* [PATCH v4 1/3] reset: Make [of_]reset_control_get[_foo] functions wrappers
2016-02-23 17:46 [PATCH v4 0/3] reset: Add support for shared reset controls Hans de Goede
@ 2016-02-23 17:46 ` Hans de Goede
2016-02-23 17:46 ` [PATCH v4 2/3] reset: Share struct reset_control between reset_control_get calls Hans de Goede
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Hans de Goede @ 2016-02-23 17:46 UTC (permalink / raw)
To: linux-arm-kernel
With both the regular, _by_index and _optional variants we already have
quite a few variants of [of_]reset_control_get[_foo], the upcoming
addition of shared reset lines support makes this worse.
This commit changes all the variants into wrappers around common core
functions. For completeness sake this commit also adds a new
devm_get_reset_control_by_index wrapper.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/reset/core.c | 84 +++++++--------------------------
include/linux/reset.h | 126 +++++++++++++++++++++++++++++++++++---------------
2 files changed, 107 insertions(+), 103 deletions(-)
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 8737663..f695429 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -139,18 +139,8 @@ int reset_control_status(struct reset_control *rstc)
}
EXPORT_SYMBOL_GPL(reset_control_status);
-/**
- * of_reset_control_get_by_index - Lookup and obtain a reference to a reset
- * controller by index.
- * @node: device to be reset by the controller
- * @index: index of the reset controller
- *
- * This is to be used to perform a list of resets for a device or power domain
- * in whatever order. Returns a struct reset_control or IS_ERR() condition
- * containing errno.
- */
-struct reset_control *of_reset_control_get_by_index(struct device_node *node,
- int index)
+struct reset_control *__of_reset_control_get(struct device_node *node,
+ const char *id, int index)
{
struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER);
struct reset_controller_dev *r, *rcdev;
@@ -158,6 +148,16 @@ struct reset_control *of_reset_control_get_by_index(struct device_node *node,
int rstc_id;
int ret;
+ if (!node)
+ return ERR_PTR(-EINVAL);
+
+ if (id) {
+ index = of_property_match_string(node,
+ "reset-names", id);
+ if (index < 0)
+ return ERR_PTR(-ENOENT);
+ }
+
ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
index, &args);
if (ret)
@@ -198,49 +198,7 @@ struct reset_control *of_reset_control_get_by_index(struct device_node *node,
return rstc;
}
-EXPORT_SYMBOL_GPL(of_reset_control_get_by_index);
-
-/**
- * of_reset_control_get - Lookup and obtain a reference to a reset controller.
- * @node: device to be reset by the controller
- * @id: reset line name
- *
- * Returns a struct reset_control or IS_ERR() condition containing errno.
- *
- * Use of id names is optional.
- */
-struct reset_control *of_reset_control_get(struct device_node *node,
- const char *id)
-{
- int index = 0;
-
- if (id) {
- index = of_property_match_string(node,
- "reset-names", id);
- if (index < 0)
- return ERR_PTR(-ENOENT);
- }
- return of_reset_control_get_by_index(node, index);
-}
-EXPORT_SYMBOL_GPL(of_reset_control_get);
-
-/**
- * reset_control_get - Lookup and obtain a reference to a reset controller.
- * @dev: device to be reset by the controller
- * @id: reset line name
- *
- * Returns a struct reset_control or IS_ERR() condition containing errno.
- *
- * Use of id names is optional.
- */
-struct reset_control *reset_control_get(struct device *dev, const char *id)
-{
- if (!dev)
- return ERR_PTR(-EINVAL);
-
- return of_reset_control_get(dev->of_node, id);
-}
-EXPORT_SYMBOL_GPL(reset_control_get);
+EXPORT_SYMBOL_GPL(__of_reset_control_get);
/**
* reset_control_put - free the reset controller
@@ -262,16 +220,8 @@ static void devm_reset_control_release(struct device *dev, void *res)
reset_control_put(*(struct reset_control **)res);
}
-/**
- * devm_reset_control_get - resource managed reset_control_get()
- * @dev: device to be reset by the controller
- * @id: reset line name
- *
- * Managed reset_control_get(). For reset controllers returned from this
- * function, reset_control_put() is called automatically on driver detach.
- * See reset_control_get() for more information.
