[PATCH 0/2] usb: host: xhci-plat: Introduce XHCI_SUSPEND_RESUME_CLKS quirk

[PATCH 0/2] usb: host: xhci-plat: Introduce XHCI_SUSPEND_RESUME_CLKS quirk

[justinpopo6]

From: Justin Chen <justinpopo6@gmail.com>

Introduce XHCI_SUSPEND_RESUME_CLKS quirk for turning off clocks during suspend and
turning on clocks on resume. Certain hardware, in our case xhci_plat_brcm, can have
power savings by turning off clocks before hitting suspend states.

Justin Chen (2):
  usb: host: xhci-plat: suspend and resume clocks
  usb: host: xhci-plat: suspend/resume clks for brcm

 drivers/usb/host/xhci-plat.c | 18 ++++++++++++++++--
 drivers/usb/host/xhci.h      |  1 +
 2 files changed, 17 insertions(+), 2 deletions(-)

-- 
2.7.4

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

[justinpopo6]

From: Justin Chen <justinpopo6@gmail.com>

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 <justinpopo6@gmail.com>
---
 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

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

[Florian Fainelli]

On 8/10/22 15:27, justinpopo6@gmail.com wrote:
> From: Justin Chen <justinpopo6@gmail.com>
> 
> 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 <justinpopo6@gmail.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

[PATCH 2/2] usb: host: xhci-plat: suspend/resume clks for brcm

[justinpopo6]

From: Justin Chen <justinpopo6@gmail.com>

The xhci_plat_brcm xhci block can enter suspend with clock disabled to save
power and re-enable them on resume. Make use of the XHCI_SUSPEND_RESUME_CLKS
quirk to do so.

Signed-off-by: Justin Chen <justinpopo6@gmail.com>
---
 drivers/usb/host/xhci-plat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index a68b2b0..62756d9 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -123,7 +123,7 @@ static const struct xhci_plat_priv xhci_plat_renesas_rcar_gen3 = {
 };
 
 static const struct xhci_plat_priv xhci_plat_brcm = {
-	.quirks = XHCI_RESET_ON_RESUME,
+	.quirks = XHCI_RESET_ON_RESUME | XHCI_SUSPEND_RESUME_CLKS,
 };
 
 static const struct of_device_id usb_xhci_of_match[] = {
-- 
2.7.4

Re: [PATCH 2/2] usb: host: xhci-plat: suspend/resume clks for brcm

[Florian Fainelli]

On 8/10/22 15:27, justinpopo6@gmail.com wrote:
> From: Justin Chen <justinpopo6@gmail.com>
> 
> The xhci_plat_brcm xhci block can enter suspend with clock disabled to save
> power and re-enable them on resume. Make use of the XHCI_SUSPEND_RESUME_CLKS
> quirk to do so.
> 
> Signed-off-by: Justin Chen <justinpopo6@gmail.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian