usb: phy: Add AM335x PHY driver

This driver is a redo of my earlier attempt. It uses parts of the
generic PHY driver and uses the new control driver for the register
the phy needs to power on/off the phy. It also enables easy access for
the wakeup register which is not yet implemented.
The difference between the omap attempt is:
- no static holding variable
- one global visible function which exports a struct with callbacks to
  access the "control" registers.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/phy/phy-am335x.c

@@ -0,0 +1,99 @@
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/usb/otg.h>
+#include <linux/usb/usb_phy_gen_xceiv.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include "am35x-phy-control.h"
+#include "phy-generic.h"
+
+struct am335x_phy {
+	struct usb_phy_gen_xceiv usb_phy_gen;
+	struct phy_control *phy_ctrl;
+	int id;
+};
+
+static int am335x_init(struct usb_phy *phy)
+{
+	struct am335x_phy *am_phy = dev_get_drvdata(phy->dev);
+
+	phy_ctrl_power(am_phy->phy_ctrl, am_phy->id, true);
+	return 0;
+}
+
+static void am335x_shutdown(struct usb_phy *phy)
+{
+	struct am335x_phy *am_phy = dev_get_drvdata(phy->dev);
+
+	phy_ctrl_power(am_phy->phy_ctrl, am_phy->id, false);
+}
+
+static int am335x_phy_probe(struct platform_device *pdev)
+{
+	struct am335x_phy *am_phy;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	am_phy = devm_kzalloc(dev, sizeof(*am_phy), GFP_KERNEL);
+	if (!am_phy)
+		return -ENOMEM;
+
+	am_phy->phy_ctrl = am335x_get_phy_control(dev);
+	if (!am_phy->phy_ctrl)
+		return -EPROBE_DEFER;
+	am_phy->id = of_alias_get_id(pdev->dev.of_node, "phy");
+	if (am_phy->id < 0) {
+		dev_err(&pdev->dev, "Missing PHY id: %d\n", am_phy->id);
+		return am_phy->id;
+	}
+
+	ret = usb_phy_gen_create_phy(dev, &am_phy->usb_phy_gen,
+			USB_PHY_TYPE_USB2, 0, false, false);
+	if (ret)
+		return ret;
+
+	ret = usb_add_phy_dev(&am_phy->usb_phy_gen.phy);
+	if (ret)
+		goto err_add;
+	am_phy->usb_phy_gen.phy.init = am335x_init;
+	am_phy->usb_phy_gen.phy.shutdown = am335x_shutdown;
+
+	platform_set_drvdata(pdev, am_phy);
+	return 0;
+
+err_add:
+	usb_phy_gen_cleanup_phy(&am_phy->usb_phy_gen);
+	return ret;
+}
+
+static int am335x_phy_remove(struct platform_device *pdev)
+{
+	struct am335x_phy *am_phy = platform_get_drvdata(pdev);
+
+	usb_remove_phy(&am_phy->usb_phy_gen.phy);
+	return 0;
+}
+
+static const struct of_device_id am335x_phy_ids[] = {
+	{ .compatible = "ti,am335x-usb-phy" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, am335x_phy_ids);
+
+static struct platform_driver am335x_phy_driver = {
+	.probe          = am335x_phy_probe,
+	.remove         = am335x_phy_remove,
+	.driver         = {
+		.name   = "am335x-phy-driver",
+		.owner  = THIS_MODULE,
+		.of_match_table = of_match_ptr(am335x_phy_ids),
+	},
+};
+
+module_platform_driver(am335x_phy_driver);
+MODULE_LICENSE("GPL v2");