u-boot/include/power-domain.h

1 /* SPDX-License-Identifier: GPL-2.0 */
10  * A power domain is a portion of an SoC or chip that is powered by a
11  * switchable source of power. In many cases, software has control over the
12  * power domain, and can turn the power source on or off. This is typically
13  * done to save power by powering off unused devices, or to enable software
15  * drivers to turn power domains on and off.
17  * A driver that implements UCLASS_POWER_DOMAIN is a power domain controller or
18  * provider. A controller will often implement multiple separate power domains,
20  * power-domain-uclass.h describes the interface which power domain controllers
23  * Depending on the power domain controller hardware, changing the state of a
24  * power domain may require performing related operations on other resources.
25  * For example, some power domains may require certain clocks to be enabled
26  * whenever the power domain is powered on, or during the time when the power
27  * domain is transitioning state. These details are implementation-specific
32  * Power domain consumers/clients are the drivers for HW modules within the
33  * power domain. This header file describes the API used by those drivers.
36  * be the sole logic contained within a power domain. In such cases, it is
37  * logical for the relevant device driver to directly control that power
39  * may be contained in a single power domain. Any logic require to co-ordinate
42  * by which power domains are managed.
48  * struct power_domain - A handle to (allowing control of) a single power domain.
50  * Clients provide storage for power domain handles. The content of the
51  * structure is managed solely by the power domain API and power domain
52  * drivers. A power domain struct is initialized by "get"ing the power domain
53  * struct. The power domain struct is passed to all other power domain APIs to
54  * identify which power domain to operate upon.
56  * @dev: The device which implements the power domain.
57  * @id: The power domain ID within the provider.
59  * Currently, the power domain API assumes that a single integer ID is enough
60  * to identify and configure any power domain for any power domain provider. If
62  * to either (a) add more fields to allow power domain providers to store
78  * power_domain_get - Get/request the power domain for a device.
80  * This looks up and requests a power domain. Each device is assumed to have
81  * a single (or, at least one) power domain associated with it somehow, and
83  * provider power domain may be via device-tree properties, board-provided
87  * @power_domain	A pointer to a power domain struct to initialize.
96 	return -ENOSYS;  in power_domain_get()
101  * power_domain_get_by_index - Get the indexed power domain for a device.
104  * @power_domain:	A pointer to a power domain struct to initialize.
105  * @index:		Power domain index to be powered on.
117 	return -ENOSYS;  in power_domain_get_by_index()
122  * power_domain_free - Free a previously requested power domain.
124  * @power_domain:	A power domain struct that was previously successfully
133 	return -ENOSYS;  in power_domain_free()
138  * power_domain_on - Enable power to a power domain.
140  * @power_domain:	A power domain struct that was previously successfully
149 	return -ENOSYS;  in power_domain_on()
154  * power_domain_off - Disable power ot a power domain.
156  * @power_domain:	A power domain struct that was previously successfully
165 	return -ENOSYS;  in power_domain_off()