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@xxxxxx>
>> ---
>> 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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