https://github.com/torvalds/linux
Tip revision: 8005c49d9aea74d382f474ce11afbbc7d7130bec authored by Linus Torvalds on 16 November 2015, 01:00:27 UTC
Linux 4.4-rc1
Linux 4.4-rc1
Tip revision: 8005c49
gpiolib-of.c
/*
* 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_parse_own_gpio() - 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_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,
const char **name,
enum gpio_lookup_flags *lflags,
enum gpiod_flags *dflags)
{
struct device_node *chip_np;
enum of_gpio_flags xlate_flags;
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;
return gg_data.out_gpio;
}
/**
* 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.
*/
static void 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;
for_each_child_of_node(chip->of_node, np) {
if (!of_property_read_bool(np, "gpio-hog"))
continue;
desc = of_parse_own_gpio(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 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 - 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 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);
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("%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)
return ret;
} 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)
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) && (chip->dev))
chip->of_node = chip->dev->of_node;
if (!chip->of_node)
return 0;
if (!chip->of_xlate) {
chip->of_gpio_n_cells = 2;
chip->of_xlate = of_gpio_simple_xlate;
}
status = of_gpiochip_add_pin_range(chip);
if (status)
return status;
of_node_get(chip->of_node);
of_gpiochip_scan_gpios(chip);
return 0;
}
void of_gpiochip_remove(struct gpio_chip *chip)
{
gpiochip_remove_pin_ranges(chip);
of_node_put(chip->of_node);
}