linux/drivers/gpio/gpiolib-of.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* OF helpers for the GPIO API
*
* Copyright (c) 2007-2008 MontaVista Software, Inc.
*
* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
*/
#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 &&
gpio: Fix crash due to registration race gpiochip_add_data_with_key() adds the gpiochip to the gpio_devices list before of_gpiochip_add() is called, but it's only the latter which sets the ->of_xlate function pointer. gpiochip_find() can be called by someone else between these two actions, and it can find the chip and call of_gpiochip_match_node_and_xlate() which leads to the following crash due to a NULL ->of_xlate(). Unhandled prefetch abort: page domain fault (0x01b) at 0x00000000 Modules linked in: leds_gpio(+) gpio_generic(+) CPU: 0 PID: 830 Comm: insmod Not tainted 4.18.0+ #43 Hardware name: ARM-Versatile Express PC is at (null) LR is at of_gpiochip_match_node_and_xlate+0x2c/0x38 Process insmod (pid: 830, stack limit = 0x(ptrval)) (of_gpiochip_match_node_and_xlate) from (gpiochip_find+0x48/0x84) (gpiochip_find) from (of_get_named_gpiod_flags+0xa8/0x238) (of_get_named_gpiod_flags) from (gpiod_get_from_of_node+0x2c/0xc8) (gpiod_get_from_of_node) from (devm_fwnode_get_index_gpiod_from_child+0xb8/0x144) (devm_fwnode_get_index_gpiod_from_child) from (gpio_led_probe+0x208/0x3c4 [leds_gpio]) (gpio_led_probe [leds_gpio]) from (platform_drv_probe+0x48/0x9c) (platform_drv_probe) from (really_probe+0x1d0/0x3d4) (really_probe) from (driver_probe_device+0x78/0x1c0) (driver_probe_device) from (__driver_attach+0x120/0x13c) (__driver_attach) from (bus_for_each_dev+0x68/0xb4) (bus_for_each_dev) from (bus_add_driver+0x1a8/0x268) (bus_add_driver) from (driver_register+0x78/0x10c) (driver_register) from (do_one_initcall+0x54/0x1fc) (do_one_initcall) from (do_init_module+0x64/0x1f4) (do_init_module) from (load_module+0x2198/0x26ac) (load_module) from (sys_finit_module+0xe0/0x110) (sys_finit_module) from (ret_fast_syscall+0x0/0x54) One way to fix this would be to rework the hairy registration sequence in gpiochip_add_data_with_key(), but since I'd probably introduce a couple of new bugs if I attempted that, simply add a check for a non-NULL of_xlate function pointer in of_gpiochip_match_node_and_xlate(). This works since the driver looking for the gpio will simply fail to find the gpio and defer its probe and be reprobed when the driver which is registering the gpiochip has fully completed its probe. Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-08-31 07:04:18 +00:00
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,
const char *propname,
enum of_gpio_flags *flags,
int index)
{
gpio: OF: Parse MMC-specific CD and WP properties When retrieveing CD (card detect) and WP (write protect) GPIO handles from the device tree, make sure to assign them active low by default unless the "cd-inverted" or "wp-inverted" properties are set. These properties mean that respective signal is active HIGH since the SDHCI specification stipulates that this kind of signals should be treated as active LOW. If the twocell GPIO flag is also specified as active low, well that's nice and we will silently ignore the tautological specification. If however the GPIO line is specified as active low in the GPIO flasg cell and "cd-inverted" or "wp-inverted" is also specified, the latter takes precedence and we print a warning. The current effect on the MMC slot-gpio core are as follows: For CD GPIOs: no effect. The current code in mmc/core/host.c calls mmc_gpiod_request_cd() with the "override_active_level" argument set to true, which means that whatever the GPIO descriptor thinks about active low/high will be ignored, the core will use the MMC_CAP2_CD_ACTIVE_HIGH to keep track of this and reads the raw value from the GPIO descriptor, totally bypassing gpiolibs inversion semantics. I plan to clean this up at a later point passing the handling of inversion semantics over to gpiolib, so this patch prepares the ground for that. Fow WP GPIOs: this is probably fixing a bug, because the code in mmc/core/host.c calls mmc_gpiod_request_ro() with the "override_active_level" argument set to false, which means it will respect the inversion semantics of the gpiolib and ignore the MMC_CAP2_RO_ACTIVE_HIGH flag for everyone using this through device tree. However the code in host.c confusingly goes to great lengths setting up the MMC_CAP2_RO_ACTIVE_HIGH flag from the GPIO descriptor and by reading the "wp-inverted" property of the node. As far as I can tell this is all in vain and the inversion is broken: device trees that use "wp-inverted" do not work as intended, instead the only way to actually get inversion on a line is by setting the second cell flag to GPIO_ACTIVE_HIGH (which will be the default) or GPIO_ACTIVE_LOW if they want the proper MMC semantics. Presumably all device trees do this right but we need to parse and handle this properly. Cc: linux-mmc@vger.kernel.org Cc: linux-gpio@vger.kernel.org Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-11-26 13:51:23 +00:00
/*
* Handle MMC "cd-inverted" and "wp-inverted" semantics.
