/* * 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/errno.h> #include <linux/module.h> #include <linux/io.h> #include <linux/gpio.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/of_gpio.h> #include <linux/pinctrl/pinctrl.h> #include <linux/slab.h> /* Private data structure for of_gpiochip_find_and_xlate */ struct gg_data { enum of_gpio_flags *flags; struct of_phandle_args gpiospec; int 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) return false; gg_data->out_gpio = ret + gc->base; return true; } /** * of_get_named_gpio_flags() - Get a GPIO number and flags to use with 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 number to use with Linux generic 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. */ int of_get_named_gpio_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 = -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 gpios property\n", __func__); return ret; } gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); of_node_put(gg_data.gpiospec.np); pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio); return gg_data.out_gpio; } 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); #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; if (!np) return; for (;; index++) { ret = of_parse_phandle_with_args(np, "gpio-ranges", "#gpio-range-cells", index, &pinspec); if (ret) break; pctldev = of_pinctrl_get(pinspec.np); if (!pctldev) break; ret = gpiochip_add_pin_range(chip, pinctrl_dev_get_devname(pctldev), pinspec.args[0], pinspec.args[1], pinspec.args[2]); 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); if (chip->of_node) of_node_put(chip->of_node); }