linux/drivers/reset/core.c
Krzysztof Kozlowski c721f189e8 reset: Instantiate reset GPIO controller for shared reset-gpios
Devices sharing a reset GPIO could use the reset framework for
coordinated handling of that shared GPIO line.  We have several cases of
such needs, at least for Devicetree-based platforms.

If Devicetree-based device requests a reset line, while "resets"
Devicetree property is missing but there is a "reset-gpios" one,
instantiate a new "reset-gpio" platform device which will handle such
reset line.  This allows seamless handling of such shared reset-gpios
without need of changing Devicetree binding [1].

To avoid creating multiple "reset-gpio" platform devices, store the
Devicetree "reset-gpios" GPIO specifiers used for new devices on a
linked list.  Later such Devicetree GPIO specifier (phandle to GPIO
controller, GPIO number and GPIO flags) is used to check if reset
controller for given GPIO was already registered.

If two devices have conflicting "reset-gpios" property, e.g. with
different ACTIVE_xxx flags, this would allow to spawn two separate
"reset-gpio" devices, where the second would fail probing on busy GPIO
request.

Link: https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/ [1]
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Sean Anderson <sean.anderson@seco.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240129115216.96479-5-krzysztof.kozlowski@linaro.org
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2024-02-21 11:53:25 +01:00

1488 lines
37 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Reset Controller framework
*
* Copyright 2013 Philipp Zabel, Pengutronix
*/
#include <linux/atomic.h>
#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/machine.h>
#include <linux/idr.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
static DEFINE_MUTEX(reset_list_mutex);
static LIST_HEAD(reset_controller_list);
static DEFINE_MUTEX(reset_lookup_mutex);
static LIST_HEAD(reset_lookup_list);
/* Protects reset_gpio_lookup_list */
static DEFINE_MUTEX(reset_gpio_lookup_mutex);
static LIST_HEAD(reset_gpio_lookup_list);
static DEFINE_IDA(reset_gpio_ida);
/**
* struct reset_control - a reset control
* @rcdev: a pointer to the reset controller device
* this reset control belongs to
* @list: list entry for the rcdev's reset controller list
* @id: ID of the reset controller in the reset
* controller device
* @refcnt: Number of gets of this reset_control
* @acquired: Only one reset_control may be acquired for a given rcdev and id.
* @shared: Is this a shared (1), or an exclusive (0) reset_control?
* @array: Is this an array of reset controls (1)?
* @deassert_count: Number of times this reset line has been deasserted
* @triggered_count: Number of times this reset line has been reset. Currently
* only used for shared resets, which means that the value
* will be either 0 or 1.
*/
struct reset_control {
struct reset_controller_dev *rcdev;
struct list_head list;
unsigned int id;
struct kref refcnt;
bool acquired;
bool shared;
bool array;
atomic_t deassert_count;
atomic_t triggered_count;
};
/**
* struct reset_control_array - an array of reset controls
* @base: reset control for compatibility with reset control API functions
* @num_rstcs: number of reset controls
* @rstc: array of reset controls
*/
struct reset_control_array {
struct reset_control base;
unsigned int num_rstcs;
struct reset_control *rstc[] __counted_by(num_rstcs);
};
/**
* struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices
* @of_args: phandle to the reset controller with all the args like GPIO number
* @list: list entry for the reset_gpio_lookup_list
*/
struct reset_gpio_lookup {
struct of_phandle_args of_args;
struct list_head list;
};
static const char *rcdev_name(struct reset_controller_dev *rcdev)
{
if (rcdev->dev)
return dev_name(rcdev->dev);
if (rcdev->of_node)
return rcdev->of_node->full_name;
if (rcdev->of_args)
return rcdev->of_args->np->full_name;
return NULL;
}
/**
* of_reset_simple_xlate - translate reset_spec to the reset line number
* @rcdev: a pointer to the reset controller device
* @reset_spec: reset line specifier as found in the device tree
*
* This static translation function is used by default if of_xlate in
* :c:type:`reset_controller_dev` is not set. It is useful for all reset
* controllers with 1:1 mapping, where reset lines can be indexed by number
* without gaps.
