/* * OF helpers for the GPIO API * * Copyright (c) 2007-2008 MontaVista Software, Inc. * * Author: Anton Vorontsov <avorontsov@ru.mvista.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include <linux/device.h> #include <linux/err.h> #include <linux/errno.h> #include <linux/module.h> #include <linux/io.h> #include <linux/gpio/consumer.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/of_gpio.h> #include <linux/pinctrl/pinctrl.h> #include <linux/slab.h> #include <linux/gpio/machine.h> #include "gpiolib.h" /* Private data structure for of_gpiochip_find_and_xlate */ struct gg_data { enum of_gpio_flags *flags; struct of_phandle_args gpiospec; struct gpio_desc *out_gpio; }; /* Private function for resolving node pointer to gpio_chip */ static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) { struct gg_data *gg_data = data; int ret; if ((gc->of_node != gg_data->gpiospec.np) || (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || (!gc->of_xlate)) return false; ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); if (ret < 0) { /* We've found a gpio chip, but the translation failed. * Store translation error in out_gpio. * Return false to keep looking, as more than one gpio chip * could be registered per of-node. */ gg_data->out_gpio = ERR_PTR(ret); return false; } gg_data->out_gpio = gpiochip_get_desc(gc, ret); return true; } /** * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API * @np: device node to get GPIO from * @propname: property name containing gpio specifier(s) * @index: index of the GPIO * @flags: a flags pointer to fill in * * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno * value on the error condition. If @flags is not NULL the function also fills * in flags for the GPIO. */ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, const char *propname, int index, enum of_gpio_flags *flags) { /* Return -EPROBE_DEFER to support probe() functions to be called * later when the GPIO actually becomes available */ struct gg_data gg_data = { .flags = flags, .out_gpio = ERR_PTR(-EPROBE_DEFER) }; int ret; /* .of_xlate might decide to not fill in the flags, so clear it. */ if (flags) *flags = 0; ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, &gg_data.gpiospec); if (ret) { pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", __func__, propname, np->full_name, index); return ERR_PTR(ret); } gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); of_node_put(gg_data.gpiospec.np); pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", __func__, propname, np->full_name, index, PTR_ERR_OR_ZERO(gg_data.out_gpio)); return gg_data.out_gpio; } int of_get_named_gpio_flags(struct device_node *np, const char *list_name, int index, enum of_gpio_flags *flags) { struct gpio_desc *desc; desc = of_get_named_gpiod_flags(np, list_name, index, flags); if (IS_ERR(desc)) return PTR_ERR(desc); else return desc_to_gpio(desc); } EXPORT_SYMBOL(of_get_named_gpio_flags); /** * of_get_gpio_hog() - Get a GPIO hog descriptor, names and flags for GPIO API * @np: device node to get GPIO from * @name: GPIO line name * @lflags: gpio_lookup_flags - returned from of_find_gpio() or * of_get_gpio_hog() * @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_get_gpio_hog(struct device_node *np, const char **name, enum gpio_lookup_flags *lflags, enum gpiod_flags *dflags) { struct device_node *chip_np; enum of_gpio_flags xlate_flags; struct gpio_desc *desc; struct gg_data gg_data = { .flags = &xlate_flags, }; u32 tmp; int i, ret; chip_np = np->parent; if (!chip_np) return ERR_PTR(-EINVAL); xlate_flags = 0; *lflags = 0; *dflags = 0; ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp); if (ret) return ERR_PTR(ret); if (tmp > MAX_PHANDLE_ARGS) return ERR_PTR(-EINVAL); gg_data.gpiospec.args_count = tmp; gg_data.gpiospec.np = chip_np; for (i = 0; i < tmp; i++) { ret = of_property_read_u32_index(np, "gpios", i, &gg_data.gpiospec.args[i]); if (ret) return ERR_PTR(ret); } gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); if (!gg_data.out_gpio) { if (np->parent == np) return ERR_PTR(-ENXIO); else return ERR_PTR(-EINVAL); } if (xlate_flags & OF_GPIO_ACTIVE_LOW) *lflags |= GPIO_ACTIVE_LOW; 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 (%s): no hogging state specified, bailing out\n", desc_to_gpio(gg_data.out_gpio), np->name); return ERR_PTR(-EINVAL); } if (name && of_property_read_string(np, "line-name", name)) *name = np->name; desc = gg_data.out_gpio; return desc; } /** * of_gpiochip_scan_hogs - Scan gpio-controller and apply GPIO hog as requested * @chip: gpio chip to act on * * This is only used by of_gpiochip_add to request/set GPIO initial * configuration. */ static void of_gpiochip_scan_hogs(struct gpio_chip *chip) { struct gpio_desc *desc = NULL; struct device_node *np; const char *name; enum gpio_lookup_flags lflags; enum gpiod_flags