From 418a2bbdee2927d543db6913073d0e7ec8b540ee Mon Sep 17 00:00:00 2001 From: Frank Li Date: Mon, 4 May 2026 19:54:38 -0400 Subject: pinctrl: add optional .release_mux() callback Add an optional .release_mux() callback to struct pinmux_ops. Some drivers acquire additional resources in .set_mux(), such as software locks. These resources may need to be released when the mux function is no longer active. Introducing a dedicated .release_mux() callback allows drivers to clean up such resources. The callback is optional and does not affect existing drivers. Commit 2243a87d90b42 ("pinctrl: avoid duplicated calling enable_pinmux_setting for a pin") removed the .disable() callback to resolve two issues: 1. desc->mux_usecount increasing monotonically 2. Hardware glitches caused by repeated .disable()/.enable() calls Adding .release_mux() does not reintroduce those problems. The callback is intended only for releasing driver-side resources (e.g. locks) and must not modify hardware registers. Signed-off-by: Frank Li Signed-off-by: Linus Walleij --- include/linux/pinctrl/pinmux.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include') diff --git a/include/linux/pinctrl/pinmux.h b/include/linux/pinctrl/pinmux.h index 094bbe2fd6fd..77664937eeb2 100644 --- a/include/linux/pinctrl/pinmux.h +++ b/include/linux/pinctrl/pinmux.h @@ -51,6 +51,8 @@ struct pinctrl_gpio_range; * are handled by the pinmux subsystem. The @func_selector selects a * certain function whereas @group_selector selects a certain set of pins * to be used. On simple controllers the latter argument may be ignored + * @release_mux: Release software resources acquired by @set_mux. This callback + * must not change hardware state to avoid glitches when switching mux. * @gpio_request_enable: requests and enables GPIO on a certain pin. * Implement this only if you can mux every pin individually as GPIO. The * affected GPIO range is passed along with an offset(pin number) into that @@ -80,6 +82,9 @@ struct pinmux_ops { unsigned int selector); int (*set_mux) (struct pinctrl_dev *pctldev, unsigned int func_selector, unsigned int group_selector); + void (*release_mux) (struct pinctrl_dev *pctldev, + unsigned int func_selector, + unsigned int group_selector); int (*gpio_request_enable) (struct pinctrl_dev *pctldev, struct pinctrl_gpio_range *range, unsigned int offset); -- cgit v1.2.3