[PATCH 6.12.y-cip v2 09/17] usb: host: ehci-platform: Call reset assert/deassert on suspend/resume

From: Claudiu Beznea <[email protected]>

commit c31a401fe7abedabb5c05b5cbf36e2fdb3e6be63 upstream.

The Renesas RZ/G3S SoC supports a power-saving mode in which power to most
of the SoC components is turned off, including the USB blocks. On the
resume path, the reset signal must be de-asserted before applying any
settings to the USB registers. To handle this properly, call
reset_control_assert() and reset_control_deassert() during suspend and
resume, respectively.

Signed-off-by: Claudiu Beznea <[email protected]>
Acked-by: Alan Stern <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
[claudiu.beznea: execute the code based on the
 ehci_platform_reset_control_allowed() return value]
Signed-off-by: Claudiu Beznea <[email protected]>
---

Changes in v2:
- added ehci_platform_reset_control_allowed() and use it in suspend/resume
  path to avoid executing code introduced by commit
  c31a401fe7abedabb5c05b5cbf36e2fdb3e6be63 on targets other than the
  Renesas RZ/G3S

 drivers/usb/host/ehci-platform.c | 39 ++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
index cca129c70276..1b85fd01cb2b 100644
--- a/drivers/usb/host/ehci-platform.c
+++ b/drivers/usb/host/ehci-platform.c
@@ -424,6 +424,16 @@ static void ehci_platform_remove(struct platform_device *dev)
 		dev->dev.platform_data = NULL;
 }
 
+static bool __maybe_unused ehci_platform_reset_control_allowed(void)
+{
+	static const char * const reset_control_allow_list[] = {
+		"renesas,r9a08g045", /* Renesas RZ/G3S */
+		NULL
+	};
+
+	return of_machine_compatible_match(reset_control_allow_list);
+}
+
 static int __maybe_unused ehci_platform_suspend(struct device *dev)
 {
 	struct usb_hcd *hcd = dev_get_drvdata(dev);
@@ -443,6 +453,20 @@ static int __maybe_unused ehci_platform_suspend(struct device *dev)
 	if (pdata->power_suspend)
 		pdata->power_suspend(pdev);
 
+	if (!ehci_platform_reset_control_allowed())
+		return ret;
+
+	ret = reset_control_assert(priv->rsts);
+	if (ret) {
+		if (pdata->power_on)
+			pdata->power_on(pdev);
+
+		ehci_resume(hcd, false);
+
+		if (priv->quirk_poll)
+			quirk_poll_init(priv);
+	}
+
 	return ret;
 }
 
@@ -452,12 +476,23 @@ static int __maybe_unused ehci_platform_resume(struct device *dev)
 	struct usb_ehci_pdata *pdata = dev_get_platdata(dev);
 	struct platform_device *pdev = to_platform_device(dev);
 	struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
+	bool reset_control_allowed = ehci_platform_reset_control_allowed();
 	struct device *companion_dev;
+	int err;
+
+	if (reset_control_allowed) {
+		err = reset_control_deassert(priv->rsts);
+		if (err)
+			return err;
+	}
 
 	if (pdata->power_on) {
-		int err = pdata->power_on(pdev);
-		if (err < 0)
+		err = pdata->power_on(pdev);
+		if (err < 0) {
+			if (reset_control_allowed)
+				reset_control_assert(priv->rsts);
 			return err;
+		}
 	}
 
 	companion_dev = usb_of_get_companion_dev(hcd->self.controller);
-- 
2.43.0