/* * 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/kernel.h> #include <linux/errno.h> #include <linux/io.h> #include <linux/of.h> #include <linux/of_gpio.h> #include <asm/prom.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 *gc; struct of_gpio_chip *of_gc = NULL; int size; const void *gpio_spec; const u32 *gpio_cells; ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index, &gc, &gpio_spec); if (ret) { pr_debug("%s: can't parse gpios property\n", __func__); goto err0; } of_gc = gc->data; if (!of_gc) { pr_debug("%s: gpio controller %s isn't registered\n", np->full_name, gc->full_name); ret = -ENODEV; goto err1; } gpio_cells = of_get_property(gc, "#gpio-cells", &size); if (!gpio_cells || size != sizeof(*gpio_cells) || *gpio_cells != of_gc->gpio_cells) { pr_debug("%s: wrong #gpio-cells for %s\n", np->full_name, gc->full_name); ret = -EINVAL; goto err1; } /* .xlate might decide to not fill in the flags, so clear it. */ if (flags) *flags = 0; ret = of_gc->xlate(of_gc, np, gpio_spec, flags); if (ret < 0) goto err1; ret += of_gc->gc.base; err1: of_node_put(gc); 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 * @of_gc: pointer to the of_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 of_gpio_chip *of_gc, struct device_node *np, const void *gpio_spec, enum of_gpio_flags *flags) { const u32 *gpio = gpio_spec; /* * 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 (of_gc->gpio_cells < 2) { WARN_ON(1); return -EINVAL; } if (*gpio > of_gc->gc.ngpio) return -EINVAL; if (flags) *flags = gpio[1]; return *gpio; } 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 * * 2) In the of_gpio_chip structure: * - gpio_cells * - 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 of_gpio_chip *of_gc = &mm_gc->of_gc; struct gpio_chip *gc = &of_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 (!of_gc->xlate) of_gc->xlate = of_gpio_simple_xlate; if (mm_gc->save_regs) mm_gc->save_regs(mm_gc); np->data = of_gc; ret = gpiochip_add(gc); if (ret) goto err2; /* We don't want to lose the node and its ->data */ of_node_get(np); pr_debug("%s: registered as generic GPIO chip, base is %d\n", np->full_name, gc->base); return 0; err2: np->data = NULL; 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);