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