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diff --git a/Documentation/misc-devices/tps6594-pfsm.rst b/Documentation/misc-devices/tps6594-pfsm.rst new file mode 100644 index 000000000000..4ada37ccdcba --- /dev/null +++ b/Documentation/misc-devices/tps6594-pfsm.rst @@ -0,0 +1,87 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================== +Texas Instruments TPS6594 PFSM driver +===================================== + +Author: Julien Panis (jpanis@baylibre.com) + +Overview +======== + +Strictly speaking, PFSM (Pre-configurable Finite State Machine) is not +hardware. It is a piece of code. + +The TPS6594 PMIC (Power Management IC) integrates a state machine which +manages operational modes. Depending on the current operational mode, +some voltage domains remain energized while others can be off. + +The PFSM driver can be used to trigger transitions between configured +states. It also provides R/W access to the device registers. + +Supported chips +--------------- + +- tps6594-q1 +- tps6593-q1 +- lp8764-q1 + +Driver location +=============== + +drivers/misc/tps6594-pfsm.c + +Driver type definitions +======================= + +include/uapi/linux/tps6594_pfsm.h + +Driver IOCTLs +============= + +:c:macro::`PMIC_GOTO_STANDBY` +All device resources are powered down. The processor is off, and +no voltage domains are energized. + +:c:macro::`PMIC_GOTO_LP_STANDBY` +The digital and analog functions of the PMIC, which are not +required to be always-on, are turned off (low-power). + +:c:macro::`PMIC_UPDATE_PGM` +Triggers a firmware update. + +:c:macro::`PMIC_SET_ACTIVE_STATE` +One of the operational modes. +The PMICs are fully functional and supply power to all PDN loads. +All voltage domains are energized in both MCU and Main processor +sections. + +:c:macro::`PMIC_SET_MCU_ONLY_STATE` +One of the operational modes. +Only the power resources assigned to the MCU Safety Island are on. + +:c:macro::`PMIC_SET_RETENTION_STATE` +One of the operational modes. +Depending on the triggers set, some DDR/GPIO voltage domains can +remain energized, while all other domains are off to minimize +total system power. + +Driver usage +============ + +See available PFSMs:: + + # ls /dev/pfsm* + +Dump the registers of pages 0 and 1:: + + # hexdump -C /dev/pfsm-0-0x48 + +See PFSM events:: + + # cat /proc/interrupts + +Userspace code example +---------------------- + +samples/pfsm/pfsm-wakeup.c |