- */
-struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
+struct reset_control *__devm_reset_control_get(struct device *dev,
+ const char *id, int index)
{
struct reset_control **ptr, *rstc;
@@ -280,7 +230,7 @@ struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
if (!ptr)
return ERR_PTR(-ENOMEM);
- rstc = reset_control_get(dev, id);
+ rstc = __of_reset_control_get(dev ? dev->of_node : NULL, id, index);
if (!IS_ERR(rstc)) {
*ptr = rstc;
devres_add(dev, ptr);
@@ -290,7 +240,7 @@ struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
return rstc;
}
-EXPORT_SYMBOL_GPL(devm_reset_control_get);
+EXPORT_SYMBOL_GPL(__devm_reset_control_get);
/**
* device_reset - find reset controller associated with the device
diff --git a/include/linux/reset.h b/include/linux/reset.h
index c4c097d..1bb69a2 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -1,8 +1,8 @@
#ifndef _LINUX_RESET_H_
#define _LINUX_RESET_H_
-struct device;
-struct device_node;
+#include <linux/device.h>
+
struct reset_control;
#ifdef CONFIG_RESET_CONTROLLER
@@ -12,9 +12,11 @@ int reset_control_assert(struct reset_control *rstc);
int reset_control_deassert(struct reset_control *rstc);
int reset_control_status(struct reset_control *rstc);
-struct reset_control *reset_control_get(struct device *dev, const char *id);
+struct reset_control *__of_reset_control_get(struct device_node *node,
+ const char *id, int index);
void reset_control_put(struct reset_control *rstc);
-struct reset_control *devm_reset_control_get(struct device *dev, const char *id);
+struct reset_control *__devm_reset_control_get(struct device *dev,
+ const char *id, int index);
int __must_check device_reset(struct device *dev);
@@ -23,24 +25,6 @@ static inline int device_reset_optional(struct device *dev)
return device_reset(dev);
}
-static inline struct reset_control *reset_control_get_optional(
- struct device *dev, const char *id)
-{
- return reset_control_get(dev, id);
-}
-
-static inline struct reset_control *devm_reset_control_get_optional(
- struct device *dev, const char *id)
-{
- return devm_reset_control_get(dev, id);
-}
-
-struct reset_control *of_reset_control_get(struct device_node *node,
- const char *id);
-
-struct reset_control *of_reset_control_get_by_index(
- struct device_node *node, int index);
-
#else
static inline int reset_control_reset(struct reset_control *rstc)
@@ -77,44 +61,114 @@ static inline int device_reset_optional(struct device *dev)
return -ENOTSUPP;
}
-static inline struct reset_control *__must_check reset_control_get(
- struct device *dev, const char *id)
+static inline struct reset_control *__of_reset_control_get(
+ struct device_node *node,
+ const char *id, int index)
{
- WARN_ON(1);
return ERR_PTR(-EINVAL);
}
-static inline struct reset_control *__must_check devm_reset_control_get(
- struct device *dev, const char *id)
+static inline struct reset_control *__devm_reset_control_get(
+ struct device *dev,
+ const char *id, int index)
{
- WARN_ON(1);
return ERR_PTR(-EINVAL);
}
-static inline struct reset_control *reset_control_get_optional(
+#endif /* CONFIG_RESET_CONTROLLER */
+
+/**
+ * reset_control_get - Lookup and obtain a reference to a reset controller.
+ * @dev: device to be reset by the controller
+ * @id: reset line name
+ *
+ * Returns a struct reset_control or IS_ERR() condition containing errno.
+ *
+ * Use of id names is optional.
+ */
+static inline struct reset_control *__must_check reset_control_get(
struct device *dev, const char *id)
{
- return ERR_PTR(-ENOTSUPP);
+#ifndef CONFIG_RESET_CONTROLLER
+ WARN_ON(1);
+#endif
+ return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0);
}
-static inline struct reset_control *devm_reset_control_get_optional(
+static inline struct reset_control *reset_control_get_optional(
struct device *dev, const char *id)
{
- return ERR_PTR(-ENOTSUPP);
+ return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0);
}
+/**
+ * of_reset_control_get - Lookup and obtain a reference to a reset controller.
