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drivers/of/gpio.c
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/* * 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. */ |
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#include <linux/device.h> |
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#include <linux/errno.h> |
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#include <linux/module.h> |
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#include <linux/io.h> #include <linux/of.h> |
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#include <linux/of_address.h> |
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#include <linux/of_gpio.h> |
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#include <linux/slab.h> |
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/** |
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* of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API |
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* @np: device node to get GPIO from |
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* @propname: property name containing gpio specifier(s) |
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* @index: index of the GPIO |
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* @flags: a flags pointer to fill in |
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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. If @flags is not NULL the function also fills * in flags for the GPIO. |
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*/ |
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int of_get_named_gpio_flags(struct device_node *np, const char *propname, int index, enum of_gpio_flags *flags) |
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{ |
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int ret; |
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struct gpio_chip *gc; |
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struct of_phandle_args gpiospec; |
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|
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ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, &gpiospec); |
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if (ret) { pr_debug("%s: can't parse gpios property ", __func__); |
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goto err0; } |
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|
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gc = of_node_to_gpiochip(gpiospec.np); |
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if (!gc) { |
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pr_debug("%s: gpio controller %s isn't registered ", |
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np->full_name, gpiospec.np->full_name); |
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ret = -ENODEV; goto err1; |
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} |
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if (gpiospec.args_count != gc->of_gpio_n_cells) { |
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pr_debug("%s: wrong #gpio-cells for %s ", |
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np->full_name, gpiospec.np->full_name); |
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ret = -EINVAL; goto err1; |
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} |
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/* .xlate might decide to not fill in the flags, so clear it. */ if (flags) *flags = 0; |
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ret = gc->of_xlate(gc, &gpiospec, flags); |
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if (ret < 0) goto err1; |
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ret += gc->base; |
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err1: |
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of_node_put(gpiospec.np); |
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err0: pr_debug("%s exited with status %d ", __func__, ret); return ret; } |
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EXPORT_SYMBOL(of_get_named_gpio_flags); |
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/** |
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* 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; |
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ret = of_parse_phandle_with_args(np, "gpios", "#gpio-cells", cnt, NULL); |
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/* A hole in the gpios = <> counts anyway. */ if (ret < 0 && ret != -EEXIST) break; } while (++cnt); return cnt; } EXPORT_SYMBOL(of_gpio_count); /** |
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* of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags |
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* @gc: pointer to the gpio_chip structure |
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* @np: device node of the GPIO chip * @gpio_spec: gpio specifier as found in the device tree |
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* @flags: a flags pointer to fill in |
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* * 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). */ |
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int of_gpio_simple_xlate(struct gpio_chip *gc, const struct of_phandle_args *gpiospec, u32 *flags) |
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{ |
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/* * 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). */ |
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if (gc->of_gpio_n_cells < 2) { |
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WARN_ON(1); return -EINVAL; } |
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if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) return -EINVAL; if (gpiospec->args[0] > gc->ngpio) |
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return -EINVAL; |
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if (flags) |
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*flags = gpiospec->args[1]; |
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|
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return gpiospec->args[0]; |
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} |
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EXPORT_SYMBOL(of_gpio_simple_xlate); |
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|
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/** * 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 |
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* - of_gpio_n_cells * - of_xlate callback (optional) |
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* * 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; |
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struct gpio_chip *gc = &mm_gc->gc; |
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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; |
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gc->base = -1; |
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|
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if (mm_gc->save_regs) mm_gc->save_regs(mm_gc); |
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mm_gc->gc.of_node = np; |
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ret = gpiochip_add(gc); if (ret) goto err2; |
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return 0; err2: |
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iounmap(mm_gc->regs); err1: kfree(gc->label); err0: pr_err("%s: GPIO chip registration failed with status %d ", np->full_name, ret); return ret; } EXPORT_SYMBOL(of_mm_gpiochip_add); |
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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); } |
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/* 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); } |