*/
if (IS_ENABLED(CONFIG_MMC)) {
/*
* Active low is the default according to the
* SDHCI specification and the device tree
* bindings. However the code in the current
* kernel was written such that the phandle
* flags were always respected, and "cd-inverted"
* would invert the flag from the device phandle.
*/
if (!strcmp(propname, "cd-gpios")) {
if (of_property_read_bool(np, "cd-inverted"))
*flags ^= OF_GPIO_ACTIVE_LOW;
gpio: OF: Parse MMC-specific CD and WP properties When retrieveing CD (card detect) and WP (write protect) GPIO handles from the device tree, make sure to assign them active low by default unless the "cd-inverted" or "wp-inverted" properties are set. These properties mean that respective signal is active HIGH since the SDHCI specification stipulates that this kind of signals should be treated as active LOW. If the twocell GPIO flag is also specified as active low, well that's nice and we will silently ignore the tautological specification. If however the GPIO line is specified as active low in the GPIO flasg cell and "cd-inverted" or "wp-inverted" is also specified, the latter takes precedence and we print a warning. The current effect on the MMC slot-gpio core are as follows: For CD GPIOs: no effect. The current code in mmc/core/host.c calls mmc_gpiod_request_cd() with the "override_active_level" argument set to true, which means that whatever the GPIO descriptor thinks about active low/high will be ignored, the core will use the MMC_CAP2_CD_ACTIVE_HIGH to keep track of this and reads the raw value from the GPIO descriptor, totally bypassing gpiolibs inversion semantics. I plan to clean this up at a later point passing the handling of inversion semantics over to gpiolib, so this patch prepares the ground for that. Fow WP GPIOs: this is probably fixing a bug, because the code in mmc/core/host.c calls mmc_gpiod_request_ro() with the "override_active_level" argument set to false, which means it will respect the inversion semantics of the gpiolib and ignore the MMC_CAP2_RO_ACTIVE_HIGH flag for everyone using this through device tree. However the code in host.c confusingly goes to great lengths setting up the MMC_CAP2_RO_ACTIVE_HIGH flag from the GPIO descriptor and by reading the "wp-inverted" property of the node. As far as I can tell this is all in vain and the inversion is broken: device trees that use "wp-inverted" do not work as intended, instead the only way to actually get inversion on a line is by setting the second cell flag to GPIO_ACTIVE_HIGH (which will be the default) or GPIO_ACTIVE_LOW if they want the proper MMC semantics. Presumably all device trees do this right but we need to parse and handle this properly. Cc: linux-mmc@vger.kernel.org Cc: linux-gpio@vger.kernel.org Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-11-26 13:51:23 +00:00
}
if (!strcmp(propname, "wp-gpios")) {
if (of_property_read_bool(np, "wp-inverted"))
*flags ^= OF_GPIO_ACTIVE_LOW;
gpio: OF: Parse MMC-specific CD and WP properties When retrieveing CD (card detect) and WP (write protect) GPIO handles from the device tree, make sure to assign them active low by default unless the "cd-inverted" or "wp-inverted" properties are set. These properties mean that respective signal is active HIGH since the SDHCI specification stipulates that this kind of signals should be treated as active LOW. If the twocell GPIO flag is also specified as active low, well that's nice and we will silently ignore the tautological specification. If however the GPIO line is specified as active low in the GPIO flasg cell and "cd-inverted" or "wp-inverted" is also specified, the latter takes precedence and we print a warning. The current effect on the MMC slot-gpio core are as follows: For CD GPIOs: no effect. The current code in mmc/core/host.c