STRUCT HIDI2C_DEV_DESCRIPTOR(9)

🌸 NAME 🌸

okay so bestie, this is struct hidi2c_dev_descriptor — the HIDI2C device descriptor definition. that's it, that's the whole vibe check. it's from the Kernel API Manual and it's literally the blueprint for how a HID-over-I2C device introduces itself. 💅

✨ SYNOPSIS ✨

struct hidi2c_dev_descriptor {
    __le16 dev_desc_len;
    __le16 bcd_ver;
    __le16 report_desc_len;
    __le16 report_desc_reg;
    __le16 input_reg;
    __le16 max_input_len;
    __le16 output_reg;
    __le16 max_output_len;
    __le16 cmd_reg;
    __le16 data_reg;
    __le16 vendor_id;
    __le16 product_id;
    __le16 version_id;
    __le16 reserved0;
    __le16 reserved1;
 };

like, that's the whole struct, no notes. it ate. 🫶

💅 Members 💅

okay so every single field, in order, no skipping — this is the main character energy right here:

• dev_desc_len — the length of the complete device descriptor, and it's fixed to 0x1E (30). no cap, it's always 30. 🎀
• bcd_ver — the version number of the HIDI2C protocol it supports, in binary coded decimal (BCD) format.
• report_desc_len — the length of the report descriptor.
• report_desc_reg — the register address where you go to retrieve the report descriptor.
• input_reg — the register address where you go to retrieve the input report.
• max_input_len — the length of the largest possible HID input (or feature) report.
• output_reg — the register address you use to send the output report.
• max_output_len — the length of the largest output (or feature) report.
• cmd_reg — the register address to send a command. 🦋
• data_reg — the register address to send command data.
• vendor_id — the Device manufacturers vendor ID.
• product_id — the Device unique model/product ID. iykyk. 👑
• version_id — the Device's unique version.
• reserved0 — Reserved and should be 0.
• reserved1 — Reserved and should be 0.

bestie, lowkey mind the reserved fields — they're reserved and should be 0, so fr fr keep them at 0. 🙈

🌈 SEE ALSO 🌈

• Kernel file ./include/linux/hid-over-i2c.h struct
• hidi2c_report_packet(9)

go read those if you want the full lore, they're iconic. ⭐

and that's the page, bestie!! 💜 this came from ./include/linux, dated October 2026, and yes the footer still calls it struct hidi2...v_descriptor(9) because it's long and we respect the abbreviation era. slay. 🔥