On Wed, 31 Jan 2024 at 04:39, Chen-Yu Tsai <[email protected]> wrote:
>
> (+CC Ulf Hansson)
>
> On Wed, Jan 31, 2024 at 6:38 AM Rob Herring <[email protected]> wrote:
> >
> > On Tue, Jan 30, 2024 at 05:25:38PM +0100, Krzysztof Kozlowski wrote:
> > > On 30/01/2024 08:47, Chen-Yu Tsai wrote:
> > > > On Tue, Jan 30, 2024 at 3:37 PM Krzysztof Kozlowski
> > > > <[email protected]> wrote:
> > > >>
> > > >> On 30/01/2024 04:32, Chen-Yu Tsai wrote:
> > > >>> On Mon, Jan 29, 2024 at 3:34 PM Krzysztof Kozlowski
> > > >>> <[email protected]> wrote:
> > > >>>>
> > > >>>> On 29/01/2024 04:38, Chen-Yu Tsai wrote:
> > > >>>>
> > > >>>>>>> +allOf:
> > > >>>>>>> + - $ref: bluetooth-controller.yaml#
> > > >>>>>>> +
> > > >>>>>>> +properties:
> > > >>>>>>> + compatible:
> > > >>>>>>> + enum:
> > > >>>>>>> + - mediatek,mt7921s-bluetooth
> > > >>>>>>
> > > >>>>>> Can it be also WiFi on separate bus? How many device nodes do you need
> > > >>>>>> for this device?
> > > >>>>>
> > > >>>>> For the "S" variant, WiFi is also on SDIO. For the other two variants,
> > > >>>>> "U" and "E", WiFi goes over USB and PCIe respectively. On both those
> > > >>>>> variants, Bluetooth can either go over USB or UART. That is what I
> > > >>>>> gathered from the pinouts. There are a dozen GPIO pins which don't
> > > >>>>> have detailed descriptions though. If you want a comprehensive
> > > >>>>> binding of the whole chip and all its variants, I suggest we ask
> > > >>>>> MediaTek to provide it instead. My goal with the binding is to document
> > > >>>>> existing usage and allow me to upstream new device trees.
> > > >>>>>
> > > >>>>> For now we only need the Bluetooth node. The WiFi part is perfectly
> > > >>>>> detectable, and the driver doesn't seem to need the WiFi reset pin.
> > > >>>>> The Bluetooth driver only uses its reset pin to reset a hung controller.
> > > >>>>
> > > >>>> Then suffix "bluetooth" seems redundant.
> > > >>>
> > > >>> I think keeping the suffix makes more sense though. The chip is a two
> > > >>> function piece, and this only targets one of the functions. Also, the
> > > >>
> > > >> That's why I asked and you said there is only one interface: SDIO.
> > > >
> > > > There's only one interface, SDIO, but two SDIO functions. The two
> > > > functions, if both were to be described in the device tree, would
> > > > be two separate nodes. We just don't have any use for the WiFi one
> > > > right now. Does that make sense to keep the suffix?
> > >
> > > Number of functions does not really matter. Number of interfaces on the
> > > bus would matter. Why would you have two separate nodes for the same
> > > SDIO interface? Or do you want to say there are two interfaces?
>
> There is only one external interface. I don't know how the functions
> are stitched together internally.
>
> It could be that the separate functions have nothing in common other
> than sharing a standard external SDIO interface. Each function can be
> individually controlled, and operations for different functions are
> directed internally to the corresponding core.
>
> > Right, one device at 2 addresses on a bus should be a node with 2 "reg"
> > entries, not 2 nodes with 1 "reg" address each.
>
> AFAICU that's not what the MMC controller binding, which I quote below,
> says. It implies that each SDIO function shall be a separate node under
> the MMC controller node.
Yes, that's what we decided to go with, a long time ago. At least in
this particular case, I think it makes sense, as each function
(child-node) may also describe additional resources routed to each
function.
A typical description could be for a WiFi-Bluetooth combo-chip, where
each function may have its own clocks, irqs and regulators being
routed.
>
>
> patternProperties:
> "^.*@[0-9]+$":
> type: object
> description: |
> On embedded systems the cards connected to a host may need
> additional properties. These can be specified in subnodes to the
> host controller node. The subnodes are identified by the
> standard \'reg\' property. Which information exactly can be
> specified depends on the bindings for the SDIO function driver
> for the subnode, as specified by the compatible string.
>
> properties:
> compatible:
> description: |
> Name of SDIO function following generic names recommended
> practice
>
> reg:
> items:
> - minimum: 0
> maximum: 7
> description:
> Must contain the SDIO function number of the function this
> subnode describes. A value of 0 denotes the memory SD
> function, values from 1 to 7 denote the SDIO functions.