calls mmc_gpiod_request_cd() with the "override_active_level" argument set to true, which means that whatever the GPIO descriptor thinks about active low/high will be ignored, the core will use the MMC_CAP2_CD_ACTIVE_HIGH to keep track of this and reads the raw value from the GPIO descriptor, totally bypassing gpiolibs inversion semantics. I plan to clean this up at a later point passing the handling of inversion semantics over to gpiolib, so this patch prepares the ground for that. Fow WP GPIOs: this is probably fixing a bug, because the code in mmc/core/host.c calls mmc_gpiod_request_ro() with the "override_active_level" argument set to false, which means it will respect the inversion semantics of the gpiolib and ignore the MMC_CAP2_RO_ACTIVE_HIGH flag for everyone using this through device tree. However the code in host.c confusingly goes to great lengths setting up the MMC_CAP2_RO_ACTIVE_HIGH flag from the GPIO descriptor and by reading the "wp-inverted" property of the node. As far as I can tell this is all in vain and the inversion is broken: device trees that use "wp-inverted" do not work as intended, instead the only way to actually get inversion on a line is by setting the second cell flag to GPIO_ACTIVE_HIGH (which will be the default) or GPIO_ACTIVE_LOW if they want the proper MMC semantics. Presumably all device trees do this right but we need to parse and handle this properly. Cc: linux-mmc@vger.kernel.org Cc: linux-gpio@vger.kernel.org Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-11-26 13:51:23 +00:00
}
}
/*
* 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));
}
/*
* Legacy handling of SPI active high chip select. If we have a
* property named "cs-gpios" we need to inspect the child node
* to determine if the flags should have inverted semantics.
*/
if (IS_ENABLED(CONFIG_SPI_MASTER) &&
of_property_read_bool(np, "cs-gpios")) {
struct device_node *child;
u32 cs;
int ret;
for_each_child_of_node(np, child) {
ret = of_property_read_u32(child, "reg", &cs);
if (ret)
continue;
if (cs == index) {
/*
* SPI children have active low chip selects
* by default. This can be specified negatively
* by just omitting "spi-cs-high" in the
* device node, or actively by tagging on
* GPIO_ACTIVE_LOW as flag in the device
* tree. If the line is simultaneously
* tagged as active low in the device tree
* and has the "spi-cs-high" set, we get a
* conflict and the "spi-cs-high" flag will
* take precedence.
*/
if (of_property_read_bool(np, "spi-cs-high")) {
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;
}
} else {
if (!(*flags & OF_GPIO_ACTIVE_LOW))
pr_info("%s enforce active low on chipselect handle\n",
of_node_full_name(np));
*flags |= OF_GPIO_ACTIVE_LOW;
}
break;
}
}
}
}
/**
* 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, propname, flags, index);
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 (%pOFn): no hogging state specified, bailing out\n",
desc_to_gpio(desc), np);
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
2010-06-08 13:48:16 +00:00
* @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).
*/
2010-06-08 13:48:16 +00:00
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
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* - 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;
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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);
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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;
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/* If the chip defines names itself, these take precedence */
if (!chip->names)
devprop_gpiochip_set_names(chip,
of_fwnode_handle(chip->of_node));
2016-04-19 13:26:26 +00:00
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);
}