*/
static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
const struct of_phandle_args *reset_spec)
{
if (reset_spec->args[0] >= rcdev->nr_resets)
return -EINVAL;
return reset_spec->args[0];
}
/**
* reset_controller_register - register a reset controller device
* @rcdev: a pointer to the initialized reset controller device
*/
int reset_controller_register(struct reset_controller_dev *rcdev)
{
if (rcdev->of_node && rcdev->of_args)
return -EINVAL;
if (!rcdev->of_xlate) {
rcdev->of_reset_n_cells = 1;
rcdev->of_xlate = of_reset_simple_xlate;
}
INIT_LIST_HEAD(&rcdev->reset_control_head);
mutex_lock(&reset_list_mutex);
list_add(&rcdev->list, &reset_controller_list);
mutex_unlock(&reset_list_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(reset_controller_register);
/**
* reset_controller_unregister - unregister a reset controller device
* @rcdev: a pointer to the reset controller device
*/
void reset_controller_unregister(struct reset_controller_dev *rcdev)
{
mutex_lock(&reset_list_mutex);
list_del(&rcdev->list);
mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_controller_unregister);
static void devm_reset_controller_release(struct device *dev, void *res)
{
reset_controller_unregister(*(struct reset_controller_dev **)res);
}
/**
* devm_reset_controller_register - resource managed reset_controller_register()
* @dev: device that is registering this reset controller
* @rcdev: a pointer to the initialized reset controller device
*
* Managed reset_controller_register(). For reset controllers registered by
* this function, reset_controller_unregister() is automatically called on
* driver detach. See reset_controller_register() for more information.
*/
int devm_reset_controller_register(struct device *dev,
struct reset_controller_dev *rcdev)
{
struct reset_controller_dev **rcdevp;
int ret;
rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
GFP_KERNEL);
if (!rcdevp)
return -ENOMEM;
ret = reset_controller_register(rcdev);
if (ret) {
devres_free(rcdevp);
return ret;
}
*rcdevp = rcdev;
devres_add(dev, rcdevp);
return ret;
}
EXPORT_SYMBOL_GPL(devm_reset_controller_register);
/**
* reset_controller_add_lookup - register a set of lookup entries
* @lookup: array of reset lookup entries
* @num_entries: number of entries in the lookup array
*/
void reset_controller_add_lookup(struct reset_control_lookup *lookup,
unsigned int num_entries)
{
struct reset_control_lookup *entry;
unsigned int i;
mutex_lock(&reset_lookup_mutex);
for (i = 0; i < num_entries; i++) {
entry = &lookup[i];
if (!entry->dev_id || !entry->provider) {
pr_warn("%s(): reset lookup entry badly specified, skipping\n",
__func__);
continue;
}
list_add_tail(&entry->list, &reset_lookup_list);
}
mutex_unlock(&reset_lookup_mutex);
}
EXPORT_SYMBOL_GPL(reset_controller_add_lookup);
static inline struct reset_control_array *
rstc_to_array(struct reset_control *rstc) {
return container_of(rstc, struct reset_control_array, base);
}
static int reset_control_array_reset(struct reset_control_array *resets)
{
int ret, i;
for (i = 0; i < resets->num_rstcs; i++) {
ret = reset_control_reset(resets->rstc[i]);
if (ret)
return ret;
}
return 0;
}
static int reset_control_array_rearm(struct reset_control_array *resets)
{
struct reset_control *rstc;
int i;
for (i = 0; i < resets->num_rstcs; i++) {
rstc = resets->rstc[i];
if (!rstc)
continue;
if (WARN_ON(IS_ERR(rstc)))
return -EINVAL;
if (rstc->shared) {
if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
return -EINVAL;
} else {
if (!rstc->acquired)
return -EPERM;
}
}
for (i = 0; i < resets->num_rstcs; i++) {
rstc = resets->rstc[i];
if (rstc && rstc->shared)
WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
}
return 0;
}
static int reset_control_array_assert(struct reset_control_array *resets)
{
int ret, i;
for (i = 0; i < resets->num_rstcs; i++) {
ret = reset_control_assert(resets->rstc[i]);
if (ret)
goto err;
}
return 0;
err:
while (i--)
reset_control_deassert(resets->rstc[i]);
return ret;
}
static int reset_control_array_deassert(struct reset_control_array *resets)
{
int ret, i;
for (i = 0; i < resets->num_rstcs; i++) {
ret = reset_control_deassert(resets->rstc[i]);
if (ret)
goto err;
}
return 0;
err:
while (i--)
reset_control_assert(resets->rstc[i]);
return ret;
}
static int reset_control_array_acquire(struct reset_control_array *resets)
{
unsigned int i;
int err;
for (i = 0; i < resets->num_rstcs; i++) {
err = reset_control_acquire(resets->rstc[i]);
if (err < 0)
goto release;
}
return 0;
release:
while (i--)
reset_control_release(resets->rstc[i]);
return err;
}
static void reset_control_array_release(struct reset_control_array *resets)
{
unsigned int i;
for (i = 0; i < resets->num_rstcs; i++)
reset_control_release(resets->rstc[i]);
}
static inline bool reset_control_is_array(struct reset_control *rstc)
{
return rstc->array;
}
/**
* reset_control_reset - reset the controlled device
* @rstc: reset controller
*
* On a shared reset line the actual reset pulse is only triggered once for the
* lifetime of the reset_control instance: for all but the first caller this is
* a no-op.
