From 0b52297f2288ca239e598afe6c92db83d8d2bfcd Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 23 Feb 2016 18:46:26 +0100 Subject: reset: Add support for shared reset controls 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 Signed-off-by: Philipp Zabel --- include/linux/reset.h | 96 +++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 81 insertions(+), 15 deletions(-) (limited to 'include/linux/reset.h') diff --git a/include/linux/reset.h b/include/linux/reset.h index 1bb69a29d6db..a552134a209e 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 -- cgit v1.2.3