> -----Original Message----- > From: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> > Sent: Monday, October 21, 2024 6:26 PM > To: Krzysztof Kozlowski <krzk@xxxxxxxxxx> > Cc: POPESCU Catalin <catalin.popescu@xxxxxxxxxxxxxxxxxxxx>; Sherry Sun > <sherry.sun@xxxxxxx>; Amitkumar Karwar <amitkumar.karwar@xxxxxxx>; > Neeraj Sanjay Kale <neeraj.sanjaykale@xxxxxxx>; marcel@xxxxxxxxxxxx; > luiz.dentz@xxxxxxxxx; robh@xxxxxxxxxx; krzk+dt@xxxxxxxxxx; > conor+dt@xxxxxxxxxx; p.zabel@xxxxxxxxxxxxxx; linux- > bluetooth@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; GEO-CHHER-bsp-development <bsp- > development.geo@xxxxxxxxxxxxxxxxxxxx> > Subject: Re: [PATCH 1/2] dt-bindings: net: bluetooth: nxp: add support for > supply and reset > > 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 > Actually we should use vcc-supply to control the PDn pin, this is the power supply for NXP wifi/BT. Best Regards Sherry
