/* * 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 - Get a GPIO number from the device tree to use with GPIO API * @np: device node to get GPIO from * @index: index of the GPIO * * Returns GPIO number to use with Linux generic GPIO API, or one of the errno * value on the error condition. */ int of_get_gpio(struct device_node *np, int index) { int ret = -EINVAL; struct device_node *gc; struct of_gpio_chip *of_gc = NULL; int size; const u32 *gpios; u32 nr_cells; int i; const void *gpio_spec; const u32 *gpio_cells; int gpio_index = 0; gpios = of_get_property(np, "gpios", &size); if (!gpios) { ret = -ENOENT; goto err0; } nr_cells = size / sizeof(u32); for (i = 0; i < nr_cells; gpio_index++) { const phandle *gpio_phandle; gpio_phandle = gpios + i; gpio_spec = gpio_phandle + 1; /* one cell hole in the gpios = <>; */ if (!*gpio_phandle) { if (gpio_index == index) return -ENOENT; i++; continue; } gc = of_find_node_by_phandle(*gpio_phandle); if (!gc) { pr_debug("%s: could not find phandle for gpios\n", np->full_name); 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); 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); goto err1; } /* Next phandle is at phandle cells + #gpio-cells */ i += sizeof(*gpio_phandle) / sizeof(u32) + *gpio_cells; if (i >= nr_cells + 1) { pr_debug("%s: insufficient gpio-spec length\n", np->full_name); goto err1; } if (gpio_index == index) break; of_gc = NULL; of_node_put(gc); } if (!of_gc) { ret = -ENOENT; goto err0; } ret = of_gc->xlate(of_gc, np, gpio_spec); 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); /** * of_gpio_simple_xlate - translate gpio_spec to the GPIO number * @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 * * 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) { const u32 *gpio = gpio_spec; if (*gpio > of_gc->gc.ngpio) return -EINVAL; return *gpio; } EXPORT_SYMBOL(of_gpio_simple_xlate); /* Should be sufficient for now, later we'll use dynamic bases. */ #if defined(CONFIG_PPC32) || defined(CONFIG_SPARC32) #define GPIOS_PER_CHIP 32 #else #define GPIOS_PER_CHIP 64 #endif static int of_get_gpiochip_base(struct device_node *np) { struct device_node *gc = NULL; int gpiochip_base = 0; while ((gc = of_find_all_nodes(gc))) { if (!of_get_property(gc, "gpio-controller", NULL)) continue; if (gc != np) { gpiochip_base += GPIOS_PER_CHIP; continue; } of_node_put(gc); if (gpiochip_base >= ARCH_NR_GPIOS) return -ENOSPC; return gpiochip_base; } return -ENOENT; } /** * 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 = of_get_gpiochip_base(np); if (gc->base < 0) { ret = gc->base; goto err1; } 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);