On Wed, 17 Jan 2024 at 20:16, Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> wrote: > > On Wed, 17 Jan 2024 at 18:08, Bartosz Golaszewski <brgl@xxxxxxxx> wrote: > > > > From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx> > > > > The responses to the RFC were rather positive so here's a proper series. > > > > During last year's Linux Plumbers we had several discussions centered > > around the need to power-on PCI devices before they can be detected on > > the bus. > > > > The consensus during the conference was that we need to introduce a > > class of "PCI slot drivers" that would handle the power-sequencing. > > > > After some additional brain-storming with Manivannan and the realization > > that DT maintainers won't like adding any "fake" nodes not representing > > actual devices, we decided to reuse existing PCI infrastructure. > > > > The general idea is to instantiate platform devices for child nodes of > > the PCIe port DT node. For those nodes for which a power-sequencing > > driver exists, we bind it and let it probe. The driver then triggers a > > rescan of the PCI bus with the aim of detecting the now powered-on > > device. The device will consume the same DT node as the platform, > > power-sequencing device. We use device links to make the latter become > > the parent of the former. > > > > The main advantage of this approach is not modifying the existing DT in > > any way and especially not adding any "fake" platform devices. > > I'd still like to see how this can be extended to handle BT power up, > having a single entity driving both of the BT and WiFI. > > The device tree changes behave in exactly the opposite way: they > define regulators for the WiFi device, while the WiFi is not being > powered by these regulators. Both WiFi and BT are powered by the PMU, > which in turn consumes all specified regulators. Some additional justification, why I think that this should be modelled as a single instance instead of two different items. This is from msm-5.10 kernel: ===== CUT HERE ===== /** * cnss_select_pinctrl_enable - select WLAN_GPIO for Active pinctrl status * @plat_priv: Platform private data structure pointer * * For QCA6490, PMU requires minimum 100ms delay between BT_EN_GPIO off and * WLAN_EN_GPIO on. This is done to avoid power up issues. * * Return: Status of pinctrl select operation. 0 - Success. */ static int cnss_select_pinctrl_enable(struct cnss_plat_data *plat_priv) ===== CUT HERE ===== Also see the bt_configure_gpios() function in the same kernel. > > > > > Changes since RFC: > > - move the pwrseq functionality out of the port driver and into PCI core > > - add support for WCN7850 to the first pwrseq driver (and update bindings) > > - describe the WLAN modules in sm8550-qrd and sm8650-qrd > > - rework Kconfig options, drop the defconfig changes from the series as > > they are no longer needed > > - drop the dt-binding changes for PCI vendor codes > > - extend the DT bindings for ath11k_pci with strict property checking > > - various minor tweaks and fixes > > > > Bartosz Golaszewski (7): > > arm64: dts: qcom: qrb5165-rb5: describe the WLAN module of QCA6390 > > PCI: create platform devices for child OF nodes of the port node > > PCI: hold the rescan mutex when scanning for the first time > > PCI/pwrseq: add pwrseq core code > > dt-bindings: wireless: ath11k: describe QCA6390 > > dt-bindings: wireless: ath11k: describe WCN7850 > > PCI/pwrseq: add a pwrseq driver for QCA6390 > > > > Neil Armstrong (2): > > arm64: dts: qcom: sm8550-qrd: add Wifi nodes > > arm64: dts: qcom: sm8650-qrd: add Wifi nodes > > > > .../net/wireless/qcom,ath11k-pci.yaml | 89 ++++++ > > arch/arm64/boot/dts/qcom/qrb5165-rb5.dts | 29 ++ > > arch/arm64/boot/dts/qcom/sm8250.dtsi | 10 + > > arch/arm64/boot/dts/qcom/sm8550-qrd.dts | 37 +++ > > arch/arm64/boot/dts/qcom/sm8550.dtsi | 10 + > > arch/arm64/boot/dts/qcom/sm8650-qrd.dts | 29 ++ > > arch/arm64/boot/dts/qcom/sm8650.dtsi | 10 + > > drivers/pci/Kconfig | 1 + > > drivers/pci/Makefile | 1 + > > drivers/pci/bus.c | 9 +- > > drivers/pci/probe.c | 2 + > > drivers/pci/pwrseq/Kconfig | 16 ++ > > drivers/pci/pwrseq/Makefile | 4 + > > drivers/pci/pwrseq/pci-pwrseq-qca6390.c | 267 ++++++++++++++++++ > > drivers/pci/pwrseq/pwrseq.c | 82 ++++++ > > drivers/pci/remove.c | 3 +- > > include/linux/pci-pwrseq.h | 24 ++ > > 17 files changed, 621 insertions(+), 2 deletions(-) > > create mode 100644 drivers/pci/pwrseq/Kconfig > > create mode 100644 drivers/pci/pwrseq/Makefile > > create mode 100644 drivers/pci/pwrseq/pci-pwrseq-qca6390.c > > create mode 100644 drivers/pci/pwrseq/pwrseq.c > > create mode 100644 include/linux/pci-pwrseq.h > > > > -- > > 2.40.1 > > > > > > > -- > With best wishes > Dmitry -- With best wishes Dmitry
