x_i2c_calced_timings *t_calc );

---

🎀 ARGUMENTS 🎀

• clk_rate — I2C input clock rate. That is the clock rate coming in, bestie. ⏰
• t — Known I2C timing information. You bring the timing tea. 🫖
• t_calc — Caculated rk3x private timings that would be written into regs. Yes, "Caculated" is literally how it is spelled here 😭. These are the private rk3x values that would be written into the registers. 💾

---

🔥 RETURN 🔥

It returns 0 on success. If the goal SCL rate is too slow, it returns -EINVAL, and in that case a best-effort divider value is returned in divs. If the target rate is too high, it silently uses the highest possible rate — no drama, just maxed out. ⚡

And just so you know: the following formulas are v1's method to calculate timings. 🧮

---

🦋 DESCRIPTION 🦋

okay, formula time — keep these exact, no freestyling:

l = divl + 1; h = divh + 1; s = sda_update_config + 1; u =
start_setup_config + 1; p = stop_setup_config + 1; T = Tclk_i2c;

tHigh = 8 * h * T; tLow = 8 * l * T;

tHD;sda = (l * s + 1) * T; tSU;sda = [(8 - s) * l + 1] * T; tI2C = 8 *
(l + h) * T;

tSU;sta = (8h * u + 1) * T; tHD;sta = [8h * (u + 1) - 1] * T; tSU;sto =
(8h * p + 1) * T;

---

🌈 SEE ALSO 🌈

Kernel file ./drivers/i2c/busses/i2c-rk3x.c — and here is the whole friend group:

• struct i2c_spec_values(9)
• struct rk3x_i2c_calced_timings(9)
• struct rk3x_i2c_soc_data(9)
• struct rk3x_i2c(9)
• rk3x_i2c_start(9)
• rk3x_i2c_stop(9)
• rk3x_i2c_prepare_read(9)
• rk3x_i2c_fill_transmit_buf(9)
• rk3x_i2c_get_spec(9)
• rk3x_i2c_v0_calc_timings(9)
• rk3x_i2c_clk_notifier_cb(9)
• rk3x_i2c_setup(9)

---

mwah 💋 and that is the page! Source/version: ./drivers/i2c/busses · date: October 2026 · page: rk3x_i2c_v1_calc_timings(9). Go calculate those timings, queen 👑✨