// SPDX-License-Identifier: GPL-2.0 /* * drivers/base/power/clock_ops.c - Generic clock manipulation PM callbacks * * Copyright (c) 2011 Rafael J. Wysocki <[email protected]>, Renesas Electronics Corp. */ #include <linux/kernel.h> #include <linux/device.h> #include <linux/io.h> #include <linux/pm.h> #include <linux/pm_clock.h> #include <linux/clk.h> #include <linux/clkdev.h> #include <linux/of_clk.h> #include <linux/slab.h> #include <linux/err.h> #include <linux/pm_domain.h> #include <linux/pm_runtime.h> #ifdef CONFIG_PM_CLK enum pce_status { … }; struct pm_clock_entry { … }; /** * pm_clk_list_lock - ensure exclusive access for modifying the PM clock * entry list. * @psd: pm_subsys_data instance corresponding to the PM clock entry list * and clk_op_might_sleep count to be modified. * * Get exclusive access before modifying the PM clock entry list and the * clock_op_might_sleep count to guard against concurrent modifications. * This also protects against a concurrent clock_op_might_sleep and PM clock * entry list usage in pm_clk_suspend()/pm_clk_resume() that may or may not * happen in atomic context, hence both the mutex and the spinlock must be * taken here. */ static void pm_clk_list_lock(struct pm_subsys_data *psd) __acquires(&psd->lock) { … } /** * pm_clk_list_unlock - counterpart to pm_clk_list_lock(). * @psd: the same pm_subsys_data instance previously passed to * pm_clk_list_lock(). */ static void pm_clk_list_unlock(struct pm_subsys_data *psd) __releases(&psd->lock) { … } /** * pm_clk_op_lock - ensure exclusive access for performing clock operations. * @psd: pm_subsys_data instance corresponding to the PM clock entry list * and clk_op_might_sleep count being used. * @flags: stored irq flags. * @fn: string for the caller function's name. * * This is used by pm_clk_suspend() and pm_clk_resume() to guard * against concurrent modifications to the clock entry list and the * clock_op_might_sleep count. If clock_op_might_sleep is != 0 then * only the mutex can be locked and those functions can only be used in * non atomic context. If clock_op_might_sleep == 0 then these functions * may be used in any context and only the spinlock can be locked. * Returns -EINVAL if called in atomic context when clock ops might sleep. */ static int pm_clk_op_lock(struct pm_subsys_data *psd, unsigned long *flags, const char *fn) /* sparse annotations don't work here as exit state isn't static */ { … } /** * pm_clk_op_unlock - counterpart to pm_clk_op_lock(). * @psd: the same pm_subsys_data instance previously passed to * pm_clk_op_lock(). * @flags: irq flags provided by pm_clk_op_lock(). */ static void pm_clk_op_unlock(struct pm_subsys_data *psd, unsigned long *flags) /* sparse annotations don't work here as entry state isn't static */ { … } /** * __pm_clk_enable - Enable a clock, reporting any errors * @dev: The device for the given clock * @ce: PM clock entry corresponding to the clock. */ static inline void __pm_clk_enable(struct device *dev, struct pm_clock_entry *ce) { … } /** * pm_clk_acquire - Acquire a device clock. * @dev: Device whose clock is to be acquired. * @ce: PM clock entry corresponding to the clock. */ static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce) { … } static int __pm_clk_add(struct device *dev, const char *con_id, struct clk *clk) { … } /** * pm_clk_add - Start using a device clock for power management. * @dev: Device whose clock is going to be used for power management. * @con_id: Connection ID of the clock. * * Add the clock represented by @con_id to the list of clocks used for * the power management of @dev. */ int pm_clk_add(struct device *dev, const char *con_id) { … } EXPORT_SYMBOL_GPL(…); /** * pm_clk_add_clk - Start using a device clock for power management. * @dev: Device whose clock is going to be used for power management. * @clk: Clock pointer * * Add the clock to the list of clocks used for the power management of @dev. * The power-management code will take control of the clock reference, so * callers should not call clk_put() on @clk after this function sucessfully * returned. */ int pm_clk_add_clk(struct device *dev, struct clk *clk) { … } EXPORT_SYMBOL_GPL(…); /** * of_pm_clk_add_clk - Start using a device clock for power management. * @dev: Device whose clock is going to be used for power management. * @name: Name of clock that is going to be used for power management. * * Add the clock described in the 'clocks' device-tree node that matches * with the 'name' provided, to the list of clocks used for the power * management of @dev. On success, returns 0. Returns a negative error * code if the clock is not found or cannot be added. */ int of_pm_clk_add_clk(struct device *dev, const char *name) { … } EXPORT_SYMBOL_GPL(…); /** * of_pm_clk_add_clks - Start using device clock(s) for power management. * @dev: Device whose clock(s) is going to be used for power management. * * Add a series of clocks described in the 'clocks' device-tree node for * a device to the list of clocks used for the power management of @dev. * On success, returns the number of clocks added. Returns a negative * error code if there are no clocks in the device node for the device * or if adding a clock fails. */ int of_pm_clk_add_clks(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * __pm_clk_remove - Destroy PM clock entry. * @ce: PM clock entry to destroy. */ static void __pm_clk_remove(struct pm_clock_entry *ce) { … } /** * pm_clk_remove - Stop using a device clock for power management. * @dev: Device whose clock should not be used for PM any more. * @con_id: Connection ID of the clock. * * Remove the clock