Skip to content
Snippets Groups Projects
Select Git revision
  • 023a6007a08d342b64895a7342e426d12d9627dd
  • master default
  • android-container
  • nanopc-t4
  • for-kernelci
  • WIP-syscall
  • v4.16-rc5
  • v4.16-rc4
  • v4.16-rc3
  • v4.16-rc2
  • v4.16-rc1
  • v4.15
  • v4.15-rc9
  • v4.15-rc8
  • v4.15-rc7
  • v4.15-rc6
  • v4.15-rc5
  • v4.15-rc4
  • v4.15-rc3
  • v4.15-rc2
  • v4.15-rc1
  • v4.14
  • v4.14-rc8
  • v4.14-rc7
  • v4.14-rc6
  • v4.14-rc5
26 results

gpiolib-of.c

Blame
  • gpiolib-of.c 8.21 KiB
    /*
     * 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/device.h>
    #include <linux/err.h>
    #include <linux/errno.h>
    #include <linux/module.h>
    #include <linux/io.h>
    #include <linux/gpio/consumer.h>
    #include <linux/of.h>
    #include <linux/of_address.h>
    #include <linux/of_gpio.h>
    #include <linux/pinctrl/pinctrl.h>
    #include <linux/slab.h>
    
    #include "gpiolib.h"
    
    /* Private data structure for of_gpiochip_find_and_xlate */
    struct gg_data {
    	enum of_gpio_flags *flags;
    	struct of_phandle_args gpiospec;
    
    	struct gpio_desc *out_gpio;
    };
    
    /* Private function for resolving node pointer to gpio_chip */
    static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
    {
    	struct gg_data *gg_data = data;
    	int ret;
    
    	if ((gc->of_node != gg_data->gpiospec.np) ||
    	    (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
    	    (!gc->of_xlate))
    		return false;
    
    	ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
    	if (ret < 0) {
    		/* We've found a gpio chip, but the translation failed.
    		 * Store translation error in out_gpio.
    		 * Return false to keep looking, as more than one gpio chip
    		 * could be registered per of-node.
    		 */
    		gg_data->out_gpio = ERR_PTR(ret);
    		return false;
    	 }
    
    	gg_data->out_gpio = gpiochip_get_desc(gc, ret);
    	return true;
    }
    
    /**
     * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
     * @np:		device node to get GPIO from
     * @propname:	property name containing gpio specifier(s)
     * @index:	index of the GPIO
     * @flags:	a flags pointer to fill in
     *
     * Returns GPIO descriptor to use with Linux 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.
     */
    struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
    		     const char *propname, int index, enum of_gpio_flags *flags)
    {
    	/* Return -EPROBE_DEFER to support probe() functions to be called
    	 * later when the GPIO actually becomes available
    	 */
    	struct gg_data gg_data = {
    		.flags = flags,
    		.out_gpio = ERR_PTR(-EPROBE_DEFER)
    	};
    	int ret;
    
    	/* .of_xlate might decide to not fill in the flags, so clear it. */
    	if (flags)
    		*flags = 0;
    
    	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
    					 &gg_data.gpiospec);
    	if (ret) {
    		pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
    			__func__, propname, np->full_name, index);
    		return ERR_PTR(ret);
    	}
    
    	gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
    
    	of_node_put(gg_data.gpiospec.np);
    	pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
    		 __func__, propname, np->full_name, index,
    		 PTR_ERR_OR_ZERO(gg_data.out_gpio));
    	return gg_data.out_gpio;
    }
    
    int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
    			    int index, enum of_gpio_flags *flags)
    {
    	struct gpio_desc *desc;
    
    	desc = of_get_named_gpiod_flags(np, list_name, index, flags);
    
    	if (IS_ERR(desc))
    		return PTR_ERR(desc);
    	else
    		return desc_to_gpio(desc);
    }
    EXPORT_SYMBOL(of_get_named_gpio_flags);
    
    /**
     * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
     * @gc:		pointer to the 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 gpio_chip *gc,
    			 const struct of_phandle_args *gpiospec, u32 *flags)
    {
    	/*
    	 * 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 (gc->of_gpio_n_cells < 2) {
    		WARN_ON(1);
    		return -EINVAL;
    	}
    
    	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
    		return -EINVAL;
    
    	if (gpiospec->args[0] >= gc->ngpio)
    		return -EINVAL;
    
    	if (flags)
    		*flags = gpiospec->args[1];
    
    	return gpiospec->args[0];
    }
    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
     *    - of_gpio_n_cells
     *    - of_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 gpio_chip *gc = &mm_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 (mm_gc->save_regs)
    		mm_gc->save_regs(mm_gc);
    
    	mm_gc->gc.of_node = np;
    
    	ret = gpiochip_add(gc);
    	if (ret)
    		goto err2;
    
    	return 0;
    err2:
    	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);
    
    /**
     * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
     * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
     */
    void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
    {
    	struct gpio_chip *gc = &mm_gc->gc;
    
    	if (!mm_gc)
    		return;
    
    	gpiochip_remove(gc);
    	iounmap(mm_gc->regs);
    	kfree(gc->label);
    }
    EXPORT_SYMBOL(of_mm_gpiochip_remove);
    
    #ifdef CONFIG_PINCTRL
    static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
    {
    	struct device_node *np = chip->of_node;
    	struct of_phandle_args pinspec;
    	struct pinctrl_dev *pctldev;
    	int index = 0, ret;
    	const char *name;
    	static const char group_names_propname[] = "gpio-ranges-group-names";
    	struct property *group_names;
    
    	if (!np)
    		return;
    
    	group_names = of_find_property(np, group_names_propname, NULL);
    
    	for (;; index++) {
    		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
    				index, &pinspec);
    		if (ret)
    			break;
    
    		pctldev = of_pinctrl_get(pinspec.np);
    		if (!pctldev)
    			break;
    
    		if (pinspec.args[2]) {
    			if (group_names) {
    				ret = of_property_read_string_index(np,
    						group_names_propname,
    						index, &name);
    				if (strlen(name)) {
    					pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
    						np->full_name);
    					break;
    				}
    			}
    			/* npins != 0: linear range */
    			ret = gpiochip_add_pin_range(chip,
    					pinctrl_dev_get_devname(pctldev),
    					pinspec.args[0],
    					pinspec.args[1],
    					pinspec.args[2]);
    			if (ret)
    				break;
    		} else {
    			/* npins == 0: special range */
    			if (pinspec.args[1]) {
    				pr_err("%s: Illegal gpio-range format.\n",
    					np->full_name);
    				break;
    			}
    
    			if (!group_names) {
    				pr_err("%s: GPIO group range requested but no %s property.\n",
    					np->full_name, group_names_propname);
    				break;
    			}
    
    			ret = of_property_read_string_index(np,
    						group_names_propname,
    						index, &name);
    			if (ret)
    				break;
    
    			if (!strlen(name)) {
    				pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
    				np->full_name);
    				break;
    			}
    
    			ret = gpiochip_add_pingroup_range(chip, pctldev,
    						pinspec.args[0], name);
    			if (ret)
    				break;
    		}
    	}
    }
    
    #else
    static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
    #endif
    
    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_gpiochip_add_pin_range(chip);
    	of_node_get(chip->of_node);
    }
    
    void of_gpiochip_remove(struct gpio_chip *chip)
    {
    	gpiochip_remove_pin_ranges(chip);
    	of_node_put(chip->of_node);
    }