[PATCH 2/6] gpio: move hogs into GPIO core
From: Bartosz Golaszewski
Date: Thu Mar 05 2026 - 04:53:27 EST
Refactor line hogging code by moving the parts duplicated in
gpiolib-acpi-core.c and gpiolib-of.c into gpiolib.c, leaving just the
OF-specific bits in the latter.
This makes fwnode the primary API for setting up hogs and allows to use
software nodes in addition to ACPI and OF nodes.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
drivers/gpio/gpiolib-acpi-core.c | 70 --------------------
drivers/gpio/gpiolib-of.c | 139 +++------------------------------------
drivers/gpio/gpiolib-of.h | 9 +++
drivers/gpio/gpiolib.c | 100 +++++++++++++++++++++++++++-
drivers/gpio/gpiolib.h | 3 +
5 files changed, 120 insertions(+), 201 deletions(-)
diff --git a/drivers/gpio/gpiolib-acpi-core.c b/drivers/gpio/gpiolib-acpi-core.c
index ced6375d1badf9e113e708ce4bc9f83071f9acca..09f860200a059b1d17c652b9aa66a49abea3cb4f 100644
--- a/drivers/gpio/gpiolib-acpi-core.c
+++ b/drivers/gpio/gpiolib-acpi-core.c
@@ -1220,75 +1220,6 @@ static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
}
}
-static struct gpio_desc *
-acpi_gpiochip_parse_own_gpio(struct acpi_gpio_chip *achip,
- struct fwnode_handle *fwnode,
- const char **name,
- unsigned long *lflags,
- enum gpiod_flags *dflags)
-{
- struct gpio_chip *chip = achip->chip;
- struct gpio_desc *desc;
- u32 gpios[2];
- int ret;
-
- *lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
- *dflags = GPIOD_ASIS;
- *name = NULL;
-
- ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios,
- ARRAY_SIZE(gpios));
- if (ret < 0)
- return ERR_PTR(ret);
-
- desc = gpiochip_get_desc(chip, gpios[0]);
- if (IS_ERR(desc))
- return desc;
-
- if (gpios[1])
- *lflags |= GPIO_ACTIVE_LOW;
-
- if (fwnode_property_present(fwnode, "input"))
- *dflags |= GPIOD_IN;
- else if (fwnode_property_present(fwnode, "output-low"))
- *dflags |= GPIOD_OUT_LOW;
- else if (fwnode_property_present(fwnode, "output-high"))
- *dflags |= GPIOD_OUT_HIGH;
- else
- return ERR_PTR(-EINVAL);
-
- fwnode_property_read_string(fwnode, "line-name", name);
-
- return desc;
-}
-
-static void acpi_gpiochip_scan_gpios(struct acpi_gpio_chip *achip)
-{
- struct gpio_chip *chip = achip->chip;
-
- device_for_each_child_node_scoped(chip->parent, fwnode) {
- unsigned long lflags;
- enum gpiod_flags dflags;
- struct gpio_desc *desc;
- const char *name;
- int ret;
-
- if (!fwnode_property_present(fwnode, "gpio-hog"))
- continue;
-
- desc = acpi_gpiochip_parse_own_gpio(achip, fwnode, &name,
- &lflags, &dflags);
- if (IS_ERR(desc))
- continue;
-
- ret = gpiod_hog(desc, name, lflags, dflags);
- if (ret) {
- dev_err(chip->parent, "Failed to hog GPIO\n");
- return;
- }
- }
-}
-
void acpi_gpiochip_add(struct gpio_chip *chip)
{
struct acpi_gpio_chip *acpi_gpio;
@@ -1321,7 +1252,6 @@ void acpi_gpiochip_add(struct gpio_chip *chip)
}
acpi_gpiochip_request_regions(acpi_gpio);
- acpi_gpiochip_scan_gpios(acpi_gpio);
acpi_dev_clear_dependencies(adev);
}
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 08b7b662512b825086cd70440be98b59befc3ffe..4554d915d57d95aadae0e4d9ea30c3d9c2782984 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -735,139 +735,19 @@ struct gpio_desc *of_find_gpio(struct device_node *np, const char *con_id,
return desc;
}
-/**
- * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
- * @np: device node to get GPIO from
- * @chip: GPIO chip whose hog is parsed
- * @idx: Index of the GPIO to parse
- * @name: GPIO line name
- * @lflags: bitmask of gpio_lookup_flags GPIO_* values - returned from
- * of_find_gpio() or of_parse_own_gpio()
- * @dflags: gpiod_flags - optional GPIO initialization flags
- *
- * Returns:
- * GPIO descriptor to use with Linux GPIO API, or one of the errno
- * value on the error condition.
