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authorLinus Torvalds <torvalds@linux-foundation.org>2024-07-15 17:34:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-07-15 17:34:31 -0700
commite763c9ec71dd462337d0b671ec5014b737c5342e (patch)
treecb077cc4599fb10db856d74ff7ac8a7508c1ca8d /LICENSES
parentcdf471c348c1200ca243775b4b8d6eaa6d7f3979 (diff)
parent50b040ef373293b4ae2ecdc5873daa4656724868 (diff)
Merge tag 'pwrseq-updates-for-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux
Pull power sequencing updates from Bartosz Golaszewski: "This has been in development since last year's Linux Plumbers Conference and was inspired by the need to enable support upstream for Bluetooth/WLAN chips on Qualcomm platforms. The main problem we're fixing is powering up devices which are represented as separate objects in the kernel (binding to different drivers) but which share parts of the power-up sequence and thus need some kind of a mediator who knows the possible interactions and can assure they don't interfere with neither device's bring up. An example of such an inter-driver interaction is the WCN family of BT/WLAN chips from Qualcomm of which some models require the user to observe a certain delay between driving the bt-enable and wlan-enable GPIOs. This is not a new problem but up to this point all attempts at addressing it ended up hitting one wall or another and being dropped. The main obstacle was the fact that most these attempts tried to introduce the concept of a "power sequence" into the device-tree bindings which breaks the main DT rule: describe the hardware, not its behavior. The solution I proposed focuses on making the power sequencer drivers interpret the actual HW description flexibly. More details on that are in the linked cover letter. The second problem fixed here is powering up PCI devices before they are detected on the bus. This is achieved by creating special platform devices for device-tree nodes describing hard-wired PCI devices which bind to the so-called PCI power control drivers which enable required resources and trigger a bus rescan once the controlled device is up then setup the correct devlink hierarchy for power-management. By combining the two new frameworks we implemented the power sequencing PCI power control driver which is capable of powering up the WLAN modules of the QCom WCN family of chipsets. All this has spent a significant amount of time in linux-next and enabled WLAN/BT support on several Qualcomm platforms. To further prove that this is useful and needed: right after this was picked up into next, I was sent a series using the subsystem for a similar use-case on Amlogic platforms. This contains the core power sequencing framework, the first driver, PCI changes using the pwrseq library (blessed by Bjorn Helgaas) and some fixes that came later" * tag 'pwrseq-updates-for-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: PCI/pwrctl: only call of_platform_populate() if CONFIG_OF is enabled power: sequencing: simplify returning pointer without cleanup PCI/pwrctl: Add a PCI power control driver for power sequenced devices PCI/pwrctl: Add PCI power control core code PCI/pwrctl: Create platform devices for child OF nodes of the port node PCI/pwrctl: Reuse the OF node for power controlled devices PCI: Hold the rescan mutex when scanning for the first time power: pwrseq: add a driver for the PMU module on the QCom WCN chipsets power: sequencing: implement the pwrseq core
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