Messages in this thread |  | | Subject | Re: [PATCH v4 13/13] usb: otg: Add dual-role device (DRD) support | From | Roger Quadros <> | Date | Mon, 7 Sep 2015 12:51:46 +0300 |
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On 07/09/15 10:53, Li Jun wrote: > On Mon, Aug 24, 2015 at 04:21:24PM +0300, Roger Quadros wrote: >> DRD mode is a reduced functionality OTG mode. In this mode >> we don't support SRP, HNP and dynamic role-swap. >> >> In DRD operation, the controller mode (Host or Peripheral) >> is decided based on the ID pin status. Once a cable plug (Type-A >> or Type-B) is attached the controller selects the state >> and doesn't change till the cable in unplugged and a different >> cable type is inserted. >> >> As we don't need most of the complex OTG states and OTG timers >> we implement a lean DRD state machine in usb-otg.c. >> The DRD state machine is only interested in 2 hardware inputs >> 'id' and 'b_sess_vld'. >> >> Signed-off-by: Roger Quadros <rogerq@ti.com> >> --- >> drivers/usb/common/usb-otg.c | 178 +++++++++++++++++++++++++++++++++++++++++-- >> include/linux/usb/otg-fsm.h | 5 ++ >> include/linux/usb/otg.h | 2 + >> 3 files changed, 177 insertions(+), 8 deletions(-) >> > > ... ... > >> +/* Called when entering a DRD state */ >> +static void drd_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state) >> +{ >> + struct usb_otg *otgd = container_of(fsm, struct usb_otg, fsm); >> + >> + if (fsm->otg->state == new_state) >> + return; >> + >> + fsm->state_changed = 1; >> + dev_dbg(otgd->dev, "otg: set state: %s\n", >> + usb_otg_state_string(new_state)); >> + switch (new_state) { >> + case OTG_STATE_B_IDLE: >> + drd_set_protocol(fsm, PROTO_UNDEF); > > You didn't address this comment for your previous version. > > otg_drv_vbus(fsm, 0); > >> + break; >> + case OTG_STATE_B_PERIPHERAL: >> + drd_set_protocol(fsm, PROTO_GADGET); > > otg_drv_vbus(fsm, 0); > >> + break; >> + case OTG_STATE_A_HOST: > > otg_drv_vbus(fsm, 1); >
Sorry, I missed it. Will add in next version.
-- cheers, -roger
>> + drd_set_protocol(fsm, PROTO_HOST); >> + break; >> + case OTG_STATE_UNDEFINED: >> + case OTG_STATE_B_SRP_INIT: >> + case OTG_STATE_B_WAIT_ACON: >> + case OTG_STATE_B_HOST: >> + case OTG_STATE_A_IDLE: >> + case OTG_STATE_A_WAIT_VRISE: >> + case OTG_STATE_A_WAIT_BCON: >> + case OTG_STATE_A_SUSPEND: >> + case OTG_STATE_A_PERIPHERAL: >> + case OTG_STATE_A_WAIT_VFALL: >> + case OTG_STATE_A_VBUS_ERR: >> + default: >> + dev_warn(otgd->dev, "%s: otg: invalid state: %s\n", >> + __func__, usb_otg_state_string(new_state)); >> + break; >> + } >> + >> + fsm->otg->state = new_state; >> +} >> + > ... ... >
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