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https://github.com/Fishwaldo/Star64_linux.git
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[POWERPC] OF helpers for the GPIO API
This implements various helpers to support OF bindings for the GPIO LIB API. Previously this was PowerPC specific, but it seems this code isn't arch-dependent anyhow, so let's place it into of/. SPARC will not see this addition yet, real hardware seem to not use GPIOs at all. But this might change: http://www.leox.org/docs/faq_MLleon.html "16-bit I/O port" sounds promising. :-) Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Anton Vorontsov
Paul Mackerras
parent
a2879fef7c
commit
863fbf4966
4 changed files with 318 additions and 0 deletions
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@ -1,3 +1,9 @@
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config OF_DEVICE
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config OF_DEVICE
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def_bool y
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def_bool y
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depends on OF && (SPARC || PPC_OF)
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depends on OF && (SPARC || PPC_OF)
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config OF_GPIO
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def_bool y
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depends on OF && PPC_OF && HAVE_GPIO_LIB
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help
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OpenFirmware GPIO accessors
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@ -1,2 +1,3 @@
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obj-y = base.o
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obj-y = base.o
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obj-$(CONFIG_OF_DEVICE) += device.o platform.o
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obj-$(CONFIG_OF_DEVICE) += device.o platform.o
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obj-$(CONFIG_OF_GPIO) += gpio.o
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242
drivers/of/gpio.c
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242
drivers/of/gpio.c
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@ -0,0 +1,242 @@
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/*
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* OF helpers for the GPIO API
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*
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* Copyright (c) 2007-2008 MontaVista Software, Inc.
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*
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* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_gpio.h>
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#include <asm/prom.h>
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/**
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* of_get_gpio - Get a GPIO number from the device tree to use with GPIO API
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* @np: device node to get GPIO from
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* @index: index of the GPIO
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*
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* Returns GPIO number to use with Linux generic GPIO API, or one of the errno
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* value on the error condition.
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*/
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int of_get_gpio(struct device_node *np, int index)
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{
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int ret = -EINVAL;
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struct device_node *gc;
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struct of_gpio_chip *of_gc = NULL;
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int size;
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const u32 *gpios;
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u32 nr_cells;
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int i;
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const void *gpio_spec;
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const u32 *gpio_cells;
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int gpio_index = 0;
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gpios = of_get_property(np, "gpios", &size);
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if (!gpios) {
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ret = -ENOENT;
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goto err0;
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}
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nr_cells = size / sizeof(u32);
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for (i = 0; i < nr_cells; gpio_index++) {
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const phandle *gpio_phandle;
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gpio_phandle = gpios + i;
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gpio_spec = gpio_phandle + 1;
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/* one cell hole in the gpios = <>; */
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if (!*gpio_phandle) {
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if (gpio_index == index)
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return -ENOENT;
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i++;
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continue;
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}
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gc = of_find_node_by_phandle(*gpio_phandle);
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if (!gc) {
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pr_debug("%s: could not find phandle for gpios\n",
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np->full_name);
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goto err0;
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}
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of_gc = gc->data;
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if (!of_gc) {
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pr_debug("%s: gpio controller %s isn't registered\n",
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np->full_name, gc->full_name);
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goto err1;
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}
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gpio_cells = of_get_property(gc, "#gpio-cells", &size);
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if (!gpio_cells || size != sizeof(*gpio_cells) ||
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*gpio_cells != of_gc->gpio_cells) {
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pr_debug("%s: wrong #gpio-cells for %s\n",
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np->full_name, gc->full_name);
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goto err1;
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}
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/* Next phandle is at phandle cells + #gpio-cells */
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i += sizeof(*gpio_phandle) / sizeof(u32) + *gpio_cells;
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if (i >= nr_cells + 1) {
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pr_debug("%s: insufficient gpio-spec length\n",
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np->full_name);
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goto err1;
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}
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if (gpio_index == index)
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break;
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of_gc = NULL;
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of_node_put(gc);
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}
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if (!of_gc) {
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ret = -ENOENT;
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goto err0;
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}
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ret = of_gc->xlate(of_gc, np, gpio_spec);
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if (ret < 0)
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goto err1;
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ret += of_gc->gc.base;
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err1:
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of_node_put(gc);
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err0:
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pr_debug("%s exited with status %d\n", __func__, ret);
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return ret;
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}
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EXPORT_SYMBOL(of_get_gpio);
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/**
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* of_gpio_simple_xlate - translate gpio_spec to the GPIO number
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* @of_gc: pointer to the of_gpio_chip structure
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* @np: device node of the GPIO chip
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* @gpio_spec: gpio specifier as found in the device tree
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*
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* This is simple translation function, suitable for the most 1:1 mapped
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* gpio chips. This function performs only one sanity check: whether gpio
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* is less than ngpios (that is specified in the gpio_chip).
