drm_of_get_d...nes_count_ep(9)

💅 drm_of_get_data_lanes_count_ep(9) — the group-chat version ✨

okay so bestie, welcome to the Kernel API Manual page for drm_of_get_d...nes_count_ep(9) — yes the title is truncated, no that's not a typo, that's just how the manpage renders it, iykyk 🎀. We're in the <pink>DRM subsystem</pink> neighborhood, specifically the devicetree helpers in ./drivers/gpu/drm, and this little icon is gonna count your data lanes for you. Slay.

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🌸 NAME 🌸

drm_of_get_data_lanes_count_ep — get the DSI/(e)DP data lane count by endpoint. That's the whole vibe. 🦋

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✨ SYNOPSIS ✨

int drm_of_get_data_lanes_count_ep (const struct device_node *port , int
port_reg , int reg , const unsigned int min , const unsigned int max );

like, it returns an int, it takes a const struct device_node *port, two ints, and two const unsigned ints. iconic signature honestly. 💜

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🫶 ARGUMENTS 🫶

• port — the DT port node of your DSI/(e)DP source or sink. either one, she's flexible like that. 💁‍♀️
• port_reg — the identifier (aka the value of the reg property) of the parent port node. important: the parent. don't mix them up bestie. 🙈
• reg — the identifier (value of the reg property) of the endpoint node itself.
• min — the minimum supported number of data lanes. the floor, the bare minimum, the "i guess" tier. 😭
• max — the maximum supported number of data lanes. the ceiling, the main character upper bound. 👑

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🎀 DESCRIPTION 🎀

So what does she do? She counts the elements of the DT "data-lanes" property and checks them for validity. that's it, that's the function. ✅

This particular variant uses the endpoint specifier — that's literally the _ep in the name, the way that detail lives right there in the function name is so satisfying honestly. 🧚

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🌈 RETURN 🌈

the vibes she can return, in list form because we love structure:

• min..max — a positive integer count of "data-lanes" elements. the good ending. 🍓
• -EINVAL — the "data-mapping" property is unsupported. not the good ending. 💀
• -ENODEV — the "data-mapping" property is missing. also not the good ending. 😭

lowkey note: those last two are about "data-mapping" even though the function is about "data-lanes" — yes it's giving plot twist, but that's what the manpage says, so that's what we're saying. no cap. 🫡

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🔥 SEE ALSO 🔥

go read these next, bestie, they're all in the same friend group:

• Kernel file ./drivers/gpu/drm/drm_of.c overview(9)
• drm_of_crtc_port_mask(9)
• drm_of_find_possible_crtcs(9)
• drm_of_component_match_add(9)
• drm_of_component_probe(9)
• drm_of_get_panel_orientation(9)
• drm_of_find_panel_or_bridge(9)
• drm_of_lvds_get_dual_link_pixel_order(9)
• drm_of_lvds_get_dual_link_pixel_order_sink(9)
• drm_of_lvds_get_data_mapping(9)
• drm_of_get_data_lanes_count(9)
• drm_of_get_data_lanes_count_remote(9)
• drm_of_get_dsi_bus(9)

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⭐ and that's the whole page!! this one came from ./drivers/gpu/drm, dated October 2026 — so like, future vibes fr fr. go count some lanes, ily, bye!! 💖✨🎀