On Wed, Feb 24, 2021 at 7:38 AM Michal Simek <michal.simek@xxxxxxxxxx> wrote: > > Hi Rob, > > On 2/11/21 3:42 PM, Rob Herring wrote: > > On Thu, Feb 11, 2021 at 3:35 AM Michal Simek <michal.simek@xxxxxxxxxx> wrote: > >> > >> Hi Rob, > >> > >> On 2/10/21 11:22 PM, Rob Herring wrote: > >>> On Tue, Feb 09, 2021 at 11:48:09AM +0100, Michal Simek wrote: > >>>> From: Piyush Mehta <piyush.mehta@xxxxxxxxxx> > >>>> > >>>> Added dt binding for usb5744 driver. > >>>> > >>>> Signed-off-by: Piyush Mehta <piyush.mehta@xxxxxxxxxx> > >>>> Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx> > >>>> --- > >>>> > >>>> Changes in v2: None > >>>> > >>>> .../bindings/usb/microchip,usb5744.yaml | 56 +++++++++++++++++++ > >>>> MAINTAINERS | 1 + > >>>> 2 files changed, 57 insertions(+) > >>>> create mode 100644 Documentation/devicetree/bindings/usb/microchip,usb5744.yaml > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/usb/microchip,usb5744.yaml b/Documentation/devicetree/bindings/usb/microchip,usb5744.yaml > >>>> new file mode 100644 > >>>> index 000000000000..fe222f6db81d > >>>> --- /dev/null > >>>> +++ b/Documentation/devicetree/bindings/usb/microchip,usb5744.yaml > >>>> @@ -0,0 +1,56 @@ > >>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > >>>> +%YAML 1.2 > >>>> +--- > >>>> +$id: "http://devicetree.org/schemas/usb/microchip,usb5744.yaml#"; > >>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"; > >>>> + > >>>> +title: Bindings for the Microchip USB5744 4-port Hub Controller > >>>> + > >>>> +description: > >>>> + Microchip’s USB5744 SmartHub™ IC is a 4 port, SuperSpeed (SS)/Hi-Speed (HS), > >>>> + low power, low pin count configurable and fully compliant with the USB 3.1 > >>>> + Gen 1 specification. The USB5744 also supports Full Speed (FS) and Low Speed > >>>> + (LS) USB signaling, offering complete coverage of all defined USB operating > >>>> + speeds. The new SuperSpeed hubs operate in parallel with the USB 2.0 > >>>> + controller, so 5 Gbps SuperSpeed data transfers are not affected by slower > >>>> + USB 2.0 traffic. > >>>> + > >>>> +maintainers: > >>>> + - Piyush Mehta <piyush.mehta@xxxxxxxxxx> > >>>> + - Michal Simek <michal.simek@xxxxxxxxxx> > >>>> + > >>>> +properties: > >>>> + compatible: > >>>> + const: microchip,usb5744 > >>>> + > >>>> + reg: > >>>> + maxItems: 1 > >>>> + description: | > >>>> + Specifies the i2c slave address, it is required and should be 0x2d > >>>> + if I2C is used. > >>> > >>> If I2C is not used, then this should be underneath the USB host as a USB > >>> device. That also implies a different compatible string. I'd suggest you > >>> just say I2C is required if that's your use. > >> > >> We can't say that i2c is required because we have both cases. One is > >> really usb hub connected over i2c which at least requires to send one > >> smbus command to start operate. But it can be extended to add more > >> features - limit speeds, disable ports, etc. > >> > >> And the second is really the same usb hub without i2c connected which > >> runs in default mode. But reset is required to ensure proper reset > >> sequence. > >> Hub also have external clock chip which is not handled now because it is > >> just crystal on the board but if you want I can also model it via fixed > >> clock and call clock enable for it. > >> > >> It is the same use case as is with > >> Documentation/devicetree/bindings/usb/usb3503.txt > > > > Yes, there are examples of how we don't want to do it. > > ok. > > > > >> Can you please elaborate why different compatible string should be used? > >> It is still the same device and not quite sure why different compatible > >> string should be used. > >> > >> Do you also want to example where this node is the part of usb node? > > > > See usb/usb-device.txt. And there is this[1] under review. > > > > For these cases with I2C, I'd really rather see the hub always under > > the USB bus with a link to the I2C bus when connected. > > I read that thread and also looked at his device and it is very similar > to this one. Binding should also have information about i2c or spi. It > is the same case here that you can use this hub without any bus > connected which works in default mode. Or when i2c/smbus is connected > and the hub is waiting for initialization sequence. And I expect spi > behaves very similarly but don't have this setup here. > > Do we have any binding doc which is using suggested bus link? 'i2c-bus' or 'ddc-i2c-bus' properties for I2C. Don't think we have anything for SPI, but I'd expect it would be similar though we'd need a cell for the chip-select. Rob
