Re: [PATCH v18 2/5] usb: dwc3: core: Host wake up support from system suspend

From: Krishna Kurapati PSSNV
Date: Fri May 27 2022 - 02:12:41 EST



On 5/26/2022 8:13 AM, Pavan Kondeti wrote:
On Wed, May 25, 2022 at 11:50:23PM +0530, Krishna Kurapati wrote:
From: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>

Check wakeup-source property for dwc3 core node to set the
wakeup capability. Drop the device_init_wakeup call from
runtime suspend and resume.

If the dwc3 is wakeup capable, don't power down the USB PHY(s).
The glue drivers are expected to take care of configuring the
additional wakeup settings if needed based on the dwc3 wakeup
capability status. In some SOC designs, powering off the PHY is
resulting in higher leakage, so this patch save power on such boards.

Signed-off-by: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>
Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
Reviewed-by: Pavankumar Kondeti <quic_pkondeti@xxxxxxxxxxx>
Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
drivers/usb/dwc3/core.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index e027c04..2b1b3f7 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1787,6 +1787,7 @@ static int dwc3_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, dwc);
dwc3_cache_hwparams(dwc);
+ device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source"));
spin_lock_init(&dwc->lock);
mutex_init(&dwc->mutex);
@@ -1948,11 +1949,6 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
dwc3_core_exit(dwc);
break;
case DWC3_GCTL_PRTCAP_HOST:
- if (!PMSG_IS_AUTO(msg)) {
- dwc3_core_exit(dwc);
- break;
- }
-
/* Let controller to suspend HSPHY before PHY driver suspends */
if (dwc->dis_u2_susphy_quirk ||
dwc->dis_enblslpm_quirk) {
@@ -1967,6 +1963,11 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
phy_pm_runtime_put_sync(dwc->usb2_generic_phy);
phy_pm_runtime_put_sync(dwc->usb3_generic_phy);
+
+ if (!PMSG_IS_AUTO(msg)) {
+ if (!device_can_wakeup(dwc->dev))
+ dwc3_core_exit(dwc);
+ }
break;
Earlier, the dwc3 which does not support wakeup just calls dwc3_core_exit().
With this patch we are modifying the behavior. Is that intentional? I expect
it to be something like

@@ -1761,8 +1782,10 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
break;
case DWC3_GCTL_PRTCAP_HOST:
if (!PMSG_IS_AUTO(msg)) {
- dwc3_core_exit(dwc);
- break;
+ if (!device_can_wakeup(dwc->dev)) {
+ dwc3_core_exit(dwc);
+ break;
+ }
}

/* Let controller to suspend HSPHY before PHY driver suspends */

Thanks,
Pavan

Hi Pavan,

Thanks for pointing out that we are changing behavior. Will try to fix it in next series.


Thanks,

Krishna,