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authorAmelie Delaunay <amelie.delaunay@foss.st.com>2021-10-05 12:53:04 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-10-21 13:49:00 +0300
commit8d387f61b0240854e81450c261beb775065bad5d (patch)
tree803351af108e3e21caea08969b5a79d09d04bd3e /drivers/usb/dwc2
parentb2cab2a24fb5d13ce1d384ecfb6de827fa08a048 (diff)
downloadlinux-8d387f61b0240854e81450c261beb775065bad5d.tar.xz
usb: dwc2: drd: fix dwc2_drd_role_sw_set when clock could be disabled
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") Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com> Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com> Link: https://lore.kernel.org/r/20211005095305.66397-3-amelie.delaunay@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/dwc2')
-rw-r--r--drivers/usb/dwc2/drd.c18
1 files changed, 18 insertions, 0 deletions
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");