of_property_read_u64_index(9)

💅 of_property_read_u64_index(9)

okay so bestie, welcome to the Kernel API Manual, and today's main character is of_property_read_u64_index(9) — say that five times fast, i promise it's worth it 🫶

---

✨ NAME ✨

of_property_read_u64_index — find and read a u64 from a multi-value property. like, you go looking for it, and then you read it. iconic behavior honestly 🎀

---

🌸 SYNOPSIS 🌸

int of_property_read_u64_index (const struct device_node *np , const
char *propname , u32 index , u64 *out_value );

---

🦋 ARGUMENTS 🦋

• np — the device node you're reading the property value from. your starting point, your home base, your main character node 💖
• propname — name of the property to be searched. literally the thing you're looking for, bestie.
• index — index of the u64 in the list of values. yes, it's a list, yes you gotta pick one 🔥
• out_value — pointer to return value, and it gets modified only if no error. no cap, it stays untouched if things go sideways 🙈

---

⭐ DESCRIPTION ⭐

So what does it actually do? it searches for a property in a device node and reads the *n*th 64-bit value from it. that's the whole vibe. one property, one node, one 64-bit value, selected by index 💜

And the important little caveat, because details matter: the out_value is modified only if a valid u64 value can be decoded. no valid u64, no touchy. periodt. ✨

---

👑 RETURN 👑

• 0 on success — slay, it worked 🎉
• -EINVAL if the property does not exist — girl, it's not there 💀
• -ENODATA if property does not have a value — it exists but it's giving absolutely nothing 😭
• -EOVERFLOW if the property data isn't large enough — too small, didn't fit, awkward 🌸

---

🌈 SEE ALSO 🌈

Kernel file ./drivers/of/property.c — that's where the magic lives, go look, iykyk 💅

• of_property_read_bool(9)
• of_graph_is_present(9)
• of_property_count_elems_of_size(9)
• of_find_property_value_of_size(9)
• of_property_read_u8_index(9)
• of_property_read_u16_index(9)
• of_property_read_u32_index(9)
• of_property_read_variable_u8_array(9)
• of_property_read_variable_u16_array(9)
• of_property_read_variable_u32_array(9)
• of_property_read_u64(9)
• of_property_read_variable_u64_array(9)
• of_property_read_string(9)
• of_property_match_string(9)
• of_property_read_string_helper(9)
• of_graph_parse_endpoint(9)
• of_graph_get_port_by_id(9)
• of_graph_get_next_port(9)
• of_graph_get_next_port_endpoint(9)
• of_graph_get_next_endpoint(9)
• of_graph_get_endpoint_by_regs(9)
• of_graph_get_remote_endpoint(9)
• of_graph_get_port_parent(9)
• of_graph_get_remote_port_parent(9)
• of_graph_get_remote_port(9)
• of_graph_get_endpoint_count(9)
• of_graph_get_port_count(9)
• of_graph_get_remote_node(9)
• parse_prop_cells(9)
• parse_suffix_prop_cells(9)
• struct supplier_bindings(9)
• of_link_property(9)

---

ok that's the whole page, bestie — go read some u64s responsibly, and remember: out_value only changes when there's a valid value to decode. no error, no write. we respect the pointer in this house 🫶

and that's a wrap!! brought to you by ./drivers/of, dated October 2026, filed lovingly under of_property_read_u64_index(9) — mwah 💋✨🎀