usb: fotg2: add Gemini-specific handling

The Cortina Systems Gemini has bolted on a PHY inside the
silicon that can be handled by six bits in a MISC register in
the system controller.

If we are running on Gemini, look up a syscon regmap through
a phandle and enable VBUS and optionally the Mini-B connector.

If the device is flagged as "wakeup-source" using the standard
DT bindings, we also enable this in the global controller for
respective port.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20221109200554.1957185-1-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 81 insertions, 0 deletions

diff --git a/drivers/usb/fotg210/Kconfig b/drivers/usb/fotg210/Kconfig
index 933c513b5728..534206ee0d1d 100644
--- a/drivers/usb/fotg210/Kconfig
+++ b/drivers/usb/fotg210/Kconfig
@@ -5,6 +5,7 @@ config USB_FOTG210
 	depends on USB || USB_GADGET
 	depends on HAS_DMA && HAS_IOMEM
 	default ARCH_GEMINI
+	select MFD_SYSCON
 	help
 	  Faraday FOTG210 is a dual-mode USB controller that can act
 	  in both host controller and peripheral controller mode.
diff --git a/drivers/usb/fotg210/fotg210-core.c b/drivers/usb/fotg210/fotg210-core.c
index 3d07ee46f6d1..8a54edf921ac 100644
--- a/drivers/usb/fotg210/fotg210-core.c
+++ b/drivers/usb/fotg210/fotg210-core.c
@@ -5,15 +5,86 @@
  * whether to proceed with probing the host or the peripheral
  * driver.
  */
+#include <linux/bitops.h>
 #include <linux/device.h>
+#include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/usb.h>
 #include <linux/usb/otg.h>
 
 #include "fotg210.h"
 
+/*
+ * Gemini-specific initialization function, only executed on the
+ * Gemini SoC using the global misc control register.
+ *
+ * The gemini USB blocks are connected to either Mini-A (host mode) or
+ * Mini-B (peripheral mode) plugs. There is no role switch support on the
+ * Gemini SoC, just either-or.
+ */
+#define GEMINI_GLOBAL_MISC_CTRL		0x30
+#define GEMINI_MISC_USB0_WAKEUP		BIT(14)
+#define GEMINI_MISC_USB1_WAKEUP		BIT(15)
+#define GEMINI_MISC_USB0_VBUS_ON	BIT(22)
+#define GEMINI_MISC_USB1_VBUS_ON	BIT(23)
+#define GEMINI_MISC_USB0_MINI_B		BIT(29)
+#define GEMINI_MISC_USB1_MINI_B		BIT(30)
+
+static int fotg210_gemini_init(struct device *dev, struct resource *res,
+			       enum usb_dr_mode mode)
+{
+	struct device_node *np = dev->of_node;
+	struct regmap *map;
+	bool wakeup;
+	u32 mask, val;
+	int ret;
+
+	map = syscon_regmap_lookup_by_phandle(np, "syscon");
+	if (IS_ERR(map)) {
+		dev_err(dev, "no syscon\n");
+		return PTR_ERR(map);
+	}
+	wakeup = of_property_read_bool(np, "wakeup-source");
+
+	/*
+	 * Figure out if this is USB0 or USB1 by simply checking the
+	 * physical base address.
+	 */
+	mask = 0;
+	if (res->start == 0x69000000) {
+		mask = GEMINI_MISC_USB1_VBUS_ON | GEMINI_MISC_USB1_MINI_B |
+			GEMINI_MISC_USB1_WAKEUP;
+		if (mode == USB_DR_MODE_HOST)
+			val = GEMINI_MISC_USB1_VBUS_ON;
+		else
+			val = GEMINI_MISC_USB1_MINI_B;
+		if (wakeup)
+			val |= GEMINI_MISC_USB1_WAKEUP;
+	} else {
+		mask = GEMINI_MISC_USB0_VBUS_ON | GEMINI_MISC_USB0_MINI_B |
+			GEMINI_MISC_USB0_WAKEUP;
+		if (mode == USB_DR_MODE_HOST)
+			val = GEMINI_MISC_USB0_VBUS_ON;
+		else
+			val = GEMINI_MISC_USB0_MINI_B;
+		if (wakeup)
+			val |= GEMINI_MISC_USB0_WAKEUP;
+	}
+
+	ret = regmap_update_bits(map, GEMINI_GLOBAL_MISC_CTRL, mask, val);
+	if (ret) {
+		dev_err(dev, "failed to initialize Gemini PHY\n");
+		return ret;
+	}
+
+	dev_info(dev, "initialized Gemini PHY in %s mode\n",
+		 (mode == USB_DR_MODE_HOST) ? "host" : "gadget");
+	return 0;
+}
+
 static int fotg210_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -22,6 +93,15 @@ static int fotg210_probe(struct platform_device *pdev)
 
 	mode = usb_get_dr_mode(dev);
 
+	if (of_device_is_compatible(dev->of_node, "cortina,gemini-usb")) {
+		struct resource *res;
+
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		ret = fotg210_gemini_init(dev, res, mode);
+		if (ret)
+			return ret;
+	}
+
 	if (mode == USB_DR_MODE_PERIPHERAL)
 		ret = fotg210_udc_probe(pdev);
 	else