From 52464f59a361a3ba49d6eabc4f65d5c0b9d1de39 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Mon, 25 Mar 2024 17:00:57 +0000 Subject: gpiolib: Add stubs for GPIO lookup functions The gpio_device_find_by_() functions do not have stubs which means that if they are referenced from code with an optiona dependency on gpiolib then the code will fail to link. Add stubs for lookups via fwnode and label. I have not added a stub for plain gpio_device_find() since it seems harder to see a use case for that which does not depend on gpiolib. With the addition of the GPIO reset controller (which lacks a gpiolib dependency) to the arm64 defconfig this is causing build breaks for arm64 virtconfig in -next: aarch64-linux-gnu-ld: drivers/reset/core.o: in function `__reset_add_reset_gpio_lookup': /build/stage/linux/drivers/reset/core.c:861:(.text+0xccc): undefined reference to `gpio_device_find_by_fwnode' Signed-off-by: Mark Brown Reviewed-by: Krzysztof Kozlowski Signed-off-by: Bartosz Golaszewski --- include/linux/gpio/driver.h | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'include/linux/gpio') diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index dc75f802e284..f8617eaf08ba 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -646,8 +646,6 @@ int devm_gpiochip_add_data_with_key(struct device *dev, struct gpio_chip *gc, struct gpio_device *gpio_device_find(const void *data, int (*match)(struct gpio_chip *gc, const void *data)); -struct gpio_device *gpio_device_find_by_label(const char *label); -struct gpio_device *gpio_device_find_by_fwnode(const struct fwnode_handle *fwnode); struct gpio_device *gpio_device_get(struct gpio_device *gdev); void gpio_device_put(struct gpio_device *gdev); @@ -814,6 +812,9 @@ struct gpio_device *gpiod_to_gpio_device(struct gpio_desc *desc); int gpio_device_get_base(struct gpio_device *gdev); const char *gpio_device_get_label(struct gpio_device *gdev); +struct gpio_device *gpio_device_find_by_label(const char *label); +struct gpio_device *gpio_device_find_by_fwnode(const struct fwnode_handle *fwnode); + #else /* CONFIG_GPIOLIB */ #include @@ -843,6 +844,18 @@ static inline const char *gpio_device_get_label(struct gpio_device *gdev) return NULL; } +static inline struct gpio_device *gpio_device_find_by_label(const char *label) +{ + WARN_ON(1); + return NULL; +} + +static inline struct gpio_device *gpio_device_find_by_fwnode(const struct fwnode_handle *fwnode) +{ + WARN_ON(1); + return NULL; +} + static inline int gpiochip_lock_as_irq(struct gpio_chip *gc, unsigned int offset) { -- cgit v1.2.3 From 9d50f95bc0d5df56f2591b950a251d90bffad094 Mon Sep 17 00:00:00 2001 From: Charles Keepax Date: Tue, 16 Apr 2024 11:09:01 +0100 Subject: gpio: swnode: Add ability to specify native chip selects for SPI SPI devices can specify a cs-gpios property to enumerate their chip selects. Under device tree, a zero entry in this property can be used to specify that a particular chip select is using the SPI controllers native chip select, for example: cs-gpios = <&gpio1 0 0>, <0>; Here, the second chip select is native. However, when using swnodes there is currently no way to specify a native chip select. The proposal here is to register a swnode_gpio_undefined software node, that can be specified to allow the indication of a native chip select. For example: static const struct software_node_ref_args device_cs_refs[] = { { .node = &device_gpiochip_swnode, .nargs = 2, .args = { 0, GPIO_ACTIVE_LOW }, }, { .node = &swnode_gpio_undefined, .nargs = 0, }, }; Register the swnode as the gpiolib is initialised and check in swnode_get_gpio_device() if the returned node matches swnode_gpio_undefined and return -ENOENT, which matches the behaviour of the device tree system when it encounters a 0 phandle. Reviewed-by: Linus Walleij Reviewed-by: Andy Shevchenko Signed-off-by: Charles Keepax Link: https://lore.kernel.org/r/20240416100904.3738093-2-ckeepax@opensource.cirrus.com Signed-off-by: Mark Brown --- drivers/gpio/Kconfig | 9 +++++++++ drivers/gpio/gpiolib-swnode.c | 44 +++++++++++++++++++++++++++++++++++++++++++ include/linux/gpio/property.h | 4 ++++ 3 files changed, 57 insertions(+) (limited to 'include/linux/gpio') diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index b50d0b470849..00b5c007a2bb 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -103,6 +103,15 @@ config GPIO_REGMAP select REGMAP tristate +config GPIO_SWNODE_UNDEFINED + bool + help + This adds a special place holder for software nodes to contain an + undefined GPIO reference, this is primarily used by SPI to allow a + list of GPIO chip selects to mark a certain chip select as being + controlled the SPI device's internal chip select mechanism and not + a GPIO. + # put drivers in the right section, in alphabetical order # This symbol is selected by both I2C and SPI expanders diff --git a/drivers/gpio/gpiolib-swnode.c b/drivers/gpio/gpiolib-swnode.c index fa52bdb1a29a..cec1ab878af8 100644 --- a/drivers/gpio/gpiolib-swnode.c +++ b/drivers/gpio/gpiolib-swnode.c @@ -4,8 +4,13 @@ * * Copyright 2022 Google LLC */ + +#define pr_fmt(fmt) "gpiolib: