On 8/29/21 8:12 AM, Dmitry Baryshkov wrote: > This is the second RFC on 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. > > To ease migration to pwrseq and to provide compatibility with older > device trees, while keeping drivers simple, this iteration of RFC > introduces pwrseq fallback support: pwrseq driver can register fallback > providers. If another device driver requests pwrseq instance and none > was declared, the pwrseq fallback code would go through the list of > fallback providers and if the match is found, driver would return a > crafted pwrseq instance. For now this mechanism is limited to the OF > device matching, but it can be extended further to use any combination > of device IDs. > > 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. > > 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 bus scan depending on the proper > device structure in the device tree. > > 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. > I tested this here, on the Lenovo Yoga C630, after creating a patch to do basically the same thing as the db845c does. One thing I noticed, if PWRSEQ=y and the rest are =m, there is a build error. I suppose once the full set is posted and not RFC, I can send the patch for that. One question I have, if you don't mind, in patch 11, you add a second channel to qca power sequencer. I've added that here, but in the c630's dts, "vreg_l23a_3p3: ldo23" is empty, so I added the same numbers in for the regulator, and I'm wondering how to test that it's actually working correctly? -- steev
