From: Adrien Thierry athierry@redhat.com
[ Upstream commit 45d89a344eb46db9dce851c28e14f5e3c635c251 ]
In the dwc3 core, both system and runtime suspend end up calling dwc3_suspend_common(). From there, what happens for the PHYs depends on the USB mode and whether the controller is entering system or runtime suspend.
HOST mode: (1) system suspend on a non-wakeup-capable controller
The [1] if branch is taken. dwc3_core_exit() is called, which ends up calling phy_power_off() and phy_exit(). Those two functions decrease the PM runtime count at some point, so they will trigger the PHY runtime sleep (assuming the count is right).
(2) runtime suspend / system suspend on a wakeup-capable controller
The [1] branch is not taken. dwc3_suspend_common() calls phy_pm_runtime_put_sync(). Assuming the ref count is right, the PHY runtime suspend op is called.
DEVICE mode: dwc3_core_exit() is called on both runtime and system sleep unless the controller is already runtime suspended.
OTG mode: (1) system suspend : dwc3_core_exit() is called
(2) runtime suspend : do nothing
In host mode, the code seems to make a distinction between 1) runtime sleep / system sleep for wakeup-capable controller, and 2) system sleep for non-wakeup-capable controller, where phy_power_off() and phy_exit() are only called for the latter. This suggests the PHY is not supposed to be in a fully powered-off state for runtime sleep and system sleep for wakeup-capable controller.
Moreover, downstream, cfg_ahb_clk only gets disabled for system suspend. The clocks are disabled by phy->set_suspend() [2] which is only called in the system sleep path through dwc3_core_exit() [3].
With that in mind, don't disable the clocks during the femto PHY runtime suspend callback. The clocks will only be disabled during system suspend for non-wakeup-capable controllers, through dwc3_core_exit().
[1] https://elixir.bootlin.com/linux/v6.4/source/drivers/usb/dwc3/core.c#L1988 [2] https://git.codelinaro.org/clo/la/kernel/msm-5.4/-/blob/LV.AU.1.2.1.r2-05300... [3] https://git.codelinaro.org/clo/la/kernel/msm-5.4/-/blob/LV.AU.1.2.1.r2-05300...
Signed-off-by: Adrien Thierry athierry@redhat.com Link: https://lore.kernel.org/r/20230629144542.14906-2-athierry@redhat.com Signed-off-by: Vinod Koul vkoul@kernel.org Stable-dep-of: 8a0eb8f9b9a0 ("phy: qcom-snps-femto-v2: properly enable ref clock") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c | 9 --------- 1 file changed, 9 deletions(-)
diff --git a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c index 6c237f3cc66db..3335480fc395a 100644 --- a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c +++ b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c @@ -165,22 +165,13 @@ static int qcom_snps_hsphy_suspend(struct qcom_snps_hsphy *hsphy) 0, USB2_AUTO_RESUME); }
- clk_disable_unprepare(hsphy->cfg_ahb_clk); return 0; }
static int qcom_snps_hsphy_resume(struct qcom_snps_hsphy *hsphy) { - int ret; - dev_dbg(&hsphy->phy->dev, "Resume QCOM SNPS PHY, mode\n");
- ret = clk_prepare_enable(hsphy->cfg_ahb_clk); - if (ret) { - dev_err(&hsphy->phy->dev, "failed to enable cfg ahb clock\n"); - return ret; - } - return 0; }