Hi, On Thu, 19 Aug 2021 at 18:23, Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote: > > This is an RFC of the 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 > > 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. > > > > This patchset being an RFC tries to demonstrate the approach, design and > > usage of the pwrseq subsystem. Following issues are present in the RFC > > at this moment but will be fixed later if the overall approach would be > > viewed as acceptable: > > > > - No documentation > > While the code tries to be self-documenting proper documentation > > would be required. > > > > - Minimal device tree bindings changes > > There are no proper updates for the DT bindings (thus neither Rob > > Herring nor devicetree are included in the To/Cc lists). The dt > > schema changes would be a part of v1. > > > > - 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. > > > > ---------------------------------------------------------------- > > Dmitry Baryshkov (15): > > power: add power sequencer subsystem > > pwrseq: port MMC's pwrseq drivers to new pwrseq subsystem > > mmc: core: switch to new pwrseq subsystem > > ath10k: add support for pwrseq sequencing > > Bluetooth: hci_qca: merge qca_power into qca_serdev > > Bluetooth: hci_qca: merge init paths > > Bluetooth: hci_qca: merge qca_power_on with qca_regulators_init > > Bluetooth: hci_qca: futher rework of power on/off handling > > Bluetooth: hci_qca: add support for pwrseq > > any chance you can try to abandon patching hci_qca. The serdev support in hci_uart is rather hacking into old line discipline code and it is not aging well. It is really becoming a mess. I wanted to stay away from rewriting the BT code. But... New driver would have a bonus point that I don't have to be compatible with old bindings. In fact we can even make it the other way around: let the old driver always use regulators and make the new driver support only the pwrseq. Then it should be possible to drop the old hci_qca driver together with dropping the old bindings. > I would say that the Qualcomm serial devices could use a separate standalone serdev driver. A while I send an RFC for a new serdev driver. > > https://www.spinics.net/lists/linux-bluetooth/msg74918.html Any reason why your driver stayed as an RFC and never made it into the kernel? Do you plan to revive your old RFCs on H:4 and H:5? > There I had the idea that simple vendor specifics can be in that driver (like the Broadcom part I added there), but frankly the QCA specifics are a bit too specific and it should be a separate driver. However I think this would be a good starting point. > > In general a H:4 based Bluetooth driver is dead simple with the help of h4_recv.h helper we have in the kernel. The complicated part is the power management pieces or any vendor specific low-power protocol they are running on that serial line. And since you are touching this anyway, doing a driver from scratch might be lot simpler and cleaner. It would surely help all the new QCA device showing up in the future. -- With best wishes Dmitry