- */
-static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
- struct gpio_chip *chip,
- unsigned int idx, const char **name,
- unsigned long *lflags,
- enum gpiod_flags *dflags)
+int of_gpiochip_get_lflags(struct gpio_chip *chip,
+ struct of_phandle_args *gpiospec,
+ unsigned long *lflags)
{
- struct device_node *chip_np;
enum of_gpio_flags xlate_flags;
- struct of_phandle_args gpiospec;
struct gpio_desc *desc;
- unsigned int i;
- u32 tmp;
- int ret;
-
- chip_np = dev_of_node(&chip->gpiodev->dev);
- if (!chip_np)
- return ERR_PTR(-EINVAL);
-
- xlate_flags = 0;
- *lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
- *dflags = GPIOD_ASIS;
-
- ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
- if (ret)
- return ERR_PTR(ret);
-
- gpiospec.np = chip_np;
- gpiospec.args_count = tmp;
- for (i = 0; i < tmp; i++) {
- ret = of_property_read_u32_index(np, "gpios", idx * tmp + i,
- &gpiospec.args[i]);
- if (ret)
- return ERR_PTR(ret);
- }
-
- desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
+ desc = of_xlate_and_get_gpiod_flags(chip, gpiospec, &xlate_flags);
if (IS_ERR(desc))
- return desc;
+ return PTR_ERR(desc);
*lflags = of_convert_gpio_flags(xlate_flags);
- if (of_property_read_bool(np, "input"))
- *dflags |= GPIOD_IN;
- else if (of_property_read_bool(np, "output-low"))
- *dflags |= GPIOD_OUT_LOW;
- else if (of_property_read_bool(np, "output-high"))
- *dflags |= GPIOD_OUT_HIGH;
- else {
- pr_warn("GPIO line %d (%pOFn): no hogging state specified, bailing out\n",
- desc_to_gpio(desc), np);
- return ERR_PTR(-EINVAL);
- }
-
- if (name && of_property_read_string(np, "line-name", name))
- *name = np->name;
-
- return desc;
-}
-
-/**
- * of_gpiochip_add_hog - Add all hogs in a hog device node
- * @chip: gpio chip to act on
- * @hog: device node describing the hogs
- *
- * Returns:
- * 0 on success, or negative errno on failure.
- */
-static int of_gpiochip_add_hog(struct gpio_chip *chip, struct device_node *hog)
-{
- enum gpiod_flags dflags;
- struct gpio_desc *desc;
- unsigned long lflags;
- const char *name;
- unsigned int i;
- int ret;
-
- for (i = 0;; i++) {
- desc = of_parse_own_gpio(hog, chip, i, &name, &lflags, &dflags);
- if (IS_ERR(desc))
- break;
-
- ret = gpiod_hog(desc, name, lflags, dflags);
- if (ret < 0)
- return ret;
-
-#ifdef CONFIG_OF_DYNAMIC
- WRITE_ONCE(desc->hog, hog);
-#endif
- }
-
- return 0;
-}
-
-/**
- * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
- * @chip: gpio chip to act on
- *
- * This is only used by of_gpiochip_add to request/set GPIO initial
- * configuration.
- *
- * Returns:
- * 0 on success, or negative errno on failure.
- */
-static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
-{
- int ret;
-
- for_each_available_child_of_node_scoped(dev_of_node(&chip->gpiodev->dev), np) {
- if (!of_property_read_bool(np, "gpio-hog"))
- continue;
-
- ret = of_gpiochip_add_hog(chip, np);
- if (ret < 0)
- return ret;
-
- of_node_set_flag(np, OF_POPULATED);
- }
-
return 0;
}
@@ -922,7 +802,7 @@ static int of_gpio_notify(struct notifier_block *nb, unsigned long action,
if (!gdev)
return NOTIFY_DONE; /* not for us */
- ret = of_gpiochip_add_hog(gpio_device_get_chip(gdev), rd->dn);
+ ret = gpiochip_add_hog(gpio_device_get_chip(gdev), of_fwnode_handle(rd->dn));
if (ret < 0) {
pr_err("%s: failed to add hogs for %pOF\n", __func__,
rd->dn);
@@ -1201,9 +1081,10 @@ int of_gpiochip_add(struct gpio_chip *chip)
of_node_get(np);
- ret = of_gpiochip_scan_gpios(chip);
- if (ret)
- of_node_put(np);
+ for_each_available_child_of_node_scoped(np, child) {
+ if (of_property_read_bool(child, "gpio-hog"))
+ of_node_set_flag(child, OF_POPULATED);
+ }
return ret;
}
diff --git a/drivers/gpio/gpiolib-of.h b/drivers/gpio/gpiolib-of.h
index 2257f7a498a10d69980f0c8afd48d5b661632d87..f864597baaede1e601fc999514c129750c2a8317 100644
--- a/drivers/gpio/gpiolib-of.h
+++ b/drivers/gpio/gpiolib-of.h
@@ -24,6 +24,9 @@ int of_gpiochip_add(struct gpio_chip *gc);
void of_gpiochip_remove(struct gpio_chip *gc);
bool of_gpiochip_instance_match(struct gpio_chip *gc, unsigned int index);
int of_gpio_count(const struct fwnode_handle *fwnode, const char *con_id);
+int of_gpiochip_get_lflags(struct gpio_chip *chip,
+ struct of_phandle_args *gpiospec,
+ unsigned long *lflags);
#else
