diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 8629e9eaf79e..010587025fc8 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -10,6 +10,7 @@ obj-$(CONFIG_OF_GPIO) += gpiolib-of.o obj-$(CONFIG_GPIO_CDEV) += gpiolib-cdev.o obj-$(CONFIG_GPIO_SYSFS) += gpiolib-sysfs.o obj-$(CONFIG_GPIO_ACPI) += gpiolib-acpi.o +obj-$(CONFIG_GPIOLIB) += gpiolib-swnode.o # Device drivers. Generally keep list sorted alphabetically obj-$(CONFIG_GPIO_REGMAP) += gpio-regmap.o diff --git a/drivers/gpio/gpiolib-swnode.c b/drivers/gpio/gpiolib-swnode.c new file mode 100644 index 000000000000..dd9ccac214d1 --- /dev/null +++ b/drivers/gpio/gpiolib-swnode.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Software Node helpers for the GPIO API + * + * Copyright 2022 Google LLC + */ +#include +#include +#include +#include +#include +#include +#include +#include + +#include "gpiolib.h" +#include "gpiolib-swnode.h" + +static void swnode_format_propname(const char *con_id, char *propname, + size_t max_size) +{ + /* + * Note we do not need to try both -gpios and -gpio suffixes, + * as, unlike OF and ACPI, we can fix software nodes to conform + * to the proper binding. + */ + if (con_id) + snprintf(propname, max_size, "%s-gpios", con_id); + else + strscpy(propname, "gpios", max_size); +} + +static int swnode_gpiochip_match_name(struct gpio_chip *chip, void *data) +{ + return !strcmp(chip->label, data); +} + +static struct gpio_chip *swnode_get_chip(struct fwnode_handle *fwnode) +{ + const struct software_node *chip_node; + struct gpio_chip *chip; + + chip_node = to_software_node(fwnode); + if (!chip_node || !chip_node->name) + return ERR_PTR(-EINVAL); + + chip = gpiochip_find((void *)chip_node->name, swnode_gpiochip_match_name); + return chip ?: ERR_PTR(-EPROBE_DEFER); +} + +struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode, + const char *con_id, unsigned int idx, + unsigned long *flags) +{ + const struct software_node *swnode; + struct fwnode_reference_args args; + struct gpio_chip *chip; + struct gpio_desc *desc; + char propname[32]; /* 32 is max size of property name */ + int error; + + swnode = to_software_node(fwnode); + if (!swnode) + return ERR_PTR(-EINVAL); + + swnode_format_propname(con_id, propname, sizeof(propname)); + + /* + * We expect all swnode-described GPIOs have GPIO number and + * polarity arguments, hence nargs is set to 2. + */ + error = fwnode_property_get_reference_args(fwnode, propname, NULL, 2, idx, &args); + if (error) { + pr_debug("%s: can't parse '%s' property of node '%pfwP[%d]'\n", + __func__, propname, fwnode, idx); + return ERR_PTR(error); + } + + chip = swnode_get_chip(args.fwnode); + fwnode_handle_put(args.fwnode); + if (IS_ERR(chip)) + return ERR_CAST(chip); + + desc = gpiochip_get_desc(chip, args.args[0]); + *flags = args.args[1]; /* We expect native GPIO flags */ + + pr_debug("%s: parsed '%s' property of node '%pfwP[%d]' - status (%d)\n", + __func__, propname, fwnode, idx, PTR_ERR_OR_ZERO(desc)); + + return desc; +} + +/** + * swnode_gpio_count - count the GPIOs associated with a device / function + * @fwnode: firmware node of the GPIO consumer, can be %NULL for + * system-global GPIOs + * @con_id: function within the GPIO consumer + * + * Return: + * The number of GPIOs associated with a device / function or %-ENOENT, + * if no GPIO has been assigned to the requested function. + */ +int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id) +{ + struct fwnode_reference_args args; + char propname[32]; + int count; + + swnode_format_propname(con_id, propname, sizeof(propname)); + + /* + * This is not very efficient, but GPIO lists usually have only + * 1 or 2 entries. + */ + count = 0; + while (fwnode_property_get_reference_args(fwnode, propname, NULL, 0, + count, &args) == 0) { + fwnode_handle_put(args.fwnode); + count++; + } + + return count ?: -ENOENT; +} diff --git a/drivers/gpio/gpiolib-swnode.h b/drivers/gpio/gpiolib-swnode.h new file mode 100644 index 000000000000..af849e56f6bc --- /dev/null +++ b/drivers/gpio/gpiolib-swnode.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef GPIOLIB_SWNODE_H +#define GPIOLIB_SWNODE_H + +struct fwnode_handle; +struct gpio_desc; + +struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode, + const char *con_id, unsigned int idx, + unsigned long *flags); +int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id); + +#endif /* GPIOLIB_SWNODE_H */ diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 7f739096c4cf..7936d54a2e30 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -26,6 +26,7 @@ #include "gpiolib.h" #include "gpiolib-of.h" #include "gpiolib-acpi.h" +#include "gpiolib-swnode.h" #include "gpiolib-cdev.h" #include "gpiolib-sysfs.h" @@ -3870,6 +3871,10 @@ static struct gpio_desc *gpiod_find_by_fwnode(struct fwnode_handle *fwnode, dev_dbg(consumer, "using ACPI '%pfw' for '%s' GPIO lookup\n", fwnode, con_id); desc = acpi_find_gpio(fwnode, con_id, idx, flags, lookupflags); + } else if (is_software_node(fwnode)) { + dev_dbg(consumer, "using swnode '%pfw' for '%s' GPIO lookup\n", + fwnode, con_id); + desc = swnode_find_gpio(fwnode, con_id, idx, lookupflags); } return desc; @@ -3987,6 +3992,8 @@ int gpiod_count(struct device *dev, const char *con_id) count = of_gpio_get_count(dev, con_id); else if (is_acpi_node(fwnode)) count = acpi_gpio_count(dev, con_id); + else if (is_software_node(fwnode)) + count = swnode_gpio_count(fwnode, con_id); if (count < 0) count = platform_gpio_count(dev, con_id); diff --git a/include/linux/gpio/property.h b/include/linux/gpio/property.h new file mode 100644 index 000000000000..6c75c8bd44a0 --- /dev/null +++ b/include/linux/gpio/property.h @@ -0,0 +1,11 @@ +// SPDX-License-Identifier: GPL-2.0+ +#ifndef __LINUX_GPIO_PROPERTY_H +#define __LINUX_GPIO_PROPERTY_H + +#include /* for GPIO_* flags */ +#include + +#define PROPERTY_ENTRY_GPIO(_name_, _chip_node_, _idx_, _flags_) \ + PROPERTY_ENTRY_REF(_name_, _chip_node_, _idx_, _flags_) + +#endif /* __LINUX_GPIO_PROPERTY_H */