[Patch V5 03/21] phy: tegra: xusb: Add usb-role-switch support

Nagarjuna Kristam
2020-02-10T08:12:38Z

If usb-role-switch property is present in USB 2 port, register
usb-role-switch to receive usb role changes.

Signed-off-by: Nagarjuna Kristam <nkristam@nvidia.com>
---
V5
- No changes
---
V4:
- Updated function name in debug messages as suggested by Thierry.
- Added owner info to port->dev during USB role switch registration.
---
V3:
- Driver aborts if usb-role-switch is not added in dt forotg/peripheral
roles.
- Added role name strings instead of enum values in debug prints.
- Updated arguments and variable allignments as per Thierry inputs.
---
V2:
- Removed dev_set_drvdata for port->dev.
- Added of_platform_depopulate during error handling and driver removal.
---
drivers/phy/tegra/Kconfig | 1 +
drivers/phy/tegra/xusb.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++
drivers/phy/tegra/xusb.h | 3 +++
3 files changed, 71 insertions(+)

diff --git a/drivers/phy/tegra/Kconfig b/drivers/phy/tegra/Kconfig
index f9817c3..df07c4d 100644
--- a/drivers/phy/tegra/Kconfig
+++ b/drivers/phy/tegra/Kconfig
@@ -2,6 +2,7 @@
config PHY_TEGRA_XUSB
tristate "NVIDIA Tegra XUSB pad controller driver"
depends on ARCH_TEGRA
+ select USB_CONN_GPIO
help
Choose this option if you have an NVIDIA Tegra SoC.

diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
index f98ec39..0fdbaa2 100644
--- a/drivers/phy/tegra/xusb.c
+++ b/drivers/phy/tegra/xusb.c
@@ -541,6 +541,11 @@ static int tegra_xusb_port_init(struct tegra_xusb_port *port,

static void tegra_xusb_port_unregister(struct tegra_xusb_port *port)
{
+ if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
+ of_platform_depopulate(&port->dev);
+ usb_role_switch_unregister(port->usb_role_sw);
+ }
+
device_unregister(&port->dev);
}

@@ -551,11 +556,59 @@ static const char *const modes[] = {
[USB_DR_MODE_OTG] = "otg",
};

+static const char * const usb_roles[] = {
+ [USB_ROLE_NONE] = "none",
+ [USB_ROLE_HOST] = "host",
+ [USB_ROLE_DEVICE] = "device",
+};
+
+static int tegra_xusb_role_sw_set(struct device *dev, enum usb_role role)
+{
+ dev_dbg(dev, "%s(): role %s\n", __func__, usb_roles[role]);
+
+ return 0;
+}
+
+static int tegra_xusb_setup_usb_role_switch(struct tegra_xusb_port *port)
+{
+ struct usb_role_switch_desc role_sx_desc = {
+ .fwnode = dev_fwnode(&port->dev),
+ .set = tegra_xusb_role_sw_set,
+ };
+ int err = 0;
+
+ /*
+ * USB role switch driver needs parent driver owner info. This is a
+ * suboptimal solution. TODO: Need to revisit this in a follow-up patch
+ * where an optimal solution is possible with changes to USB role
+ * switch driver.
+ */
+ port->dev.driver = devm_kzalloc(&port->dev,
+ sizeof(struct device_driver),
+ GFP_KERNEL);
+ port->dev.driver->owner = THIS_MODULE;
+
+ port->usb_role_sw = usb_role_switch_register(&port->dev,
+ &role_sx_desc);
+ if (IS_ERR(port->usb_role_sw)) {
+ err = PTR_ERR(port->usb_role_sw);
+ dev_err(&port->dev, "failed to register USB role switch: %d",
+ err);
+ return err;
+ }
+
+ /* populate connector entry */
+ of_platform_populate(port->dev.of_node, NULL, NULL, &port->dev);
+
+ return err;
+}
+
static int tegra_xusb_usb2_port_parse_dt(struct tegra_xusb_usb2_port *usb2)
{
struct tegra_xusb_port *port = &usb2->base;
struct device_node *np = port->dev.of_node;
const char *mode;
+ int err;

usb2->internal = of_property_read_bool(np, "nvidia,internal");

@@ -572,6 +625,20 @@ static int tegra_xusb_usb2_port_parse_dt(struct tegra_xusb_usb2_port *usb2)
usb2->mode = USB_DR_MODE_HOST;
}

+ /* usb-role-switch property is mandatory for OTG/Peripheral modes */
+ if (usb2->mode == USB_DR_MODE_PERIPHERAL ||
+ usb2->mode == USB_DR_MODE_OTG) {
+ if (of_property_read_bool(np, "usb-role-switch")) {
+ err = tegra_xusb_setup_usb_role_switch(port);
+ if (err < 0)
+ return err;
+ } else {
+ dev_err(&port->dev, "usb-role-switch not found for %s mode",
+ modes[usb2->mode]);
+ return -EINVAL;
+ }
+ }
+
usb2->supply = devm_regulator_get(&port->dev, "vbus");
return PTR_ERR_OR_ZERO(usb2->supply);
}
diff --git a/drivers/phy/tegra/xusb.h b/drivers/phy/tegra/xusb.h
index da94fcc..9f27899 100644
--- a/drivers/phy/tegra/xusb.h
+++ b/drivers/phy/tegra/xusb.h
@@ -12,6 +12,7 @@
#include <linux/workqueue.h>

#include <linux/usb/otg.h>
+#include <linux/usb/role.h>

/* legacy entry points for backwards-compatibility */
int tegra_xusb_padctl_legacy_probe(struct platform_device *pdev);
@@ -266,6 +267,8 @@ struct tegra_xusb_port {
struct list_head list;
struct device dev;

+ struct usb_role_switch *usb_role_sw;
+
const struct tegra_xusb_port_ops *ops;
};

--
2.7.4