linux-kernel - [PATCH v2 1/2] usb: cdns3: Add quirk flag to enable suspend residency

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Date: Thu, 16 May 2024 09:58:44 +0530
From: Ravi Gunasekaran <r-gunasekaran@...com>
To: <peter.chen@...nel.org>, <pawell@...ence.com>, <rogerq@...nel.org>
CC: <gregkh@...uxfoundation.org>, <linux-usb@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <srk@...com>, <r-gunasekaran@...com>
Subject: [PATCH v2 1/2] usb: cdns3: Add quirk flag to enable suspend residency

From: Roger Quadros <rogerq@...nel.org>

Some platforms (e.g. ti,j721e-usb, ti,am64-usb) require
this bit to be set to workaround a lockup issue with PHY
short suspend intervals [1]. Add a platform quirk flag
to indicate if Suspend Residency should be enabled.

[1] - https://www.ti.com/lit/er/sprz457h/sprz457h.pdf
i2409 - USB: USB2 PHY locks up due to short suspend

Signed-off-by: Roger Quadros <rogerq@...nel.org>
Signed-off-by: Ravi Gunasekaran <r-gunasekaran@...com>
---
Change log:
----------

Changes since v1:
----------------
* Grouped the susp_ctrl register update along with
  existing CDNS3 snippet as suggested by Peter Chen

v1: https://lore.kernel.org/all/20240514092421.20897-1-r-gunasekaran@ti.com/#t

 drivers/usb/cdns3/core.h |  1 +
 drivers/usb/cdns3/drd.c  | 11 ++++++++++-
 drivers/usb/cdns3/drd.h  |  3 +++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
index 81a9c9d6be08..57d47348dc19 100644
--- a/drivers/usb/cdns3/core.h
+++ b/drivers/usb/cdns3/core.h
@@ -44,6 +44,7 @@ struct cdns3_platform_data {
 			bool suspend, bool wakeup);
 	unsigned long quirks;
 #define CDNS3_DEFAULT_PM_RUNTIME_ALLOW	BIT(0)
+#define CDNS3_DRD_SUSPEND_RESIDENCY_ENABLE	BIT(1)
 };
 
 /**
diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
index 8b936a2e93a0..4902849d28d6 100644
--- a/drivers/usb/cdns3/drd.c
+++ b/drivers/usb/cdns3/drd.c
@@ -389,7 +389,7 @@ static irqreturn_t cdns_drd_irq(int irq, void *data)
 int cdns_drd_init(struct cdns *cdns)
 {
 	void __iomem *regs;
-	u32 state;
+	u32 state, reg;
 	int ret;
 
 	regs = devm_ioremap_resource(cdns->dev, &cdns->otg_res);
@@ -433,12 +433,21 @@ int cdns_drd_init(struct cdns *cdns)
 			cdns->otg_irq_regs = (struct cdns_otg_irq_regs __iomem *)
 					      &cdns->otg_v1_regs->ien;
 			writel(1, &cdns->otg_v1_regs->simulate);
+
+			if (cdns->pdata &&
+			    (cdns->pdata->quirks & CDNS3_DRD_SUSPEND_RESIDENCY_ENABLE)) {
+				reg = readl(&cdns->otg_v1_regs->susp_ctrl);
+				reg |= SUSP_CTRL_SUSPEND_RESIDENCY_ENABLE;
+				writel(reg, &cdns->otg_v1_regs->susp_ctrl);
+			}
+
 			cdns->version  = CDNS3_CONTROLLER_V1;
 		} else {
 			dev_err(cdns->dev, "not supported DID=0x%08x\n", state);
 			return -EINVAL;
 		}
 
+
 		dev_dbg(cdns->dev, "DRD version v1 (ID: %08x, rev: %08x)\n",
 			 readl(&cdns->otg_v1_regs->did),
 			 readl(&cdns->otg_v1_regs->rid));
diff --git a/drivers/usb/cdns3/drd.h b/drivers/usb/cdns3/drd.h
index d72370c321d3..1e2aee14d629 100644
--- a/drivers/usb/cdns3/drd.h
+++ b/drivers/usb/cdns3/drd.h
@@ -193,6 +193,9 @@ struct cdns_otg_irq_regs {
 /* OTGREFCLK - bitmasks */
 #define OTGREFCLK_STB_CLK_SWITCH_EN	BIT(31)
 
+/* SUPS_CTRL - bitmasks */
+#define SUSP_CTRL_SUSPEND_RESIDENCY_ENABLE	BIT(17)
+
 /* OVERRIDE - bitmasks */
 #define OVERRIDE_IDPULLUP		BIT(0)
 /* Only for CDNS3_CONTROLLER_V0 version */
-- 
2.17.1