| .. 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 |
