linux-kernel - [PATCH v2 5/7] usb: fotg210: Check role register in core

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Message-Id: <20230103-gemini-fotg210-usb-v2-5-100388af9810@linaro.org>
Date:   Wed, 18 Jan 2023 08:09:19 +0100
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Cc:     linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Fabian Vogt <fabian@...ter-vogt.de>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: [PATCH v2 5/7] usb: fotg210: Check role register in core

Read the role register and check that we are in host/peripheral
mode and issue warnings if we're not in the right role when
probing respective driver.

Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
---
 drivers/usb/fotg210/fotg210-core.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/fotg210/fotg210-core.c b/drivers/usb/fotg210/fotg210-core.c
index 58d84747fb30..013a1d0112fc 100644
--- a/drivers/usb/fotg210/fotg210-core.c
+++ b/drivers/usb/fotg210/fotg210-core.c
@@ -18,6 +18,11 @@
 
 #include "fotg210.h"
 
+/* Role Register 0x80 */
+#define FOTG210_RR			0x80
+#define FOTG210_RR_ID			BIT(21) /* 1 = B-device, 0 = A-device */
+#define FOTG210_RR_CROLE		BIT(20) /* 1 = device, 0 = host */
+
 /*
  * Gemini-specific initialization function, only executed on the
  * Gemini SoC using the global misc control register.
@@ -95,6 +100,7 @@ static int fotg210_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	enum usb_dr_mode mode;
 	struct fotg210 *fotg;
+	u32 val;
 	int ret;
 
 	fotg = devm_kzalloc(dev, sizeof(*fotg), GFP_KERNEL);
@@ -122,10 +128,16 @@ static int fotg210_probe(struct platform_device *pdev)
 			return ret;
 	}
 
-	if (mode == USB_DR_MODE_PERIPHERAL)
+	val = readl(fotg->base + FOTG210_RR);
+	if (mode == USB_DR_MODE_PERIPHERAL) {
+		if (!(val & FOTG210_RR_CROLE))
+			dev_err(dev, "block not in device role\n");
 		ret = fotg210_udc_probe(pdev, fotg);
-	else
+	} else {
+		if (val & FOTG210_RR_CROLE)
+			dev_err(dev, "block not in host role\n");
 		ret = fotg210_hcd_probe(pdev, fotg);
+	}
 
 	return ret;
 }

-- 
2.39.0