On 24-10-21, Krzysztof Kozlowski wrote: > On 21/10/2024 08:41, Marco Felsch wrote: > > On 24-10-07, Krzysztof Kozlowski wrote: > >> On 07/10/2024 14:58, POPESCU Catalin wrote: > >>>>>> > >>>>>> + vcc-supply: > >>>>>> + description: > >>>>>> + phandle of the regulator that provides the supply voltage. > >>>>>> + > >>>>>> + reset-gpios: > >>>>>> + description: > >>>>>> + Chip powerdown/reset signal (PDn). > >>>>>> + > >>>>> Hi Catalin, > >>>>> > >>>>> For NXP WIFI/BT chip, WIFI and BT share the one PDn pin, which means that both wifi and BT controller will be powered on and off at the same time. > >>>>> Taking the M.2 NXP WIFI/BT module as an example, pin56(W_DISABLE1) is connected to the WIFI/BT chip PDn pin, we has already controlled this pin in the corresponding PCIe/SDIO controller dts nodes. > >>>>> It is not clear to me what exactly pins for vcc-supply and reset-gpios you describing here. Can you help understand the corresponding pins on M.2 interface as an example? Thanks. > >>> > >>> Hi Sherry, > >>> > >>> Regulators and reset controls being refcounted, we can then implement > >>> powerup sequence in both bluetooth/wlan drivers and have the drivers > >>> operate independently. This way bluetooth driver would has no dependance > >>> on the wlan driver for : > >>> > >>> - its power supply > >>> > >>> - its reset pin (PDn) > >>> > >>> - its firmware (being downloaded as part of the combo firmware) > >>> > >>> For the wlan driver we use mmc power sequence to drive the chip reset > >>> pin and there's another patchset that adds support for reset control > >>> into the mmc pwrseq simple driver. > >>> > >>>> Please wrap your replies. > >>>> > >>>> It seems you need power sequencing just like Bartosz did for Qualcomm WCN. > >>> > >>> Hi Krzysztof, > >>> > >>> I'm not familiar with power sequencing, but looks like way more > >>> complicated than reset controls. So, why power sequencing is recommended > >>> here ? Is it b/c a supply is involved ? > >> > >> Based on earlier message: > >> > >> "For NXP WIFI/BT chip, WIFI and BT share the one PDn pin, which means > >> that both wifi and BT controller will be powered on and off at the same > >> time." > >> > >> but maybe that's not needed. No clue, I don't know the hardware. But be > >> carefully what you write in the bindings, because then it will be ABI. > > > > We noticed the new power-sequencing infrastructure which is part of 6.11 > > too but I don't think that this patch is wrong. The DT ABI won't break > > if we switch to the power-sequencing later on since the "reset-gpios" > > are not marked as required. So it is up to the driver to handle it > > either via a separate power-sequence driver or via "power-supply" and > > "reset-gpios" directly. > > That's not the point. We expect correct hardware description. If you say > now it has "reset-gpios" but later say "actually no, because it has > PMU", I respond: no. Describe the hardware, not current Linux. I know that DT abstracts the HW. That said I don't see the problem with this patch. The HW is abstracted just fine: shared PDn -> reset-gpios shared power-supply -> vcc-supply Right now the DT ABI for the BT part is incomplete since it assume a running WLAN part or some hog-gpios to pull the device out-of-reset which is addressed by this patchset. Making use of the new power-sequencing fw is a Linux detail and I don't see why the DT can't be extended later on. We always extend the DT if something is missing or if we found a better way to handle devices. Regards, Marco