* Consumers must not use reset_control_(de)assert on shared reset lines when
* reset_control_reset has been used.
*
* If rstc is NULL it is an optional reset and the function will just
* return 0.
*/
int reset_control_reset(struct reset_control *rstc)
{
int ret;
if (!rstc)
return 0;
if (WARN_ON(IS_ERR(rstc)))
return -EINVAL;
if (reset_control_is_array(rstc))
return reset_control_array_reset(rstc_to_array(rstc));
if (!rstc->rcdev->ops->reset)
return -ENOTSUPP;
if (rstc->shared) {
if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
return -EINVAL;
if (atomic_inc_return(&rstc->triggered_count) != 1)
return 0;
} else {
if (!rstc->acquired)
return -EPERM;
}
ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
if (rstc->shared && ret)
atomic_dec(&rstc->triggered_count);
return ret;
}
EXPORT_SYMBOL_GPL(reset_control_reset);
/**
* reset_control_bulk_reset - reset the controlled devices in order
* @num_rstcs: number of entries in rstcs array
* @rstcs: array of struct reset_control_bulk_data with reset controls set
*
* Issue a reset on all provided reset controls, in order.
*
* See also: reset_control_reset()
*/
int reset_control_bulk_reset(int num_rstcs,
struct reset_control_bulk_data *rstcs)
{
int ret, i;
for (i = 0; i < num_rstcs; i++) {
ret = reset_control_reset(rstcs[i].rstc);
if (ret)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(reset_control_bulk_reset);
/**
* reset_control_rearm - allow shared reset line to be re-triggered"
* @rstc: reset controller
*
* On a shared reset line the actual reset pulse is only triggered once for the
* lifetime of the reset_control instance, except if this call is used.
*
* Calls to this function must be balanced with calls to reset_control_reset,
* a warning is thrown in case triggered_count ever dips below 0.
*
* Consumers must not use reset_control_(de)assert on shared reset lines when
* reset_control_reset or reset_control_rearm have been used.
*
* If rstc is NULL the function will just return 0.
*/
int reset_control_rearm(struct reset_control *rstc)
{
if (!rstc)
return 0;
if (WARN_ON(IS_ERR(rstc)))
return -EINVAL;
if (reset_control_is_array(rstc))
return reset_control_array_rearm(rstc_to_array(rstc));
if (rstc->shared) {
if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
return -EINVAL;
WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
} else {
if (!rstc->acquired)
return -EPERM;
}
return 0;
}
EXPORT_SYMBOL_GPL(reset_control_rearm);
/**
* reset_control_assert - asserts the reset line
* @rstc: reset controller
*
* Calling this on an exclusive reset controller guarantees that the reset
* will be asserted. When called on a shared reset controller the line may
* still be deasserted, as long as other users keep it so.
*
* For shared reset controls a driver cannot expect the hw's registers and
* internal state to be reset, but must be prepared for this to happen.
* Consumers must not use reset_control_reset on shared reset lines when
* reset_control_(de)assert has been used.
*
* If rstc is NULL it is an optional reset and the function will just
* return 0.
*/
int reset_control_assert(struct reset_control *rstc)
{
if (!rstc)
return 0;
if (WARN_ON(IS_ERR(rstc)))
return -EINVAL;
if (reset_control_is_array(rstc))
return reset_control_array_assert(rstc_to_array(rstc));
if (rstc->shared) {
if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
return -EINVAL;
if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
return -EINVAL;
if (atomic_dec_return(&rstc->deassert_count) != 0)
return 0;
/*
* Shared reset controls allow the reset line to be in any state
* after this call, so doing nothing is a valid option.
*/
if (!rstc->rcdev->ops->assert)
return 0;
} else {
/*
* If the reset controller does not implement .assert(), there
* is no way to guarantee that the reset line is asserted after
* this call.
*/
if (!rstc->rcdev->ops->assert)
return -ENOTSUPP;
if (!rstc->acquired) {
WARN(1, "reset %s (ID: %u) is not acquired\n",
rcdev_name(rstc->rcdev), rstc->id);
return -EPERM;
}
}
return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_assert);
/**
* reset_control_bulk_assert - asserts the reset lines in order
* @num_rstcs: number of entries in rstcs array
* @rstcs: array of struct reset_control_bulk_data with reset controls set
*
* Assert the reset lines for all provided reset controls, in order.
* If an assertion fails, already asserted resets are deasserted again.
*
* See also: reset_control_assert()
*/
int reset_control_bulk_assert(int num_rstcs,
struct reset_control_bulk_data *rstcs)
{
int ret, i;
for (i = 0; i < num_rstcs; i++) {
ret = reset_control_assert(rstcs[i].rstc);
if (ret)
goto err;
}
return 0;
err:
while (i--)
reset_control_deassert(rstcs[i].rstc);
return ret;
}
EXPORT_SYMBOL_GPL(reset_control_bulk_assert);
/**
* reset_control_deassert - deasserts the reset line
* @rstc: reset controller
*
* After calling this function, the reset is guaranteed to be deasserted.
