[PATCH] usb: dwc3: meson-g12a: Add support for IRQ based OTG switching

[Neil Armstrong]

Add support for the OTG ID change interrupt to switch between Host
and Device mode.

Tested on the Hardkernel Odroid-N2 board.

Signed-off-by: Neil Armstrong <narmstr...@baylibre.com>
---
 drivers/usb/dwc3/dwc3-meson-g12a.c | 32 ++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-meson-g12a.c 
b/drivers/usb/dwc3/dwc3-meson-g12a.c
index 2aec31a2eacb..e5c5ad0d529e 100644
--- a/drivers/usb/dwc3/dwc3-meson-g12a.c
+++ b/drivers/usb/dwc3/dwc3-meson-g12a.c
@@ -348,6 +348,22 @@ static enum usb_role dwc3_meson_g12a_role_get(struct 
device *dev)
                USB_ROLE_HOST : USB_ROLE_DEVICE;
 }
 
+static irqreturn_t dwc3_meson_g12a_irq_thread(int irq, void *data)
+{
+       struct dwc3_meson_g12a *priv = data;
+       enum phy_mode otg_id;
+
+       otg_id = dwc3_meson_g12a_get_id(priv);
+       if (otg_id != priv->otg_phy_mode) {
+               if (dwc3_meson_g12a_otg_mode_set(priv, otg_id))
+                       dev_warn(priv->dev, "Failed to switch OTG mode\n");
+       }
+
+       regmap_update_bits(priv->regmap, USB_R5, USB_R5_ID_DIG_IRQ, 0);
+
+       return IRQ_HANDLED;
+}
+
 static struct device *dwc3_meson_g12_find_child(struct device *dev,
                                                const char *compatible)
 {
@@ -374,7 +390,7 @@ static int dwc3_meson_g12a_probe(struct platform_device 
*pdev)
        void __iomem *base;
        struct resource *res;
        enum phy_mode otg_id;
-       int ret, i;
+       int ret, i, irq;
 
        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
@@ -436,6 +452,19 @@ static int dwc3_meson_g12a_probe(struct platform_device 
*pdev)
        /* Get dr_mode */
        priv->otg_mode = usb_get_dr_mode(dev);
 
+       if (priv->otg_mode == USB_DR_MODE_OTG) {
+               /* Ack irq before registering */
+               regmap_update_bits(priv->regmap, USB_R5,
+                                  USB_R5_ID_DIG_IRQ, 0);
+
+               irq = platform_get_irq(pdev, 0);
+               ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+                                               dwc3_meson_g12a_irq_thread,
+                                               IRQF_ONESHOT, pdev->name, priv);
+               if (ret)
+                       return ret;
+       }
+
        dwc3_meson_g12a_usb_init(priv);
 
        /* Init PHYs */
@@ -460,7 +489,6 @@ static int dwc3_meson_g12a_probe(struct platform_device 
*pdev)
 
        /* Setup OTG mode corresponding to the ID pin */
        if (priv->otg_mode == USB_DR_MODE_OTG) {
-               /* TOFIX Handle ID mode toggling via IRQ */
                otg_id = dwc3_meson_g12a_get_id(priv);
                if (otg_id != priv->otg_phy_mode) {
                        if (dwc3_meson_g12a_otg_mode_set(priv, otg_id))
-- 
2.21.0