From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: [PATCH v4 1/2] usb: host: ehci-tegra: Grab the correct UTMI pads reset Date: Thu, 26 May 2016 17:23:29 +0200 Message-ID: <20160526152330.10929-1-thierry.reding@gmail.com> Return-path: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Alan Stern , Greg Kroah-Hartman Cc: Stephen Warren , Thierry Reding , Alexandre Courbot , Jon Hunter , linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org From: Thierry Reding There are three EHCI controllers on Tegra SoCs, each with its own reset line. However, the first controller contains a set of UTMI configuration registers that are shared with its siblings. These registers will only be reset as part of the first controller's reset. For proper operation it must be ensured that the UTMI configuration registers are reset before any of the EHCI controllers are enabled, irrespective of the probe order. Commit a47cc24cd1e5 ("USB: EHCI: tegra: Fix probe order issue leading to broken USB") introduced code that ensures the first controller is always reset before setting up any of the controllers, and is never again reset afterwards. This code, however, grabs the wrong reset. Each EHCI controller has two reset controls attached: 1) the USB controller reset and 2) the UTMI pads reset (really the first controller's reset). In order to reset the UTMI pads registers the code must grab the second reset, but instead it grabbing the first. Fixes: a47cc24cd1e5 ("USB: EHCI: tegra: Fix probe order issue leading to broken USB") Acked-by: Jon Hunter Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Signed-off-by: Thierry Reding --- Changes in v4: - add stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org to stable and add Fixes: tag - add Jon's Acked-by drivers/usb/host/ehci-tegra.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c index 4031b372008e..c1c1024a054c 100644 --- a/drivers/usb/host/ehci-tegra.c +++ b/drivers/usb/host/ehci-tegra.c @@ -89,7 +89,7 @@ static int tegra_reset_usb_controller(struct platform_device *pdev) if (!usb1_reset_attempted) { struct reset_control *usb1_reset; - usb1_reset = of_reset_control_get(phy_np, "usb"); + usb1_reset = of_reset_control_get(phy_np, "utmi-pads"); if (IS_ERR(usb1_reset)) { dev_warn(&pdev->dev, "can't get utmi-pads reset from the PHY\n"); -- 2.8.3