usb: add devicetree helpers for determining dr_mode and phy_type

This adds two little devicetree helper functions for determining the
dr_mode (host, peripheral, otg) and phy_type (utmi, ulpi,...) from
the devicetree.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/drivers/usb/usb-common.c b/drivers/usb/usb-common.c
index 0db0a919d72b..675384dabfe9 100644
--- a/drivers/usb/usb-common.c
+++ b/drivers/usb/usb-common.c
@@ -13,7 +13,9 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/usb/ch9.h>
+#include <linux/usb/of.h>
 #include <linux/usb/otg.h>
 
 const char *usb_otg_state_string(enum usb_otg_state state)
@@ -79,4 +81,37 @@ const char *usb_state_string(enum usb_device_state state)
 }
 EXPORT_SYMBOL_GPL(usb_state_string);
 
+#ifdef CONFIG_OF
+static const char *const usb_dr_modes[] = {
+        [USB_DR_MODE_UNKNOWN]           = "",
+        [USB_DR_MODE_HOST]              = "host",
+        [USB_DR_MODE_PERIPHERAL]        = "peripheral",
+        [USB_DR_MODE_OTG]               = "otg",
+};
+
+/**
+ * of_usb_get_dr_mode - Get dual role mode for given device_node
+ * @np: Pointer to the given device_node
+ *
+ * The function gets phy interface string from property 'dr_mode',
+ * and returns the correspondig enum usb_dr_mode
+ */
+enum usb_dr_mode of_usb_get_dr_mode(struct device_node *np)
+{
+        const char *dr_mode;
+        int err, i;
+
+        err = of_property_read_string(np, "dr_mode", &dr_mode);
+        if (err < 0)
+                return USB_DR_MODE_UNKNOWN;
+
+        for (i = 0; i < ARRAY_SIZE(usb_dr_modes); i++)
+                if (!strcmp(dr_mode, usb_dr_modes[i]))
+                        return i;
+
+        return USB_DR_MODE_UNKNOWN;
+}
+EXPORT_SYMBOL_GPL(of_usb_get_dr_mode);
+#endif
+
 MODULE_LICENSE("GPL");