* Consumers must not use reset_control_reset on shared reset lines when
* reset_control_(de)assert has been used.
*
* If rstc is NULL it is an optional reset and the function will just
* return 0.
*/
int reset_control_deassert(struct reset_control *rstc)
{
if (!rstc)
return 0;
if (WARN_ON(IS_ERR(rstc)))
return -EINVAL;
if (reset_control_is_array(rstc))
return reset_control_array_deassert(rstc_to_array(rstc));
if (rstc->shared) {
if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
return -EINVAL;
if (atomic_inc_return(&rstc->deassert_count) != 1)
return 0;
} else {
if (!rstc->acquired) {
WARN(1, "reset %s (ID: %u) is not acquired\n",
rcdev_name(rstc->rcdev), rstc->id);
return -EPERM;
}
}
/*
* If the reset controller does not implement .deassert(), we assume
* that it handles self-deasserting reset lines via .reset(). In that
* case, the reset lines are deasserted by default. If that is not the
* case, the reset controller driver should implement .deassert() and
* return -ENOTSUPP.
*/
if (!rstc->rcdev->ops->deassert)
return 0;
return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_deassert);
/**
* reset_control_bulk_deassert - deasserts the reset lines in reverse order
* @num_rstcs: number of entries in rstcs array
* @rstcs: array of struct reset_control_bulk_data with reset controls set
*
* Deassert the reset lines for all provided reset controls, in reverse order.
* If a deassertion fails, already deasserted resets are asserted again.
*
* See also: reset_control_deassert()
*/
int reset_control_bulk_deassert(int num_rstcs,
struct reset_control_bulk_data *rstcs)
{
int ret, i;
for (i = num_rstcs - 1; i >= 0; i--) {
ret = reset_control_deassert(rstcs[i].rstc);
if (ret)
goto err;
}
return 0;
err:
while (i < num_rstcs)
reset_control_assert(rstcs[i++].rstc);
return ret;
}
EXPORT_SYMBOL_GPL(reset_control_bulk_deassert);
/**
* reset_control_status - returns a negative errno if not supported, a
* positive value if the reset line is asserted, or zero if the reset
* line is not asserted or if the desc is NULL (optional reset).
* @rstc: reset controller
*/
int reset_control_status(struct reset_control *rstc)
{
if (!rstc)
return 0;
if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc))
return -EINVAL;
if (rstc->rcdev->ops->status)
return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(reset_control_status);
/**
* reset_control_acquire() - acquires a reset control for exclusive use
* @rstc: reset control
*
* This is used to explicitly acquire a reset control for exclusive use. Note
* that exclusive resets are requested as acquired by default. In order for a
* second consumer to be able to control the reset, the first consumer has to
* release it first. Typically the easiest way to achieve this is to call the
* reset_control_get_exclusive_released() to obtain an instance of the reset
* control. Such reset controls are not acquired by default.
*
* Consumers implementing shared access to an exclusive reset need to follow
* a specific protocol in order to work together. Before consumers can change
* a reset they must acquire exclusive access using reset_control_acquire().
* After they are done operating the reset, they must release exclusive access
* with a call to reset_control_release(). Consumers are not granted exclusive
* access to the reset as long as another consumer hasn't released a reset.
*
* See also: reset_control_release()
*/
int reset_control_acquire(struct reset_control *rstc)
{
struct reset_control *rc;
if (!rstc)
return 0;
if (WARN_ON(IS_ERR(rstc)))
return -EINVAL;
if (reset_control_is_array(rstc))
return reset_control_array_acquire(rstc_to_array(rstc));
mutex_lock(&reset_list_mutex);
if (rstc->acquired) {
mutex_unlock(&reset_list_mutex);
return 0;
}
list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) {
if (rstc != rc && rstc->id == rc->id) {
if (rc->acquired) {
mutex_unlock(&reset_list_mutex);
return -EBUSY;
}
}
}
rstc->acquired = true;
mutex_unlock(&reset_list_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(reset_control_acquire);
/**
* reset_control_bulk_acquire - acquires reset controls for exclusive use
* @num_rstcs: number of entries in rstcs array
* @rstcs: array of struct reset_control_bulk_data with reset controls set
*
* This is used to explicitly acquire reset controls requested with
* reset_control_bulk_get_exclusive_release() for temporary exclusive use.
