usb: omap1: Tahvo USB transceiver driver

Add Tahvo USB transceiver driver.

Based on old code from linux-omap tree. The original driver was written
by Juha Yrjölä, Tony Lindgren, and Timo Teräs.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Felipe Balbi <balbi@ti.com>

4 files changed, 495 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-platform-tahvo-usb b/Documentation/ABI/testing/sysfs-platform-tahvo-usb
new file mode 100644
index 000000000000..f6e20ce4b538
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-tahvo-usb
@@ -0,0 +1,16 @@
+What:           /sys/bus/platform/devices/tahvo-usb/otg_mode
+Date:           December 2013
+Contact:        Aaro Koskinen <aaro.koskinen@iki.fi>
+Description:
+                Set or read the current OTG mode. Valid values are "host" and
+                "peripheral".
+
+                Reading: returns the current mode.
+
+What:           /sys/bus/platform/devices/tahvo-usb/vbus
+Date:           December 2013
+Contact:        Aaro Koskinen <aaro.koskinen@iki.fi>
+Description:
+                Read the current VBUS state.
+
+                Reading: returns "on" or "off".
diff --git a/drivers/usb/phy/Kconfig b/drivers/usb/phy/Kconfig
index 0dbab6f5c2d4..4f22762f3d6f 100644
--- a/drivers/usb/phy/Kconfig
+++ b/drivers/usb/phy/Kconfig
@@ -152,6 +152,21 @@ config OMAP_OTG
           This driver can also be built as a module. If so, the module
           will be called omap-otg.
 
+config TAHVO_USB
+        tristate "Tahvo USB transceiver driver"
+        depends on MFD_RETU && EXTCON
+        select USB_PHY
+        help
+          Enable this to support USB transceiver on Tahvo. This is used
+          at least on Nokia 770.
+
+config TAHVO_USB_HOST_BY_DEFAULT
+        depends on TAHVO_USB
+        boolean "Device in USB host mode by default"
+        help
+          Say Y here, if you want the device to enter USB host mode
+          by default on bootup.
+
 config USB_ISP1301
         tristate "NXP ISP1301 USB transceiver support"
         depends on USB || USB_GADGET
diff --git a/drivers/usb/phy/Makefile b/drivers/usb/phy/Makefile
index 64a9345e5633..9b3be9e0aeb4 100644
--- a/drivers/usb/phy/Makefile
+++ b/drivers/usb/phy/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_FSL_USB2_OTG)		+= phy-fsl-usb.o
 obj-$(CONFIG_ISP1301_OMAP)              += phy-isp1301-omap.o
 obj-$(CONFIG_MV_U3D_PHY)                += phy-mv-u3d-usb.o
 obj-$(CONFIG_NOP_USB_XCEIV)             += phy-generic.o
+obj-$(CONFIG_TAHVO_USB)                 += phy-tahvo.o
 obj-$(CONFIG_OMAP_CONTROL_USB)          += phy-omap-control.o
 obj-$(CONFIG_AM335X_CONTROL_USB)        += phy-am335x-control.o
 obj-$(CONFIG_AM335X_PHY_USB)            += phy-am335x.o
diff --git a/drivers/usb/phy/phy-tahvo.c b/drivers/usb/phy/phy-tahvo.c
new file mode 100644
index 000000000000..8bb833e22d64
--- /dev/null
+++ b/drivers/usb/phy/phy-tahvo.c
@@ -0,0 +1,463 @@
+/*
+ * Tahvo USB transceiver driver
+ *
+ * Copyright (C) 2005-2006 Nokia Corporation
+ *
+ * Parts copied from isp1301_omap.c.
+ * Copyright (C) 2004 Texas Instruments
+ * Copyright (C) 2004 David Brownell
+ *
+ * Original driver written by Juha Yrjölä, Tony Lindgren and Timo Teräs.
+ * Modified for Retu/Tahvo MFD by Aaro Koskinen.