represented by @con_id from the list of clocks used for * the power management of @dev. */ void pm_clk_remove(struct device *dev, const char *con_id) { … } EXPORT_SYMBOL_GPL(…); /** * pm_clk_remove_clk - Stop using a device clock for power management. * @dev: Device whose clock should not be used for PM any more. * @clk: Clock pointer * * Remove the clock pointed to by @clk from the list of clocks used for * the power management of @dev. */ void pm_clk_remove_clk(struct device *dev, struct clk *clk) { … } EXPORT_SYMBOL_GPL(…); /** * pm_clk_init - Initialize a device's list of power management clocks. * @dev: Device to initialize the list of PM clocks for. * * Initialize the lock and clock_list members of the device's pm_subsys_data * object, set the count of clocks that might sleep to 0. */ void pm_clk_init(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_clk_create - Create and initialize a device's list of PM clocks. * @dev: Device to create and initialize the list of PM clocks for. * * Allocate a struct pm_subsys_data object, initialize its lock and clock_list * members and make the @dev's power.subsys_data field point to it. */ int pm_clk_create(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_clk_destroy - Destroy a device's list of power management clocks. * @dev: Device to destroy the list of PM clocks for. * * Clear the @dev's power.subsys_data field, remove the list of clock entries * from the struct pm_subsys_data object pointed to by it before and free * that object. */ void pm_clk_destroy(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); static void pm_clk_destroy_action(void *data) { … } int devm_pm_clk_create(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_clk_suspend - Disable clocks in a device's PM clock list. * @dev: Device to disable the clocks for. */ int pm_clk_suspend(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_clk_resume - Enable clocks in a device's PM clock list. * @dev: Device to enable the clocks for. */ int pm_clk_resume(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_clk_notify - Notify routine for device addition and removal. * @nb: Notifier block object this function is a member of. * @action: Operation being carried out by the caller. * @data: Device the routine is being run for. * * For this function to work, @nb must be a member of an object of type * struct pm_clk_notifier_block containing all of the requisite data. * Specifically, the pm_domain member of that object is copied to the device's * pm_domain field and its con_ids member is used to populate the device's list * of PM clocks, depending on @action. * * If the device's pm_domain field is already populated with a value different * from the one stored in the struct pm_clk_notifier_block object, the function * does nothing. */ static int pm_clk_notify(struct notifier_block *nb, unsigned long action, void *data) { … } int pm_clk_runtime_suspend(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); int pm_clk_runtime_resume(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); #else /* !CONFIG_PM_CLK */ /** * enable_clock - Enable a device clock. * @dev: Device whose clock is to be enabled. * @con_id: Connection ID of the clock. */ static void enable_clock(struct device *dev, const char *con_id) { struct clk *clk; clk = clk_get(dev, con_id); if (!IS_ERR(clk)) { clk_prepare_enable(clk); clk_put(clk); dev_info(dev, "Runtime PM disabled, clock forced on.\n"); } } /** * disable_clock - Disable a device clock. * @dev: Device whose clock is to be disabled. * @con_id: Connection ID of the clock. */ static void disable_clock(struct device *dev, const char *con_id) { struct clk *clk; clk = clk_get(dev, con_id); if (!IS_ERR(clk)) { clk_disable_unprepare(clk); clk_put(clk); dev_info(dev, "Runtime PM disabled, clock forced off.\n"); } } /** * pm_clk_notify - Notify routine for device addition and removal. * @nb: Notifier block object this function is a member of. * @action: Operation being carried out by the caller. * @data: Device the routine is being run for. * * For this function to work, @nb must be a member of an object of type * struct pm_clk_notifier_block containing all of the requisite data. * Specifically, the con_ids member of that object is used to enable or disable * the device's clocks, depending on @action. */ static int pm_clk_notify(struct notifier_block *nb, unsigned long action, void *data) { struct pm_clk_notifier_block *clknb; struct device *dev = data; char **con_id; dev_dbg(dev, "%s() %ld\n", __func__, action); clknb = container_of(nb, struct pm_clk_notifier_block, nb); switch (action) { case BUS_NOTIFY_BIND_DRIVER: if (clknb->con_ids[0]) { for (con_id = clknb->con_ids; *con_id; con_id++) enable_clock(dev, *con_id); } else { enable_clock(dev, NULL); } break; case BUS_NOTIFY_DRIVER_NOT_BOUND: case BUS_NOTIFY_UNBOUND_DRIVER: if (clknb->con_ids[0]) { for (con_id = clknb->con_ids; *con_id; con_id++) disable_clock(dev, *con_id); } else { disable_clock(dev, NULL); } break; } return 0; } #endif /* !CONFIG_PM_CLK */ /** * pm_clk_add_notifier - Add bus type notifier for power management clocks. * @bus: Bus type to add the notifier to. * @clknb: Notifier to be added to the given bus type. * * The nb member of @clknb is not expected to be initialized and its * notifier_call member will be replaced with pm_clk_notify(). However, * the remaining members of @clknb should be populated prior to calling this * routine. */ void pm_clk_add_notifier(const struct bus_type *bus, struct pm_clk_notifier_block *clknb) { … } EXPORT_SYMBOL_GPL(…);
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