*
* See also: reset_control_acquire(), reset_control_bulk_release()
*/
int reset_control_bulk_acquire(int num_rstcs,
struct reset_control_bulk_data *rstcs)
{
int ret, i;
for (i = 0; i < num_rstcs; i++) {
ret = reset_control_acquire(rstcs[i].rstc);
if (ret)
goto err;
}
return 0;
err:
while (i--)
reset_control_release(rstcs[i].rstc);
return ret;
}
EXPORT_SYMBOL_GPL(reset_control_bulk_acquire);
/**
* reset_control_release() - releases exclusive access to a reset control
* @rstc: reset control
*
* Releases exclusive access right to a reset control previously obtained by a
* call to reset_control_acquire(). Until a consumer calls this function, no
* other consumers will be granted exclusive access.
*
* See also: reset_control_acquire()
*/
void reset_control_release(struct reset_control *rstc)
{
if (!rstc || WARN_ON(IS_ERR(rstc)))
return;
if (reset_control_is_array(rstc))
reset_control_array_release(rstc_to_array(rstc));
else
rstc->acquired = false;
}
EXPORT_SYMBOL_GPL(reset_control_release);
/**
* reset_control_bulk_release() - releases exclusive access to reset controls
* @num_rstcs: number of entries in rstcs array
* @rstcs: array of struct reset_control_bulk_data with reset controls set
*
* Releases exclusive access right to reset controls previously obtained by a
* call to reset_control_bulk_acquire().
*
* See also: reset_control_release(), reset_control_bulk_acquire()
*/
void reset_control_bulk_release(int num_rstcs,
struct reset_control_bulk_data *rstcs)
{
int i;
for (i = 0; i < num_rstcs; i++)
reset_control_release(rstcs[i].rstc);
}
EXPORT_SYMBOL_GPL(reset_control_bulk_release);
static struct reset_control *
__reset_control_get_internal(struct reset_controller_dev *rcdev,
unsigned int index, bool shared, bool acquired)
{
struct reset_control *rstc;
lockdep_assert_held(&reset_list_mutex);
list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
if (rstc->id == index) {
/*
* Allow creating a secondary exclusive reset_control
* that is initially not acquired for an already
* controlled reset line.
*/
if (!rstc->shared && !shared && !acquired)
break;
if (WARN_ON(!rstc->shared || !shared))
return ERR_PTR(-EBUSY);
kref_get(&rstc->refcnt);
return rstc;
}
}
rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
if (!rstc)
return ERR_PTR(-ENOMEM);
if (!try_module_get(rcdev->owner)) {
kfree(rstc);
return ERR_PTR(-ENODEV);
}
rstc->rcdev = rcdev;
list_add(&rstc->list, &rcdev->reset_control_head);
rstc->id = index;
kref_init(&rstc->refcnt);
rstc->acquired = acquired;
rstc->shared = shared;
return rstc;
}
static void __reset_control_release(struct kref *kref)
{
struct reset_control *rstc = container_of(kref, struct reset_control,
refcnt);
lockdep_assert_held(&reset_list_mutex);
module_put(rstc->rcdev->owner);
list_del(&rstc->list);
kfree(rstc);
}
static void __reset_control_put_internal(struct reset_control *rstc)
{
lockdep_assert_held(&reset_list_mutex);
if (IS_ERR_OR_NULL(rstc))
return;
kref_put(&rstc->refcnt, __reset_control_release);
}
static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
unsigned int gpio,
unsigned int of_flags)
{
const struct fwnode_handle *fwnode = of_fwnode_handle(np);
unsigned int lookup_flags;
const char *label_tmp;
/*
* Later we map GPIO flags between OF and Linux, however not all
* constants from include/dt-bindings/gpio/gpio.h and
* include/linux/gpio/machine.h match each other.
*/
if (of_flags > GPIO_ACTIVE_LOW) {
pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
of_flags, gpio);
return -EINVAL;
}
struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
if (!gdev)
return -EPROBE_DEFER;
label_tmp = gpio_device_get_label(gdev);
if (!label_tmp)
return -EINVAL;
char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL);
if (!label)
return -ENOMEM;
/* Size: one lookup entry plus sentinel */
struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
GFP_KERNEL);
if (!lookup)
return -ENOMEM;
lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);
if (!lookup->dev_id)
return -ENOMEM;
lookup_flags = GPIO_PERSISTENT;
lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
lookup_flags);
/* Not freed on success, because it is persisent subsystem data. */
gpiod_add_lookup_table(no_free_ptr(lookup));
return 0;
}
/*
* @args: phandle to the GPIO provider with all the args like GPIO number
*/
static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
{
struct reset_gpio_lookup *rgpio_dev;
struct platform_device *pdev;
int id, ret;
/*
* Currently only #gpio-cells=2 is supported with the meaning of:
* args[0]: GPIO number
* args[1]: GPIO flags
* TODO: Handle other cases.