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/usb.h>
+#include <linux/extcon.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/usb/otg.h>
+#include <linux/mfd/retu.h>
+#include <linux/usb/gadget.h>
+#include <linux/platform_device.h>
+
+#define DRIVER_NAME     "tahvo-usb"
+
+#define TAHVO_REG_IDSR  0x02
+#define TAHVO_REG_USBR  0x06
+
+#define USBR_SLAVE_CONTROL      (1 << 8)
+#define USBR_VPPVIO_SW          (1 << 7)
+#define USBR_SPEED              (1 << 6)
+#define USBR_REGOUT             (1 << 5)
+#define USBR_MASTER_SW2         (1 << 4)
+#define USBR_MASTER_SW1         (1 << 3)
+#define USBR_SLAVE_SW           (1 << 2)
+#define USBR_NSUSPEND           (1 << 1)
+#define USBR_SEMODE             (1 << 0)
+
+#define TAHVO_MODE_HOST         0
+#define TAHVO_MODE_PERIPHERAL   1
+
+struct tahvo_usb {
+        struct platform_device  *pt_dev;
+        struct usb_phy          phy;
+        int                     vbus_state;
+        struct mutex            serialize;
+        struct clk              *ick;
+        int                     irq;
+        int                     tahvo_mode;
+        struct extcon_dev       extcon;
+};
+
+static const char *tahvo_cable[] = {
+        "USB-HOST",
+        "USB",
+        NULL,
+};
+
+static ssize_t vbus_state_show(struct device *device,
+                               struct device_attribute *attr, char *buf)
+{
+        struct tahvo_usb *tu = dev_get_drvdata(device);
+        return sprintf(buf, "%s\n", tu->vbus_state ? "on" : "off");
+}
+static DEVICE_ATTR(vbus, 0444, vbus_state_show, NULL);
+
+static void check_vbus_state(struct tahvo_usb *tu)
+{
+        struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
+        int reg, prev_state;
+
+        reg = retu_read(rdev, TAHVO_REG_IDSR);
+        if (reg & TAHVO_STAT_VBUS) {
+                switch (tu->phy.state) {
+                case OTG_STATE_B_IDLE:
+                        /* Enable the gadget driver */
+                        if (tu->phy.otg->gadget)
+                                usb_gadget_vbus_connect(tu->phy.otg->gadget);
+                        tu->phy.state = OTG_STATE_B_PERIPHERAL;
+                        break;
+                case OTG_STATE_A_IDLE:
+                        /*
+                         * Session is now valid assuming the USB hub is driving
+                         * Vbus.
+                         */
+                        tu->phy.state = OTG_STATE_A_HOST;
+                        break;
+                default:
+                        break;
+                }
+                dev_info(&tu->pt_dev->dev, "USB cable connected\n");
+        } else {
+                switch (tu->phy.state) {
+                case OTG_STATE_B_PERIPHERAL:
+                        if (tu->phy.otg->gadget)
+                                usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
+                        tu->phy.state = OTG_STATE_B_IDLE;
+                        break;
+                case OTG_STATE_A_HOST:
+                        tu->phy.state = OTG_STATE_A_IDLE;
+                        break;
+                default:
+                        break;
+                }
+                dev_info(&tu->pt_dev->dev, "USB cable disconnected\n");
+        }
+
+        prev_state = tu->vbus_state;
+        tu->vbus_state = reg & TAHVO_STAT_VBUS;
+        if (prev_state != tu->vbus_state) {
+                extcon_set_cable_state(&tu->extcon, "USB", tu->vbus_state);
+                sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state");
+        }
+}
+
+static void tahvo_usb_become_host(struct tahvo_usb *tu)
+{
+        struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
+
+        extcon_set_cable_state(&tu->extcon, "USB-HOST", true);
+
+        /* Power up the transceiver in USB host mode */
+        retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND |
+                   USBR_MASTER_SW2 | USBR_MASTER_SW1);
+        tu->phy.state = OTG_STATE_A_IDLE;
+
+        check_vbus_state(tu);
+}
+
+static void tahvo_usb_stop_host(struct tahvo_usb *tu)
+{
+        tu->phy.state = OTG_STATE_A_IDLE;
+}
+
+static void tahvo_usb_become_peripheral(struct tahvo_usb *tu)
+{
+        struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
+
+        extcon_set_cable_state(&tu->extcon, "USB-HOST", false);
+
+        /* Power up transceiver and set it in USB peripheral mode */
+        retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL | USBR_REGOUT |
+                   USBR_NSUSPEND | USBR_SLAVE_SW);
+        tu->phy.state = OTG_STATE_B_IDLE;
+
+        check_vbus_state(tu);
+}
+
+static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu)
+{
+        if (tu->phy.otg->gadget)
+                usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
+        tu->phy.state = OTG_STATE_B_IDLE;
+}
+
+static void tahvo_usb_power_off(struct tahvo_usb *tu)
+{
+        struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
+
+        /* Disable gadget controller if any */
+        if (tu->phy.otg->gadget)
+                usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
+
+        /* Power off transceiver */
+        retu_write(rdev, TAHVO_REG_USBR, 0);
+        tu->phy.state = OTG_STATE_UNDEFINED;
+}
+
+static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend)
+{
+        struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy);
