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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: 17f934024e
("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>
This commit is contained in:
parent
b2cab2a24f
commit
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1 changed files with 18 additions and 0 deletions
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@ -7,6 +7,7 @@
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* Author(s): Amelie Delaunay <amelie.delaunay@st.com>
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*/
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#include <linux/clk.h>
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#include <linux/iopoll.h>
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#include <linux/platform_device.h>
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#include <linux/usb/role.h>
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@ -86,6 +87,20 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
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}
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#endif
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/*
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* In case of USB_DR_MODE_PERIPHERAL, clock is disabled at the end of
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* the probe and enabled on udc_start.
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* If role-switch set is called before the udc_start, we need to enable
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* the clock to read/write GOTGCTL and GUSBCFG registers to override
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* mode and sessions. It is the case if cable is plugged at boot.
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*/
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if (!hsotg->ll_hw_enabled && hsotg->clk) {
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int ret = clk_prepare_enable(hsotg->clk);
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if (ret)
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return ret;
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}
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spin_lock_irqsave(&hsotg->lock, flags);
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if (role == USB_ROLE_HOST) {
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@ -110,6 +125,9 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
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/* This will raise a Connector ID Status Change Interrupt */
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dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
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if (!hsotg->ll_hw_enabled && hsotg->clk)
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clk_disable_unprepare(hsotg->clk);
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dev_dbg(hsotg->dev, "%s-session valid\n",
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role == USB_ROLE_NONE ? "No" :
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role == USB_ROLE_HOST ? "A" : "B");
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