From 197b3f3c70d61ff1c7ca24f66d567e06fe8ed3d9 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 12 Nov 2025 14:55:30 +0100 Subject: [PATCH 1/7] string: provide strends() Implement a function for checking if a string ends with a different string and add its kunit test cases. Acked-by: Linus Walleij Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-1-b51f97b1abd8@linaro.org Signed-off-by: Bartosz Golaszewski --- include/linux/string.h | 18 ++++++++++++++++++ lib/tests/string_kunit.c | 13 +++++++++++++ 2 files changed, 31 insertions(+) diff --git a/include/linux/string.h b/include/linux/string.h index fdd3442c6bcb..929d05d1247c 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -562,4 +562,22 @@ static inline bool strstarts(const char *str, const char *prefix) return strncmp(str, prefix, strlen(prefix)) == 0; } +/** + * strends - Check if a string ends with another string. + * @str - NULL-terminated string to check against @suffix + * @suffix - NULL-terminated string defining the suffix to look for in @str + * + * Returns: + * True if @str ends with @suffix. False in all other cases. + */ +static inline bool strends(const char *str, const char *suffix) +{ + unsigned int str_len = strlen(str), suffix_len = strlen(suffix); + + if (str_len < suffix_len) + return false; + + return !(strcmp(str + str_len - suffix_len, suffix)); +} + #endif /* _LINUX_STRING_H_ */ diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c index 0ed7448a26d3..f9a8e557ba77 100644 --- a/lib/tests/string_kunit.c +++ b/lib/tests/string_kunit.c @@ -602,6 +602,18 @@ static void string_test_memtostr(struct kunit *test) KUNIT_EXPECT_EQ(test, dest[7], '\0'); } +static void string_test_strends(struct kunit *test) +{ + KUNIT_EXPECT_TRUE(test, strends("foo-bar", "bar")); + KUNIT_EXPECT_TRUE(test, strends("foo-bar", "-bar")); + KUNIT_EXPECT_TRUE(test, strends("foobar", "foobar")); + KUNIT_EXPECT_TRUE(test, strends("foobar", "")); + KUNIT_EXPECT_FALSE(test, strends("bar", "foobar")); + KUNIT_EXPECT_FALSE(test, strends("", "foo")); + KUNIT_EXPECT_FALSE(test, strends("foobar", "ba")); + KUNIT_EXPECT_TRUE(test, strends("", "")); +} + static struct kunit_case string_test_cases[] = { KUNIT_CASE(string_test_memset16), KUNIT_CASE(string_test_memset32), @@ -623,6 +635,7 @@ static struct kunit_case string_test_cases[] = { KUNIT_CASE(string_test_strlcat), KUNIT_CASE(string_test_strtomem), KUNIT_CASE(string_test_memtostr), + KUNIT_CASE(string_test_strends), {} }; From d4340ff75eaa083f261e16d49f13191236bfad06 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 12 Nov 2025 14:55:31 +0100 Subject: [PATCH 2/7] gpiolib: define GPIOD_FLAG_SHARED Define a new GPIO descriptor flag for marking pins that are shared by multiple consumer. This flag will be used in several places so we need to do it in advance and separately from other changes. Reviewed-by: Linus Walleij Acked-by: Linus Walleij Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-2-b51f97b1abd8@linaro.org Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib.h | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 2a003a7311e7..09ac92ed0853 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -204,6 +204,7 @@ struct gpio_desc { #define GPIOD_FLAG_EDGE_FALLING 17 /* GPIO CDEV detects falling edge events */ #define GPIOD_FLAG_EVENT_CLOCK_REALTIME 18 /* GPIO CDEV reports REALTIME timestamps in events */ #define GPIOD_FLAG_EVENT_CLOCK_HTE 19 /* GPIO CDEV reports hardware timestamps in events */ +#define GPIOD_FLAG_SHARED 20 /* GPIO is shared by multiple consumers */ /* Connection label */ struct gpio_desc_label __rcu *label; From a060b8c511abb0997381b397e52149a5e3e5259a Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 12 Nov 2025 14:55:32 +0100 Subject: [PATCH 3/7] gpiolib: implement low-level, shared GPIO support This module scans the device tree (for now only OF nodes are supported but care is taken to make other fwnode implementations easy to integrate) and determines which GPIO lines are shared by multiple users. It stores that information in memory. When the GPIO chip exposing shared lines is registered, the shared GPIO descriptors it exposes are marked as shared and virtual "proxy" devices that mediate access to the shared lines are created. When a consumer of a shared GPIO looks it up, its fwnode lookup is redirected to a just-in-time machine lookup that points to this proxy device. This code can be compiled out on platforms which don't use shared GPIOs. Reviewed-by: Linus Walleij Acked-by: Linus Walleij Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-3-b51f97b1abd8@linaro.org Signed-off-by: Bartosz Golaszewski --- drivers/gpio/Kconfig | 8 + drivers/gpio/Makefile | 1 + drivers/gpio/gpiolib-shared.c | 540 ++++++++++++++++++++++++++++++++++ drivers/gpio/gpiolib-shared.h | 71 +++++ 4 files changed, 620 insertions(+) create mode 100644 drivers/gpio/gpiolib-shared.c create mode 100644 drivers/gpio/gpiolib-shared.h diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 7ee3afbc2b05..92139e75484f 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -6,6 +6,9 @@ config GPIOLIB_LEGACY def_bool y +config HAVE_SHARED_GPIOS + bool + menuconfig GPIOLIB