linux/drivers/gpio/gpiolib-of.c
Linus Walleij a603a2b8d8 gpio: of: Add special quirk to parse regulator flags
While most GPIOs are indicated to be active low or open drain using
their twocell flags, we have legacy regulator bindings to take into
account.

Add a quirk respecting the special boolean active-high and open
drain flags when parsing regulator nodes for GPIOs.

This makes it possible to get rid of duplicated inversion semantics
handling in the regulator core and any regulator drivers parsing
and handling this separately.

Unfortunately the old regulator inversion semantics are specified
such that the presence or absence of "enable-active-high" solely
controls the semantics, so we cannot deprecate this in favor
of the phandle-provided inversion flag, instead any such phandle
inversion flag provided in the second cell of a GPIO handle must be
actively ignored, so we print a warning to contain the situation
and make things easy for the users.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-01-12 11:05:24 +01:00

622 lines
15 KiB
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"
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, 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, "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(np, propname, "#gpio-cells", 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;
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);
for (i = 0; i < ARRAY_SIZE(whitelist); i++)
if (!strcmp(con_id, whitelist[i]))
break;
if (i == ARRAY_SIZE(whitelist))
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);
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))
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);
#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) && (chip->parent))
chip->of_node = chip->parent->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;
}
if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
return -EINVAL;
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_node_get(chip->of_node);
return of_gpiochip_scan_gpios(chip);
}
void of_gpiochip_remove(struct gpio_chip *chip)
{
gpiochip_remove_pin_ranges(chip);
of_node_put(chip->of_node);
}