STRUCT HIDSPI_DEV_DESCRIPTOR(9)

🌸 struct hidspi_dev_descriptor(9) 🌸

okay so we're in the Kernel API Manual bestie, and this is literally the whole vibe of HID-over-SPI device descriptors. strap in 💖

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✨ NAME ✨

struct hidspi_dev_descriptor — the actual definition of a HIDSPI device descriptor. that's it, that's the whole thing, and yes she is important 👑

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🌈 SYNOPSIS 🌈

struct hidspi_dev_descriptor {
    __le16 dev_desc_len;
    __le16 bcd_ver;
    __le16 rep_desc_len;
    __le16 max_input_len;
    __le16 max_output_len;
    __le16 max_frag_len;
    __le16 vendor_id;
    __le16 product_id;
    __le16 version_id;
    __le16 flags;
    __le32 reserved;
 };

look at her. all those __le16s lined up like a little choir 🎀 (and one lone __le32 at the end serving main character energy, we love to see it)

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💅 Members 💅

okay so here's the member-by-member breakdown, no cap, nothing skipped:

• dev_desc_len — the length of the complete device descriptor. and it is fixed to 0x18 (that's 24 in human numbers). do not freestyle this one, she's not negotiable 🙅‍♀️
• bcd_ver — the version number of the HIDSPI protocol supported, in binary coded decimal (BCD) format. Must be fixed to 0x0300. again: fixed. not a suggestion. periodt 💀
• rep_desc_len — the length of the report descriptor 📋
• max_input_len — the length of the largest possible HID input (or feature) report
• max_output_len — the length of the largest output (or feature) report 📤
• max_frag_len — the length of the largest fragment, where a fragment represents the body of an input report. fancy!! 🧚
• vendor_id — device manufacturer's vendor ID 🏭
• product_id — the device's unique model/product ID
• version_id — the device's unique version
• flags — specify flags for the device's operation 🚩
• reserved — reserved, and should be 0. she's just sitting there. leave her at 0 🫶

⚠️ friendly reminder bestie: dev_desc_len is fixed at 0x18 (24) and bcd_ver must be 0x0300, and reserved should be 0. those aren't vibes, those are rules 😭

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🔥 SEE ALSO 🔥

• Kernel file ./include/linux/hid-over-spi.h struct input_report_body_header(9), struct input_report_body(9), struct output_report_header(9), struct output_report(9)

like, go read the whole friend group, they're all connected, iykyk 💜

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and that's the page!! this lil icon lives in ./include/linux, dated October 2026, and she's filed under struct hidspi_dev_descriptor(9). slay, go forth and set your reserved to 0 🦋✨