pin_free(9)

👑 pin_free(9) 💅

okay so bestie, we're in the Kernel API Manual (section 9, iykyk) and today's main character is pin_free — the girl whose entire job is letting go so someone else can have a turn. iconic behavior honestly.

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✨ NAME ✨

pin_free — release a single muxed in pin so something else can be muxed 🦋

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🌸 SYNOPSIS 🌸

const char * pin_free (struct pinctrl_dev *pctldev , int pin , struct
pinctrl_gpio_range *gpio_range );

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🎀 ARGUMENTS 🎀

• pctldev — the pin controller device that's handling this pin, like the group chat admin for this specific pin 🫶
• pin — the pin you're freeing. yes literally the pin to free, that's the whole vibe
• gpio_range — the range that matches the GPIO pin if this is a request for a single GPIO pin. conditional queen 💅

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💖 DESCRIPTION 💖

so what does it actually do? it returns a pointer to the previous owner. that's it, that's the return value 🌈

and why do we care?? because callers that dynamically allocate an owner name need it back so they can free it once the pin is free. the way that memory gets handled… obsessed 😭 this whole dance is done for GPIO request functions, fr fr.

bestie reminder: dynamic allocation means someone's gotta clean it up. this function is literally handing you the receipt so you can return the item. no leaks, no drama 💀

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🧚 SEE ALSO 🧚

kernel file ./drivers/pinctrl/pinmux.c plus the whole squad:

• pinmux_can_be_used_for_gpio(9)
• pin_request(9)
• pinmux_request_gpio(9)
• pinmux_free_gpio(9)
• pinmux_gpio_direction(9)
• pinmux_generic_get_function_count(9)
• pinmux_generic_get_function_name(9)
• pinmux_generic_get_function_groups(9)
• pinmux_generic_get_function(9)
• pinmux_generic_function_is_gpio(9)
• pinmux_generic_add_function(9)
• pinmux_generic_add_pinfunction(9)
• pinmux_generic_remove_function(9)
• pinmux_generic_free_functions(9)

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⭐ and that's the whole page, bestie! this little beauty lives over in ./drivers/pinctrl, dated October 2026, and honestly? pin_free(9) ate. periodt 💜🦋✨