diff options
Diffstat (limited to 'drivers/gpio/gpiolib-of.c')
| -rw-r--r-- | drivers/gpio/gpiolib-of.c | 662 |
1 files changed, 662 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c new file mode 100644 index 000000000..09999e3e3 --- /dev/null +++ b/drivers/gpio/gpiolib-of.c @@ -0,0 +1,662 @@ +/* + * 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 <linux/gpio/machine.h> + +#include "gpiolib.h" + +static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data) +{ + struct of_phandle_args *gpiospec = data; + + return chip->gpiodev->dev.of_node == gpiospec->np && + chip->of_xlate && + chip->of_xlate(chip, gpiospec, NULL) >= 0; +} + +static struct gpio_chip *of_find_gpiochip_by_xlate( + struct of_phandle_args *gpiospec) +{ + return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate); +} + +static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip, + struct of_phandle_args *gpiospec, + enum of_gpio_flags *flags) +{ + int ret; + + if (chip->of_gpio_n_cells != gpiospec->args_count) + return ERR_PTR(-EINVAL); + + ret = chip->of_xlate(chip, gpiospec, flags); + if (ret < 0) + return ERR_PTR(ret); + + return gpiochip_get_desc(chip, ret); +} + +static void of_gpio_flags_quirks(struct device_node *np, + enum of_gpio_flags *flags) +{ + /* + * Some GPIO fixed regulator quirks. + * Note that active low is the default. + */ + if (IS_ENABLED(CONFIG_REGULATOR) && + (of_device_is_compatible(np, "regulator-fixed") || + of_device_is_compatible(np, "reg-fixed-voltage") || + of_device_is_compatible(np, "regulator-gpio"))) { + /* + * The regulator GPIO handles are specified such that the + * presence or absence of "enable-active-high" solely controls + * the polarity of the GPIO line. Any phandle flags must + * be actively ignored. + */ + if (*flags & OF_GPIO_ACTIVE_LOW) { + pr_warn("%s GPIO handle specifies active low - ignored\n", + of_node_full_name(np)); + *flags &= ~OF_GPIO_ACTIVE_LOW; + } + if (!of_property_read_bool(np, "enable-active-high")) + *flags |= OF_GPIO_ACTIVE_LOW; + } + /* + * Legacy open drain handling for fixed voltage regulators. + */ + if (IS_ENABLED(CONFIG_REGULATOR) && + of_device_is_compatible(np, "reg-fixed-voltage") && + of_property_read_bool(np, "gpio-open-drain")) { + *flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN); + pr_info("%s uses legacy open drain flag - update the DTS if you can\n", + of_node_full_name(np)); + } +} + +/** + * 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) +{ + struct of_phandle_args gpiospec; + struct gpio_chip *chip; + struct gpio_desc *desc; + int ret; + + ret = of_parse_phandle_with_args_map(np, propname, "gpio", index, + &gpiospec); + if (ret) { + pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n", + __func__, propname, np, index); + return ERR_PTR(ret); + } + + chip = of_find_gpiochip_by_xlate(&gpiospec); + if (!chip) { + desc = ERR_PTR(-EPROBE_DEFER); + goto out; + } + + desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags); + if (IS_ERR(desc)) + goto out; + + if (flags) + of_gpio_flags_quirks(np, flags); + + pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n", + __func__, propname, np, index, + PTR_ERR_OR_ZERO(desc)); + +out: + of_node_put(gpiospec.np); + + return desc; +} + +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); + +/* + * The SPI GPIO bindings happened before we managed to establish that GPIO + * properties should be named "foo-gpios" so we have this special kludge for + * them. + */ +static struct gpio_desc *of_find_spi_gpio(struct device *dev, const char *con_id, + enum of_gpio_flags *of_flags) +{ + char prop_name[32]; /* 32 is max size of property name */ + struct device_node *np = dev->of_node; + struct gpio_desc *desc; + + /* + * Hopefully the compiler stubs the rest of the function if this + * is false. + */ + if (!IS_ENABLED(CONFIG_SPI_MASTER)) + return ERR_PTR(-ENOENT); + + /* Allow this specifically for "spi-gpio" devices */ + if (!of_device_is_compatible(np, "spi-gpio") || !con_id) + return ERR_PTR(-ENOENT); + + /* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */ + snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id); + + desc = of_get_named_gpiod_flags(np, prop_name, 0, of_flags); + return desc; +} + +/* + * Some regulator bindings happened before we managed to establish that GPIO + * properties should be named "foo-gpios" so we have this special kludge for + * them. + */ +static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *con_id, + enum