/* * 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/errno.h> #include <linux/module.h> #include <linux/io.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/of_gpio.h> #include <linux/slab.h> /** * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API * @np: device node to get GPIO from * @index: index of the GPIO * @flags: a flags pointer to fill in * * Returns GPIO number to use with Linux generic 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. */ int of_get_gpio_flags(struct device_node *np, int index, enum of_gpio_flags *flags) { int ret; struct device_node *gpio_np; struct gpio_chip *gc; int size; const void *gpio_spec; const __be32 *gpio_cells; ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index, &gpio_np, &gpio_spec); if (ret) { pr_debug("%s: can't parse gpios property\n", __func__); goto err0; } gc = of_node_to_gpiochip(gpio_np); if (!gc) { pr_debug("%s: gpio controller %s isn't registered\n", np->full_name, gpio_np->full_name); ret = -ENODEV; goto err1; } gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size); if (!gpio_cells || size != sizeof(*gpio_cells) || be32_to_cpup(gpio_cells) != gc->of_gpio_n_cells) { pr_debug("%s: wrong #gpio-cells for %s\n", np->full_name, gpio_np->full_name); ret = -EINVAL; goto err1; } /* .xlate might decide to not fill in the flags, so clear it. */ if (flags) *flags = 0; ret = gc->of_xlate(gc, np, gpio_spec, flags); if (ret < 0) goto err1; ret += gc->base; err1: of_node_put(gpio_np); err0: pr_debug("%s exited with status %d\n", __func__, ret); return ret; } EXPORT_SYMBOL(of_get_gpio_flags); /** * of_gpio_count - Count GPIOs for a device * @np: device node to count GPIOs for * * The function returns the count of GPIOs specified for a node. * * Note that the empty GPIO specifiers counts too. For example, * * gpios = <0 * &pio1 1 2 * 0 * &pio2 3 4>; * * defines four GPIOs (so this function will return 4), two of which * are not specified. */ unsigned int of_gpio_count(struct device_node *np) { unsigned int cnt = 0; do { int ret; ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", cnt, NULL, NULL); /* A hole in the gpios = <> counts anyway. */ if (ret < 0 && ret != -EEXIST) break; } while (++cnt); return cnt; } EXPORT_SYMBOL(of_gpio_count); /** * 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). */ static int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np, const void *gpio_spec, u32 *flags) { const __be32 *gpio = gpio_spec; const u32 n = be32_to_cpup(gpio); /* * 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 (n > gc->ngpio) return -EINVAL; if (flags) *flags = be32_to_cpu(gpio[1]); return n; } /** * 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; pr_debug("%s: registered as generic GPIO chip, base is %d\n", np->full_name, gc->base); 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); 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_node_get(chip->of_node); } void of_gpiochip_remove(struct gpio_chip *chip) { if (chip->of_node) of_node_put(chip->of_node); } /* Private function for resolving node pointer to gpio_chip */ static int of_gpiochip_is_match(struct gpio_chip *chip, void *data) { return chip->of_node == data; } struct gpio_chip *of_node_to_gpiochip(struct device_node *np) { return gpiochip_find(np, of_gpiochip_is_match); }