*/
if (args->args_count != 2)
return -ENOENT;
/*
* Registering reset-gpio device might cause immediate
* bind, resulting in its probe() registering new reset controller thus
* taking reset_list_mutex lock via reset_controller_register().
*/
lockdep_assert_not_held(&reset_list_mutex);
mutex_lock(&reset_gpio_lookup_mutex);
list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
if (args->np == rgpio_dev->of_args.np) {
if (of_phandle_args_equal(args, &rgpio_dev->of_args))
goto out; /* Already on the list, done */
}
}
id = ida_alloc(&reset_gpio_ida, GFP_KERNEL);
if (id < 0) {
ret = id;
goto err_unlock;
}
/* Not freed on success, because it is persisent subsystem data. */
rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL);
if (!rgpio_dev) {
ret = -ENOMEM;
goto err_ida_free;
}
ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
args->args[1]);
if (ret < 0)
goto err_kfree;
rgpio_dev->of_args = *args;
/*
* We keep the device_node reference, but of_args.np is put at the end
* of __of_reset_control_get(), so get it one more time.
* Hold reference as long as rgpio_dev memory is valid.
*/
of_node_get(rgpio_dev->of_args.np);
pdev = platform_device_register_data(NULL, "reset-gpio", id,
&rgpio_dev->of_args,
sizeof(rgpio_dev->of_args));
ret = PTR_ERR_OR_ZERO(pdev);
if (ret)
goto err_put;
list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
out:
mutex_unlock(&reset_gpio_lookup_mutex);
return 0;
err_put:
of_node_put(rgpio_dev->of_args.np);
err_kfree:
kfree(rgpio_dev);
err_ida_free:
ida_free(&reset_gpio_ida, id);
err_unlock:
mutex_unlock(&reset_gpio_lookup_mutex);
return ret;
}
static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args,
bool gpio_fallback)
{
struct reset_controller_dev *rcdev;
lockdep_assert_held(&reset_list_mutex);
list_for_each_entry(rcdev, &reset_controller_list, list) {
if (gpio_fallback) {
if (rcdev->of_args && of_phandle_args_equal(args,
rcdev->of_args))
return rcdev;
} else {
if (args->np == rcdev->of_node)
return rcdev;
}
}
return NULL;
}
struct reset_control *
__of_reset_control_get(struct device_node *node, const char *id, int index,
bool shared, bool optional, bool acquired)
{
bool gpio_fallback = false;
struct reset_control *rstc;
struct reset_controller_dev *rcdev;
struct of_phandle_args args;
int rstc_id;
int ret;
if (!node)
return ERR_PTR(-EINVAL);
if (id) {
index = of_property_match_string(node,
"reset-names", id);
if (index == -EILSEQ)
return ERR_PTR(index);
if (index < 0)
return optional ? NULL : ERR_PTR(-ENOENT);
}
ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
index, &args);
if (ret == -EINVAL)
return ERR_PTR(ret);
if (ret) {
if (!IS_ENABLED(CONFIG_RESET_GPIO))
return optional ? NULL : ERR_PTR(ret);
/*
* There can be only one reset-gpio for regular devices, so
* don't bother with the "reset-gpios" phandle index.
*/
ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells",
0, &args);
if (ret)
return optional ? NULL : ERR_PTR(ret);
gpio_fallback = true;
ret = __reset_add_reset_gpio_device(&args);
if (ret) {
rstc = ERR_PTR(ret);
goto out_put;
}
}
mutex_lock(&reset_list_mutex);
rcdev = __reset_find_rcdev(&args, gpio_fallback);
if (!rcdev) {
rstc = ERR_PTR(-EPROBE_DEFER);
goto out_unlock;
}
if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
rstc = ERR_PTR(-EINVAL);
goto out_unlock;
}
rstc_id = rcdev->of_xlate(rcdev, &args);
if (rstc_id < 0) {
rstc = ERR_PTR(rstc_id);
goto out_unlock;
}
/* reset_list_mutex also protects the rcdev's reset_control list */
rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
out_unlock:
mutex_unlock(&reset_list_mutex);
out_put:
of_node_put(args.np);
return rstc;
}
EXPORT_SYMBOL_GPL(__of_reset_control_get);
static struct reset_controller_dev *
__reset_controller_by_name(const char *name)
{
struct reset_controller_dev *rcdev;
lockdep_assert_held(&reset_list_mutex);
list_for_each_entry(rcdev, &reset_controller_list, list) {
if (!rcdev->dev)
continue;
if (!strcmp(name, dev_name(rcdev->dev)))
return rcdev;
}
return NULL;
}
static struct reset_control *
__reset_control_get_from_lookup(struct device *dev, const char *con_id,
bool shared, bool optional, bool acquired)
{
const struct reset_control_lookup *lookup;
struct reset_controller_dev *rcdev;
const char *dev_id = dev_name(dev);
struct reset_control *rstc = NULL;
mutex_lock(&reset_lookup_mutex);
list_for_each_entry(lookup, &reset_lookup_list, list) {
