sunxi: usb-phy: Never power off the usb ports

USB devices are not really designed to get the power bounced off and on
at them. Esp. USB powered harddisks do not like this.

Currently we power off the USB ports both on a "usb reset" and when
booting the kernel, causing the usb-power to bounce off and then back
on again.

This patch removes the powering off calls, fixing the undesirable power
bouncing.

Note this requires some special handling for the OTG port:
1) We must skip the external vbus check if we've already enabled our own
vbus to avoid false positives
2) If on an usb reset we no longer detect that the id-pin is grounded, turn
off vbus as that means an external vbus may be present now

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

1 files changed, 16 insertions, 12 deletions

diff --git a/drivers/usb/musb-new/sunxi.c b/drivers/usb/musb-new/sunxi.c
index 16a264a9dd..a146c0861f 100644
--- a/drivers/usb/musb-new/sunxi.c
+++ b/drivers/usb/musb-new/sunxi.c
@@ -196,8 +196,6 @@ static bool enabled = false;
 
 static int sunxi_musb_enable(struct musb *musb)
 {
-	int ret;
-
 	pr_debug("%s():\n", __func__);
 
 	musb_ep_select(musb->mregs, 0);
@@ -210,17 +208,26 @@ static int sunxi_musb_enable(struct musb *musb)
 	musb_writeb(musb->mregs, USBC_REG_o_VEND0, 0);
 
 	if (is_host_enabled(musb)) {
-		ret = sunxi_usb_phy_vbus_detect(0);
-		if (ret == 1) {
-			printf("A charger is plugged into the OTG: ");
-			return -ENODEV;
+		int id = sunxi_usb_phy_id_detect(0);
+
+		if (id == 1 && sunxi_usb_phy_power_is_on(0))
+			sunxi_usb_phy_power_off(0);
+
+		if (!sunxi_usb_phy_power_is_on(0)) {
+			int vbus = sunxi_usb_phy_vbus_detect(0);
+			if (vbus == 1) {
+				printf("A charger is plugged into the OTG: ");
+				return -ENODEV;
+			}
 		}
-		ret = sunxi_usb_phy_id_detect(0);
-		if (ret == 1) {
+
+		if (id == 1) {
 			printf("No host cable detected: ");
 			return -ENODEV;
 		}
-		sunxi_usb_phy_power_on(0); /* port power on */
+
+		if (!sunxi_usb_phy_power_is_on(0))
+			sunxi_usb_phy_power_on(0);
 	}
 
 	USBC_ForceVbusValidToHigh(musb->mregs);
@@ -236,9 +243,6 @@ static void sunxi_musb_disable(struct musb *musb)
 	if (!enabled)
 		return;
 
-	if (is_host_enabled(musb))
-		sunxi_usb_phy_power_off(0); /* port power off */
-
 	USBC_ForceVbusValidToLow(musb->mregs);
 	mdelay(200); /* Wait for the current session to timeout */