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From: Ravi Gunasekaran <r-gunasekaran@ti.com>
To: <peter.chen@kernel.org>, <pawell@cadence.com>, <rogerq@kernel.org>
CC: <gregkh@linuxfoundation.org>, <linux-usb@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <srk@ti.com>, <r-gunasekaran@ti.com>
Subject: [PATCH v3 1/2] usb: cdns3: Add quirk flag to enable suspend residency
Date: Thu, 16 May 2024 10:15:36 +0530
Message-ID: <20240516044537.16801-2-r-gunasekaran@ti.com>
In-Reply-To: <20240516044537.16801-1-r-gunasekaran@ti.com>
References: <20240516044537.16801-1-r-gunasekaran@ti.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain

From: Roger Quadros <rogerq@kernel.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@kernel.org>
Signed-off-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
---
Change log:
----------
Changes since v2:
----------------
* Fixed the redundant blank line added in v2

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

v2: https://lore.kernel.org/all/20240516042845.31211-1-r-gunasekaran@ti.com/
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  | 10 +++++++++-
 drivers/usb/cdns3/drd.h  |  3 +++
 3 files changed, 13 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..84fb38a5723a 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);
@@ -433,6 +433,14 @@ 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);
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