+ * @node: device to be reset by the controller
+ * @id: reset line name
+ *
+ * Returns a struct reset_control or IS_ERR() condition containing errno.
+ *
+ * Use of id names is optional.
+ */
static inline struct reset_control *of_reset_control_get(
struct device_node *node, const char *id)
{
- return ERR_PTR(-ENOTSUPP);
+ return __of_reset_control_get(node, id, 0);
}
+/**
+ * of_reset_control_get_by_index - Lookup and obtain a reference to a reset
+ * controller by index.
+ * @node: device to be reset by the controller
+ * @index: index of the reset controller
+ *
+ * This is to be used to perform a list of resets for a device or power domain
+ * in whatever order. Returns a struct reset_control or IS_ERR() condition
+ * containing errno.
+ */
static inline struct reset_control *of_reset_control_get_by_index(
- struct device_node *node, int index)
+ struct device_node *node, int index)
{
- return ERR_PTR(-ENOTSUPP);
+ return __of_reset_control_get(node, NULL, index);
}
-#endif /* CONFIG_RESET_CONTROLLER */
+/**
+ * devm_reset_control_get - resource managed reset_control_get()
+ * @dev: device to be reset by the controller
+ * @id: reset line name
+ *
+ * Managed reset_control_get(). For reset controllers returned from this
+ * function, reset_control_put() is called automatically on driver detach.
+ * See reset_control_get() for more information.
+ */
+static inline struct reset_control *__must_check devm_reset_control_get(
+ struct device *dev, const char *id)
+{
+#ifndef CONFIG_RESET_CONTROLLER
+ WARN_ON(1);
+#endif
+ return __devm_reset_control_get(dev, id, 0);
+}
+
+static inline struct reset_control *devm_reset_control_get_optional(
+ struct device *dev, const char *id)
+{
+ return __devm_reset_control_get(dev, id, 0);
+}
+
+/**
+ * devm_reset_control_get_by_index - resource managed reset_control_get
+ * @dev: device to be reset by the controller
+ * @index: index of the reset controller
+ *
+ * Managed reset_control_get(). For reset controllers returned from this
+ * function, reset_control_put() is called automatically on driver detach.
+ * See reset_control_get() for more information.
+ */
+static inline struct reset_control *devm_reset_control_get_by_index(
+ struct device *dev, int index)
+{
+ return __devm_reset_control_get(dev, NULL, index);
+}
#endif
--
2.7.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v4 2/3] reset: Share struct reset_control between reset_control_get calls
2016-02-23 17:46 [PATCH v4 0/3] reset: Add support for shared reset controls Hans de Goede
2016-02-23 17:46 ` [PATCH v4 1/3] reset: Make [of_]reset_control_get[_foo] functions wrappers Hans de Goede
@ 2016-02-23 17:46 ` Hans de Goede
2016-02-23 17:46 ` [PATCH v4 3/3] reset: Add support for shared reset controls Hans de Goede
2016-02-24 10:42 ` [PATCH v4 0/3] " Philipp Zabel
3 siblings, 0 replies; 5+ messages in thread
From: Hans de Goede @ 2016-02-23 17:46 UTC (permalink / raw)
To: linux-arm-kernel
Now that struct reset_control no longer stores the device pointer for
the device calling reset_control_get we can share a single struct
reset_control when multiple calls to reset_control_get are made for
the same reset line (same id / index).
