linux-kernel - [PATCH] usb: dwc2: disable erroneous overcurrent condition

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Date:   Mon, 16 Oct 2017 08:57:18 -0500
From:   Dinh Nguyen <dinguyen@...nel.org>
To:     johnyoun@...opsys.com
Cc:     dinguyen@...nel.org, balbi@...nel.org, marex@...x.de,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] usb: dwc2: disable erroneous overcurrent condition

For the case where an external VBUS is used, we should enable the external
VBUS comparator in the driver. This would prevent an unnecessary
overcurrent error which would then disable the host port.

This patch uses the standard 'disable-over-current' binding to allow of the
option of disabling the over-current condition.

Signed-off-by: Dinh Nguyen <dinguyen@...nel.org>
---
 drivers/usb/dwc2/core.h   | 4 ++++
 drivers/usb/dwc2/hcd.c    | 5 +++++
 drivers/usb/dwc2/params.c | 3 +++
 3 files changed, 12 insertions(+)

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 8367d4f9..730d7eb 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -395,6 +395,9 @@ enum dwc2_ep0_state {
  *                           (default when phy_type is UTMI+ or ULPI)
  *                       1 - 6 MHz
  *                           (default when phy_type is Full Speed)
+ * @oc_disable:		Flag to disable overcurrent condition.
+ *			0 - Allow overcurrent condition to get detected
+ *			1 - Disable overcurrent condtion to get detected
  * @ts_dline:           Enable Term Select Dline pulsing
  *                       0 - No (default)
  *                       1 - Yes
@@ -492,6 +495,7 @@ struct dwc2_core_params {
 	bool dma_desc_fs_enable;
 	bool host_support_fs_ls_low_power;
 	bool host_ls_low_power_phy_clk;
+	bool oc_disable;
 
 	u8 host_channels;
 	u16 host_rx_fifo_size;
diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index c263114..5e20336 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -213,6 +213,11 @@ static int dwc2_hs_phy_init(struct dwc2_hsotg *hsotg, bool select_phy)
 		usbcfg &= ~(GUSBCFG_PHYIF16 | GUSBCFG_DDRSEL);
 		if (hsotg->params.phy_ulpi_ddr)
 			usbcfg |= GUSBCFG_DDRSEL;
+
+		/* Set external VBUS indicator as needed. */
+		if (hsotg->params.oc_disable)
+			usbcfg |= (GUSBCFG_ULPI_INT_VBUS_IND |
+				   GUSBCFG_INDICATORPASSTHROUGH);
 		break;
 	case DWC2_PHY_TYPE_PARAM_UTMI:
 		/* UTMI+ interface */
diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
index a3ffe97..39e02cd 100644
--- a/drivers/usb/dwc2/params.c
+++ b/drivers/usb/dwc2/params.c
@@ -335,6 +335,9 @@ static void dwc2_get_device_properties(struct dwc2_hsotg *hsotg)
 						       num);
 		}
 	}
+
+	if (of_find_property(hsotg->dev->of_node, "disable-over-current", NULL))
+		p->oc_disable = true;
 }
 
 static void dwc2_check_param_otg_cap(struct dwc2_hsotg *hsotg)
-- 
2.7.4