>
>
> ChenYu
Kind regards
Uffe
On Tue, Feb 6, 2024 at 1:50 AM Ulf Hansson <[email protected]> wrote:
>
> On Wed, 31 Jan 2024 at 04:39, Chen-Yu Tsai <[email protected]> wrote:
> >
> > (+CC Ulf Hansson)
> >
> > On Wed, Jan 31, 2024 at 6:38 AM Rob Herring <[email protected]> wrote:
> > >
> > > On Tue, Jan 30, 2024 at 05:25:38PM +0100, Krzysztof Kozlowski wrote:
> > > > On 30/01/2024 08:47, Chen-Yu Tsai wrote:
> > > > > On Tue, Jan 30, 2024 at 3:37 PM Krzysztof Kozlowski
> > > > > <[email protected]> wrote:
> > > > >>
> > > > >> On 30/01/2024 04:32, Chen-Yu Tsai wrote:
> > > > >>> On Mon, Jan 29, 2024 at 3:34 PM Krzysztof Kozlowski
> > > > >>> <[email protected]> wrote:
> > > > >>>>
> > > > >>>> On 29/01/2024 04:38, Chen-Yu Tsai wrote:
> > > > >>>>
> > > > >>>>>>> +allOf:
> > > > >>>>>>> + - $ref: bluetooth-controller.yaml#
> > > > >>>>>>> +
> > > > >>>>>>> +properties:
> > > > >>>>>>> + compatible:
> > > > >>>>>>> + enum:
> > > > >>>>>>> + - mediatek,mt7921s-bluetooth
> > > > >>>>>>
> > > > >>>>>> Can it be also WiFi on separate bus? How many device nodes do you need
> > > > >>>>>> for this device?
> > > > >>>>>
> > > > >>>>> For the "S" variant, WiFi is also on SDIO. For the other two variants,
> > > > >>>>> "U" and "E", WiFi goes over USB and PCIe respectively. On both those
> > > > >>>>> variants, Bluetooth can either go over USB or UART. That is what I
> > > > >>>>> gathered from the pinouts. There are a dozen GPIO pins which don't
> > > > >>>>> have detailed descriptions though. If you want a comprehensive
> > > > >>>>> binding of the whole chip and all its variants, I suggest we ask
> > > > >>>>> MediaTek to provide it instead. My goal with the binding is to document
> > > > >>>>> existing usage and allow me to upstream new device trees.
> > > > >>>>>
> > > > >>>>> For now we only need the Bluetooth node. The WiFi part is perfectly
> > > > >>>>> detectable, and the driver doesn't seem to need the WiFi reset pin.
> > > > >>>>> The Bluetooth driver only uses its reset pin to reset a hung controller.
> > > > >>>>
> > > > >>>> Then suffix "bluetooth" seems redundant.
> > > > >>>
> > > > >>> I think keeping the suffix makes more sense though. The chip is a two
> > > > >>> function piece, and this only targets one of the functions. Also, the
> > > > >>
> > > > >> That's why I asked and you said there is only one interface: SDIO.
> > > > >
> > > > > There's only one interface, SDIO, but two SDIO functions. The two
> > > > > functions, if both were to be described in the device tree, would
> > > > > be two separate nodes. We just don't have any use for the WiFi one
> > > > > right now. Does that make sense to keep the suffix?
> > > >
> > > > Number of functions does not really matter. Number of interfaces on the
> > > > bus would matter. Why would you have two separate nodes for the same
> > > > SDIO interface? Or do you want to say there are two interfaces?
> >
> > There is only one external interface. I don't know how the functions
> > are stitched together internally.
> >
> > It could be that the separate functions have nothing in common other
> > than sharing a standard external SDIO interface. Each function can be
> > individually controlled, and operations for different functions are
> > directed internally to the corresponding core.
> >
> > > Right, one device at 2 addresses on a bus should be a node with 2 "reg"
> > > entries, not 2 nodes with 1 "reg" address each.
> >
> > AFAICU that's not what the MMC controller binding, which I quote below,
> > says. It implies that each SDIO function shall be a separate node under
> > the MMC controller node.
>
> Yes, that's what we decided to go with, a long time ago. At least in
> this particular case, I think it makes sense, as each function
> (child-node) may also describe additional resources routed to each
> function.
>
> A typical description could be for a WiFi-Bluetooth combo-chip, where
> each function may have its own clocks, irqs and regulators being
> routed.
Rob, Krzysztof, does that help you understand why the binding and example
are written with bluetooth being one node and WiFi (should it ever be added)
being a separate node? It is based on the existing MMC controller bindings.
ChenYu
> >
> >
> > patternProperties:
> > "^.*@[0-9]+$":
> > type: object
> > description: |
> > On embedded systems the cards connected to a host may need
> > additional properties. These can be specified in subnodes to the
> > host controller node. The subnodes are identified by the
> > standard \'reg\' property. Which information exactly can be
> > specified depends on the bindings for the SDIO function driver
> > for the subnode, as specified by the compatible string.
> >
> > properties:
> > compatible:
> > description: |
> > Name of SDIO function following generic names recommended
> > practice
> >
> > reg:
> > items:
> > - minimum: 0
> > maximum: 7
> > description:
> > Must contain the SDIO function number of the function this
> > subnode describes. A value of 0 denotes the memory SD
> > function, values from 1 to 7 denote the SDIO functions.
> >
> >
> > ChenYu
>
> Kind regards
> Uffe