STRUCT UCSI_OPERATIONS(9)

💅 struct ucsi_operations(9) 💅

okay bestie, welcome to the Kernel API Manual page for struct ucsi_operations — UCSI I/O operations, aka the whole little vibe committee of function pointers that a UCSI driver has to fill in 🎀

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✨ SYNOPSIS ✨

like, here's the whole struct, exactly as it is, no cap:

struct ucsi_operations {
    int (*read_version)(struct ucsi *ucsi, u16 *version);
    int (*read_cci)(struct ucsi *ucsi, u32 *cci);
    int (*poll_cci)(struct ucsi *ucsi, u32 *cci);
    int (*read_message_in)(struct ucsi *ucsi, void *val, size_t
val_len);
    int (*write_message_out)(struct ucsi *ucsi, void *data, size_t
data_len);
    int (*sync_control)(struct ucsi *ucsi, u64 command, u32 *cci, void
*data, size_t size, void *msg_out, size_t msg_out_size);
    int (*async_control)(struct ucsi *ucsi, u64 command);
    bool (*update_altmodes)(struct ucsi *ucsi, u8 recipient, struct
ucsi_altmode *orig, struct ucsi_altmode *updated);
    void (*update_connector)(struct ucsi_connector *con);
    void (*connector_status)(struct ucsi_connector *con);
    void (*add_partner_altmodes)(struct ucsi_connector *con);
    void (*remove_partner_altmodes)(struct ucsi_connector *con);
 };

she's giving very much "fill in the blanks but make it USB-C" energy 🦋

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🌸 MEMBERS 🌸

each one of these is a member, and yes we're going through all of them, periodt:

• read_version — reads the implemented UCSI version ✨
• read_cci — reads the CCI register 👑
• poll_cci — reads the CCI register while polling with notifications disabled 💫
• read_message_in — reads message data from UCSI 🎀
• write_message_out — writes message data to UCSI 🖊️
• sync_control — a blocking control operation, like it will literally sit there and wait 🙈
• async_control — a non-blocking control operation, main character energy, no waiting around 💅
• update_altmodes — squashes duplicate DP altmodes 🫶
• update_connector — updates connector capabilities before registering 🌈
• connector_status — updates connector status, and it's called holding the connector lock 🔒
• add_partner_altmodes — starts mode selection ⭐
• remove_partner_altmodes — cleans up mode selection 🧚

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💖 DESCRIPTION 💖

so these are the read and write routines for the UCSI interface — the little I/O plumbing crew 🍓

bestie, listen, this part is important: sync_write must wait for the Command Completion Event from the PPM before returning, and async_write must return immediately after sending the data to the PPM. no cap, that's the rule 😤

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🔥 SEE ALSO 🔥

• Kernel file ./drivers/usb/typec/ucsi/ucsi.h
• ucsi_bitfield_read(9)

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that's the whole page, you ate that 💅✨ go forth and implement your ops, iykyk 🦋

signing off from ./drivers/usb/typec/ucsi — date on the tin says October 2026, so yeah, future vibes only 👑