STRUCT STM32F7_I2C_MSG(9)

💖 struct stm32f7_i2c_msg(9) 💖

okay so bestie, welcome to the Kernel API Manual ✨ — this one's all about struct stm32f7_i2c_msg, and it's genuinely iconic. it's the little struct that holds client specific data for the STM32F7 I2C driver, and honestly? it ate. let's get into it 🎀

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🦋 NAME 🦋

struct stm32f7_i2c_msg — client specific data 💅 that's it, that's the whole vibe. it's the per-message data holder, and she's serving exactly what she needs to serve.

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✨ SYNOPSIS ✨

here's the whole struct, copied exactly, no edits, no cap 🫶:

struct stm32f7_i2c_msg {
    u16 addr;
    u32 count;
    u8 *buf;
    int result;
    bool stop;
    bool smbus;
    int size;
    char read_write;
    u8 smbus_buf[I2C_SMBUS_BLOCK_MAX + 3];
 };

like… look at her. structured. aligned. main character energy 🌈

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🌸 Members 🌸

time for the member-by-member breakdown, and bestie I am obsessed with how organized this is 🍓

• addr — the 8-bit or 10-bit slave addr, and yes it includes the r/w bit ⭐ don't forget that part, iykyk.
• count — the number of bytes to be transferred. literally just the byte count, no drama 💜
• buf — the data buffer. she holds the data. queen behavior 👑
• result — the result of the transfer. how'd it go? this field knows 🙈
• stop — the last I2C msg to be sent, i.e. STOP to be generated. so like, if this is the final message, STOP gets generated. periodt 💅
• smbus — a boolean to know if the I2C IP is used in SMBus mode. true/false, simple as 🦋
• size — the type of SMBus protocol. which protocol are we doing? this says 🔥
• read_write — the direction of the SMBus protocol — specifically for SMBus block read and SMBus block write block read process call protocols 🌈
• smbus_buf — the buffer used for SMBus protocol transfer. it'll contain a maximum of 32 bytes of data + byte command + byte count + PEC ✨ and this is the important caveat bestie, listen up: this buffer has to be 32-bit aligned to be compliant with the memory address register in DMA mode. so don't be out here misaligning her 😭

ngl the alignment thing on smbus_buf is not a suggestion, it's a requirement — 32-bit aligned or it's not DMA-compliant. you've been warned 💀

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🧚 SEE ALSO 🧚

go read these next, bestie, they're all part of the same friend group 🫶:

• Kernel file ./drivers/i2c/busses/i2c-stm32f7.c struct stm32f7_i2c_regs(9)
• struct stm32f7_i2c_spec(9)
• struct stm32f7_i2c_setup(9)
• struct stm32f7_i2c_timings(9)
• struct stm32f7_i2c_alert(9)
• struct stm32f7_i2c_dev(9)

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aaaand that's the whole page 💖 this one came to you from the source/version ./drivers/i2c/busses, dated October 2026 ✨ mwah, go forth and send some messages, you've got this 🎀💅🌟