This is a preparation patch for adding support for shared reset lines.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/reset/core.c | 82 ++++++++++++++++++++++++++++++----------
include/linux/reset-controller.h | 2 +
2 files changed, 64 insertions(+), 20 deletions(-)
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index f695429..e439ae2 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -18,19 +18,23 @@
#include <linux/reset-controller.h>
#include <linux/slab.h>
-static DEFINE_MUTEX(reset_controller_list_mutex);
+static DEFINE_MUTEX(reset_list_mutex);
static LIST_HEAD(reset_controller_list);
/**
* 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
*/
struct reset_control {
struct reset_controller_dev *rcdev;
+ struct list_head list;
unsigned int id;
+ unsigned int refcnt;
};
/**
@@ -65,9 +69,11 @@ int reset_controller_register(struct reset_controller_dev *rcdev)
rcdev->of_xlate = of_reset_simple_xlate;
}
- mutex_lock(&reset_controller_list_mutex);
+ INIT_LIST_HEAD(&rcdev->reset_control_head);
+
+ mutex_lock(&reset_list_mutex);
list_add(&rcdev->list, &reset_controller_list);
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
return 0;
}
@@ -79,9 +85,9 @@ EXPORT_SYMBOL_GPL(reset_controller_register);
*/
void reset_controller_unregister(struct reset_controller_dev *rcdev)
{
- mutex_lock(&reset_controller_list_mutex);
+ mutex_lock(&reset_list_mutex);
list_del(&rcdev->list);
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_controller_unregister);
@@ -139,6 +145,48 @@ int reset_control_status(struct reset_control *rstc)
}
EXPORT_SYMBOL_GPL(reset_control_status);
+static struct reset_control *__reset_control_get(
+ struct reset_controller_dev *rcdev,
+ unsigned int index)
+{
+ struct reset_control *rstc;
+
+ lockdep_assert_held(&reset_list_mutex);
+
+ list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
+ if (rstc->id == index) {
+ rstc->refcnt++;
+ return rstc;
+ }
+ }
+
+ rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
+ if (!rstc)
+ return ERR_PTR(-ENOMEM);
+
+ try_module_get(rcdev->owner);
+
+ rstc->rcdev = rcdev;
+ list_add(&rstc->list, &rcdev->reset_control_head);
+ rstc->id = index;
+ rstc->refcnt = 1;
+
+ return rstc;
+}
+
+static void __reset_control_put(struct reset_control *rstc)
+{
+ lockdep_assert_held(&reset_list_mutex);
+
+ if (--rstc->refcnt)
+ return;
+
+ module_put(rstc->rcdev->owner);
+
+ list_del(&rstc->list);
+ kfree(rstc);
+}
+
struct reset_control *__of_reset_control_get(struct device_node *node,
const char *id, int index)
{
@@ -163,7 +211,7 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
if (ret)
return ERR_PTR(ret);
- mutex_lock(&reset_controller_list_mutex);
+ mutex_lock(&reset_list_mutex);
rcdev = NULL;
list_for_each_entry(r, &reset_controller_list, list) {
if (args.np == r->of_node) {
@@ -174,27 +222,20 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
of_node_put(args.np);
if (!rcdev) {
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
return ERR_PTR(-EPROBE_DEFER);
}
rstc_id = rcdev->of_xlate(rcdev, &args);
if (rstc_id < 0) {
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
return ERR_PTR(rstc_id);
}
- try_module_get(rcdev->owner);
- mutex_unlock(&reset_controller_list_mutex);
-
- rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
- if (!rstc) {
- module_put(rcdev->owner);
- return ERR_PTR(-ENOMEM);
- }
+ /* reset_list_mutex also protects the rcdev's reset_control list */
+ rstc = __reset_control_get(rcdev, rstc_id);
- rstc->rcdev = rcdev;
- rstc->id = rstc_id;
+ mutex_unlock(&reset_list_mutex);
return rstc;
}
@@ -210,8 +251,9 @@ void reset_control_put(struct reset_control *rstc)
if (IS_ERR(rstc))
return;
- module_put(rstc->rcdev->owner);
- kfree(rstc);
+ mutex_lock(&reset_list_mutex);
+ __reset_control_put(rstc);
+ mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_control_put);
diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
index ce6b962..2decc20 100644
--- a/include/linux/reset-controller.h
+++ b/include/linux/reset-controller.h
@@ -31,6 +31,7 @@ struct of_phandle_args;
* @ops: a pointer to device specific struct reset_control_ops
* @owner: kernel module of the reset controller driver
* @list: internal list of reset controller devices
+ * @reset_control_head: head of internal list of requested reset controls
* @of_node: corresponding device tree node as phandle target
* @of_reset_n_cells: number of cells in reset line specifiers
* @of_xlate: translation function to translate from specifier as found in the
@@ -41,6 +42,7 @@ struct reset_controller_dev {
struct reset_control_ops *ops;
struct module *owner;
struct list_head list;
+ struct list_head reset_control_head;
struct device_node *of_node;
int of_reset_n_cells;
int (*of_xlate)(struct reset_controller_dev *rcdev,
--
2.7.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v4 3/3] reset: Add support for shared reset controls
2016-02-23 17:46 [PATCH v4 0/3] reset: Add support for shared reset controls Hans de Goede
2016-02-23 17:46 ` [PATCH v4 1/3] reset: Make [of_]reset_control_get[_foo] functions wrappers Hans de Goede
2016-02-23 17:46 ` [PATCH v4 2/3] reset: Share struct reset_control between reset_control_get calls Hans de Goede
@ 2016-02-23 17:46 ` Hans de Goede
2016-02-24 10:42 ` [PATCH v4 0/3] " Philipp Zabel
3 siblings, 0 replies; 5+ messages in thread
From: Hans de Goede @ 2016-02-23 17:46 UTC (permalink / raw)
To: linux-arm-kernel
In some SoCs some hw-blocks share a reset control. Add support for this
setup by adding new:
reset_control_get_shared()
devm_reset_control_get_shared()
devm_reset_control_get_shared_by_index()
methods to get a reset_control. Note that this patch omits adding of_
variants, if these are needed later they can be easily added.
