The 06/28/2022 23:07, Michael Walle wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Am 2022-06-28 22:52, schrieb Horatiu Vultur: > > The 06/28/2022 22:28, Andy Shevchenko wrote: > > > EXTERNAL EMAIL: Do not click links or open attachments unless you know > > > the content is safe > > > > > > On Tue, Jun 28, 2022 at 5:17 PM Krzysztof Kozlowski > > > <krzysztof.kozlowski@xxxxxxxxxx> wrote: > > > > On 28/06/2022 17:09, Michael Walle wrote: > > > > Hi, > > > > Sorry for joint this late. > > > > > > > > ... > > > > > > > > Mh. Assume a SoC with an integrated ethernet switch. Some ports > > > > > are externally connected, some don't. I'd think they should be disabled, > > > > > no? Until now, all bindings I know, treat them as disabled. But OTOH > > > > > you still need to do some configurations on them, like disable port > > > > > forwarding, disable them or whatever. So the hardware is present, but > > > > > it is not connected to anything. > > > > > > > > I see your point and the meaning is okay... except that drivers don't > > > > touch disabled nodes. If a device (with some address space) is disabled, > > > > you do not write there "please be power off". Here the case is a bit > > > > different, because I think ports do not have their own address space. > > > > Yet it contradicts the logic - something is disabled in DT and you > > > > expect to perform actual operations on it. > > > > > > You beat me up to this comment, I also see a contradiction of what > > > "disabled" means in your, Michael, case and what it should be. > > > > > > If you need to perform an operation on some piece of HW, it has not to > > > be disabled. > > > > > > Or, you may deduce them by knowing how many ports in hardware (this is > > > usually done not by counting the nodes, but by a property) and do > > > whatever you want on ones, you have not listed (by port_num) in the > > > array of parsed children. > > > > It is not possible to have a defined for the MAX number of ports that > > supported by lan966x. Which is 8. And assigned that define to > > num_phys_ports instead of counting the entries in DT? > > You mean also for the lan9662? I'm pretty sure that doesn't > work. Have a look where num_phys_ports is used. One random > example: > https://elixir.bootlin.com/linux/latest/source/drivers/net/ethernet/microchip/lan966x/lan966x_main.c#L874 > > So if your switch only has 4 ports, then I'd guess you'll > access a non-existing register. Underneath lan662 and lan668 is the same chip. The HW people disable some ports/features on each platform but from what I know you will still be able to access the registers. > > -michael -- /Horatiu
