On 17/07/15 11:14, Li Jun wrote:
> Hi,
>
> On Wed, Jul 08, 2015 at 01:19:36PM +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 'vbus; that are still passed via the origintal struct otg_fsm.
>>
>> Most of the usb-otg.c functionality remains the same except
>> adding a new parameter to usb_otg_register() to indicate that
>> the OTG controller needs to operate in DRD mode.
>>
>> Signed-off-by: Roger Quadros <rog...@ti.com>
>> ---
>> drivers/usb/common/usb-otg.c | 179
>> ++++++++++++++++++++++++++++++++++++++++---
>> include/linux/usb/otg-fsm.h | 8 +-
>> include/linux/usb/otg.h | 5 +-
>> 3 files changed, 180 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c
>> index 1f19001..9b89f4b 100644
>> --- a/drivers/usb/common/usb-otg.c
>> +++ b/drivers/usb/common/usb-otg.c
>> @@ -44,6 +44,7 @@ struct otg_hcd {
>> struct otg_data {
>> struct device *dev; /* HCD & GCD's parent device */
>>
>> + bool drd_only; /* Dual-role only, no OTG features */
>
> After we introduce otg caps, we can use hnp_support to judge it it's
> drd or OTG.
Yes. I will rebase this series on top of your otg_caps patches
and incorporate it.
>
>> struct otg_fsm fsm;
>> /* HCD, GCD and usb_otg_state are present in otg_fsm->otg
>> * HCD is bus_to_hcd(fsm->otg->host)
>> @@ -272,20 +273,172 @@ static int usb_otg_start_gadget(struct otg_fsm *fsm,
>> int on)
>> return 0;
>> }
>>
>> +/* Change USB protocol when there is a protocol change */
>> +static int drd_set_protocol(struct otg_fsm *fsm, int protocol)
>> +{
>> + struct otg_data *otgd = container_of(fsm, struct otg_data, fsm);
>> + int ret = 0;
>> +
>> + if (fsm->protocol != protocol) {
>> + dev_dbg(otgd->dev, "otg: changing role fsm->protocol= %d; new
>> protocol= %d\n",
>> + fsm->protocol, protocol);
>> + /* stop old protocol */
>> + if (fsm->protocol == PROTO_HOST)
>> + ret = otg_start_host(fsm, 0);
>> + else if (fsm->protocol == PROTO_GADGET)
>> + ret = otg_start_gadget(fsm, 0);
>> + if (ret)
>> + return ret;
>> +
>> + /* start new protocol */
>> + if (protocol == PROTO_HOST)
>> + ret = otg_start_host(fsm, 1);
>> + else if (protocol == PROTO_GADGET)
>> + ret = otg_start_gadget(fsm, 1);
>> + if (ret)
>> + return ret;
>> +
>> + fsm->protocol = protocol;
>> + return 0;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/* Called when entering a DRD state */
>> +static void drd_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
>> +{
>> + struct otg_data *otgd = container_of(fsm, struct otg_data, 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:
>
> otg_drv_vbus(fsm, 0);
>
>> + drd_set_protocol(fsm, PROTO_UNDEF);
>> + break;
>> + case OTG_STATE_B_PERIPHERAL:
>
> otg_drv_vbus(fsm, 0);
>
>> + drd_set_protocol(fsm, PROTO_GADGET);
>> + break;
>> + case OTG_STATE_A_HOST:
>
> otg_drv_vbus(fsm, 1);
OK.
>
>> + 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;
>> +}
>> +
cheers,
-roger
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