1 .. SPDX-License-Identifier: GPL-2.0 2 3 ===================================== 4 Texas Instruments TPS6594 PFSM driver 5 ===================================== 6 7 Author: Julien Panis (jpanis@baylibre.com) 8 9 Overview 10 ======== 11 12 Strictly speaking, PFSM (Pre-configurable Finite State Machine) is not 13 hardware. It is a piece of code. 14 15 The TPS6594 PMIC (Power Management IC) integrates a state machine which 16 manages operational modes. Depending on the current operational mode, 17 some voltage domains remain energized while others can be off. 18 19 The PFSM driver can be used to trigger transitions between configured 20 states. It also provides R/W access to the device registers. 21 22 Supported chips 23 --------------- 24 25 - tps6594-q1 26 - tps6593-q1 27 - lp8764-q1 28 29 Driver location 30 =============== 31 32 drivers/misc/tps6594-pfsm.c 33 34 Driver type definitions 35 ======================= 36 37 include/uapi/linux/tps6594_pfsm.h 38 39 Driver IOCTLs 40 ============= 41 42 :c:macro::`PMIC_GOTO_STANDBY` 43 All device resources are powered down. The processor is off, and 44 no voltage domains are energized. 45 46 :c:macro::`PMIC_GOTO_LP_STANDBY` 47 The digital and analog functions of the PMIC, which are not 48 required to be always-on, are turned off (low-power). 49 50 :c:macro::`PMIC_UPDATE_PGM` 51 Triggers a firmware update. 52 53 :c:macro::`PMIC_SET_ACTIVE_STATE` 54 One of the operational modes. 55 The PMICs are fully functional and supply power to all PDN loads. 56 All voltage domains are energized in both MCU and Main processor 57 sections. 58 59 :c:macro::`PMIC_SET_MCU_ONLY_STATE` 60 One of the operational modes. 61 Only the power resources assigned to the MCU Safety Island are on. 62 63 :c:macro::`PMIC_SET_RETENTION_STATE` 64 One of the operational modes. 65 Depending on the triggers set, some DDR/GPIO voltage domains can 66 remain energized, while all other domains are off to minimize 67 total system power. 68 69 Driver usage 70 ============ 71 72 See available PFSMs:: 73 74 # ls /dev/pfsm* 75 76 Dump the registers of pages 0 and 1:: 77 78 # hexdump -C /dev/pfsm-0-0x48 79 80 See PFSM events:: 81 82 # cat /proc/interrupts 83 84 Userspace code example 85 ---------------------- 86 87 samples/pfsm/pfsm-wakeup.c
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