diff options
Diffstat (limited to 'drivers/base/power/common.c')
| -rw-r--r-- | drivers/base/power/common.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c new file mode 100644 index 0000000000..72115917e0 --- /dev/null +++ b/drivers/base/power/common.c @@ -0,0 +1,230 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * drivers/base/power/common.c - Common device power management code. + * + * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp. + */ +#include <linux/kernel.h> +#include <linux/device.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/pm_clock.h> +#include <linux/acpi.h> +#include <linux/pm_domain.h> + +#include "power.h" + +/** + * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device. + * @dev: Device to handle. + * + * If power.subsys_data is NULL, point it to a new object, otherwise increment + * its reference counter. Return 0 if new object has been created or refcount + * increased, otherwise negative error code. + */ +int dev_pm_get_subsys_data(struct device *dev) +{ + struct pm_subsys_data *psd; + + psd = kzalloc(sizeof(*psd), GFP_KERNEL); + if (!psd) + return -ENOMEM; + + spin_lock_irq(&dev->power.lock); + + if (dev->power.subsys_data) { + dev->power.subsys_data->refcount++; + } else { + spin_lock_init(&psd->lock); + psd->refcount = 1; + dev->power.subsys_data = psd; + pm_clk_init(dev); + psd = NULL; + } + + spin_unlock_irq(&dev->power.lock); + + /* kfree() verifies that its argument is nonzero. */ + kfree(psd); + + return 0; +} +EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data); + +/** + * dev_pm_put_subsys_data - Drop reference to power.subsys_data. + * @dev: Device to handle. + * + * If the reference counter of power.subsys_data is zero after dropping the + * reference, power.subsys_data is removed. + */ +void dev_pm_put_subsys_data(struct device *dev) +{ + struct pm_subsys_data *psd; + + spin_lock_irq(&dev->power.lock); + + psd = dev_to_psd(dev); + if (!psd) + goto out; + + if (--psd->refcount == 0) + dev->power.subsys_data = NULL; + else + psd = NULL; + + out: + spin_unlock_irq(&dev->power.lock); + kfree(psd); +} +EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data); + +/** + * dev_pm_domain_attach - Attach a device to its PM domain. + * @dev: Device to attach. + * @power_on: Used to indicate whether we should power on the device. + * + * The @dev may only be attached to a single PM domain. By iterating through + * the available alternatives we try to find a valid PM domain for the device. + * As attachment succeeds, the ->detach() callback in the struct dev_pm_domain + * should be assigned by the corresponding attach function. + * + * This function should typically be invoked from subsystem level code during + * the probe phase. Especially for those that holds devices which requires + * power management through PM domains. + * + * Callers must ensure proper synchronization of this function with power + * management callbacks. + * + * Returns 0 on successfully attached PM domain, or when it is found that the + * device doesn't need a PM domain, else a negative error code. + */ +int dev_pm_domain_attach(struct device *dev, bool power_on) +{ + int ret; + + if (dev->pm_domain) + return 0; + + ret = acpi_dev_pm_attach(dev, power_on); + if (!ret) + ret = genpd_dev_pm_attach(dev); + + return ret < 0 ? ret : 0; +} +EXPORT_SYMBOL_GPL(dev_pm_domain_attach); + +/** + * dev_pm_domain_attach_by_id - Associate a device with one of its PM domains. + * @dev: The device used to lookup the PM domain. + * @index: The index of the PM domain. + * + * As @dev may only be attached to a single PM domain, the backend PM domain + * provider creates a virtual device to attach instead. If attachment succeeds, + * the ->detach() callback in the struct dev_pm_domain are assigned by the + * corresponding backend attach function, as to deal with detaching of the + * created virtual device. + * + * This function should typically be invoked by a driver during the probe phase, + * in case its device requires power management through multiple PM domains. The + * driver may benefit from using the received device, to configure device-links + * towards its original device. Depending on the use-case and if needed, the + * links may be dynamically changed by the driver, which allows it to control + * the power to the PM domains independently from each other. + * + * Callers must ensure proper synchronization of this function with power + * management callbacks. + * + * Returns the virtual created device when successfully attached to its PM + * domain, NULL in case @dev don't need a PM domain, else an ERR_PTR(). + * Note that, to detach the returned virtual device, the driver shall call + * dev_pm_domain_detach() on it, typically during the remove phase. + */ +struct device *dev_pm_domain_attach_by_id(struct device *dev, + unsigned int index) +{ + if (dev->pm_domain) + return ERR_PTR(-EEXIST); + + return genpd_dev_pm_attach_by_id(dev, index); +} +EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id); + +/** + * dev_pm_domain_attach_by_name - Associate a device with one of its PM domains. + * @dev: The device used to lookup the PM domain. + * @name: The name of the PM domain. + * + * For a detailed function description, see dev_pm_domain_attach_by_id(). + */ +struct device *dev_pm_domain_attach_by_name(struct device *dev, + const char *name) +{ + if (dev->pm_domain) + return ERR_PTR(-EEXIST); + + return genpd_dev_pm_attach_by_name(dev, name); +} +EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name); + +/** + * dev_pm_domain_detach - Detach a device from its PM domain. + * @dev: Device to detach. + * @power_off: Used to indicate whether we should power off the device. + * + * This functions will reverse the actions from dev_pm_domain_attach(), + * dev_pm_domain_attach_by_id() and dev_pm_domain_attach_by_name(), thus it + * detaches @dev from its PM domain. Typically it should be invoked during the + * remove phase, either from subsystem level code or from drivers. + * + * Callers must ensure proper synchronization of this function with power + * management callbacks. + */ +void dev_pm_domain_detach(struct device *dev, bool power_off) +{ + if (dev->pm_domain && dev->pm_domain->detach) + dev->pm_domain->detach(dev, power_off); +} +EXPORT_SYMBOL_GPL(dev_pm_domain_detach); + +/** + * dev_pm_domain_start - Start the device through its PM domain. + * @dev: Device to start. + * + * This function should typically be called during probe by a subsystem/driver, + * when it needs to start its device from the PM domain's perspective. Note + * that, it's assumed that the PM domain is already powered on when this + * function is called. + * + * Returns 0 on success and negative error values on failures. + */ +int dev_pm_domain_start(struct device *dev) +{ + if (dev->pm_domain && dev->pm_domain->start) + return dev->pm_domain->start(dev); + + return 0; +} +EXPORT_SYMBOL_GPL(dev_pm_domain_start); + +/** + * dev_pm_domain_set - Set PM domain of a device. + * @dev: Device whose PM domain is to be set. + * @pd: PM domain to be set, or NULL. + * + * Sets the PM domain the device belongs to. The PM domain of a device needs + * to be set before its probe finishes (it's bound to a driver). + * + * This function must be called with the device lock held. + */ +void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd) +{ + if (dev->pm_domain == pd) + return; + + WARN(pd && device_is_bound(dev), + "PM domains can only be changed for unbound devices\n"); + dev->pm_domain = pd; + device_pm_check_callbacks(dev); +} +EXPORT_SYMBOL_GPL(dev_pm_domain_set); |