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usb: dwc3: core: Avoid redundant system suspend/resume callbacks

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dwc3 device suspend/resume callbacks were being triggered during system
suspend and resume even if the device was already runtime-suspended.
This is redundant for device mode because the suspend and resume routines
are essentially identical for system PM and runtime PM.

To prevent these unnecessary callbacks, indicate to the PM core that it
can safely leave the device in runtime suspend if it's already
runtime-suspended in device mode by returning a positive value in
prepare() callback. This optimization only applies to devices without
pinctrl, as pinctrl has distinct logic tied to system suspend/resume.

Signed-off-by: Roy Luo <royluo@google.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20250312223434.3071598-1-royluo@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Roy Luo 2025-03-12 22:34:34 +00:00 committed by Greg Kroah-Hartman
parent b4b38ffb38
commit 850e634006
1 changed files with 19 additions and 1 deletions
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20
drivers/usb/dwc3/core.c
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@ -26,6 +26,7 @@
#include <linux/of_graph.h>
#include <linux/acpi.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pinctrl/devinfo.h>
#include <linux/reset.h>
#include <linux/bitfield.h>
@ -2670,14 +2671,31 @@ static void dwc3_complete(struct device *dev)
dwc3_writel(dwc->regs, DWC3_GUCTL3, reg);
}
}
static int dwc3_prepare(struct device *dev)
{
struct dwc3 *dwc = dev_get_drvdata(dev);
/*
* Indicate to the PM core that it may safely leave the device in
* runtime suspend if runtime-suspended already in device mode.
*/
if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_DEVICE &&
pm_runtime_suspended(dev) &&
!dev_pinctrl(dev))
return 1;
return 0;
}
#else
#define dwc3_complete NULL
#define dwc3_prepare NULL
#endif /* CONFIG_PM_SLEEP */
static const struct dev_pm_ops dwc3_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(dwc3_suspend, dwc3_resume)
.complete = dwc3_complete,
.prepare = dwc3_prepare,
/*
* Runtime suspend halts the controller on disconnection. It relies on
* platforms with custom connection notification to start the controller