[PATCH v15 1/7] pwm: Export `pwmchip_release` for external use
From: Michal Wilczynski <m.wilczynski@samsung.com>
Date: 2025-09-30 12:27:32
Also in:
linux-pwm, linux-riscv, lkml, rust-for-linux
Subsystem:
pwm subsystem, the rest · Maintainers:
Uwe Kleine-König, Linus Torvalds
The upcoming Rust abstraction layer for the PWM subsystem uses a custom `dev->release` handler to safely manage the lifetime of its driver data. To prevent leaking the memory of the `struct pwm_chip` (allocated by `pwmchip_alloc`), this custom handler must also call the original `pwmchip_release` function to complete the cleanup. Make `pwmchip_release` a global, exported function so that it can be called from the Rust FFI bridge. This involves removing the `static` keyword, adding a prototype to the public header, and exporting the symbol. Reviewed-by: Elle Rhumsaa <redacted> Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com> --- drivers/pwm/core.c | 3 ++- include/linux/pwm.h | 6 ++++++ 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 0d66376a83ec350e0c3718959f4d794efd71595a..a33da3dff608fdff91251e5fd07b0dbd295be022 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c@@ -1600,12 +1600,13 @@ void pwmchip_put(struct pwm_chip *chip) } EXPORT_SYMBOL_GPL(pwmchip_put); -static void pwmchip_release(struct device *pwmchip_dev) +void pwmchip_release(struct device *pwmchip_dev) { struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev); kfree(chip); } +EXPORT_SYMBOL_GPL(pwmchip_release); struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) {
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 8cafc483db53addf95591d1ac74287532c0fa0ee..d86061024b52172edf3845bf9252a966f120e365 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h@@ -485,6 +485,12 @@ int __pwmchip_add(struct pwm_chip *chip, struct module *owner); #define pwmchip_add(chip) __pwmchip_add(chip, THIS_MODULE) void pwmchip_remove(struct pwm_chip *chip); +/* + * For FFI wrapper use only: + * The Rust PWM abstraction needs this to properly free the pwm_chip. + */ +void pwmchip_release(struct device *dev); + int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner); #define devm_pwmchip_add(dev, chip) __devm_pwmchip_add(dev, chip, THIS_MODULE)
--
2.34.1