bool "GPIO Support" help @@ -50,6 +53,11 @@ config OF_GPIO_MM_GPIOCHIP this symbol, but new drivers should use the generic gpio-regmap infrastructure instead. +config GPIO_SHARED + def_bool y + depends on HAVE_SHARED_GPIOS || COMPILE_TEST + select AUXILIARY_BUS + config DEBUG_GPIO bool "Debug GPIO calls" depends on DEBUG_KERNEL diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index ec296fa14bfd..f702f7e27e5b 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -12,6 +12,7 @@ obj-$(CONFIG_GPIO_SYSFS) += gpiolib-sysfs.o obj-$(CONFIG_GPIO_ACPI) += gpiolib-acpi.o gpiolib-acpi-y := gpiolib-acpi-core.o gpiolib-acpi-quirks.o obj-$(CONFIG_GPIOLIB) += gpiolib-swnode.o +obj-$(CONFIG_GPIO_SHARED) += gpiolib-shared.o # Device drivers. Generally keep list sorted alphabetically obj-$(CONFIG_GPIO_REGMAP) += gpio-regmap.o diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c new file mode 100644 index 000000000000..1fcbf53b6eca --- /dev/null +++ b/drivers/gpio/gpiolib-shared.c @@ -0,0 +1,540 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2025 Linaro Ltd. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "gpiolib.h" +#include "gpiolib-shared.h" + +/* Represents a single reference to a GPIO pin. */ +struct gpio_shared_ref { + struct list_head list; + /* Firmware node associated with this GPIO's consumer. */ + struct fwnode_handle *fwnode; + /* GPIO flags this consumer uses for the request. */ + enum gpiod_flags flags; + char *con_id; + int dev_id; + struct auxiliary_device adev; + struct gpiod_lookup_table *lookup; +}; + +/* Represents a single GPIO pin. */ +struct gpio_shared_entry { + struct list_head list; + /* Firmware node associated with the GPIO controller. */ + struct fwnode_handle *fwnode; + /* Hardware offset of the GPIO within its chip. */ + unsigned int offset; + /* Index in the property value array. */ + size_t index; + struct gpio_shared_desc *shared_desc; + struct kref ref; + struct list_head refs; +}; + +static LIST_HEAD(gpio_shared_list); +static DEFINE_MUTEX(gpio_shared_lock); +static DEFINE_IDA(gpio_shared_ida); + +static struct gpio_shared_entry * +gpio_shared_find_entry(struct fwnode_handle *controller_node, + unsigned int offset) +{ + struct gpio_shared_entry *entry; + + list_for_each_entry(entry, &gpio_shared_list, list) { + if (entry->fwnode == controller_node && entry->offset == offset) + return entry; + } + + return NULL; +} + +#if IS_ENABLED(CONFIG_OF) +static int gpio_shared_of_traverse(struct device_node *curr) +{ + struct gpio_shared_entry *entry; + size_t con_id_len, suffix_len; + struct fwnode_handle *fwnode; + struct of_phandle_args args; + struct property *prop; + unsigned int offset; + const char *suffix; + int ret, count, i; + + for_each_property_of_node(curr, prop) { + /* + * The standard name for a GPIO property is "foo-gpios" + * or "foo-gpio". Some bindings also use "gpios" or "gpio". + * There are some legacy device-trees which have a different + * naming convention and for which we have rename quirks in + * place in gpiolib-of.c. I don't think any of them require + * support for shared GPIOs so for now let's just ignore + * them. We can always just export the quirk list and + * iterate over it here. + */ + if (!strends(prop->name, "-gpios") && + !strends(prop->name, "-gpio") && + strcmp(prop->name, "gpios") != 0 && + strcmp(prop->name, "gpio") != 0) + continue; + + count = of_count_phandle_with_args(curr, prop->name, + "#gpio-cells"); + if (count <= 0) + continue; + + for (i = 0; i < count; i++) { + struct device_node *np __free(device_node) = NULL; + + ret = of_parse_phandle_with_args(curr, prop->name, + "#gpio-cells", i, + &args); + if (ret) + continue; + + np = args.np; + + if (!of_property_present(np, "gpio-controller")) + continue; + + /* + * We support 1, 2 and 3 cell GPIO bindings in the + * kernel currently. There's only one old MIPS dts that + * has a one-cell binding but there's no associated + * consumer so it may as well be an error. There don't + * seem to be any 3-cell users of non-exclusive GPIOs, + * so we can skip this as well. Let's occupy ourselves + * with the predominant 2-cell binding with the first + * cell indicating the hardware offset of the GPIO and + * the second defining the GPIO flags of the request. + */ + if (args.args_count != 2) + continue; + + fwnode = of_fwnode_handle(args.np); + offset = args.args[0]; + + entry = gpio_shared_find_entry(fwnode, offset); + if (!entry) { + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + + entry->fwnode = fwnode_handle_get(fwnode); + entry->offset = offset; + entry->index = count; + INIT_LIST_HEAD(&entry->refs); + + list_add_tail(&entry->list, &gpio_shared_list); + } + + struct gpio_shared_ref *ref __free(kfree) = + kzalloc(sizeof(*ref), GFP_KERNEL); + if (!ref) + return -ENOMEM; + + ref->fwnode = fwnode_handle_get(of_fwnode_handle(curr)); + ref->flags = args.args[1]; + + if (strends(prop->name, "gpios")) + suffix = "-gpios"; + else if (strends(prop->name, "gpio")) + suffix = "-gpio"; + else + suffix = NULL; + if (!suffix) + continue; + + /* We only set con_id if there's actually one. */ + if (strcmp(prop->name, "gpios") && strcmp(prop->name, "gpio")) { + ref->con_id = kstrdup(prop->name, GFP_KERNEL); + if (!ref->con_id) + return -ENOMEM; + + con_id_len = strlen(ref->con_id); + suffix_len = strlen(suffix); + + ref->con_id[con_id_len - suffix_len] = '\0'; + } + + ref->dev_id = ida_alloc(&gpio_shared_ida, GFP_KERNEL); + if (ref->dev_id < 0) { + kfree(ref->con_id); + return -ENOMEM; + } + + if (!list_empty(&entry->refs)) + pr_debug("GPIO %u at %s is shared by multiple firmware nodes\n", + entry->offset, fwnode_get_name(entry->fwnode)); + + list_add_tail(&no_free_ptr(ref)->list, &entry->refs); + } + } + + for_each_child_of_node_scoped(curr, child) { + ret = gpio_shared_of_traverse(child); + if (ret) + return ret; + } + + return 0; +} + +static int gpio_shared_of_scan(void) +{ + return gpio_shared_of_traverse(of_root); +} +#else +static int gpio_shared_of_scan(void) +{ + return 0; +} +#endif /* CONFIG_OF */ + +static void gpio_shared_adev_release(struct device *dev) +{ + +} + +static int gpio_shared_make_adev(struct gpio_device *gdev, + struct gpio_shared_ref *ref) +{ + struct auxiliary_device *adev = &ref->adev; + int ret; + + lockdep_assert_held(&gpio_shared_lock); + + memset(adev, 0, sizeof(*adev)); + + adev->id = ref->dev_id; + adev->name = "proxy"; + adev->dev.parent = gdev->dev.parent; + adev->dev.release = gpio_shared_adev_release; + + ret = auxiliary_device_init(adev); + if (ret) + return ret; + + ret = auxiliary_device_add(adev); + if (ret) { + auxiliary_device_uninit(adev); + return ret; + } + + pr_debug("Created an auxiliary GPIO proxy %s for GPIO device %s\n", + dev_name(&adev->dev), gpio_device_get_label(gdev)); + + return 0; +} + +int gpio_shared_add_proxy_lookup(struct device *consumer, unsigned long lflags) +{ + const char *dev_id = dev_name(consumer); + struct gpio_shared_entry *entry; + struct gpio_shared_ref *ref; + + struct gpiod_lookup_table *lookup __free(kfree) = + kzalloc(struct_size(lookup, table, 2), GFP_KERNEL); + if (!lookup) + return -ENOMEM; + + guard(mutex)(&gpio_shared_lock); + + list_for_each_entry(entry, &gpio_shared_list, list) { + list_for_each_entry(ref, &entry->refs, list) { + if (!device_match_fwnode(consumer, ref->fwnode)) + continue; + + /* We've already done that on a previous request. */ + if (ref->lookup) + return 0; + + char *key __free(kfree) = + kasprintf(GFP_KERNEL, + KBUILD_MODNAME ".proxy.%u", + ref->adev.id); + if (!key) + return -ENOMEM; + + pr_debug("Adding machine lookup entry for a shared GPIO for consumer %s, with key '%s' and con_id '%s'\n", + dev_id, key, ref->con_id ?: "none"); + + lookup->dev_id = dev_id; + lookup->table[0] = GPIO_LOOKUP(no_free_ptr(key), 0, + ref->con_id, lflags); + + gpiod_add_lookup_table(no_free_ptr(lookup)); + + return 0; + } + } + + /* We warn here because this can only happen if the programmer borked. */ + WARN_ON(1); + return -ENOENT; +} + +static void gpio_shared_remove_adev(struct auxiliary_device *adev) +{ + lockdep_assert_held(&gpio_shared_lock); + + auxiliary_device_uninit(adev); + auxiliary_device_delete(adev); +} + +int gpio_device_setup_shared(struct gpio_device *gdev) +{ + struct gpio_shared_entry *entry; + struct gpio_shared_ref *ref; + unsigned long *flags; + int ret; + + guard(mutex)(&gpio_shared_lock); + + list_for_each_entry(entry, &gpio_shared_list, list) { + if (!device_match_fwnode(&gdev->dev, entry->fwnode)) + continue; + + if (list_count_nodes(&entry->refs) <= 1) + continue; + + flags = &gdev->descs[entry->offset].flags; + + __set_bit(GPIOD_FLAG_SHARED, flags); + /* + * Shared GPIOs are not requested via the normal path. Make + * them inaccessible to anyone even before we register the + * chip. + */ + __set_bit(GPIOD_FLAG_REQUESTED, flags); + + pr_debug("GPIO %u owned by %s is shared by multiple consumers\n", + entry->offset, gpio_device_get_label(gdev)); + + list_for_each_entry(ref, &entry->refs, list) { + pr_debug("Setting up a shared GPIO entry for %s\n", + fwnode_get_name(ref->fwnode)); + + ret = gpio_shared_make_adev(gdev, ref); + if (ret) + return ret; + } + } + + return 0; +} + +void gpio_device_teardown_shared(struct gpio_device *gdev) +{ + struct gpio_shared_entry *entry; + struct gpio_shared_ref *ref; + + guard(mutex)(&gpio_shared_lock); + + list_for_each_entry(entry, &gpio_shared_list, list) { + if (!device_match_fwnode(&gdev->dev, entry->fwnode)) + continue; + + list_for_each_entry(ref, &entry->refs, list) { + gpiod_remove_lookup_table(ref->lookup); + kfree(ref->lookup->table[0].key); + kfree(ref->lookup); + ref->lookup = NULL; + gpio_shared_remove_adev(&ref->adev); + } + } +} + +static void gpio_shared_release(struct kref *kref) +{ + struct gpio_shared_entry *entry = + container_of(kref, struct gpio_shared_entry, ref); + struct gpio_shared_desc *shared_desc = entry->shared_desc; + + guard(mutex)(&gpio_shared_lock); + + gpio_device_put(shared_desc->desc->gdev); + if (shared_desc->can_sleep) + mutex_destroy(&shared_desc->mutex); + kfree(shared_desc); + entry->shared_desc = NULL; +} + +static void gpiod_shared_put(void *data) +{ + struct gpio_shared_entry *entry = data; + + lockdep_assert_not_held(&gpio_shared_lock); + + kref_put(&entry->ref, gpio_shared_release); +} + +static struct gpio_shared_desc * +gpiod_shared_desc_create(struct gpio_shared_entry *entry) +{ + struct gpio_shared_desc *shared_desc; + struct gpio_device *gdev; + + shared_desc = kzalloc(sizeof(*shared_desc), GFP_KERNEL); + if (!shared_desc) + return ERR_PTR(-ENOMEM); + + gdev = gpio_device_find_by_fwnode(entry->fwnode); + if (!gdev) { + kfree(shared_desc); + return ERR_PTR(-EPROBE_DEFER); + } + + shared_desc->desc = &gdev->descs[entry->offset]; + shared_desc->can_sleep = gpiod_cansleep(shared_desc->desc); + if (shared_desc->can_sleep) + mutex_init(&shared_desc->mutex); + else + spin_lock_init(&shared_desc->spinlock); + + return shared_desc; +} + +static struct gpio_shared_entry *gpiod_shared_find(struct auxiliary_device *adev) +{ + struct gpio_shared_desc *shared_desc; + struct gpio_shared_entry *entry; + struct gpio_shared_ref *ref; + + guard(mutex)(&gpio_shared_lock); + + list_for_each_entry(entry, &gpio_shared_list, list) { + list_for_each_entry(ref, &entry->refs, list) { + if (adev != &ref->adev) + continue; + + if (entry->shared_desc) { + kref_get(&entry->ref); + return entry; + } + + shared_desc = gpiod_shared_desc_create(entry); + if (IS_ERR(shared_desc)) + return ERR_CAST(shared_desc); + + kref_init(&entry->ref); + entry->shared_desc = shared_desc; + + pr_debug("Device %s acquired a reference to the shared GPIO %u owned by %s\n", + dev_name(&adev->dev), gpio_chip_hwgpio(shared_desc->desc), + gpio_device_get_label(shared_desc->desc->gdev)); + + + return entry; + } + } + + return ERR_PTR(-ENOENT); +} + +struct gpio_shared_desc *devm_gpiod_shared_get(struct device *dev) +{ + struct gpio_shared_entry *entry; + int ret; + + entry = gpiod_shared_find(to_auxiliary_dev(dev)); + if (IS_ERR(entry)) + return ERR_CAST(entry); + + ret = devm_add_action_or_reset(dev, gpiod_shared_put, entry); + if (ret) + return ERR_PTR(ret); + + return entry->shared_desc; +} +EXPORT_SYMBOL_GPL(devm_gpiod_shared_get); + +static void gpio_shared_drop_ref(struct gpio_shared_ref *ref) +{ + list_del(&ref->list); + kfree(ref->con_id); + ida_free(&gpio_shared_ida, ref->dev_id); + fwnode_handle_put(ref->fwnode); + kfree(ref); +} + +static void gpio_shared_drop_entry(struct gpio_shared_entry *entry) +{ + list_del(&entry->list); + fwnode_handle_put(entry->fwnode); + kfree(entry); +} + +/* + * This is only called if gpio_shared_init() fails so it's in fact __init and + * not __exit. + */ +static void __init gpio_shared_teardown(void) +{ + struct gpio_shared_entry *entry, *epos; + struct gpio_shared_ref *ref, *rpos; + + list_for_each_entry_safe(entry, epos, &gpio_shared_list, list) { + list_for_each_entry_safe(ref, rpos, &entry->refs, list) + gpio_shared_drop_ref(ref); + + gpio_shared_drop_entry(entry); + } +} + +static void gpio_shared_free_exclusive(void) +{ + struct gpio_shared_entry *entry, *epos; + + list_for_each_entry_safe(entry, epos, &gpio_shared_list, list) { + if (list_count_nodes(&entry->refs) > 1) + continue; + + gpio_shared_drop_ref(list_first_entry(&entry->refs, + struct gpio_shared_ref, + list)); + gpio_shared_drop_entry(entry); + } +} + +static int __init gpio_shared_init(void) +{ + int ret; + + /* Right now, we only support OF-based systems. */ + ret = gpio_shared_of_scan(); + if (ret) { + gpio_shared_teardown(); + pr_err("Failed to scan OF nodes for shared GPIOs: %d\n", ret); + return ret; + } + + gpio_shared_free_exclusive(); + + pr_debug("Finished scanning firmware nodes for shared GPIOs\n"); + return 0; +} +postcore_initcall(gpio_shared_init); diff --git a/drivers/gpio/gpiolib-shared.h b/drivers/gpio/gpiolib-shared.h new file mode 100644 index 000000000000..667dbdff3585 --- /dev/null +++ b/drivers/gpio/gpiolib-shared.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __LINUX_GPIO_SHARED_H +#define __LINUX_GPIO_SHARED_H + +#include +#include +#include +#include + +struct gpio_device; +struct gpio_desc; +struct device; + +#if IS_ENABLED(CONFIG_GPIO_SHARED) + +int gpio_device_setup_shared(struct gpio_device *gdev); +void gpio_device_teardown_shared(struct gpio_device *gdev); +int gpio_shared_add_proxy_lookup(struct device *consumer, unsigned long lflags); + +#else + +static inline int gpio_device_setup_shared(struct gpio_device *gdev) +{ + return 0; +} + +static inline void gpio_device_teardown_shared(struct gpio_device *gdev) { } + +static inline int gpio_shared_add_proxy_lookup(struct device *consumer, + unsigned long lflags) +{ + return 0; +} + +#endif /* CONFIG_GPIO_SHARED */ + +struct gpio_shared_desc { + struct gpio_desc *desc; + bool can_sleep; + unsigned long cfg; + unsigned int usecnt; + unsigned int highcnt; + union { + struct mutex mutex; + spinlock_t spinlock; + }; +}; + +struct gpio_shared_desc *devm_gpiod_shared_get(struct device *dev); + +DEFINE_LOCK_GUARD_1(gpio_shared_desc_lock, struct gpio_shared_desc, + if (_T->lock->can_sleep) + mutex_lock(&_T->lock->mutex); + else + spin_lock_irqsave(&_T->lock->spinlock, _T->flags), + if (_T->lock->can_sleep) + mutex_unlock(&_T->lock->mutex); + else + spin_unlock_irqrestore(&_T->lock->spinlock, _T->flags), + unsigned long flags) + +static inline void gpio_shared_lockdep_assert(struct gpio_shared_desc *shared_desc) +{ + if (shared_desc->can_sleep) + lockdep_assert_held(&shared_desc->mutex); + else + lockdep_assert_held(&shared_desc->spinlock); +} + +#endif /* __LINUX_GPIO_SHARED_H */ From e992d54c6f970b382ffeacd7c88f68b94a3c6caf Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 12 Nov 2025 14:55:33 +0100 Subject: [PATCH 4/7] gpio: shared-proxy: implement the shared GPIO proxy driver Add a virtual GPIO proxy driver which arbitrates access to a single shared GPIO by multiple users. It works together with the core shared GPIO support from GPIOLIB and functions by acquiring a reference to a shared GPIO descriptor exposed by gpiolib-shared and making sure that the state of the GPIO stays consistent. In general: if there's only one user at the moment: allow it to do anything as if this was a normal GPIO (in essence: just propagate calls to the underlying real hardware driver). If there are more users: don't allow to change the direction set by the initial user, allow to change configuration options but warn about possible conflicts and finally: treat the output-high value as a reference counted, logical "GPIO enabled" setting, meaning: the GPIO value is set to high when the first user requests it to be high and back to low once the last user stops "voting" for high. Reviewed-by: Linus Walleij Acked-by: Linus Walleij Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-4-b51f97b1abd8@linaro.org Signed-off-by: Bartosz Golaszewski --- drivers/gpio/Kconfig | 9 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-shared-proxy.c | 333 +++++++++++++++++++++++++++++++ 3 files changed, 343 insertions(+) create mode 100644 drivers/gpio/gpio-shared-proxy.c diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 92139e75484f..b8b6537290b0 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -2025,6 +2025,15 @@ config GPIO_SIM This enables the GPIO simulator - a configfs-based GPIO testing driver. +config GPIO_SHARED_PROXY + tristate "Proxy driver for non-exclusive GPIOs" + default m + depends on GPIO_SHARED || COMPILE_TEST + select AUXILIARY_BUS + help + This enables the GPIO shared proxy driver - an abstraction layer + for GPIO pins that are shared by multiple devices. + endmenu menu "GPIO Debugging utilities" diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index f702f7e27e5b..d0020bc70b84 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -160,6 +160,7 @@ obj-$(CONFIG_ARCH_SA1100) += gpio-sa1100.o obj-$(CONFIG_GPIO_SAMA5D2_PIOBU) += gpio-sama5d2-piobu.o obj-$(CONFIG_GPIO_SCH311X) += gpio-sch311x.o obj-$(CONFIG_GPIO_SCH) += gpio-sch.o +obj-$(CONFIG_GPIO_SHARED_PROXY) += gpio-shared-proxy.o obj-$(CONFIG_GPIO_SIFIVE) += gpio-sifive.o obj-$(CONFIG_GPIO_SIM) += gpio-sim.o obj-$(CONFIG_GPIO_SIOX) += gpio-siox.o diff --git a/drivers/gpio/gpio-shared-proxy.c b/drivers/gpio/gpio-shared-proxy.c new file mode 100644 index 000000000000..3ef2c40ed152 --- /dev/null +++ b/drivers/gpio/gpio-shared-proxy.c @@ -0,0 +1,333 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2025 Linaro Ltd. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "gpiolib-shared.h" + +struct gpio_shared_proxy_data { + struct gpio_chip gc; + struct gpio_shared_desc *shared_desc; + struct device *dev; + bool voted_high; +}; + +static int +gpio_shared_proxy_set_unlocked(struct gpio_shared_proxy_data *proxy, + int (*set_func)(struct gpio_desc *desc, int value), + int value) +{ + struct gpio_shared_desc *shared_desc = proxy->shared_desc; + struct gpio_desc *desc = shared_desc->desc; + int ret = 0; + + gpio_shared_lockdep_assert(shared_desc); + + if (value) { + /* User wants to set value to high. */ + if (proxy->voted_high) + /* Already voted for high, nothing to do. */ + goto out; + + /* Haven't voted for high yet. */ + if (!shared_desc->highcnt) { + /* + * Current value is low, need to actually set value + * to high. + */ + ret = set_func(desc, 1); + if (ret) + goto out; + } + + shared_desc->highcnt++; + proxy->voted_high = true; + + goto out; + } + + /* Desired value is low. */ + if (!proxy->voted_high) + /* We didn't vote for high, nothing to do. */ + goto out; + + /* We previously voted for high. */ + if (shared_desc->highcnt == 1) { + /* This is the last remaining vote for high, set value to low. */ + ret = set_func(desc, 0); + if (ret) + goto out; + } + + shared_desc->highcnt--; + proxy->voted_high = false; + +out: + if (shared_desc->highcnt) + dev_dbg(proxy->dev, + "Voted for value '%s', effective value is 'high', number of votes for 'high': %u\n", + str_high_low(value), shared_desc->highcnt); + else + dev_dbg(proxy->dev, "Voted for value 'low', effective value is 'low'\n"); + + return ret; +} + +static int gpio_shared_proxy_request(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + struct gpio_shared_desc *shared_desc = proxy->shared_desc; + + guard(gpio_shared_desc_lock)(shared_desc); + + proxy->shared_desc->usecnt++; + + dev_dbg(proxy->dev, "Shared GPIO requested, number of users: %u\n", + proxy->shared_desc->usecnt); + + return 0; +} + +static void gpio_shared_proxy_free(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + struct gpio_shared_desc *shared_desc = proxy->shared_desc; + + guard(gpio_shared_desc_lock)(shared_desc); + + proxy->shared_desc->usecnt--; + + dev_dbg(proxy->dev, "Shared GPIO freed, number of users: %u\n", + proxy->shared_desc->usecnt); +} + +static int gpio_shared_proxy_set_config(struct gpio_chip *gc, + unsigned int offset, unsigned long cfg) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + struct gpio_shared_desc *shared_desc = proxy->shared_desc; + struct gpio_desc *desc = shared_desc->desc; + int ret; + + guard(gpio_shared_desc_lock)(shared_desc); + + if (shared_desc->usecnt > 1) { + if (shared_desc->cfg != cfg) { + dev_dbg(proxy->dev, + "Shared GPIO's configuration already set, accepting changes but users may conflict!!