dflags; for_each_child_of_node(chip->of_node, np) { if (!of_property_read_bool(np, "gpio-hog")) continue; desc = of_get_gpio_hog(np, &name, &lflags, &dflags); if (IS_ERR(desc)) continue; if (gpiod_hog(desc, name, lflags, dflags)) continue; } } /** * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags * @gc: pointer to the gpio_chip structure * @np: device node of the GPIO chip * @gpio_spec: gpio specifier as found in the device tree * @flags: a flags pointer to fill in * * This is simple translation function, suitable for the most 1:1 mapped * gpio chips. This function performs only one sanity check: whether gpio * is less than ngpios (that is specified in the gpio_chip). */ int of_gpio_simple_xlate(struct gpio_chip *gc, const struct of_phandle_args *gpiospec, u32 *flags) { /* * We're discouraging gpio_cells < 2, since that way you'll have to * write your own xlate function (that will have to retrive the GPIO * number and the flags from a single gpio cell -- this is possible, * but not recommended). */ if (gc->of_gpio_n_cells < 2) { WARN_ON(1); return -EINVAL; } if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) return -EINVAL; if (gpiospec->args[0] >= gc->ngpio) return -EINVAL; if (flags) *flags = gpiospec->args[1]; return gpiospec->args[0]; } EXPORT_SYMBOL(of_gpio_simple_xlate); /** * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) * @np: device node of the GPIO chip * @mm_gc: pointer to the of_mm_gpio_chip allocated structure * * To use this function you should allocate and fill mm_gc with: * * 1) In the gpio_chip structure: * - all the callbacks * - of_gpio_n_cells * - of_xlate callback (optional) * * 3) In the of_mm_gpio_chip structure: * - save_regs callback (optional) * * If succeeded, this function will map bank's memory and will * do all necessary work for you. Then you'll able to use .regs * to manage GPIOs from the callbacks. */ int of_mm_gpiochip_add(struct device_node *np, struct of_mm_gpio_chip *mm_gc) { int ret = -ENOMEM; struct gpio_chip *gc = &mm_gc->gc; gc->label = kstrdup(np->full_name, GFP_KERNEL); if (!gc->label) goto err0; mm_gc->regs = of_iomap(np, 0); if (!mm_gc->regs) goto err1; gc->base = -1; if (mm_gc->save_regs) mm_gc->save_regs(mm_gc); mm_gc->gc.of_node = np; ret = gpiochip_add(gc); if (ret) goto err2; return 0; err2: iounmap(mm_gc->regs); err1: kfree(gc->label); err0: pr_err("%s: GPIO chip registration failed with status %d\n", np->full_name, ret); return ret; } EXPORT_SYMBOL(of_mm_gpiochip_add); /** * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) * @mm_gc: pointer to the of_mm_gpio_chip allocated structure */ void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) { struct gpio_chip *gc = &mm_gc->gc; if (!mm_gc) return; gpiochip_remove(gc); iounmap(mm_gc->regs); kfree(gc->label); } EXPORT_SYMBOL(of_mm_gpiochip_remove); #ifdef CONFIG_PINCTRL static void of_gpiochip_add_pin_range(struct gpio_chip *chip) { struct device_node *np = chip->of_node; struct of_phandle_args pinspec; struct pinctrl_dev *pctldev; int index = 0, ret; const char *name; static const char group_names_propname[] = "gpio-ranges-group-names"; struct property *group_names; if (!np) return; group_names = of_find_property(np, group_names_propname, NULL); for (;; index++) { ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, index, &pinspec); if (ret) break; pctldev = of_pinctrl_get(pinspec.np); if (!pctldev) break; if (pinspec.args[2]) { if (group_names) { ret = of_property_read_string_index(np, group_names_propname, index, &name); if (strlen(name)) { pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", np->full_name); break; } } /* npins != 0: linear range */ ret = gpiochip_add_pin_range(chip, pinctrl_dev_get_devname(pctldev), pinspec.args[0], pinspec.args[1], pinspec.args[2]); if (ret) break; } else { /* npins == 0: special range */ if (pinspec.args[1]) { pr_err("%s: Illegal gpio-range format.\n", np->full_name); break; } if (!group_names) { pr_err("%s: GPIO group range requested but no %s property.\n", np->full_name, group_names_propname); break; } ret = of_property_read_string_index(np, group_names_propname, index, &name); if (ret) break; if (!strlen(name)) { pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", np->full_name); break; } ret = gpiochip_add_pingroup_range(chip, pctldev, pinspec.args[0], name); if (ret) break; } } } #else static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} #endif void of_gpiochip_add(struct gpio_chip *chip) { if ((!chip->of_node) && (chip->dev)) chip->of_node = chip->dev->of_node; if (!chip->of_node) return; if (!chip->of_xlate) { chip->of_gpio_n_cells = 2; chip->of_xlate = of_gpio_simple_xlate; } of_gpiochip_add_pin_range(chip); of_node_get(chip->of_node); of_gpiochip_scan_hogs(chip); } void of_gpiochip_remove(struct gpio_chip *chip) { gpiochip_remove_pin_ranges(chip); of_node_put(chip->of_node); }