From: Amelie Delaunay <amelie.delaunay@foss.st.com>
To: Minas Harutyunyan <hminas@synopsys.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-stm32@st-md-mailman.stormreply.com>,
Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
Amelie Delaunay <amelie.delaunay@foss.st.com>
Subject: [PATCH 2/3] usb: dwc2: drd: fix dwc2_drd_role_sw_set when clock could be disabled
Date: Tue, 5 Oct 2021 11:53:04 +0200 [thread overview]
Message-ID: <20211005095305.66397-3-amelie.delaunay@foss.st.com> (raw)
In-Reply-To: <20211005095305.66397-1-amelie.delaunay@foss.st.com>
In case of USB_DR_MODE_PERIPHERAL, the OTG clock is disabled at the end of
the probe (it is not the case if USB_DR_MODE_HOST or USB_DR_MODE_OTG).
The clock is then enabled on udc_start.
If dwc2_drd_role_sw_set is called before udc_start (it is the case if the
usb cable is plugged at boot), GOTGCTL and GUSBCFG registers cannot be
read/written, so session cannot be overridden.
To avoid this case, check the ll_hw_enabled value and enable the clock if
it is available, and disable it after the override.
Fixes: 17f934024e84 ("usb: dwc2: override PHY input signals with usb role switch support")
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
---
drivers/usb/dwc2/drd.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
index 80eae88d76dd..99672360f34b 100644
--- a/drivers/usb/dwc2/drd.c
+++ b/drivers/usb/dwc2/drd.c
@@ -7,6 +7,7 @@
* Author(s): Amelie Delaunay <amelie.delaunay@st.com>
*/
+#include <linux/clk.h>
#include <linux/iopoll.h>
#include <linux/platform_device.h>
#include <linux/usb/role.h>
@@ -86,6 +87,20 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
}
#endif
+ /*
+ * In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of
+ * the probe and enabled on udc_start.
+ * If role-switch set is called before the udc_start, we need to enable
+ * the clock to read/write GOTGCTL and GUSBCFG registers to override
+ * mode and sessions. It is the case if cable is plugged at boot.
+ */
+ if (!hsotg->ll_hw_enabled && hsotg->clk) {
+ int ret = clk_prepare_enable(hsotg->clk);
+
+ if (ret)
+ return ret;
+ }
+
spin_lock_irqsave(&hsotg->lock, flags);
if (role == USB_ROLE_HOST) {
@@ -110,6 +125,9 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
/* This will raise a Connector ID Status Change Interrupt */
dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
+ if (!hsotg->ll_hw_enabled && hsotg->clk)
+ clk_disable_unprepare(hsotg->clk);
+
dev_dbg(hsotg->dev, "%s-session valid\n",
role == USB_ROLE_NONE ? "No" :
role == USB_ROLE_HOST ? "A" : "B");
--
2.25.1
next prev parent reply other threads:[~2021-10-05 9:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 9:53 [PATCH 0/3] usb: dwc2: drd: fix some issues Amelie Delaunay
2021-10-05 9:53 ` [PATCH 1/3] usb: dwc2: drd: fix dwc2_force_mode call in dwc2_ovr_init Amelie Delaunay
2021-10-15 10:53 ` Minas Harutyunyan
2021-10-05 9:53 ` Amelie Delaunay [this message]
2021-10-15 10:54 ` [PATCH 2/3] usb: dwc2: drd: fix dwc2_drd_role_sw_set when clock could be disabled Minas Harutyunyan
2021-10-05 9:53 ` [PATCH 3/3] usb: dwc2: drd: reset current session before setting the new one Amelie Delaunay
2021-10-15 10:54 ` Minas Harutyunyan
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