linux-kernel - [PATCH v5 4/7] usb: dwc3: core: Don't touch resets and clocks

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Message-Id: <20250318-dwc3-refactor-v5-4-90ea6e5b3ba4@oss.qualcomm.com>
Date: Tue, 18 Mar 2025 14:05:04 -0500
From: Bjorn Andersson <bjorn.andersson@....qualcomm.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>, Felipe Balbi <balbi@...nel.org>,
        Wesley Cheng <quic_wcheng@...cinc.com>,
        Saravana Kannan <saravanak@...gle.com>,
        Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Frank Li <Frank.li@....com>
Cc: linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Frank Li <Frank.Li@....com>,
        Bjorn Andersson <bjorn.andersson@....qualcomm.com>
Subject: [PATCH v5 4/7] usb: dwc3: core: Don't touch resets and clocks

When the core is integrated with glue, it's reasonable to assume that
the glue driver will have to touch the IP before/after the core takes
the hardware out and into reset. As such the glue must own these
resources and be allowed to turn them on/off outside the core's
handling.

Allow the platform or glue layer to indicate if the core logic for
clocks and resets should be skipped to deal with this.

Reviewed-by: Frank Li <Frank.Li@....com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@....qualcomm.com>
---
 drivers/usb/dwc3/core.c | 20 +++++++++++---------
 drivers/usb/dwc3/glue.h |  3 +++
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index b428b6fc3d0a55811e2f75d33d79df4b0c67dcac..77a9848a0ac70fbe563988cecbe489130989aadc 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -2198,15 +2198,17 @@ int dwc3_core_probe(const struct dwc3_probe_data *data)
 	if (IS_ERR(dwc->usb_psy))
 		return dev_err_probe(dev, PTR_ERR(dwc->usb_psy), "couldn't get usb power supply\n");
 
-	dwc->reset = devm_reset_control_array_get_optional_shared(dev);
-	if (IS_ERR(dwc->reset)) {
-		ret = PTR_ERR(dwc->reset);
-		goto err_put_psy;
-	}
+	if (!data->ignore_clocks_and_resets) {
+		dwc->reset = devm_reset_control_array_get_optional_shared(dev);
+		if (IS_ERR(dwc->reset)) {
+			ret = PTR_ERR(dwc->reset);
+			goto err_put_psy;
+		}
 
-	ret = dwc3_get_clocks(dwc);
-	if (ret)
-		goto err_put_psy;
+		ret = dwc3_get_clocks(dwc);
+		if (ret)
+			goto err_put_psy;
+	}
 
 	ret = reset_control_deassert(dwc->reset);
 	if (ret)
@@ -2321,7 +2323,7 @@ EXPORT_SYMBOL_GPL(dwc3_core_probe);
 
 static int dwc3_probe(struct platform_device *pdev)
 {
-	struct dwc3_probe_data probe_data;
+	struct dwc3_probe_data probe_data = {};
 	struct resource *res;
 	struct dwc3 *dwc;
 
diff --git a/drivers/usb/dwc3/glue.h b/drivers/usb/dwc3/glue.h
index e73cfc466012f07214291abe56454934ab014013..703d40c189565b1e28ae28afb8728b78f4cd2fca 100644
--- a/drivers/usb/dwc3/glue.h
+++ b/drivers/usb/dwc3/glue.h
@@ -13,10 +13,13 @@
  * dwc3_probe_data: Initialization parameters passed to dwc3_core_probe()
  * @dwc: Reference to dwc3 context structure
  * @res: resource for the DWC3 core mmio region
+ * @ignore_clocks_and_resets: clocks and resets defined for the device should
+ *		be ignored by the DWC3 core, as they are managed by the glue
  */
 struct dwc3_probe_data {
 	struct dwc3 *dwc;
 	struct resource *res;
+	bool ignore_clocks_and_resets;
 };
 
 int dwc3_core_probe(const struct dwc3_probe_data *data);

-- 
2.48.1