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*/
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int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np,
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const void *gpio_spec)
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{
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const u32 *gpio = gpio_spec;
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if (*gpio > of_gc->gc.ngpio)
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return -EINVAL;
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return *gpio;
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}
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EXPORT_SYMBOL(of_gpio_simple_xlate);
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/* Should be sufficient for now, later we'll use dynamic bases. */
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#if defined(CONFIG_PPC32) || defined(CONFIG_SPARC32)
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#define GPIOS_PER_CHIP 32
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#else
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#define GPIOS_PER_CHIP 64
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#endif
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static int of_get_gpiochip_base(struct device_node *np)
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{
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struct device_node *gc = NULL;
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int gpiochip_base = 0;
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while ((gc = of_find_all_nodes(gc))) {
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if (!of_get_property(gc, "gpio-controller", NULL))
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continue;
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if (gc != np) {
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gpiochip_base += GPIOS_PER_CHIP;
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continue;
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}
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of_node_put(gc);
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if (gpiochip_base >= ARCH_NR_GPIOS)
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return -ENOSPC;
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return gpiochip_base;
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}
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return -ENOENT;
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}
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/**
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* of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
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* @np: device node of the GPIO chip
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* @mm_gc: pointer to the of_mm_gpio_chip allocated structure
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*
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* To use this function you should allocate and fill mm_gc with:
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*
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* 1) In the gpio_chip structure:
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* - all the callbacks
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*
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* 2) In the of_gpio_chip structure:
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* - gpio_cells
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* - xlate callback (optional)
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*
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* 3) In the of_mm_gpio_chip structure:
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* - save_regs callback (optional)
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*
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* If succeeded, this function will map bank's memory and will
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* do all necessary work for you. Then you'll able to use .regs
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* to manage GPIOs from the callbacks.
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*/
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int of_mm_gpiochip_add(struct device_node *np,
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struct of_mm_gpio_chip *mm_gc)
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{
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int ret = -ENOMEM;
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struct of_gpio_chip *of_gc = &mm_gc->of_gc;
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struct gpio_chip *gc = &of_gc->gc;
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gc->label = kstrdup(np->full_name, GFP_KERNEL);
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if (!gc->label)
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goto err0;
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mm_gc->regs = of_iomap(np, 0);
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if (!mm_gc->regs)
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goto err1;
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gc->base = of_get_gpiochip_base(np);
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if (gc->base < 0) {
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ret = gc->base;
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goto err1;
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}
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if (!of_gc->xlate)
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of_gc->xlate = of_gpio_simple_xlate;
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if (mm_gc->save_regs)
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mm_gc->save_regs(mm_gc);
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np->data = of_gc;
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ret = gpiochip_add(gc);
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if (ret)
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goto err2;
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/* We don't want to lose the node and its ->data */
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of_node_get(np);
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pr_debug("%s: registered as generic GPIO chip, base is %d\n",
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np->full_name, gc->base);
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return 0;
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err2:
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np->data = NULL;
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iounmap(mm_gc->regs);
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err1:
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kfree(gc->label);
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err0:
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pr_err("%s: GPIO chip registration failed with status %d\n",
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np->full_name, ret);
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return ret;
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}
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EXPORT_SYMBOL(of_mm_gpiochip_add);
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69
include/linux/of_gpio.h
Normal file
69
include/linux/of_gpio.h
Normal file
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@ -0,0 +1,69 @@
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/*
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* OF helpers for the GPIO API
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*
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* Copyright (c) 2007-2008 MontaVista Software, Inc.
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*
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* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#ifndef __LINUX_OF_GPIO_H
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#define __LINUX_OF_GPIO_H
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#include <linux/errno.h>
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#include <asm/gpio.h>
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#ifdef CONFIG_OF_GPIO
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/*
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* Generic OF GPIO chip
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*/
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struct of_gpio_chip {
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struct gpio_chip gc;
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int gpio_cells;
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int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
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const void *gpio_spec);
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};
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static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
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{
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return container_of(gc, struct of_gpio_chip, gc);
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}
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/*
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* OF GPIO chip for memory mapped banks
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*/
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struct of_mm_gpio_chip {
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struct of_gpio_chip of_gc;
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void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
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void __iomem *regs;
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};
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static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
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{
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struct of_gpio_chip *of_gc = to_of_gpio_chip(gc);
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return container_of(of_gc, struct of_mm_gpio_chip, of_gc);
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}
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extern int of_get_gpio(struct device_node *np, int index);
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extern int of_mm_gpiochip_add(struct device_node *np,
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struct of_mm_gpio_chip *mm_gc);
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extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,
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struct device_node *np,
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const void *gpio_spec);
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#else
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/* Drivers may not strictly depend on the GPIO support, so let them link. */
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static inline int of_get_gpio(struct device_node *np, int index)
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{
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return -ENOSYS;
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}
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#endif /* CONFIG_OF_GPIO */
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#endif /* __LINUX_OF_GPIO_H */
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