sdw_nread(9)

💖 sdw_nread(9) — like, the Kernel API Manual page you actually want to read 💖

okay so bestie, welcome to sdw_nread(9) from the Kernel API Manual (section 9, soundwire girlies rise). this one is short and sweet and it slays — let me put you on. 🎀

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✨ NAME ✨

sdw_nread — read "n" contiguous SDW Slave registers. that's it, that's the whole vibe. n registers, all lined up next to each other, read in one go. 🦋

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🌸 SYNOPSIS 🌸

int sdw_nread (struct sdw_slave *slave , u32 addr , size_t count , u8
*val );

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💅 ARGUMENTS 💅

• slave — the SDW Slave. like, the actual device we're talking to. your main character. 👑
• addr — the register address. where the reading adventure begins. ✨
• count — the length. how many registers we're grabbing, i.e. the "n" in nread. literally the whole point. 🔥
• val — the buffer where the values that got read end up living. the little home for your bytes. 🏡

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🧚 DESCRIPTION 🧚

so this version of the function will take a PM reference to the slave device. yes, this version — the PM-referencing one. noted. 💜

⚠️ important caveat bestie, do not skip this: if the message crosses a page boundary, each page will be transferred under a separate invocation of the msg_lock. so like… multiple lock grabs, one per page. no cap, that's how it goes. 😭

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👀 SEE ALSO 👀

it's all in the Kernel file ./drivers/soundwire/bus.c — go read the source, it's giving iconic. and while you're there, here's the whole friend group:

• sdw_bus_master_add(9)
• sdw_bus_master_delete(9)
• sdw_transfer(9)
• sdw_show_ping_status(9)
• sdw_transfer_defer(9)
• sdw_nread_no_pm(9)
• sdw_nwrite_no_pm(9)
• sdw_write_no_pm(9)
• sdw_read_no_pm(9)
• sdw_nwrite(9)
• sdw_read(9)
• sdw_write(9)
• sdw_bus_prep_clk_stop(9)
• sdw_bus_clk_stop(9)
• sdw_bus_exit_clk_stop(9)
• sdw_handle_slave_status(9)

they all ate, fr fr. 🫶

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mwah 💋 that's the page!! this little beauty lives in ./drivers/soundwire, dated October 2026, and you can cite it as sdw_nread(9) forever and ever. go read some registers bestie, you got this 💖✨🌈