[PATCH, RFC] usb: add devicetree helpers for determining dr_mode and phy_type

[s.hauer@pengutronix.de (Sascha Hauer)]

From: Michael Grzeschik <m.grzeschik@pengutronix.de>

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>
---

The properties and their values have been taken from the fsl-mph-dr driver.
This binding is also documented (though currently not used) for the tegra
ehci driver (Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt).
This is a first attempt to parse these bindings at a common place so that
others can make use of it.

Basically I want to know whether this binding is recommended for new drivers
since normally the devicetree uses '-' instead of '_', and maybe there are
other problems with it.

I need this binding for the chipidea driver. I suspect that the fsl-mph-dr
driver also really handles a chipidea core.

Should we agree on this I would convert the fsl-mph-dr driver to use these
helpers.

Sascha

 drivers/usb/core/Makefile |    1 +
 drivers/usb/core/of.c     |   76 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/usb/of.h    |   22 +++++++++++++
 include/linux/usb/phy.h   |    9 ++++++
 4 files changed, 108 insertions(+)
 create mode 100644 drivers/usb/core/of.c
 create mode 100644 include/linux/usb/of.h

diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
index 26059b9..5378add 100644
--- a/drivers/usb/core/Makefile
+++ b/drivers/usb/core/Makefile
@@ -10,5 +10,6 @@ usbcore-y += devio.o notify.o generic.o quirks.o devices.o
 
 usbcore-$(CONFIG_PCI)		+= hcd-pci.o
 usbcore-$(CONFIG_ACPI)		+= usb-acpi.o
+usbcore-$(CONFIG_OF)		+= of.o
 
 obj-$(CONFIG_USB)		+= usbcore.o
diff --git a/drivers/usb/core/of.c b/drivers/usb/core/of.c
new file mode 100644
index 0000000..d000d9f
--- /dev/null
+++ b/drivers/usb/core/of.c
@@ -0,0 +1,76 @@
+/*
+ * OF helpers for usb devices.
+ *
+ * This file is released under the GPLv2
+ *
+ * Initially copied out of drivers/of/of_net.c
+ */
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/usb/of.h>
+#include <linux/usb/phy.h>
+#include <linux/export.h>
+
+static const char *usbphy_modes[] = {
+	[USBPHY_INTERFACE_MODE_NA]	= "",
+	[USBPHY_INTERFACE_MODE_UTMI]	= "utmi",
+	[USBPHY_INTERFACE_MODE_UTMIW]	= "utmi_wide",
+	[USBPHY_INTERFACE_MODE_ULPI]	= "ulpi",
+	[USBPHY_INTERFACE_MODE_SERIAL]	= "serial",
+	[USBPHY_INTERFACE_MODE_HSIC]	= "hsic",
+};
+
+/**
+ * of_get_usbphy_mode - Get phy mode for given device_node
+ * @np:	Pointer to the given device_node
+ *
+ * The function gets phy interface string from property 'phy_type',
+ * and returns the correspondig enum usb_phy_interface
+ */
+enum usb_phy_interface of_usb_get_phy_mode(struct device_node *np)
+{
+	const char *phy_type;
+	int err, i;
+
+	err = of_property_read_string(np, "phy_type", &phy_type);
+	if (err < 0)
+		return USBPHY_INTERFACE_MODE_NA;
+
+	for (i = 0; i < ARRAY_SIZE(usbphy_modes); i++)
+		if (!strcasecmp(phy_type, usbphy_modes[i]))
+			return i;
+
+	return USBPHY_INTERFACE_MODE_NA;
+}
+EXPORT_SYMBOL_GPL(of_usb_get_phy_mode);
+
+static const char *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_phy_dr_mode
+ */
+enum usb_phy_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 (!strcasecmp(dr_mode, usb_dr_modes[i]))
+			return i;
+
+	return USB_DR_MODE_UNKNOWN;
+}
+EXPORT_SYMBOL_GPL(of_usb_get_dr_mode);
diff --git a/include/linux/usb/of.h b/include/linux/usb/of.h
new file mode 100644
index 0000000..582ba96
--- /dev/null
+++ b/include/linux/usb/of.h
@@ -0,0 +1,22 @@
+/*
+ * OF helpers for usb devices.
+ *
+ * This file is released under the GPLv2
+ */
+
+#ifndef __LINUX_USB_OF_H
+#define __LINUX_USB_OF_H
+
+#include <linux/usb/phy.h>
+
+enum usb_phy_dr_mode {
+	USB_DR_MODE_UNKNOWN,
+	USB_DR_MODE_HOST,
+	USB_DR_MODE_PERIPHERAL,
+	USB_DR_MODE_OTG,
+};
+
+enum usb_phy_interface of_usb_get_phy_mode(struct device_node *np);
+enum usb_phy_dr_mode of_usb_get_dr_mode(struct device_node *np);
+
+#endif /* __LINUX_USB_OF_H */
diff --git a/include/linux/usb/phy.h b/include/linux/usb/phy.h
index a29ae1e..c5154cf 100644
--- a/include/linux/usb/phy.h
+++ b/include/linux/usb/phy.h
@@ -12,6 +12,15 @@
 #include <linux/notifier.h>
 #include <linux/usb.h>
 
+enum usb_phy_interface {
+	USBPHY_INTERFACE_MODE_NA,
+	USBPHY_INTERFACE_MODE_UTMI,
+	USBPHY_INTERFACE_MODE_UTMIW,
+	USBPHY_INTERFACE_MODE_ULPI,
+	USBPHY_INTERFACE_MODE_SERIAL,
+	USBPHY_INTERFACE_MODE_HSIC,
+};
+
 enum usb_phy_events {
 	USB_EVENT_NONE,         /* no events or cable disconnected */
 	USB_EVENT_VBUS,         /* vbus valid event */
-- 
1.7.10.4