\n"); + } else { + dev_dbg(proxy->dev, "Equal config requested, nothing to do\n"); + return 0; + } + } + + ret = gpiod_set_config(desc, cfg); + if (ret && ret != -ENOTSUPP) + return ret; + + shared_desc->cfg = cfg; + return 0; +} + +static int gpio_shared_proxy_direction_input(struct gpio_chip *gc, + unsigned int offset) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + struct gpio_shared_desc *shared_desc = proxy->shared_desc; + struct gpio_desc *desc = shared_desc->desc; + int dir; + + guard(gpio_shared_desc_lock)(shared_desc); + + if (shared_desc->usecnt == 1) { + dev_dbg(proxy->dev, + "Only one user of this shared GPIO, allowing to set direction to input\n"); + + return gpiod_direction_input(desc); + } + + dir = gpiod_get_direction(desc); + if (dir < 0) + return dir; + + if (dir == GPIO_LINE_DIRECTION_OUT) { + dev_dbg(proxy->dev, + "Shared GPIO's direction already set to output, refusing to change\n"); + return -EPERM; + } + + return 0; +} + +static int gpio_shared_proxy_direction_output(struct gpio_chip *gc, + unsigned int offset, int value) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + struct gpio_shared_desc *shared_desc = proxy->shared_desc; + struct gpio_desc *desc = shared_desc->desc; + int ret, dir; + + guard(gpio_shared_desc_lock)(shared_desc); + + if (shared_desc->usecnt == 1) { + dev_dbg(proxy->dev, + "Only one user of this shared GPIO, allowing to set direction to output with value '%s'\n", + str_high_low(value)); + + ret = gpiod_direction_output(desc, value); + if (ret) + return ret; + + if (value) { + proxy->voted_high = true; + shared_desc->highcnt = 1; + } else { + proxy->voted_high = false; + shared_desc->highcnt = 0; + } + + return 0; + } + + dir = gpiod_get_direction(desc); + if (dir < 0) + return dir; + + if (dir == GPIO_LINE_DIRECTION_IN) { + dev_dbg(proxy->dev, + "Shared GPIO's direction already set to input, refusing to change\n"); + return -EPERM; + } + + return gpio_shared_proxy_set_unlocked(proxy, gpiod_direction_output, value); +} + +static int gpio_shared_proxy_get(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + + return gpiod_get_value(proxy->shared_desc->desc); +} + +static int gpio_shared_proxy_get_cansleep(struct gpio_chip *gc, + unsigned int offset) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + + return gpiod_get_value_cansleep(proxy->shared_desc->desc); +} + +static int gpio_shared_proxy_do_set(struct gpio_shared_proxy_data *proxy, + int (*set_func)(struct gpio_desc *desc, int value), + int value) +{ + guard(gpio_shared_desc_lock)(proxy->shared_desc); + + return gpio_shared_proxy_set_unlocked(proxy, set_func, value); +} + +static int gpio_shared_proxy_set(struct gpio_chip *gc, unsigned int offset, + int value) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + + return gpio_shared_proxy_do_set(proxy, gpiod_set_value, value); +} + +static int gpio_shared_proxy_set_cansleep(struct gpio_chip *gc, + unsigned int offset, int value) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + + return gpio_shared_proxy_do_set(proxy, gpiod_set_value_cansleep, value); +} + +static int gpio_shared_proxy_get_direction(struct gpio_chip *gc, + unsigned int offset) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + + return gpiod_get_direction(proxy->shared_desc->desc); +} + +static int gpio_shared_proxy_to_irq(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_shared_proxy_data *proxy = gpiochip_get_data(gc); + + return gpiod_to_irq(proxy->shared_desc->desc); +} + +static int gpio_shared_proxy_probe(struct auxiliary_device *adev, + const struct auxiliary_device_id *id) +{ + struct gpio_shared_proxy_data *proxy; + struct gpio_shared_desc *shared_desc; + struct device *dev = &adev->dev; + struct gpio_chip *gc; + + shared_desc = devm_gpiod_shared_get(dev); + if (IS_ERR(shared_desc)) + return PTR_ERR(shared_desc); + + proxy = devm_kzalloc(dev, sizeof(*proxy), GFP_KERNEL); + if (!proxy) + return -ENOMEM; + + proxy->shared_desc = shared_desc; + proxy->dev = dev; + + gc = &proxy->gc; + gc->base = -1; + gc->ngpio = 1; + gc->label = dev_name(dev); + gc->parent = dev; + gc->owner = THIS_MODULE; + gc->can_sleep = shared_desc->can_sleep; + + gc->request = gpio_shared_proxy_request; + gc->free = gpio_shared_proxy_free; + gc->set_config = gpio_shared_proxy_set_config; + gc->direction_input = gpio_shared_proxy_direction_input; + gc->direction_output = gpio_shared_proxy_direction_output; + if (gc->can_sleep) { + gc->set = gpio_shared_proxy_set_cansleep; + gc->get = gpio_shared_proxy_get_cansleep; + } else { + gc->set = gpio_shared_proxy_set; + gc->get = gpio_shared_proxy_get; + } + gc->get_direction = gpio_shared_proxy_get_direction; + gc->to_irq = gpio_shared_proxy_to_irq; + + return devm_gpiochip_add_data(dev, &proxy->gc, proxy); +} + +static const struct auxiliary_device_id gpio_shared_proxy_id_table[] = { + { .name = "gpiolib_shared.proxy" }, + {}, +}; +MODULE_DEVICE_TABLE(auxiliary, gpio_shared_proxy_id_table); + +static struct auxiliary_driver gpio_shared_proxy_driver = { + .driver = { + .name = "gpio-shared-proxy", + }, + .probe = gpio_shared_proxy_probe, + .id_table = gpio_shared_proxy_id_table, +}; +module_auxiliary_driver(gpio_shared_proxy_driver); + +MODULE_AUTHOR("Bartosz Golaszewski "); +MODULE_DESCRIPTION("Shared GPIO mux driver."); +MODULE_LICENSE("GPL"); From 1e4f6db614a310cc34d07ffbf031c76ea9581bcf Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 12 Nov 2025 14:55:34 +0100 Subject: [PATCH 5/7] gpiolib: support shared GPIOs in core subsystem code As the final step in adding official support for shared GPIOs, enable the previously added elements in core GPIO subsystem code. Set-up shared GPIOs when adding a GPIO chip, tear it down on removal and check if a GPIO descriptor looked up during the firmware-node stage is shared and fall-back to machine lookup in this case. Reviewed-by: Linus Walleij Acked-by: Linus Walleij Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-5-b51f97b1abd8@linaro.org Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib.c | 50 ++++++++++++++++++++++++++++++++++-------- 1 file changed, 41 insertions(+), 9 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 9952e412da50..1e4c99179712 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -37,6 +37,7 @@ #include "gpiolib-acpi.h" #include "gpiolib-cdev.h" #include "gpiolib-of.h" +#include "gpiolib-shared.h" #include "gpiolib-swnode.h" #include "gpiolib-sysfs.h" #include "gpiolib.h" @@ -1200,6 +1201,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, if (ret) goto err_remove_irqchip_mask; + ret = gpio_device_setup_shared(gdev); + if (ret) + goto err_remove_irqchip; + /* * By first adding the chardev, and then adding the device, * we get a device node entry in sysfs under @@ -1211,10 +1216,13 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, if (gpiolib_initialized) { ret = gpiochip_setup_dev(gdev); if (ret) - goto err_remove_irqchip; + goto err_teardown_shared; } + return 0; +err_teardown_shared: + gpio_device_teardown_shared(gdev); err_remove_irqchip: gpiochip_irqchip_remove(gc); err_remove_irqchip_mask: @@ -1283,6 +1291,7 @@ void gpiochip_remove(struct gpio_chip *gc) /* Numb the device, cancelling all outstanding operations */ rcu_assign_pointer(gdev->chip, NULL); synchronize_srcu(&gdev->srcu); + gpio_device_teardown_shared(gdev); gpiochip_irqchip_remove(gc); acpi_gpiochip_remove(gc); of_gpiochip_remove(gc); @@ -4652,11 +4661,29 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer, scoped_guard(srcu, &gpio_devices_srcu) { desc = gpiod_fwnode_lookup(fwnode, consumer, con_id, idx, &flags, &lookupflags); + if (!IS_ERR_OR_NULL(desc) && + test_bit(GPIOD_FLAG_SHARED, &desc->flags)) { + /* + * We're dealing with a GPIO shared by multiple + * consumers. This is the moment to add the machine + * lookup table for the proxy device as previously + * we only knew the consumer's fwnode. + */ + ret = gpio_shared_add_proxy_lookup(consumer, lookupflags); + if (ret) + return ERR_PTR(ret); + + /* Trigger platform lookup for shared GPIO proxy. */ + desc = ERR_PTR(-ENOENT); + /* Trigger it even for fwnode-only gpiod_get(). */ + platform_lookup_allowed = true; + } + if (gpiod_not_found(desc) && platform_lookup_allowed) { /* * Either we are not using DT or ACPI, or their lookup - * did not return a result. In that case, use platform - * lookup as a fallback. + * did not return a result or this is a shared GPIO. In + * that case, use platform lookup as a fallback. */ dev_dbg(consumer, "using lookup tables for GPIO lookup\n"); @@ -4679,14 +4706,19 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer, return ERR_PTR(ret); /* - * This happens when there are several consumers for - * the same GPIO line: we just return here without - * further initialization. It is a bit of a hack. - * This is necessary to support fixed regulators. + * This happens when there are several consumers for the same + * GPIO line: we just return here without further + * initialization. It's a hack introduced long ago to support + * fixed regulators. We now have a better solution with + * automated scanning where affected platforms just need to + * select the provided Kconfig option. * - * FIXME: Make this more sane and safe. + * FIXME: Remove the GPIOD_FLAGS_BIT_NONEXCLUSIVE flag after + * making sure all platforms use the new mechanism. */ - dev_info(consumer, "nonexclusive access to GPIO for %s\n", name); + dev_info(consumer, + "nonexclusive access to GPIO for %s, consider updating your code to using gpio-shared-proxy\n", + name); return desc; } From eb374f764a7012eda28019266a6d9191670c4fa5 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 12 Nov 2025 14:55:35 +0100 Subject: [PATCH 6/7] gpio: provide gpiod_is_shared() Provide an