if (strcmp(lookup->dev_id, dev_id))
continue;
if ((!con_id && !lookup->con_id) ||
((con_id && lookup->con_id) &&
!strcmp(con_id, lookup->con_id))) {
mutex_lock(&reset_list_mutex);
rcdev = __reset_controller_by_name(lookup->provider);
if (!rcdev) {
mutex_unlock(&reset_list_mutex);
mutex_unlock(&reset_lookup_mutex);
/* Reset provider may not be ready yet. */
return ERR_PTR(-EPROBE_DEFER);
}
rstc = __reset_control_get_internal(rcdev,
lookup->index,
shared, acquired);
mutex_unlock(&reset_list_mutex);
break;
}
}
mutex_unlock(&reset_lookup_mutex);
if (!rstc)
return optional ? NULL : ERR_PTR(-ENOENT);
return rstc;
}
struct reset_control *__reset_control_get(struct device *dev, const char *id,
int index, bool shared, bool optional,
bool acquired)
{
if (WARN_ON(shared && acquired))
return ERR_PTR(-EINVAL);
if (dev->of_node)
return __of_reset_control_get(dev->of_node, id, index, shared,
optional, acquired);
return __reset_control_get_from_lookup(dev, id, shared, optional,
acquired);
}
EXPORT_SYMBOL_GPL(__reset_control_get);
int __reset_control_bulk_get(struct device *dev, int num_rstcs,
struct reset_control_bulk_data *rstcs,
bool shared, bool optional, bool acquired)
{
int ret, i;
for (i = 0; i < num_rstcs; i++) {
rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, 0,
shared, optional, acquired);
if (IS_ERR(rstcs[i].rstc)) {
ret = PTR_ERR(rstcs[i].rstc);
goto err;
}
}
return 0;
err:
mutex_lock(&reset_list_mutex);
while (i--)
__reset_control_put_internal(rstcs[i].rstc);
mutex_unlock(&reset_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(__reset_control_bulk_get);
static void reset_control_array_put(struct reset_control_array *resets)
{
int i;
mutex_lock(&reset_list_mutex);
for (i = 0; i < resets->num_rstcs; i++)
__reset_control_put_internal(resets->rstc[i]);
mutex_unlock(&reset_list_mutex);
kfree(resets);
}
/**
* reset_control_put - free the reset controller
* @rstc: reset controller
*/
void reset_control_put(struct reset_control *rstc)
{
if (IS_ERR_OR_NULL(rstc))
return;
if (reset_control_is_array(rstc)) {
reset_control_array_put(rstc_to_array(rstc));
return;
}
mutex_lock(&reset_list_mutex);
__reset_control_put_internal(rstc);
mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_control_put);
/**
* reset_control_bulk_put - free the reset controllers
* @num_rstcs: number of entries in rstcs array
* @rstcs: array of struct reset_control_bulk_data with reset controls set
*/
void reset_control_bulk_put(int num_rstcs, struct reset_control_bulk_data *rstcs)
{
mutex_lock(&reset_list_mutex);
while (num_rstcs--)
__reset_control_put_internal(rstcs[num_rstcs].rstc);
mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_control_bulk_put);
static void devm_reset_control_release(struct device *dev, void *res)
{
reset_control_put(*(struct reset_control **)res);
}
struct reset_control *
__devm_reset_control_get(struct device *dev, const char *id, int index,
bool shared, bool optional, bool acquired)
{
struct reset_control **ptr, *rstc;
ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
rstc = __reset_control_get(dev, id, index, shared, optional, acquired);
if (IS_ERR_OR_NULL(rstc)) {
devres_free(ptr);
return rstc;
}
*ptr = rstc;
devres_add(dev, ptr);
return rstc;
}
EXPORT_SYMBOL_GPL(__devm_reset_control_get);
struct reset_control_bulk_devres {
int num_rstcs;
struct reset_control_bulk_data *rstcs;
};
static void devm_reset_control_bulk_release(struct device *dev, void *res)
{
struct reset_control_bulk_devres *devres = res;
reset_control_bulk_put(devres->num_rstcs, devres->rstcs);
}
int __devm_reset_control_bulk_get(struct device *dev, int num_rstcs,
struct reset_control_bulk_data *rstcs,
bool shared, bool optional, bool acquired)
{
struct reset_control_bulk_devres *ptr;
int ret;
ptr = devres_alloc(devm_reset_control_bulk_release, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return -ENOMEM;
ret = __reset_control_bulk_get(dev, num_rstcs, rstcs, shared, optional, acquired);
if (ret < 0) {
devres_free(ptr);
return ret;
}
ptr->num_rstcs = num_rstcs;
ptr->rstcs = rstcs;
devres_add(dev, ptr);
return 0;
}
EXPORT_SYMBOL_GPL(__devm_reset_control_bulk_get);
/**
* __device_reset - find reset controller associated with the device
* and perform reset
* @dev: device to be reset by the controller
* @optional: whether it is optional to reset the device
*
* Convenience wrapper for __reset_control_get() and reset_control_reset().
