STRUCT SPI_BOARD_INFO(9)

🌸 NAME 🌸

okay so bestie, welcome to struct spi_board_info(9) from the Kernel API Manual — this is literally the board-specific template for a SPI device, and it's giving “partial device glow-up” energy. 🫶✨

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💅 SYNOPSIS 💅

       struct spi_board_info {
           char modalias[SPI_NAME_SIZE];
           const void      *platform_data;
           const struct software_node *swnode;
           void *controller_data;
           int irq;
           u32 max_speed_hz;
           u16 bus_num;
           u16 chip_select;
           u32 mode;
        };

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🧚 Members 🧚

each member is lowkey a little starter pack for the matching spi_device field, so let’s go through them one by one, no cap:

• modalias — initializes spi_device.modalias; identifies the driver. iykyk 💅
• platform_data — initializes spi_device.platform_data; the particular data stored there is driver-specific. 🍓
• swnode — software node for the device. ✨
• controller_data — initializes spi_device.controller_data; some controllers need hints about hardware setup, e.g. for DMA. 🧚
• irq — initializes spi_device.irq; depends on how the board is wired. 🔥
• max_speed_hz — initializes spi_device.max_speed_hz; based on limits from the chip datasheet and board-specific signal quality issues. ⚡
• bus_num — identifies which spi_controller parents the spi_device; unused by spi_new_device, and otherwise depends on board wiring. 🦋
• chip_select — initializes spi_device.chip_select; depends on how the board is wired. 🎀
• mode — initializes spi_device.mode; based on the chip datasheet, board wiring (some devices support both 3WIRE and standard modes), and possibly presence of an inverter in the chipselect path. 🌈

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🌈 Description 🌈

When adding new SPI devices to the device tree, these structures serve as a partial device template. They hold information which can't always be determined by drivers. Information that probe can establish (such as the default transfer wordsize) is not included here. 😌

bestie, this is a partial template — probe can fill in stuff like the default transfer wordsize, and that’s not listed here. periodt. 💖

These structures are used in two places. Their primary role is to be stored in tables of board-specific device descriptors, which are declared early in board initialization and then used (much later) to populate a controller's device tree after the that controller's driver initializes. A secondary (and atypical) role is as a parameter to spi_new_device call, which happens after those controller drivers are active in some dynamic board configuration models. 👑

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🦋 SEE ALSO 🦋

start with the Kernel file ./include/linux/spi/spi.h, then the whole bestie lineup:

• struct spi_statistics(9)
• struct spi_delay(9)
• struct spi_device(9)
• struct spi_driver(9)
• spi_unregister_driver(9)
• module_spi_driver(9)
• struct spi_controller(9)
• struct spi_res(9)
• struct spi_transfer(9)
• struct spi_message(9)
• spi_message_init_with_transfers(9)
• spi_is_bpw_supported(9)
• spi_bpw_to_bytes(9)
• spi_controller_xfer_timeout(9)
• struct spi_replaced_transfers(9)
• spi_sync_transfer(9)
• spi_write(9)
• spi_read(9)
• spi_w8r8(9)
• spi_w8r16(9)
• spi_w8r16be(9)

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and that’s the page, bestie 💖 source: ./include/linux/spi · date: October 2026 · page: struct spi_board_info(9) — bye byeee 🎀✨