| Message ID | 20220127104905.899341-1-o.rempel@pengutronix.de (mailing list archive) |
|---|---|
| Headers | show |
| Series | usbnet: add "label" support | expand |
On Thu, Jan 27, 2022 at 11:49:01AM +0100, Oleksij Rempel wrote: > Add devicetree label property for usbnet devices and related yaml > schema. That says _what_ you are doing, but not _why_ you would want to do such a crazy thing, nor what problem you are attempting to solve here. thanks, greg k-h
On 27.01.22 11:57, Greg KH wrote: > On Thu, Jan 27, 2022 at 11:49:01AM +0100, Oleksij Rempel wrote: >> Add devicetree label property for usbnet devices and related yaml >> schema. > That says _what_ you are doing, but not _why_ you would want to do such > a crazy thing, nor what problem you are attempting to solve here. Hi, could you at least describe what kind of systems we are talking about? Is this for a limited set of embedded devices? Are we talking about devices embedded on a motherboard, which happen to be connected by USB? That is, are we talking about another kind of firmware we are to take information about devices from? And if so, why are you proposing to solve this on the USB driver level? It looks to me like those devices are addressed by their USB path. But still there is no reason that a USB driver should actively interpret firmware stuff that comes from a source that tells us nothing about USB properties. In other words it looks to me like you are trying to put a generic facility for getting device properties into a specific driver. The question whether device names should be read out of firmware is not a USB question. I would suggest you implement a generic facility in the network layer and if everybody is happy with that obviously usbnet can pass through a pointer for that to operate on. Frankly, it looks to me like you are implementing only a subset of what device tree could contain for your specific use case. Regards Oliver
On Thu, Feb 03, 2022 at 10:34:25AM +0100, Oliver Neukum wrote: > > On 27.01.22 11:57, Greg KH wrote: > > On Thu, Jan 27, 2022 at 11:49:01AM +0100, Oleksij Rempel wrote: > >> Add devicetree label property for usbnet devices and related yaml > >> schema. > > That says _what_ you are doing, but not _why_ you would want to do such > > a crazy thing, nor what problem you are attempting to solve here. > > could you at least describe what kind of systems we are talking > about? Is this for a limited set of embedded devices? > Are we talking about devices embedded on a motherboard, > which happen to be connected by USB? In this particular use case there is a PCB with a imx6 SoC with hard wired USB attached USB-Ethernet-MAC adapters. One of these adapters is connected in the same PCB to an Ethernet switch chip. There is a DSA driver for the switch, so we want to describe the whole boards in a DT. Putting a label in the DT that renames the network interface is "nice to have" but not so important. As the DT DSA bindings rely on linking a MAC phandle to the switch we need to describe the USB Ethernet adapter in the DT, this is more important. See this discussion: https://lore.kernel.org/all/20220127120039.GE9150@pengutronix.de/ > That is, are we talking about another kind of firmware > we are to take information about devices from? There is no other firmware involved. The switch chip is attached via RGMII to the USB/MAC and with SPI to the CPU for the configuration interface. (I2C to the CPU or MDIO to the USB/MAC would be another option for the configuration interface.) > And if so, why are you proposing to solve this on the > USB driver level? > It looks to me like those devices are addressed by > their USB path. But still there is no reason that a USB > driver should actively interpret firmware stuff that > comes from a source that tells us nothing about USB > properties. > In other words it looks to me like you are trying to put > a generic facility for getting device properties into > a specific driver. The question whether device names > should be read out of firmware is not a USB question. > > I would suggest you implement a generic facility > in the network layer and if everybody is happy with that > obviously usbnet can pass through a pointer for that > to operate on. Frankly, it looks to me like you are > implementing only a subset of what device tree > could contain for your specific use case. Sounds good, but we'll focus on the DSA use case, as this is more important. So patches 1 and 2 of this patches set have highest prio for us. Regards, Oleksij & Marc
On 03.02.22 11:27, Oleksij Rempel wrote: > On Thu, Feb 03, 2022 at 10:34:25AM +0100, Oliver Neukum wrote: >> On 27.01.22 11:57, Greg KH wrote: >>> On Thu, Jan 27, 2022 at 11:49:01AM +0100, Oleksij Rempel wrote: >>> > In this particular use case there is a PCB with a imx6 SoC with hard > wired USB attached USB-Ethernet-MAC adapters. One of these adapters is > connected in the same PCB to an Ethernet switch chip. There is a DSA > driver for the switch, so we want to describe the whole boards in a DT. OK, so you are talking about what is technically an embedded device with a DT as is usual for such devices. > Putting a label in the DT that renames the network interface is "nice to > have" but not so important. Well, this applies to your particular device only, doesn't it? > > As the DT DSA bindings rely on linking a MAC phandle to the switch we > need to describe the USB Ethernet adapter in the DT, this is more > important. See this discussion: > > https://lore.kernel.org/all/20220127120039.GE9150@pengutronix.de/ And this one irks me. The USB list is not the place to talk about how to build switches. The question here is whether OF and DSA have features that need support in USB drivers. I am not ready to discuss the merits of features in OF >> I would suggest you implement a generic facility >> in the network layer and if everybody is happy with that >> obviously usbnet can pass through a pointer for that >> to operate on. Frankly, it looks to me like you are >> implementing only a subset of what device tree >> could contain for your specific use case. > Sounds good, but we'll focus on the DSA use case, as this is more > important. So patches 1 and 2 of this patches set have highest prio for > us. It looks to me like you want a layering violation for a special case. Is there any reason for you not to provide a generic helper in the networking core? Regards Oliver
Add devicetree label property for usbnet devices and related yaml schema. Oleksij Rempel (4): dt-bindings: net: add schema for ASIX USB Ethernet controllers dt-bindings: net: add schema for Microchip/SMSC LAN95xx USB Ethernet controllers dt-bindings: net: add "label" property for all usbnet Ethernet controllers usbnet: add support for label from device tree .../devicetree/bindings/net/asix,ax88178.yaml | 102 ++++++++++++++++++ .../bindings/net/microchip,lan95xx.yaml | 84 +++++++++++++++ .../devicetree/bindings/net/usbnet.yaml | 36 +++++++ drivers/net/usb/usbnet.c | 15 +++ 4 files changed, 237 insertions(+) create mode 100644 Documentation/devicetree/bindings/net/asix,ax88178.yaml create mode 100644 Documentation/devicetree/bindings/net/microchip,lan95xx.yaml create mode 100644 Documentation/devicetree/bindings/net/usbnet.yaml