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reset: Add support for shared reset controls

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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>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
This commit is contained in:
Hans de Goede
2016-02-23 18:46:26 +01:00
committed by Philipp Zabel
parent c15ddec2ca
commit 0b52297f22
2 changed files with 129 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

96
include/linux/reset.h
View File

@@ -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