[PATCH v2 5/6] gpio: remove machine hogs
From: Bartosz Golaszewski
Date: Mon Mar 09 2026 - 08:46:01 EST
With no more users, remove legacy machine hog API from the kernel.
Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
Documentation/driver-api/gpio/board.rst | 16 --------
drivers/gpio/gpiolib.c | 71 ---------------------------------
include/linux/gpio/machine.h | 33 ---------------
3 files changed, 120 deletions(-)
diff --git a/Documentation/driver-api/gpio/board.rst b/Documentation/driver-api/gpio/board.rst
index 069b54d8591bdeb975a6c650d643db4f7eb98ab7..0993cac891fb5e4887a1aee6deae273197c6aae1 100644
--- a/Documentation/driver-api/gpio/board.rst
+++ b/Documentation/driver-api/gpio/board.rst
@@ -239,22 +239,6 @@ mapping and is thus transparent to GPIO consumers.
A set of functions such as gpiod_set_value() is available to work with
the new descriptor-oriented interface.
-Boards using platform data can also hog GPIO lines by defining GPIO hog tables.
-
-.. code-block:: c
-
- struct gpiod_hog gpio_hog_table[] = {
- GPIO_HOG("gpio.0", 10, "foo", GPIO_ACTIVE_LOW, GPIOD_OUT_HIGH),
- { }
- };
-
-And the table can be added to the board code as follows::
-
- gpiod_add_hogs(gpio_hog_table);
-
-The line will be hogged as soon as the gpiochip is created or - in case the
-chip was created earlier - when the hog table is registered.
-
Arrays of pins
--------------
In addition to requesting pins belonging to a function one by one, a device may
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index b993cdae79e6dc389ca42ed079b3e39d1f9fed5a..829774322f3595d191e13e89ef83001507f6fdea 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -103,9 +103,6 @@ static DEFINE_MUTEX(gpio_devices_lock);
/* Ensures coherence during read-only accesses to the list of GPIO devices. */
DEFINE_STATIC_SRCU(gpio_devices_srcu);
-static DEFINE_MUTEX(gpio_machine_hogs_mutex);
-static LIST_HEAD(gpio_machine_hogs);
-
const char *const gpio_suffixes[] = { "gpios", "gpio", NULL };
static void gpiochip_free_hogs(struct gpio_chip *gc);
@@ -930,36 +927,6 @@ static int gpiochip_setup_dev(struct gpio_chip *gc)
return ret;
}
-static void gpiochip_machine_hog(struct gpio_chip *gc, struct gpiod_hog *hog)
-{
- struct gpio_desc *desc;
- int rv;
-
- desc = gpiochip_get_desc(gc, hog->chip_hwnum);
- if (IS_ERR(desc)) {
- gpiochip_err(gc, "%s: unable to get GPIO desc: %ld\n",
- __func__, PTR_ERR(desc));
- return;
- }
-
- rv = gpiod_hog(desc, hog->line_name, hog->lflags, hog->dflags);
- if (rv)
- gpiod_err(desc, "%s: unable to hog GPIO line (%s:%u): %d\n",
- __func__, gc->label, hog->chip_hwnum, rv);
-}
-
-static void gpiochip_machine_hog_lines(struct gpio_chip *gc)
-{
- struct gpiod_hog *hog;
-
- guard(mutex)(&gpio_machine_hogs_mutex);
-
- list_for_each_entry(hog, &gpio_machine_hogs, list) {
- if (!strcmp(gc->label, hog->chip_label))
- gpiochip_machine_hog(gc, hog);
- }
-}
-
int gpiochip_add_hog(struct gpio_chip *gc, struct fwnode_handle *fwnode)
{
struct fwnode_handle *gc_node = dev_fwnode(&gc->gpiodev->dev);
@@ -1047,8 +1014,6 @@ static int gpiochip_hog_lines(struct gpio_chip *gc)
return ret;
}
- gpiochip_machine_hog_lines(gc);
-
return 0;
}
@@ -4582,42 +4547,6 @@ void gpiod_remove_lookup_table(struct gpiod_lookup_table *table)
}
EXPORT_SYMBOL_GPL(gpiod_remove_lookup_table);
-/**
- * gpiod_add_hogs() - register a set of GPIO hogs from machine code
- * @hogs: table of gpio hog entries with a zeroed sentinel at the end
- */
-void gpiod_add_hogs(struct gpiod_hog *hogs)
-{
- struct gpiod_hog *hog;
-
- guard(mutex)(&gpio_machine_hogs_mutex);
-
- for (hog = &hogs[0]; hog->chip_label; hog++) {
- list_add_tail(&hog->list, &gpio_machine_hogs);
-
- /*
- * The chip may have been registered earlier, so check if it
- * exists and, if so, try to hog the line now.
- */
- struct gpio_device *gdev __free(gpio_device_put) =
- gpio_device_find_by_label(hog->chip_label);
- if (gdev)
- gpiochip_machine_hog(gpio_device_get_chip(gdev), hog);
- }
-}
-EXPORT_SYMBOL_GPL(gpiod_add_hogs);
-
-void gpiod_remove_hogs(struct gpiod_hog *hogs)
-{
- struct gpiod_hog *hog;
-
- guard(mutex)(&gpio_machine_hogs_mutex);
-
- for (hog = &hogs[0]; hog->chip_label; hog++)
- list_del(&hog->list);
-}
-EXPORT_SYMBOL_GPL(gpiod_remove_hogs);
-
static bool gpiod_match_lookup_table(struct device *dev,
const struct gpiod_lookup_table *table)
{
diff --git a/include/linux/gpio/machine.h b/include/linux/gpio/machine.h
index 44e5f162973eb6f6e85188f56ec34e1e3e2beab6..5eb88f5d0630f83b6a3a0e6727103c319e139b27 100644
--- a/include/linux/gpio/machine.h
+++ b/include/linux/gpio/machine.h
@@ -46,23 +46,6 @@ struct gpiod_lookup_table {
struct gpiod_lookup table[];
};
-/**
- * struct gpiod_hog - GPIO line hog table
- * @chip_label: name of the chip the GPIO belongs to
- * @chip_hwnum: hardware number (i.e. relative to the chip) of the GPIO
- * @line_name: consumer name for the hogged line
- * @lflags: bitmask of gpio_lookup_flags GPIO_* values
- * @dflags: GPIO flags used to specify the direction and value
- */
-struct gpiod_hog {
- struct list_head list;
- const char *chip_label;
- u16 chip_hwnum;
- const char *line_name;
- unsigned long lflags;
- int dflags;
-};
-
/*
* Helper for lookup tables with just one single lookup for a device.
*/
@@ -95,24 +78,10 @@ static struct gpiod_lookup_table _name = { \
.flags = _flags, \
}
-/*
- * Simple definition of a single GPIO hog in an array.
- */
-#define GPIO_HOG(_chip_label, _chip_hwnum, _line_name, _lflags, _dflags) \
-(struct gpiod_hog) { \
- .chip_label = _chip_label, \
- .chip_hwnum = _chip_hwnum, \
- .line_name = _line_name, \
- .lflags = _lflags, \
- .dflags = _dflags, \
-}
-
#ifdef CONFIG_GPIOLIB
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) {}
@@ -120,8 +89,6 @@ static inline
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 */
--
2.47.3