swnode: " fmt + #include #include +#include +#include #include #include #include @@ -17,6 +22,8 @@ #include "gpiolib.h" #include "gpiolib-swnode.h" +#define GPIOLIB_SWNODE_UNDEFINED_NAME "swnode-gpio-undefined" + static void swnode_format_propname(const char *con_id, char *propname, size_t max_size) { @@ -40,6 +47,14 @@ static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode) if (!gdev_node || !gdev_node->name) return ERR_PTR(-EINVAL); + /* + * Check for a special node that identifies undefined GPIOs, this is + * primarily used as a key for internal chip selects in SPI bindings. + */ + if (IS_ENABLED(CONFIG_GPIO_SWNODE_UNDEFINED) && + !strcmp(gdev_node->name, GPIOLIB_SWNODE_UNDEFINED_NAME)) + return ERR_PTR(-ENOENT); + gdev = gpio_device_find_by_label(gdev_node->name); return gdev ?: ERR_PTR(-EPROBE_DEFER); } @@ -121,3 +136,32 @@ int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id) return count ?: -ENOENT; } + +#if IS_ENABLED(CONFIG_GPIO_SWNODE_UNDEFINED) +/* + * A special node that identifies undefined GPIOs, this is primarily used as + * a key for internal chip selects in SPI bindings. + */ +const struct software_node swnode_gpio_undefined = { + .name = GPIOLIB_SWNODE_UNDEFINED_NAME, +}; +EXPORT_SYMBOL_NS_GPL(swnode_gpio_undefined, GPIO_SWNODE); + +static int __init swnode_gpio_init(void) +{ + int ret; + + ret = software_node_register(&swnode_gpio_undefined); + if (ret < 0) + pr_err("failed to register swnode: %d\n", ret); + + return ret; +} +subsys_initcall(swnode_gpio_init); + +static void __exit swnode_gpio_cleanup(void) +{ + software_node_unregister(&swnode_gpio_undefined); +} +__exitcall(swnode_gpio_cleanup); +#endif diff --git a/include/linux/gpio/property.h b/include/linux/gpio/property.h index 6c75c8bd44a0..832a60c2e0b9 100644 --- a/include/linux/gpio/property.h +++ b/include/linux/gpio/property.h @@ -5,7 +5,11 @@ #include /* for GPIO_* flags */ #include +struct software_node; + #define PROPERTY_ENTRY_GPIO(_name_, _chip_node_, _idx_, _flags_) \ PROPERTY_ENTRY_REF(_name_, _chip_node_, _idx_, _flags_) +extern const struct software_node swnode_gpio_undefined; + #endif /* __LINUX_GPIO_PROPERTY_H */ -- cgit v1.2.3 From 69ffed4b62523bbc85511f150500329d28aba356 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 17 Apr 2024 17:19:13 +0300 Subject: gpiolib: swnode: Remove wrong header inclusion The flags in the software node properties are supposed to be the GPIO lookup flags, which are provided by gpio/machine.h, as the software nodes are the kernel internal thing and doesn't need to rely to any of ABIs. Fixes: e7f9ff5dc90c ("gpiolib: add support for software nodes") Signed-off-by: Andy Shevchenko Signed-off-by: Bartosz Golaszewski --- include/linux/gpio/property.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/gpio') diff --git a/include/linux/gpio/property.h b/include/linux/gpio/property.h index 6c75c8bd44a0..1a14e239221f 100644 --- a/include/linux/gpio/property.h +++ b/include/linux/gpio/property.h @@ -2,7 +2,6 @@ #ifndef __LINUX_GPIO_PROPERTY_H #define __LINUX_GPIO_PROPERTY_H -#include /* for GPIO_* flags */ #include #define PROPERTY_ENTRY_GPIO(_name_, _chip_node_, _idx_, _flags_) \ -- cgit v1.2.3 From 2b5ae9c7d9e5ef4bc52c932fdf10328feb5167c6 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Sun, 5 May 2024 17:14:20 +0300 Subject: gpiolib: Discourage to use formatting strings in line names Currently the documentation for line names allows to use %u inside the alternative name. This is broken in character device approach from day 1 and being in use solely in sysfs. Character device interface has a line number as a part of its address, so the users better rely on it. Hence remove the misleading documentation. On top of that, there are no in-kernel users (out of 6, if I'm correct) for such names and moreover if one exists it won't help in distinguishing lines with the same naming as '%u' will also be in them and we will get a warning in gpiochip_set_desc_names() for such cases. Signed-off-by: Andy Shevchenko Reviewed-by: Linus Walleij Reviewed-by: Kent Gibson Link: https://lore.kernel.org/r/20240505141420.627398-1-andy.shevchenko@gmail.com Signed-off-by: Bartosz Golaszewski --- include/linux/gpio/driver.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'include/linux/gpio') diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index f8617eaf08ba..0032bb6e7d8f 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -376,9 +376,7 @@ struct gpio_irq_chip { * @names: if set, must be an array of strings to use as alternative * names for the GPIOs in this chip. Any entry in the array * may be NULL if there is no alias for the GPIO, however the - * array must be @ngpio entries long. A name can include a single printk - * format specifier for an unsigned int. It is substituted by the actual - * number of the gpio. + * array must be @ngpio entries long. * @can_sleep: flag must be set iff get()/set() methods sleep, as they * must while accessing GPIO expander chips over I2C or SPI. This * implies that if the chip supports IRQs, these IRQs need to be threaded -- cgit v1.2.3