292 lines
7.3 KiB
C
292 lines
7.3 KiB
C
/*
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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/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>
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#include <linux/gpio.h>
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#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/pinctrl/pinctrl.h>
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#include <linux/slab.h>
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/* Private data structure for of_gpiochip_find_and_xlate */
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struct gg_data {
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enum of_gpio_flags *flags;
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struct of_phandle_args gpiospec;
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int out_gpio;
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};
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/* Private function for resolving node pointer to gpio_chip */
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static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
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{
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struct gg_data *gg_data = data;
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int ret;
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if ((gc->of_node != gg_data->gpiospec.np) ||
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(gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
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(!gc->of_xlate))
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return false;
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ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
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if (ret < 0)
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return false;
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gg_data->out_gpio = ret + gc->base;
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return true;
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}
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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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*
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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
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* 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,
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int index, enum of_gpio_flags *flags)
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{
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/* Return -EPROBE_DEFER to support probe() functions to be called
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* later when the GPIO actually becomes available
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*/
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struct gg_data gg_data = { .flags = flags, .out_gpio = -EPROBE_DEFER };
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int ret;
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/* .of_xlate might decide to not fill in the flags, so clear it. */
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if (flags)
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*flags = 0;
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ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
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&gg_data.gpiospec);
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if (ret) {
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pr_debug("%s: can't parse gpios property\n", __func__);
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return ret;
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}
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gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
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of_node_put(gg_data.gpiospec.np);
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pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio);
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return gg_data.out_gpio;
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}
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EXPORT_SYMBOL(of_get_named_gpio_flags);
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/**
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* of_gpio_named_count - Count GPIOs for a device
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* @np: device node to count GPIOs for
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* @propname: property name containing gpio specifier(s)
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*
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* The function returns the count of GPIOs specified for a node.
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*
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* Note that the empty GPIO specifiers counts too. For example,
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*
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* gpios = <0
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* &pio1 1 2
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* 0
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* &pio2 3 4>;
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*
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* defines four GPIOs (so this function will return 4), two of which
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* are not specified.
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*/
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unsigned int of_gpio_named_count(struct device_node *np, const char* propname)
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{
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unsigned int cnt = 0;
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do {
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int ret;
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ret = of_parse_phandle_with_args(np, propname, "#gpio-cells",
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cnt, NULL);
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/* A hole in the gpios = <> counts anyway. */
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if (ret < 0 && ret != -EEXIST)
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break;
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} while (++cnt);
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return cnt;
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}
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EXPORT_SYMBOL(of_gpio_named_count);
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/**
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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
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* @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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*
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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 gpio_chip *gc,
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const struct of_phandle_args *gpiospec, u32 *flags)
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{
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/*
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* We're discouraging gpio_cells < 2, since that way you'll have to
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* write your own xlate function (that will have to retrive the GPIO
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* number and the flags from a single gpio cell -- this is possible,
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* but not recommended).
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*/
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if (gc->of_gpio_n_cells < 2) {
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WARN_ON(1);
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return -EINVAL;
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}
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if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
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return -EINVAL;
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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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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)
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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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* - of_gpio_n_cells
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* - of_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 gpio_chip *gc = &mm_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 = -1;
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if (mm_gc->save_regs)
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mm_gc->save_regs(mm_gc);
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mm_gc->gc.of_node = np;
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ret = gpiochip_add(gc);
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if (ret)
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goto err2;
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return 0;
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err2:
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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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#ifdef CONFIG_PINCTRL
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static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
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{
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struct device_node *np = chip->of_node;
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struct of_phandle_args pinspec;
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struct pinctrl_dev *pctldev;
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int index = 0, ret;
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if (!np)
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return;
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do {
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ret = of_parse_phandle_with_args(np, "gpio-ranges",
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"#gpio-range-cells", index, &pinspec);
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if (ret)
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break;
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pctldev = of_pinctrl_get(pinspec.np);
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if (!pctldev)
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break;
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/*
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* This assumes that the n GPIO pins are consecutive in the
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* GPIO number space, and that the pins are also consecutive
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* in their local number space. Currently it is not possible
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* to add different ranges for one and the same GPIO chip,
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* as the code assumes that we have one consecutive range
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* on both, mapping 1-to-1.
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*
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* TODO: make the OF bindings handle multiple sparse ranges
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* on the same GPIO chip.
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*/
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ret = gpiochip_add_pin_range(chip,
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pinctrl_dev_get_name(pctldev),
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0, /* offset in gpiochip */
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pinspec.args[0],
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pinspec.args[1]);
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if (ret)
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break;
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} while (index++);
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}
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#else
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static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
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#endif
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void of_gpiochip_add(struct gpio_chip *chip)
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{
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if ((!chip->of_node) && (chip->dev))
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chip->of_node = chip->dev->of_node;
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if (!chip->of_node)
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return;
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if (!chip->of_xlate) {
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chip->of_gpio_n_cells = 2;
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chip->of_xlate = of_gpio_simple_xlate;
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}
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of_gpiochip_add_pin_range(chip);
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of_node_get(chip->of_node);
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}
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void of_gpiochip_remove(struct gpio_chip *chip)
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{
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gpiochip_remove_pin_ranges(chip);
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if (chip->of_node)
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of_node_put(chip->of_node);
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}
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