interface allowing consumers to check if a GPIO descriptor represents a GPIO that can potentially be shared by multiple consumers at the same time. This is exposed to allow subsystems that already work around the limitations of the current non-exclusive GPIO handling in some ways, to gradually convert to relying on the new shared GPIO feature of GPIOLIB. Extend the gpiolib-shared module to mark the GPIO shared proxy descriptors with a flag checked by the new interface. Reviewed-by: Linus Walleij Acked-by: Linus Walleij Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-6-b51f97b1abd8@linaro.org Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-shared.c | 18 ++++++++++++++++++ drivers/gpio/gpiolib.c | 20 ++++++++++++++++++++ drivers/gpio/gpiolib.h | 1 + include/linux/gpio/consumer.h | 9 +++++++++ 4 files changed, 48 insertions(+) diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c index 1fcbf53b6eca..fa1d16635ea7 100644 --- a/drivers/gpio/gpiolib-shared.c +++ b/drivers/gpio/gpiolib-shared.c @@ -314,6 +314,24 @@ int gpio_device_setup_shared(struct gpio_device *gdev) guard(mutex)(&gpio_shared_lock); + list_for_each_entry(entry, &gpio_shared_list, list) { + list_for_each_entry(ref, &entry->refs, list) { + if (gdev->dev.parent == &ref->adev.dev) { + /* + * This is a shared GPIO proxy. Mark its + * descriptor as such and return here. + */ + __set_bit(GPIOD_FLAG_SHARED_PROXY, + &gdev->descs[0].flags); + return 0; + } + } + } + + /* + * This is not a shared GPIO proxy but it still may be the device + * exposing shared pins. Find them and create the proxy devices. + */ list_for_each_entry(entry, &gpio_shared_list, list) { if (!device_match_fwnode(&gdev->dev, entry->fwnode)) continue; diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 1e4c99179712..678d07dc768c 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -3990,6 +3990,26 @@ int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name) } EXPORT_SYMBOL_GPL(gpiod_set_consumer_name); +/** + * gpiod_is_shared() - check if this GPIO can be shared by multiple consumers + * @desc: GPIO to inspect + * + * Returns: + * True if this GPIO can be shared by multiple consumers at once. False if it's + * a regular, exclusive GPIO. + * + * Note: + * This function returning true does not mean that this GPIO is currently being + * shared. It means the GPIO core has registered the fact that the firmware + * configuration indicates that it can be shared by multiple consumers and is + * in charge of arbitrating the access. + */ +bool gpiod_is_shared(const struct gpio_desc *desc) +{ + return test_bit(GPIOD_FLAG_SHARED_PROXY, &desc->flags); +} +EXPORT_SYMBOL_GPL(gpiod_is_shared); + /** * gpiod_to_irq() - return the IRQ corresponding to a GPIO * @desc: gpio whose IRQ will be returned (already requested) diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 09ac92ed0853..abd870fb4a3b 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -205,6 +205,7 @@ struct gpio_desc { #define GPIOD_FLAG_EVENT_CLOCK_REALTIME 18 /* GPIO CDEV reports REALTIME timestamps in events */ #define GPIOD_FLAG_EVENT_CLOCK_HTE 19 /* GPIO CDEV reports hardware timestamps in events */ #define GPIOD_FLAG_SHARED 20 /* GPIO is shared by multiple consumers */ +#define GPIOD_FLAG_SHARED_PROXY 21 /* GPIO is a virtual proxy to a physically shared pin. */ /* Connection label */ struct gpio_desc_label __rcu *label; diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h index 00df68c51405..a8acb7c0b5af 100644 --- a/include/linux/gpio/consumer.h +++ b/include/linux/gpio/consumer.h @@ -167,6 +167,8 @@ int gpiod_cansleep(const struct gpio_desc *desc); int gpiod_to_irq(const struct gpio_desc *desc); int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name); +bool gpiod_is_shared(const struct gpio_desc *desc); + /* Convert between the old gpio_ and new gpiod_ interfaces */ struct gpio_desc *gpio_to_desc(unsigned gpio); int desc_to_gpio(const struct gpio_desc *desc); @@ -520,6 +522,13 @@ static inline int gpiod_set_consumer_name(struct gpio_desc *desc, return -EINVAL; } +static inline bool gpiod_is_shared(const struct gpio_desc *desc) +{ + /* GPIO can never have been requested */ + WARN_ON(desc); + return false; +} + static inline struct gpio_desc *gpio_to_desc(unsigned gpio) { return NULL; From e511d484cbe44fe48a1b9f621f6a947c72503f9e Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Wed, 12 Nov 2025 14:55:36 +0100 Subject: [PATCH 7/7] arm64: select HAVE_SHARED_GPIOS for ARCH_QCOM Some qualcomm platforms use shared GPIOs. Enable support for them by selecting the Kconfig switch provided by GPIOLIB. Acked-by: Linus Walleij Acked-by: Bjorn Andersson Acked-by: Arnd Bergmann Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-7-b51f97b1abd8@linaro.org Signed-off-by: Bartosz Golaszewski --- arch/arm64/Kconfig.platforms | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms index 13173795c43d..3dbff0261f0a 100644 --- a/arch/arm64/Kconfig.platforms +++ b/arch/arm64/Kconfig.platforms @@ -316,6 +316,7 @@ config ARCH_QCOM select GPIOLIB select PINCTRL select HAVE_PWRCTRL if PCI + select HAVE_SHARED_GPIOS help This enables support for the ARMv8 based Qualcomm chipsets.