[PATCH v3 2/2] usb: host: XHCI: xhci-mtk.c: support mediatek, str-clock-on

[Macpaul Lin]

Some platform dose not support turn off clock when system suspending.
We add an option "mediatek,str-clock-on" for distinquish these platforms.
When "mediatek,str-clock-on" has been set, xhci-mtk driver will skip
turning clock on and off during system suspend and resume.

Fixes: 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
Signed-off-by: Macpaul Lin <macpaul.lin at mediatek.com>
Cc: stable at vger.kernel.org
---
Changes for v3:
  - Add "Fixes" tag as a bug fix on phone system.
Changes for v2:
  - Replace "mediatek,keep-clock-on" to "mediatek,str-clock-on" which implies
    this option related to STR functions.

 drivers/usb/host/xhci-mtk.c |    9 +++++++--
 drivers/usb/host/xhci-mtk.h |    1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index 4311d4c..77b0d7a 100644
--- a/drivers/usb/host/xhci-mtk.c
+++ b/drivers/usb/host/xhci-mtk.c
@@ -464,6 +464,9 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 	of_property_read_u32(node, "mediatek,u3p-dis-msk",
 			     &mtk->u3p_dis_msk);
 
+	/* STR: keep clock on when suspending on some platform */
+	mtk->str_clk_on = of_property_read_bool(node, "mediatek,str-clock-on");
+
 	ret = usb_wakeup_of_property_parse(mtk, node);
 	if (ret) {
 		dev_err(dev, "failed to parse uwk property\n");
@@ -624,7 +627,8 @@ static int __maybe_unused xhci_mtk_suspend(struct device *dev)
 	del_timer_sync(&xhci->shared_hcd->rh_timer);
 
 	xhci_mtk_host_disable(mtk);
-	xhci_mtk_clks_disable(mtk);
+	if (!mtk->str_clk_on)
+		xhci_mtk_clks_disable(mtk);
 	usb_wakeup_set(mtk, true);
 	return 0;
 }
@@ -636,7 +640,8 @@ static int __maybe_unused xhci_mtk_resume(struct device *dev)
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 
 	usb_wakeup_set(mtk, false);
-	xhci_mtk_clks_enable(mtk);
+	if (!mtk->str_clk_on)
+		xhci_mtk_clks_enable(mtk);
 	xhci_mtk_host_enable(mtk);
 
 	xhci_dbg(xhci, "%s: restart port polling\n", __func__);
diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
index a93cfe8..4039b025 100644
--- a/drivers/usb/host/xhci-mtk.h
+++ b/drivers/usb/host/xhci-mtk.h
@@ -152,6 +152,7 @@ struct xhci_hcd_mtk {
 	struct regmap *uwk;
 	u32 uwk_reg_base;
 	u32 uwk_vers;
+	bool str_clk_on;
 };
 
 static inline struct xhci_hcd_mtk *hcd_to_mtk(struct usb_hcd *hcd)
-- 
1.7.9.5