This patch also changes the behavior of the existing exclusive
reset_control_get() variants, if these are now called more then once
for the same reset_control they will return -EBUSY. To catch existing
drivers triggering this error (there should not be any) a WARN_ON(1)
is added in this path.
When a reset_control is shared, the behavior of reset_control_assert /
deassert is changed, for shared reset_controls these will work like the
clock-enable/disable and regulator-on/off functions. They will keep a
deassert_count, and only (re-)assert the reset after reset_control_assert
has been called as many times as reset_control_deassert was called.
Calling reset_control_assert without first calling reset_control_deassert
is not allowed on a shared reset control. Calling reset_control_reset is
also not allowed on a shared reset control.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/reset/core.c | 59 +++++++++++++++++++++++++------
include/linux/reset.h | 96 +++++++++++++++++++++++++++++++++++++++++++--------
2 files changed, 129 insertions(+), 26 deletions(-)
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index e439ae2..400e42f 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -8,6 +8,7 @@
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
+#include <linux/atomic.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
@@ -29,12 +30,16 @@ static LIST_HEAD(reset_controller_list);
* @id: ID of the reset controller in the reset
* controller device
* @refcnt: Number of gets of this reset_control
+ * @shared: Is this a shared (1), or an exclusive (0) reset_control?
+ * @deassert_cnt: Number of times this reset line has been deasserted
*/
struct reset_control {
struct reset_controller_dev *rcdev;
struct list_head list;
unsigned int id;
unsigned int refcnt;
+ int shared;
+ atomic_t deassert_count;
};
/**
@@ -94,9 +99,14 @@ EXPORT_SYMBOL_GPL(reset_controller_unregister);
/**
* reset_control_reset - reset the controlled device
* @rstc: reset controller
+ *
+ * Calling this on a shared reset controller is an error.
*/
int reset_control_reset(struct reset_control *rstc)
{
+ if (WARN_ON(rstc->shared))
+ return -EINVAL;
+
if (rstc->rcdev->ops->reset)
return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
@@ -107,26 +117,48 @@ EXPORT_SYMBOL_GPL(reset_control_reset);
/**
* 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.
*/
int reset_control_assert(struct reset_control *rstc)
{
- if (rstc->rcdev->ops->assert)
- return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
+ if (!rstc->rcdev->ops->assert)
+ return -ENOTSUPP;
- return -ENOTSUPP;
+ if (rstc->shared) {
+ if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
+ return -EINVAL;
+
+ if (atomic_dec_return(&rstc->deassert_count) != 0)
+ return 0;
+ }
+
+ return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_assert);
/**
* reset_control_deassert - deasserts the reset line
* @rstc: reset controller
+ *
+ * After calling this function, the reset is guaranteed to be deasserted.