of_gpio_flags *of_flags) +{ + /* These are the connection IDs we accept as legacy GPIO phandles */ + const char *whitelist[] = { + "wlf,ldoena", /* Arizona */ + "wlf,ldo1ena", /* WM8994 */ + "wlf,ldo2ena", /* WM8994 */ + }; + struct device_node *np = dev->of_node; + struct gpio_desc *desc; + int i; + + if (!IS_ENABLED(CONFIG_REGULATOR)) + return ERR_PTR(-ENOENT); + + if (!con_id) + return ERR_PTR(-ENOENT); + + i = match_string(whitelist, ARRAY_SIZE(whitelist), con_id); + if (i < 0) + return ERR_PTR(-ENOENT); + + desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags); + return desc; +} + +struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, + unsigned int idx, + enum gpio_lookup_flags *flags) +{ + char prop_name[32]; /* 32 is max size of property name */ + enum of_gpio_flags of_flags; + struct gpio_desc *desc; + unsigned int i; + + /* Try GPIO property "foo-gpios" and "foo-gpio" */ + for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) { + if (con_id) + snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id, + gpio_suffixes[i]); + else + snprintf(prop_name, sizeof(prop_name), "%s", + gpio_suffixes[i]); + + desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx, + &of_flags); + /* + * -EPROBE_DEFER in our case means that we found a + * valid GPIO property, but no controller has been + * registered so far. + * + * This means we don't need to look any further for + * alternate name conventions, and we should really + * preserve the return code for our user to be able to + * retry probing later. + */ + if (IS_ERR(desc) && PTR_ERR(desc) == -EPROBE_DEFER) + return desc; + + if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT)) + break; + } + + /* Special handling for SPI GPIOs if used */ + if (IS_ERR(desc)) + desc = of_find_spi_gpio(dev, con_id, &of_flags); + + /* Special handling for regulator GPIOs if used */ + if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER) + desc = of_find_regulator_gpio(dev, con_id, &of_flags); + + if (IS_ERR(desc)) + return desc; + + if (of_flags & OF_GPIO_ACTIVE_LOW) + *flags |= GPIO_ACTIVE_LOW; + + if (of_flags & OF_GPIO_SINGLE_ENDED) { + if (of_flags & OF_GPIO_OPEN_DRAIN) + *flags |= GPIO_OPEN_DRAIN; + else + *flags |= GPIO_OPEN_SOURCE; + } + + if (of_flags & OF_GPIO_TRANSITORY) + *flags |= GPIO_TRANSITORY; + + return desc; +} + +/** + * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API + * @np: device node to get GPIO from + * @chip: GPIO chip whose hog is parsed + * @idx: Index of the GPIO to parse + * @name: GPIO line name + * @lflags: gpio_lookup_flags - returned from of_find_gpio() or + * of_parse_own_gpio() + * @dflags: gpiod_flags - optional GPIO initialization flags + * + * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno + * value on the error condition. + */ +static struct gpio_desc *of_parse_own_gpio(struct device_node *np, + struct gpio_chip *chip, + unsigned int idx, const char **name, + enum gpio_lookup_flags *lflags, + enum gpiod_flags *dflags) +{ + struct device_node *chip_np; + enum of_gpio_flags xlate_flags; + struct of_phandle_args gpiospec; + struct gpio_desc *desc; + unsigned int i; + u32 tmp; + int ret; + + chip_np = chip->of_node; + if (!chip_np) + return ERR_PTR(-EINVAL); + + xlate_flags = 0; + *lflags = 0; + *dflags = 0; + + ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp); + if (ret) + return ERR_PTR(ret); + + gpiospec.np = chip_np; + gpiospec.args_count = tmp; + + for (i = 0; i < tmp; i++) { + ret = of_property_read_u32_index(np, "gpios", idx * tmp + i, + &gpiospec.args[i]); + if (ret) + return ERR_PTR(ret); + } + + desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags); + if (IS_ERR(desc)) + return desc; + + if (xlate_flags & OF_GPIO_ACTIVE_LOW) + *lflags |= GPIO_ACTIVE_LOW; + if (xlate_flags & OF_GPIO_TRANSITORY) + *lflags |= GPIO_TRANSITORY; + + if (of_property_read_bool(np, "input")) + *dflags |= GPIOD_IN; + else if (of_property_read_bool(np, "output-low")) + *dflags |= GPIOD_OUT_LOW; + else if (of_property_read_bool(np, "output-high")) + *dflags |= GPIOD_OUT_HIGH; + else { + pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n", + desc_to_gpio(desc), np->name); + return ERR_PTR(-EINVAL); + } + + if (name && of_property_read_string(np, "line-name", name)) + *name = np->name; + + return desc; +} + +/** + * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions + * @chip: gpio chip to act on + * + * This is only used by of_gpiochip_add to request/set GPIO initial + * configuration. + * It returns error if it fails otherwise 0 on success. + */ +static int of_gpiochip_scan_gpios(struct gpio_chip *chip) +{ + struct gpio_desc *desc = NULL; + struct device_node *np; + const char *name; + enum gpio_lookup_flags lflags; + enum gpiod_flags dflags; + unsigned int i; + int ret; + + for_each_available_child_of_node(chip->of_node, np) { + if (!of_property_read_bool(np, "gpio-hog")) + continue; + + for (i = 0;; i++) { + desc = of_parse_own_gpio(np, chip, i, &name, &lflags, + &dflags); + if (IS_ERR(desc)) + break; + + ret = gpiod_hog(desc, name, lflags, dflags); + if (ret < 0) { + of_node_put(np); + return ret; + } + } + } + + return 0; +} + +/** + * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags + * @gc: pointer to the gpio_chip structure + * @gpiospec: 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 retrieve 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_data - Add memory mapped GPIO chip (bank) + * @np: device node of the GPIO chip + * @mm_gc: pointer to the of_mm_gpio_chip allocated structure + * @data: driver data to store in the struct gpio_chip + * + * 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_data(struct device_node *np, + struct of_mm_gpio_chip *mm_gc, + void *data) +{ + int ret = -ENOMEM; + struct gpio_chip *gc = &mm_gc->gc; + + gc->label = kasprintf(GFP_KERNEL, "%pOF", np); + 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_data(gc, data); + if (ret) + goto err2; + + return 0; +err2: + iounmap(mm_gc->regs); +err1: + kfree(gc->label); +err0: + pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret); + return ret; +} +EXPORT_SYMBOL(of_mm_gpiochip_add_data); + +/** + * 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); + +static void of_gpiochip_init_valid_mask(struct gpio_chip *chip) +{ + int len, i; + u32 start, count; + struct device_node *np = chip->of_node; + + len = of_property_count_u32_elems(np, "gpio-reserved-ranges"); + if (len < 0 || len % 2 != 0) + return; + + for (i = 0; i < len; i += 2) { + of_property_read_u32_index(np, "gpio-reserved-ranges", + i, &start); + of_property_read_u32_index(np, "gpio-reserved-ranges", + i + 1, &count); + if (start >= chip->ngpio || start + count > chip->ngpio) + continue; + + bitmap_clear(chip->valid_mask, start, count); + } +}; + +#ifdef CONFIG_PINCTRL +static int 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 0; + + 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); + of_node_put(pinspec.np); + if (!pctldev) + return -EPROBE_DEFER; + + if (pinspec.args[2]) { + if (group_names) { + of_property_read_string_index(np, + group_names_propname, + index, &name); + if (strlen(name)) { + pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n", + np); + 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) + return ret; + } else { + /* npins == 0: special range */ + if (pinspec.args[1]) { + pr_err("%pOF: Illegal gpio-range format.\n", + np); + break; + } + + if (!group_names) { + pr_err("%pOF: GPIO group range requested but no %s property.\n", + np, group_names_propname); + break; + } + + ret = of_property_read_string_index(np, + group_names_propname, + index, &name); + if (ret) + break; + + if (!strlen(name)) { + pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n", + np); + break; + } + + ret = gpiochip_add_pingroup_range(chip, pctldev, + pinspec.args[0], name); + if (ret) + return ret; + } + } + + return 0; +} + +#else +static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; } +#endif + +int of_gpiochip_add(struct gpio_chip *chip) +{ + int status; + + if (!chip->of_node) + return 0; + + if (!chip->of_xlate) { + chip->of_gpio_n_cells = 2; + chip->of_xlate = of_gpio_simple_xlate; + } + + if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS) + return -EINVAL; + + of_gpiochip_init_valid_mask(chip); + + status = of_gpiochip_add_pin_range(chip); + if (status) + return status; + + /* If the chip defines names itself, these take precedence */ + if (!chip->names) + devprop_gpiochip_set_names(chip, + of_fwnode_handle(chip->of_node)); + + of_node_get(chip->of_node); + + status = of_gpiochip_scan_gpios(chip); + if (status) { + of_node_put(chip->of_node); + gpiochip_remove_pin_ranges(chip); + } + + return status; +} + +void of_gpiochip_remove(struct gpio_chip *chip) +{ + gpiochip_remove_pin_ranges(chip); + of_node_put(chip->of_node); +} |