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-rw-r--r--drivers/gpio/gpiolib-of.c446
1 files changed, 446 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
new file mode 100644
index 000000000..a6c67c6b4
--- /dev/null
+++ b/drivers/gpio/gpiolib-of.c
@@ -0,0 +1,446 @@
+/*
+ * 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"
+
+/* 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_get_gpio_hog() - Get a GPIO hog descriptor, names and flags for GPIO API
+ * @np: device node to get GPIO from
+ * @name: GPIO line name
+ * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
+ * of_get_gpio_hog()
+ * @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_get_gpio_hog(struct device_node *np,
+ const char **name,
+ enum gpio_lookup_flags *lflags,
+ enum gpiod_flags *dflags)
+{
+ struct device_node *chip_np;
+ enum of_gpio_flags xlate_flags;
+ struct gpio_desc *desc;
+ struct gg_data gg_data = {
+ .flags = &xlate_flags,
+ };
+ u32 tmp;
+ int i, ret;
+
+ chip_np = np->parent;
+ 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);
+
+ if (tmp > MAX_PHANDLE_ARGS)
+ return ERR_PTR(-EINVAL);
+
+ gg_data.gpiospec.args_count = tmp;
+ gg_data.gpiospec.np = chip_np;
+ for (i = 0; i < tmp; i++) {
+ ret = of_property_read_u32_index(np, "gpios", i,
+ &gg_data.gpiospec.args[i]);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+
+ gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
+ if (!gg_data.out_gpio) {
+ if (np->parent == np)
+ return ERR_PTR(-ENXIO);
+ else
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (xlate_flags & OF_GPIO_ACTIVE_LOW)
+ *lflags |= GPIO_ACTIVE_LOW;
+
+ 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(gg_data.out_gpio), np->name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (name && of_property_read_string(np, "line-name", name))
+ *name = np->name;
+
+ desc = gg_data.out_gpio;
+
+ return desc;
+}
+
+/**
+ * of_gpiochip_scan_hogs - Scan gpio-controller and apply GPIO hog as requested
+ * @chip: gpio chip to act on
+ *
+ * This is only used by of_gpiochip_add to request/set GPIO initial
+ * configuration.
+ */
+static void of_gpiochip_scan_hogs(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;
+
+ for_each_child_of_node(chip->of_node, np) {
+ if (!of_property_read_bool(np, "gpio-hog"))
+ continue;
+
+ desc = of_get_gpio_hog(np, &name, &lflags, &dflags);
+ if (IS_ERR(desc))
+ continue;
+
+ if (gpiod_hog(desc, name, lflags, dflags))
+ continue;
+ }
+}
+
+/**
+ * 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);
+
+ of_gpiochip_scan_hogs(chip);
+}
+
+void of_gpiochip_remove(struct gpio_chip *chip)
+{
+ gpiochip_remove_pin_ranges(chip);
+ of_node_put(chip->of_node);
+}