*/
int reset_control_deassert(struct reset_control *rstc)
{
- if (rstc->rcdev->ops->deassert)
- return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
+ if (!rstc->rcdev->ops->deassert)
+ return -ENOTSUPP;
- return -ENOTSUPP;
+ if (rstc->shared) {
+ if (atomic_inc_return(&rstc->deassert_count) != 1)
+ return 0;
+ }
+
+ return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_deassert);
@@ -147,7 +179,7 @@ EXPORT_SYMBOL_GPL(reset_control_status);
static struct reset_control *__reset_control_get(
struct reset_controller_dev *rcdev,
- unsigned int index)
+ unsigned int index, int shared)
{
struct reset_control *rstc;
@@ -155,6 +187,9 @@ static struct reset_control *__reset_control_get(
list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
if (rstc->id == index) {
+ if (WARN_ON(!rstc->shared || !shared))
+ return ERR_PTR(-EBUSY);
+
rstc->refcnt++;
return rstc;
}
@@ -170,6 +205,7 @@ static struct reset_control *__reset_control_get(
list_add(&rstc->list, &rcdev->reset_control_head);
rstc->id = index;
rstc->refcnt = 1;
+ rstc->shared = shared;
return rstc;
}
@@ -188,7 +224,7 @@ static void __reset_control_put(struct reset_control *rstc)
}
struct reset_control *__of_reset_control_get(struct device_node *node,
- const char *id, int index)
+ const char *id, int index, int shared)
{
struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER);
struct reset_controller_dev *r, *rcdev;
@@ -233,7 +269,7 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
}
/* reset_list_mutex also protects the rcdev's reset_control list */
- rstc = __reset_control_get(rcdev, rstc_id);
+ rstc = __reset_control_get(rcdev, rstc_id, shared);
mutex_unlock(&reset_list_mutex);
@@ -263,7 +299,7 @@ static void devm_reset_control_release(struct device *dev, void *res)
}
struct reset_control *__devm_reset_control_get(struct device *dev,
- const char *id, int index)
+ const char *id, int index, int shared)
{
struct reset_control **ptr, *rstc;
@@ -272,7 +308,8 @@ struct reset_control *__devm_reset_control_get(struct device *dev,
if (!ptr)
return ERR_PTR(-ENOMEM);
- rstc = __of_reset_control_get(dev ? dev->of_node : NULL, id, index);
+ rstc = __of_reset_control_get(dev ? dev->of_node : NULL,
+ id, index, shared);
if (!IS_ERR(rstc)) {
*ptr = rstc;
devres_add(dev, ptr);
diff --git a/include/linux/reset.h b/include/linux/reset.h
index 1bb69a2..a552134 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -13,10 +13,10 @@ int reset_control_deassert(struct reset_control *rstc);
int reset_control_status(struct reset_control *rstc);
struct reset_control *__of_reset_control_get(struct device_node *node,
- const char *id, int index);
+ const char *id, int index, int shared);
void reset_control_put(struct reset_control *rstc);
struct reset_control *__devm_reset_control_get(struct device *dev,
- const char *id, int index);
+ const char *id, int index, int shared);
int __must_check device_reset(struct device *dev);
@@ -63,14 +63,14 @@ static inline int device_reset_optional(struct device *dev)
static inline struct reset_control *__of_reset_control_get(
struct device_node *node,
- const char *id, int index)
+ const char *id, int index, int shared)
{
return ERR_PTR(-EINVAL);
}
static inline struct reset_control *__devm_reset_control_get(
struct device *dev,
- const char *id, int index)
+ const char *id, int index, int shared)
{
return ERR_PTR(-EINVAL);
}
@@ -78,11 +78,17 @@ static inline struct reset_control *__devm_reset_control_get(
#endif /* CONFIG_RESET_CONTROLLER */
/**
- * reset_control_get - Lookup and obtain a reference to a reset controller.
+ * reset_control_get - Lookup and obtain an exclusive reference to a
+ * reset controller.
* @dev: device to be reset by the controller
* @id: reset line name
*
* Returns a struct reset_control or IS_ERR() condition containing errno.
+ * If this function is called more then once for the same reset_control it will
+ * return -EBUSY.
+ *
+ * See reset_control_get_shared for details on shared references to
+ * reset-controls.
*
* Use of id names is optional.
*/
@@ -92,17 +98,46 @@ static inline struct reset_control *__must_check reset_control_get(
#ifndef CONFIG_RESET_CONTROLLER
WARN_ON(1);
#endif
- return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0);
+ return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0);
}
static inline struct reset_control *reset_control_get_optional(
struct device *dev, const char *id)
{
- return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0);
+ return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0);
}
/**
- * of_reset_control_get - Lookup and obtain a reference to a reset controller.
