On Mon, Dec 10, 2012 at 3:18 PM, Roger Quadros <rogerq@xxxxxx> wrote: > On 12/06/2012 04:34 PM, Jassi Brar wrote: >>> >>> Yes, this is where we can think of a generic PHY driver to make sure thy >>> PHY has necessary resources enabled. In the Panda case it would be the >>> PHY clock and RESET gpio. >>> >> I wonder if ehci-omap should assume, besides regulator, a clock might >> also be need to setup for the transceiver chip. >> Maybe "usbhs_bdata" in board-omap4panda.c should have >> .reset_gpio_port[0] = GPIO_HUB_NRESET ? >> > > Just like the regulator, reset_gpio_port has nothing to do with OMAP > EHCI. So we would want to get rid of that too from the OMAP USB driver. > Looking at the code I realized we already book resources only for populated ports. Saving power from LAN9514 chip would come from a separate solution. So, for now when our transceiver, USB3320, has simple hardwired configuration probably just platform_data/DT would do. When we come across some programmable transceiver (like USB3503 over i2c), that might warrant a separate PHY driver. Still I don't think we could have a 'generic' phy driver. >> >>> The LAN95xx chip still needs to be powered up and the PHY driver isn't >>> the right place for that (though it could be done there as a hack). The >>> closest we can get to emulating right USB behavior is to map the >>> SET/CLEAR PORT_FEATURE of the root hub port to the regulator that powers >>> the LAN95xx. >>> >>> This way, we still don't fall in the dynamically probed space, so we >>> could still provide the regulator information to the ehci hub via >>> platform data and handle the regulator in ehci_hub_control >>> (Set/ClearPortFeature). I'm looking at this as a software workaround for >>> all platforms not implementing the EHCI set port power feature >>> correctly. The same could be repeated for other HCDs as well if required. >>> >> IMHO it's not a matter of platforms not implementing EHCI set port >> power feature correctly, we should think about onboard devices >> connected to onboard non-root hubs. Setups like LAN9514 on Panda (HSIC >> too ?) that don't run on VBUS of USB, would like their local supply to >> be treated as if it came from the parent hub's port i.e, tie together >> the USB's set port power control with their OOB regulated power supply >> (U9 on PandaBoard). >> > > On Pandaboards we are still talking about root hub ports. > > Do you know any of such platforms which power their USB devices out of > band for _non_ root hub ports? > I don't know of any. But I do believe we shouldn't discount that scenario. IIANW lan9514 doesn't take in VBUS because it wants to avoid 5V->3.3V regulating. What if someone designs an omap4 platform with 3 high-speed devices and the same concern in mind ? > Assuming they do exist, the only solution is to match platform data for > dynamically probed devices and deal with the regulators in the hub/port > driver. Something like Andy already proposed. > Yes, but I doubt if that is the only implementation. One USB specific solution could be to abstract out OOB port power control in, say, port-power.c which constructs a regulator topology mapped directly onto onboard devices', from a generic DT binding, platform_data, ACPI whatever. And then catch any set/clear_port_feature(POWER) call to enable/disable the regulator corresponding to that port. Where each regulator could be a board-specific virtual one, that does all that is necessary (like clock/reg hierarchy setup) to power up the device. Regards. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
