[PATCH v13 1/7] gpiolib: provide gpiod_remove_hogs()

Bartosz Golaszewski
2021-12-07T09:34:26Z

Currently all users of gpiod_add_hogs() call it only once at system
init so there never was any need for a mechanism allowing to remove
them. Now the upcoming gpio-sim will need to tear down chips with hogged
lines so provide a function that allows to remove hogs.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
drivers/gpio/gpiolib.c | 11 +++++++++++
include/linux/gpio/machine.h | 2 ++
2 files changed, 13 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index abfbf546d159..22b98a590a88 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3540,6 +3540,17 @@ void gpiod_add_hogs(struct gpiod_hog *hogs)
}
EXPORT_SYMBOL_GPL(gpiod_add_hogs);

+void gpiod_remove_hogs(struct gpiod_hog *hogs)
+{
+ struct gpiod_hog *hog;
+
+ mutex_lock(&gpio_machine_hogs_mutex);
+ for (hog = &hogs[0]; hog->chip_label; hog++)
+ list_del(&hog->list);
+ mutex_unlock(&gpio_machine_hogs_mutex);
+}
+EXPORT_SYMBOL_GPL(gpiod_remove_hogs);
+
static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
{
const char *dev_id = dev ? dev_name(dev) : NULL;
diff --git a/include/linux/gpio/machine.h b/include/linux/gpio/machine.h
index d755e529c1e3..2647dd10b541 100644
--- a/include/linux/gpio/machine.h
+++ b/include/linux/gpio/machine.h
@@ -100,6 +100,7 @@ void gpiod_add_lookup_table(struct gpiod_lookup_table *table);
void gpiod_add_lookup_tables(struct gpiod_lookup_table **tables, size_t n);
void gpiod_remove_lookup_table(struct gpiod_lookup_table *table);
void gpiod_add_hogs(struct gpiod_hog *hogs);
+void gpiod_remove_hogs(struct gpiod_hog *hogs);
#else /* ! CONFIG_GPIOLIB */
static inline
void gpiod_add_lookup_table(struct gpiod_lookup_table *table) {}
@@ -108,6 +109,7 @@ void gpiod_add_lookup_tables(struct gpiod_lookup_table **tables, size_t n) {}
static inline
void gpiod_remove_lookup_table(struct gpiod_lookup_table *table) {}
static inline void gpiod_add_hogs(struct gpiod_hog *hogs) {}
+static inline void gpiod_remove_hogs(struct gpiod_hog *hogs) {}
#endif /* CONFIG_GPIOLIB */

#endif /* __LINUX_GPIO_MACHINE_H */
--
2.25.1