mma9551_write_config_byte(9)

✨ mma9551_write_config_byte — the kernel API glow-up 🎀

okay bestie so this is a page from the Kernel API Manual, and it's about one lil function that writes a single config byte. tiny function, big main character energy. let's get into it 💅

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🌸 NAME 🌸

mma9551_write_config_byte — literally just writes 1 configuration byte. one. single. byte. and she ate 🫶

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🌈 SYNOPSIS 🌈

int mma9551_write_config_byte (struct i2c_client *client , u8 app_id ,
u16 reg , u8 val );

like look at her go 😭✨

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🦋 ARGUMENTS 🦋

• client — the I2C client. your device bestie, basically 🫶
• app_id — the Application ID. yep, that one 💜
• reg — the Application register. the lil address you're poking at 🎀
• val — the Value to write. the payload, the moment, the whole point ngl ✨

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💖 DESCRIPTION 💖

so basically she writes one configuration byte from the device, using the MMA955xL command format. and no cap, commands to the MMA955xL platform are a whole two-step vibe: a write, followed by one or more reads. she's not a one-and-done girlie, she's a "write then read read read" girlie 🌸

🔒 locking note, and this is important bestie, don't skip it: this function must be called with the device lock held. locking is not handled inside the function — she does not do it for you, she will not hold your hand on this. callers should ensure they serialize access to the HW. periodt. 💀

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⭐ RETURN ⭐

• 0 on success 🥳
• a negative value on failure 😭

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👑 SEE ALSO 👑

• Kernel file ./drivers/iio/accel/mma9551_core.c — the source, go read her 💖
• mma9551_read_config_byte(9)
• mma9551_read_status_byte(9)
• mma9551_read_config_word(9)
• mma9551_write_config_word(9)
• mma9551_read_status_word(9)
• mma9551_read_config_words(9)
• mma9551_read_status_words(9)
• mma9551_write_config_words(9)
• mma9551_update_config_bits(9)
• mma9551_gpio_config(9)
• mma9551_read_version(9)
• mma9551_set_device_state(9)
• mma9551_set_power_state(9)
• mma9551_sleep(9)
• mma9551_read_accel_chan(9)
• mma9551_read_accel_scale(9)
• mma9551_app_reset(9)

the whole friend group fr fr, they all live in ./drivers/iio/accel and honestly? iconic lineup 🧚💜

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mwah 💋 that's the page — sourced from ./drivers/iio/accel, dated October 2026, and this whole manual-page moment was brought to you by the Kernel API Manual. go forth and hold that lock, bestie 🫶✨