gpiolib: provide gpiod_remove_hogs()

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>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 535eb1b509c1964981b16e230d7db5cfac278260..467f4a8586a06942ae8262dde12683c72fef9ce4 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3557,6 +3557,17 @@ 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 d755e529c1e31f8d67260dc577715de6d54a627a..2647dd10b5419015a20cb16752220efd83a51a06 100644 (file)
--- 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 */