* This is useful for the common case of devices with single, dedicated reset
* lines. _RST firmware method will be called for devices with ACPI.
*/
int __device_reset(struct device *dev, bool optional)
{
struct reset_control *rstc;
int ret;
#ifdef CONFIG_ACPI
acpi_handle handle = ACPI_HANDLE(dev);
if (handle) {
if (!acpi_has_method(handle, "_RST"))
return optional ? 0 : -ENOENT;
if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL,
NULL)))
return -EIO;
}
#endif
rstc = __reset_control_get(dev, NULL, 0, 0, optional, true);
if (IS_ERR(rstc))
return PTR_ERR(rstc);
ret = reset_control_reset(rstc);
reset_control_put(rstc);
return ret;
}
EXPORT_SYMBOL_GPL(__device_reset);
/*
* APIs to manage an array of reset controls.
*/
/**
* of_reset_control_get_count - Count number of resets available with a device
*
* @node: device node that contains 'resets'.
*
* Returns positive reset count on success, or error number on failure and
* on count being zero.
*/
static int of_reset_control_get_count(struct device_node *node)
{
int count;
if (!node)
return -EINVAL;
count = of_count_phandle_with_args(node, "resets", "#reset-cells");
if (count == 0)
count = -ENOENT;
return count;
}
/**
* of_reset_control_array_get - Get a list of reset controls using
* device node.
*
* @np: device node for the device that requests the reset controls array
* @shared: whether reset controls are shared or not
* @optional: whether it is optional to get the reset controls
* @acquired: only one reset control may be acquired for a given controller
* and ID
*
* Returns pointer to allocated reset_control on success or error on failure
*/
struct reset_control *
of_reset_control_array_get(struct device_node *np, bool shared, bool optional,
bool acquired)
{
struct reset_control_array *resets;
struct reset_control *rstc;
int num, i;
num = of_reset_control_get_count(np);
if (num < 0)
return optional ? NULL : ERR_PTR(num);
resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL);
if (!resets)
return ERR_PTR(-ENOMEM);
resets->num_rstcs = num;
for (i = 0; i < num; i++) {
rstc = __of_reset_control_get(np, NULL, i, shared, optional,
acquired);
if (IS_ERR(rstc))
goto err_rst;
resets->rstc[i] = rstc;
}
resets->base.array = true;
return &resets->base;
err_rst:
mutex_lock(&reset_list_mutex);
while (--i >= 0)
__reset_control_put_internal(resets->rstc[i]);
mutex_unlock(&reset_list_mutex);
kfree(resets);
return rstc;
}
EXPORT_SYMBOL_GPL(of_reset_control_array_get);
/**
* devm_reset_control_array_get - Resource managed reset control array get
*
* @dev: device that requests the list of reset controls
* @shared: whether reset controls are shared or not
* @optional: whether it is optional to get the reset controls
*
* The reset control array APIs are intended for a list of resets
* that just have to be asserted or deasserted, without any
* requirements on the order.
*
* Returns pointer to allocated reset_control on success or error on failure
*/
struct reset_control *
devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
{
struct reset_control **ptr, *rstc;
ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
rstc = of_reset_control_array_get(dev->of_node, shared, optional, true);
if (IS_ERR_OR_NULL(rstc)) {
devres_free(ptr);
return rstc;
}
*ptr = rstc;
devres_add(dev, ptr);
return rstc;
}
EXPORT_SYMBOL_GPL(devm_reset_control_array_get);
static int reset_control_get_count_from_lookup(struct device *dev)
{
const struct reset_control_lookup *lookup;
const char *dev_id;
int count = 0;
if (!dev)
return -EINVAL;
dev_id = dev_name(dev);
mutex_lock(&reset_lookup_mutex);
list_for_each_entry(lookup, &reset_lookup_list, list) {
if (!strcmp(lookup->dev_id, dev_id))
count++;
}
mutex_unlock(&reset_lookup_mutex);
if (count == 0)
count = -ENOENT;
return count;
}
/**
* reset_control_get_count - Count number of resets available with a device
*
* @dev: device for which to return the number of resets
*
* Returns positive reset count on success, or error number on failure and
* on count being zero.
*/
int reset_control_get_count(struct device *dev)
{
if (dev->of_node)
return of_reset_control_get_count(dev->of_node);
return reset_control_get_count_from_lookup(dev);
}
EXPORT_SYMBOL_GPL(reset_control_get_count);