2022-08-10 22:37:21

by Justin Chen

Subject: [PATCH 1/2] usb: host: xhci-plat: suspend and resume clocks

From: Justin Chen <[email protected]>

Introduce XHCI_SUSPEND_RESUME_CLKS quirk as a means to suspend and resume
clocks if the hardware is capable of doing so. We assume that clocks will
be needed if the device may wake.

Signed-off-by: Justin Chen <[email protected]>
---
drivers/usb/host/xhci-plat.c | 16 +++++++++++++++-
drivers/usb/host/xhci.h | 1 +
2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 0448558..a68b2b0 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -432,7 +432,16 @@ static int __maybe_unused xhci_plat_suspend(struct device *dev)
* xhci_suspend() needs `do_wakeup` to know whether host is allowed
* to do wakeup during suspend.
*/
- return xhci_suspend(xhci, device_may_wakeup(dev));
+ ret = xhci_suspend(xhci, device_may_wakeup(dev));
+ if (ret)
+ return ret;
+
+ if (!device_may_wakeup(dev) && (xhci->quirks & XHCI_SUSPEND_RESUME_CLKS)) {
+ clk_disable_unprepare(xhci->clk);
+ clk_disable_unprepare(xhci->reg_clk);
+ }
+
+ return 0;
}

static int __maybe_unused xhci_plat_resume(struct device *dev)
@@ -441,6 +450,11 @@ static int __maybe_unused xhci_plat_resume(struct device *dev)
struct xhci_hcd *xhci = hcd_to_xhci(hcd);
int ret;

+ if (!device_may_wakeup(dev) && (xhci->quirks & XHCI_SUSPEND_RESUME_CLKS)) {
+ clk_prepare_enable(xhci->clk);
+ clk_prepare_enable(xhci->reg_clk);
+ }
+
ret = xhci_priv_resume_quirk(hcd);
if (ret)
return ret;
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 1960b47..182d1d4 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1899,6 +1899,7 @@ struct xhci_hcd {
#define XHCI_NO_SOFT_RETRY BIT_ULL(40)
#define XHCI_BROKEN_D3COLD BIT_ULL(41)
#define XHCI_EP_CTX_BROKEN_DCS BIT_ULL(42)
+#define XHCI_SUSPEND_RESUME_CLKS BIT_ULL(43)

unsigned int num_active_eps;
unsigned int limit_active_eps;
--
2.7.4

2022-08-10 22:42:25

by Florian Fainelli

Subject: Re: [PATCH 1/2] usb: host: xhci-plat: suspend and resume clocks

On 8/10/22 15:27, [email protected] wrote:
> From: Justin Chen <[email protected]>
>
> Introduce XHCI_SUSPEND_RESUME_CLKS quirk as a means to suspend and resume
> clocks if the hardware is capable of doing so. We assume that clocks will
> be needed if the device may wake.
>
> Signed-off-by: Justin Chen <[email protected]>

Reviewed-by: Florian Fainelli <[email protected]>
--
Florian