This is a proposed power sequencer subsystem. This is a generification of the MMC pwrseq code. The subsystem tries to abstract the idea of complex power-up/power-down/reset of the devices. The primary set of devices that promted me to create this patchset is the Qualcomm BT+WiFi family of chips. They reside on serial+platform or serial + SDIO interfaces (older generations) or on serial+PCIe (newer generations). They require a set of external voltage regulators to be powered on and (some of them) have separate WiFi and Bluetooth enable GPIOs. The major drawback for now is the lack of proper PCIe integration At this moment support for PCIe is hacked up to be able to test the PCIe part of qca6390. Proper PCIe support would require automatically powering up the devices before the scan basing on the proper device structure in the device tree. This two last patches are noted as WIP and are included into the patchset for the purpose of testing WiFi on newer chips (like qca6390/qca6391). Changes since RFC v2: - Add documentation for the pwrseq code. Document data structures, macros and exported functions. - Export of_pwrseq_xlate_onecell() - Add separate pwrseq_set_drvdata() function to follow the typical API design - Remove pwrseq_get_optional()/devm_pwrseq_get_optional() - Moved code to handle old mmc-pwrseq binding to the MMC patch - Split of_pwrseq_xlate_onecell() support to a separate patch Changes since RFC v1: - Provider pwrseq fallback support - Implement fallback support in pwrseq_qca. - Mmove susclk handling to pwrseq_qca. - Significantly simplify hci_qca.c changes, by dropping all legacy code. Now hci_qca uses only pwrseq calls to power up/down bluetooth parts of the chip.
