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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 | // SPDX-License-Identifier: GPL-2.0+ /* * Software Node helpers for the GPIO API * * Copyright 2022 Google LLC */ #include <linux/err.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/printk.h> #include <linux/property.h> #include <linux/string.h> #include <linux/gpio/consumer.h> #include <linux/gpio/driver.h> #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 struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode) { const struct software_node *gdev_node; struct gpio_device *gdev; gdev_node = to_software_node(fwnode); if (!gdev_node || !gdev_node->name) return ERR_PTR(-EINVAL); gdev = gpio_device_find_by_label(gdev_node->name); return gdev ?: 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_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); } struct gpio_device *gdev __free(gpio_device_put) = swnode_get_gpio_device(args.fwnode); fwnode_handle_put(args.fwnode); if (IS_ERR(gdev)) return ERR_CAST(gdev); /* * FIXME: The GPIO device reference is put at return but the descriptor * is passed on. Find a proper solution. */ desc = gpio_device_get_desc(gdev, 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; } |