+ * reset_control_get_shared - Lookup and obtain a shared reference to a
+ * reset controller.
+ * @dev: device to be reset by the controller
+ * @id: reset line name
+ *
+ * Returns a struct reset_control or IS_ERR() condition containing errno.
+ * This function is intended for use with reset-controls which are shared
+ * between hardware-blocks.
+ *
+ * When a reset-control is shared, the behavior of reset_control_assert /
+ * deassert is changed, the reset-core will keep track of a deassert_count
+ * and only (re-)assert the reset after reset_control_assert has been called
+ * as many times as reset_control_deassert was called. Also see the remark
+ * about shared reset-controls in the reset_control_assert docs.
+ *
+ * Calling reset_control_assert without first calling reset_control_deassert
+ * is not allowed on a shared reset control. Calling reset_control_reset is
+ * also not allowed on a shared reset control.
+ *
+ * Use of id names is optional.
+ */
+static inline struct reset_control *reset_control_get_shared(
+ struct device *dev, const char *id)
+{
+ return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 1);
+}
+
+/**
+ * of_reset_control_get - Lookup and obtain an exclusive reference to a
+ * reset controller.
* @node: device to be reset by the controller
* @id: reset line name
*
@@ -113,12 +148,12 @@ static inline struct reset_control *reset_control_get_optional(
static inline struct reset_control *of_reset_control_get(
struct device_node *node, const char *id)
{
- return __of_reset_control_get(node, id, 0);
+ return __of_reset_control_get(node, id, 0, 0);
}
/**
- * of_reset_control_get_by_index - Lookup and obtain a reference to a reset
- * controller by index.
+ * of_reset_control_get_by_index - Lookup and obtain an exclusive reference to
+ * a reset controller by index.
* @node: device to be reset by the controller
* @index: index of the reset controller
*
@@ -129,7 +164,7 @@ static inline struct reset_control *of_reset_control_get(
static inline struct reset_control *of_reset_control_get_by_index(
struct device_node *node, int index)
{
- return __of_reset_control_get(node, NULL, index);
+ return __of_reset_control_get(node, NULL, index, 0);
}
/**
@@ -147,13 +182,13 @@ static inline struct reset_control *__must_check devm_reset_control_get(
#ifndef CONFIG_RESET_CONTROLLER
WARN_ON(1);
#endif
- return __devm_reset_control_get(dev, id, 0);
+ return __devm_reset_control_get(dev, id, 0, 0);
}
static inline struct reset_control *devm_reset_control_get_optional(
struct device *dev, const char *id)
{
- return __devm_reset_control_get(dev, id, 0);
+ return __devm_reset_control_get(dev, id, 0, 0);
}
/**
@@ -168,7 +203,38 @@ static inline struct reset_control *devm_reset_control_get_optional(
static inline struct reset_control *devm_reset_control_get_by_index(
struct device *dev, int index)
{
- return __devm_reset_control_get(dev, NULL, index);
+ return __devm_reset_control_get(dev, NULL, index, 0);
+}
+
+/**
+ * devm_reset_control_get_shared - resource managed reset_control_get_shared()
+ * @dev: device to be reset by the controller
+ * @id: reset line name
+ *
+ * Managed reset_control_get_shared(). For reset controllers returned from
+ * this function, reset_control_put() is called automatically on driver detach.
+ * See reset_control_get_shared() for more information.
+ */
+static inline struct reset_control *devm_reset_control_get_shared(
+ struct device *dev, const char *id)
+{
+ return __devm_reset_control_get(dev, id, 0, 1);
+}
+
+/**
+ * devm_reset_control_get_shared_by_index - resource managed
+ * reset_control_get_shared
+ * @dev: device to be reset by the controller
+ * @index: index of the reset controller
+ *
+ * Managed reset_control_get_shared(). For reset controllers returned from
+ * this function, reset_control_put() is called automatically on driver detach.
+ * See reset_control_get_shared() for more information.
+ */
+static inline struct reset_control *devm_reset_control_get_shared_by_index(
+ struct device *dev, int index)
+{
+ return __devm_reset_control_get(dev, NULL, index, 1);
}
#endif
--
2.7.1
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