Re: [PATCH 4/4] usb: musb: dsps: improve ID change polling

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Felipe,

On 05/12/2015 05:11 PM, Felipe Balbi wrote:
As it turns out, all we have to do is set
Session bit and MUSB will figure out automatically,
based on ID pin, if it should enter host or
peripheral roles.

Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
  drivers/usb/musb/musb_dsps.c | 43 +++++++++++--------------------------------
  1 file changed, 11 insertions(+), 32 deletions(-)

diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
index 659c1099b21f..e7d2d1eb1270 100644
--- a/drivers/usb/musb/musb_dsps.c
+++ b/drivers/usb/musb/musb_dsps.c
@@ -253,45 +253,24 @@ static void otg_timer(unsigned long _musb)
  	const struct dsps_musb_wrapper *wrp = glue->wrp;
  	u8 devctl;
  	unsigned long flags;
-	int skip_session = 0;

  	/*
  	 * We poll because DSPS IP's won't expose several OTG-critical
  	 * status change events (from the transceiver) otherwise.
  	 */
-	devctl = dsps_readb(mregs, MUSB_DEVCTL);
-	dev_dbg(musb->controller, "Poll devctl %02x (%s)\n", devctl,
-				usb_otg_state_string(musb->xceiv->otg->state));
-
  	spin_lock_irqsave(&musb->lock, flags);
-	switch (musb->xceiv->otg->state) {
-	case OTG_STATE_A_WAIT_BCON:
-		dsps_writeb(musb->mregs, MUSB_DEVCTL, 0);
-		skip_session = 1;
-		/* fall */
-
-	case OTG_STATE_A_IDLE:
-	case OTG_STATE_B_IDLE:
-		if (devctl & MUSB_DEVCTL_BDEVICE) {
-			musb->xceiv->otg->state = OTG_STATE_B_IDLE;
-			MUSB_DEV_MODE(musb);
-		} else {
-			musb->xceiv->otg->state = OTG_STATE_A_IDLE;
-			MUSB_HST_MODE(musb);
-		}
-		if (!(devctl & MUSB_DEVCTL_SESSION) && !skip_session)
-			dsps_writeb(mregs, MUSB_DEVCTL, MUSB_DEVCTL_SESSION);
-		mod_timer(&glue->timer, jiffies +
-				msecs_to_jiffies(wrp->poll_timeout));
-		break;
-	case OTG_STATE_A_WAIT_VFALL:
-		musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
-		dsps_writel(musb->ctrl_base, wrp->coreintr_set,
-			    MUSB_INTR_VBUSERROR << wrp->usb_shift);
-		break;

This case is for handling VBUSERROR recovery. I am wondering removing it breaks the recovery.

Regards,
-Bin.

-	default:
-		break;
+	devctl = dsps_readb(mregs, MUSB_DEVCTL);
+	if (devctl & MUSB_DEVCTL_SESSION) {
+		goto out;
+	} else {
+		devctl |= MUSB_DEVCTL_SESSION;
+		dsps_writeb(mregs, MUSB_DEVCTL, devctl);

Is it guaranteed this is for A_IDLE and B_IDLE states? The original code has otg state check.

Regards,
-Bin.

  	}
+
+out:
+	mod_timer(&glue->timer, jiffies +
+			msecs_to_jiffies(wrp->poll_timeout));
+
  	spin_unlock_irqrestore(&musb->lock, flags);
  }


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