* Kishon Vijay Abraham I <kishon@xxxxxx> [150819 23:38]: > Hi, > > On Thursday 06 August 2015 02:17 PM, Tony Lindgren wrote: > > * Kishon Vijay Abraham I <kishon@xxxxxx> [150805 07:10]: > >> On Wednesday 05 August 2015 01:31 PM, Tony Lindgren wrote: > >>> > >>> We don't have syscon-otghs and to me it seems we need a PHY driver > >>> as I pointed out at: > >> > >> If *syscon-otghs* is not present, then it'll fall-back to using the *ctrl-module*. > > > > OK great. > > > >>> > >>> https://lkml.org/lkml/2015/6/24/231 > >> > >> Maybe I should have explained this in the previous thread. The *otghs* register > >> that we are trying to access here does _not_ belong to the PHY. It acts as > >> mailbox register from MUSB glue (TI integration layer) to MUSB core. That's why > >> it's programmed in the TI glue layer (omap2430.c). > >> > >> Even when we were using the older API [omap_control_usb_set_mode()], we first > >> call omap_musb_mailbox from the PHY drivers (phy-twl4030-usb.c, > >> phy-twl6030-usb.c) and then omap_musb_mailbox in the TI glue writes to the > >> control module instead of PHY drivers directly calling omap_control_usb_set_mode(). > > > > Hmm looking at "Table 18-204. CONTROL_USBOTGHS_CONTROL" it seems to mention > > "transceiver" for quite a few bitfields :) Probably what that register does > > is control a PHY over ULPI. > > OMAP4 uses UTMI PHY and it uses CONTROL_USBOTGHS_CONTROL too. So can't we make the phy-omap-usb2.c driver the onlly user of this register then and get rid of the mailbox stuff? I think the phy framework can handle everything now? > > So from Linux kernel point of view we're best off treating it as a PHY. > > It seems it should have a minimal PHY driver similar to what we have for > > dm816x control module in drivers/phy/phy-dm816x-usb.c. > > hmm.. IMHO CONTROL_USBOTGHS_CONTROL register belongs to the TI MUSB glue and > should be programmed in omap2430.c. It's better to get the opinion of Felipe > here. Felipe? > > > > For reference, here is the register bitfields pasted from 4460 TRM: > > > > Table 18-204. CONTROL_USBOTGHS_CONTROL, p3972 > > Physical Address 0x4A00 233C > > > > BIT NAME DESCIPTION > > 8 DISCHRGVBUS ... OTG transceiver does (not) discharge VBUS ... > > 7 CHRGVBUS ... OTG transceiver does (not) charge VBUS ... > > 6 IDPULLUP ... OTG transceiver does (not) drive VBUS ... > > 4 IDDIG ... OTG transceiver does (not) apply a pullup to ID ... > > 3 SESSEND ... VBUS voltage is above/below VB_SESS_END ... > > 2 VBUSVALID ... VBUS is above the threshold ... > > 1 BVALID ... VBUS voltage is above/below VB_SESS_VLD ... > > 0 AVALID ... BUS voltage is above/below VA_SESS_VLD ... > > > > So how about just adding ONTROL_USBOTGHS_CONTROL support to the existing > > drivers/phy/phy-omap-usb2.c instead? It seems that it should allow us > > to completely get rid of the custom mailbox stuff for MUSB 2430 support? > > Not in phy-omap-usb2.c. It's the UTMI PHY driver and is not used by OMAP3 based > boards (uses twl4030 ULPI PHY). CONTROL_USBOTGHS_CONTROL has to be programmed > for OMAP3 also. Hmm I don't think omap3 uses that register? There's no ti,control-phy anything in the omap3 dts files? And no USBOTGHS_CONTROL in the TRM? Or am I missing something here? Regards, Tony -- 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