static inline struct gpio_desc *of_find_gpio(struct device_node *np,
const char *con_id,
@@ -44,6 +47,12 @@ static inline int of_gpio_count(const struct fwnode_handle *fwnode,
{
return 0;
}
+static inline int of_gpiochip_get_lflags(struct gpio_chip *chip,
+ struct of_phandle_args *gpiospec,
+ unsigned long *lflags)
+{
+ return -ENOENT;
+}
#endif /* CONFIG_OF_GPIO */
extern struct notifier_block gpio_of_notifier;
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 581d00c128b608c30f45c12e968c15628e205870..be2e6ed0e744c23939491717a060d3a8456c842b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -948,7 +948,7 @@ static void gpiochip_machine_hog(struct gpio_chip *gc, struct gpiod_hog *hog)
__func__, gc->label, hog->chip_hwnum, rv);
}
-static void machine_gpiochip_add(struct gpio_chip *gc)
+static void gpiochip_machine_hog_lines(struct gpio_chip *gc)
{
struct gpiod_hog *hog;
@@ -960,6 +960,100 @@ static void machine_gpiochip_add(struct gpio_chip *gc)
}
}
+int gpiochip_add_hog(struct gpio_chip *gc, struct fwnode_handle *fwnode)
+{
+ struct fwnode_handle *gc_node = dev_fwnode(&gc->gpiodev->dev);
+ struct of_phandle_args gpiospec;
+ enum gpiod_flags dflags;
+ struct gpio_desc *desc;
+ unsigned long lflags;
+ const char *name;
+ int ret, argc;
+ u32 gpios[3]; /* We support up to three-cell bindings. */
+ u32 cells;
+
+ lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
+ dflags = GPIOD_ASIS;
+ name = NULL;
+
+ argc = fwnode_property_count_u32(fwnode, "gpios");
+ if (argc < 0)
+ return ret;
+ if (argc > 3)
+ return -EINVAL;
+
+ ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios, argc);
+ if (ret < 0)
+ return ret;
+
+ if (is_of_node(fwnode)) {
+ /*
+ * OF-nodes need some additional special handling for
+ * translating of devicetree flags.
+ */
+ ret = fwnode_property_read_u32(gc_node, "#gpio-cells", &cells);
+ if (ret)
+ return ret;
+ if (cells && argc != cells)
+ return -EINVAL;
+
+ memset(&gpiospec, 0, sizeof(gpiospec));
+ gpiospec.np = to_of_node(fwnode);
+ gpiospec.args_count = argc;
+ memcpy(&gpiospec.args, gpios, argc * sizeof(u32));
+
+ ret = of_gpiochip_get_lflags(gc, &gpiospec, &lflags);
+ if (ret)
+ return ret;
+ } else {
+ /*
+ * GPIO_ACTIVE_LOW is currently the only lookup flag
+ * supported for non-OF firmware nodes.
+ */
+ if (gpios[1])
+ lflags |= GPIO_ACTIVE_LOW;
+ }
+
+ if (fwnode_property_present(fwnode, "input"))
+ dflags |= GPIOD_IN;
+ else if (fwnode_property_present(fwnode, "output-low"))
+ dflags |= GPIOD_OUT_LOW;
+ else if (fwnode_property_present(fwnode, "output-high"))
+ dflags |= GPIOD_OUT_HIGH;
+ else
+ return -EINVAL;
+
+ fwnode_property_read_string(fwnode, "line-name", &name);
+
+ desc = gpiochip_get_desc(gc, gpios[0]);
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+
+ ret = gpiod_hog(desc, name, lflags, dflags);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int gpiochip_hog_lines(struct gpio_chip *gc)
+{
+ int ret;
+
+ device_for_each_child_node_scoped(&gc->gpiodev->dev, fwnode) {
+ if (!fwnode_property_present(fwnode, "gpio-hog"))
+ continue;
+
+ ret = gpiochip_add_hog(gc, fwnode);
+ if (ret)
+ return ret;
+ }
+
+ gpiochip_machine_hog_lines(gc);
+
+ return 0;
+}
+
static void gpiochip_setup_devs(void)
{
struct gpio_device *gdev;
@@ -1209,7 +1303,9 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
acpi_gpiochip_add(gc);
- machine_gpiochip_add(gc);
+ ret = gpiochip_hog_lines(gc);
+ if (ret)
+ goto err_remove_of_chip;
ret = gpiochip_irqchip_init_valid_mask(gc);
if (ret)
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 8d1a762f9d11bfc29c9102be02d7b640aa7daad3..dc4cb61a93187659d943f4ce3622bc1755e9fd42 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -23,6 +23,8 @@
#define GPIOCHIP_NAME "gpiochip"
+struct fwnode_handle;
+
/**
* struct gpio_device - internal state container for GPIO devices
* @dev: the GPIO device struct
@@ -274,6 +276,7 @@ int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce);
int gpiod_hog(struct gpio_desc *desc, const char *name,
unsigned long lflags, enum gpiod_flags dflags);
+int gpiochip_add_hog(struct gpio_chip *gc, struct fwnode_handle *fwnode);
int gpiochip_get_ngpios(struct gpio_chip *gc, struct device *dev);
struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum);
const char *gpiod_get_label(struct gpio_desc *desc);
--
2.47.3