[PATCH 03/03] ARM: shmobile: Lager USB0 cable detection workaround

[Magnus Damm]

From: Magnus Damm <damm at opensource.se>

Add Lager board code to check the PWEN GPIO signal and refuse to
allow probe of the USBHS driver in case of DIP misconfiguration.

For correct operation Lager DIP switches SW5 and SW6 shall be
configured in 2-3 position to enable USB Function support.

If the DIP switch is configured incorrectly then the user can
simply adjust the hardware and either reboot or use the bind interface
to try to probe again:

# echo renesas_usbhs > /sys/bus/platform/drivers/renesas_usbhs/bind

Signed-off-by: Magnus Damm <damm at opensource.se>
---

 Depends on "[PATCH 02/03] pinctrl: sh-pfc: r8a7790: Break out USB0 OVC/VBUS"

 arch/arm/mach-shmobile/board-lager.c |   25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

--- 0004/arch/arm/mach-shmobile/board-lager.c
+++ work/arch/arm/mach-shmobile/board-lager.c	2014-01-24 10:17:20.000000000 +0900
@@ -406,13 +406,30 @@ static int usbhs_hardware_init(struct pl
 {
 	struct usbhs_private *priv = usbhs_get_priv(pdev);
 	struct usb_phy *phy;
+	int ret;
+
+	/* USB0 Function - use PWEN as GPIO input to detect DIP Switch SW5
+	 * setting to avoid VBUS short circuit due to wrong cable.
+	 * PWEN should be pulled up high if USB Function is selected by SW5
+	 */
+	gpio_request_one(RCAR_GP_PIN(5, 18), GPIOF_IN, NULL); /* USB0_PWEN */
+	if (!gpio_get_value(RCAR_GP_PIN(5, 18))) {
+		pr_warn("Error: USB Function not selected - check SW5 + SW6\n");
+		ret = -ENOTSUPP;
+		goto error;
+	}
 
 	phy = usb_get_phy_dev(&pdev->dev, 0);
-	if (IS_ERR(phy))
-		return PTR_ERR(phy);
+	if (IS_ERR(phy)) {
+		ret = PTR_ERR(phy);
+		goto error;
+	}
 
 	priv->phy = phy;
 	return 0;
+ error:
+	gpio_free(RCAR_GP_PIN(5, 18));
+	return ret;
 }
 
 static int usbhs_hardware_exit(struct platform_device *pdev)
@@ -424,6 +441,8 @@ static int usbhs_hardware_exit(struct pl
 
 	usb_put_phy(priv->phy);
 	priv->phy = NULL;
+
+	gpio_free(RCAR_GP_PIN(5, 18));
 	return 0;
 }
 
@@ -534,7 +553,7 @@ static const struct pinctrl_map lager_pi
 				  "vin1_clk", "vin1"),
 	/* USB0 */
 	PIN_MAP_MUX_GROUP_DEFAULT("renesas_usbhs", "pfc-r8a7790",
-				  "usb0", "usb0"),
+				  "usb0_ovc_vbus", "usb0"),
 };
 
 static void __init lager_add_standard_devices(void)