+        struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
+        u16 w;
+
+        dev_dbg(&tu->pt_dev->dev, "%s\n", __func__);
+
+        w = retu_read(rdev, TAHVO_REG_USBR);
+        if (suspend)
+                w &= ~USBR_NSUSPEND;
+        else
+                w |= USBR_NSUSPEND;
+        retu_write(rdev, TAHVO_REG_USBR, w);
+
+        return 0;
+}
+
+static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host)
+{
+        struct tahvo_usb *tu = container_of(otg->phy, struct tahvo_usb, phy);
+
+        dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, host);
+
+        if (otg == NULL)
+                return -ENODEV;
+
+        mutex_lock(&tu->serialize);
+
+        if (host == NULL) {
+                if (tu->tahvo_mode == TAHVO_MODE_HOST)
+                        tahvo_usb_power_off(tu);
+                otg->host = NULL;
+                mutex_unlock(&tu->serialize);
+                return 0;
+        }
+
+        if (tu->tahvo_mode == TAHVO_MODE_HOST) {
+                otg->host = NULL;
+                tahvo_usb_become_host(tu);
+        }
+
+        otg->host = host;
+
+        mutex_unlock(&tu->serialize);
+
+        return 0;
+}
+
+static int tahvo_usb_set_peripheral(struct usb_otg *otg,
+                                    struct usb_gadget *gadget)
+{
+        struct tahvo_usb *tu = container_of(otg->phy, struct tahvo_usb, phy);
+
+        dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, gadget);
+
+        if (!otg)
+                return -ENODEV;
+
+        mutex_lock(&tu->serialize);
+
+        if (!gadget) {
+                if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
+                        tahvo_usb_power_off(tu);
+                tu->phy.otg->gadget = NULL;
+                mutex_unlock(&tu->serialize);
+                return 0;
+        }
+
+        tu->phy.otg->gadget = gadget;
+        if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
+                tahvo_usb_become_peripheral(tu);
+
+        mutex_unlock(&tu->serialize);
+
+        return 0;
+}
+
+static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu)
+{
+        struct tahvo_usb *tu = _tu;
+
+        mutex_lock(&tu->serialize);
+        check_vbus_state(tu);
+        mutex_unlock(&tu->serialize);
+
+        return IRQ_HANDLED;
+}
+
+static ssize_t otg_mode_show(struct device *device,
+                             struct device_attribute *attr, char *buf)
+{
+        struct tahvo_usb *tu = dev_get_drvdata(device);
+
+        switch (tu->tahvo_mode) {
+        case TAHVO_MODE_HOST:
+                return sprintf(buf, "host\n");
+        case TAHVO_MODE_PERIPHERAL:
+                return sprintf(buf, "peripheral\n");
+        }
+
+        return -EINVAL;
+}
+
+static ssize_t otg_mode_store(struct device *device,
+                              struct device_attribute *attr,
+                              const char *buf, size_t count)
+{
+        struct tahvo_usb *tu = dev_get_drvdata(device);
+        int r;
+
+        mutex_lock(&tu->serialize);
+        if (count >= 4 && strncmp(buf, "host", 4) == 0) {
+                if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
+                        tahvo_usb_stop_peripheral(tu);
+                tu->tahvo_mode = TAHVO_MODE_HOST;
+                if (tu->phy.otg->host) {
+                        dev_info(device, "HOST mode: host controller present\n");
+                        tahvo_usb_become_host(tu);
+                } else {
+                        dev_info(device, "HOST mode: no host controller, powering off\n");
+                        tahvo_usb_power_off(tu);
+                }
+                r = strlen(buf);
+        } else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) {
+                if (tu->tahvo_mode == TAHVO_MODE_HOST)
+                        tahvo_usb_stop_host(tu);
+                tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
+                if (tu->phy.otg->gadget) {
+                        dev_info(device, "PERIPHERAL mode: gadget driver present\n");
+                        tahvo_usb_become_peripheral(tu);
+                } else {
+                        dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n");
+                        tahvo_usb_power_off(tu);
+                }
+                r = strlen(buf);
+        } else {
+                r = -EINVAL;
+        }
+        mutex_unlock(&tu->serialize);
+
+        return r;
+}
+static DEVICE_ATTR(otg_mode, 0644, otg_mode_show, otg_mode_store);
+
+static struct attribute *tahvo_attributes[] = {
+        &dev_attr_vbus.attr,
+        &dev_attr_otg_mode.attr,
+        NULL
+};
+
+static struct attribute_group tahvo_attr_group = {
+        .attrs = tahvo_attributes,
+};
+
+static int tahvo_usb_probe(struct platform_device *pdev)
+{
+        struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
+        struct tahvo_usb *tu;
+        int ret;
+
+        tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL);
+        if (!tu)
+                return -ENOMEM;
+
+        tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg),
+                                   GFP_KERNEL);
+        if (!tu->phy.otg)
+                return -ENOMEM;
+
+        tu->pt_dev = pdev;
+
+        /* Default mode */
+#ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT
+        tu->tahvo_mode = TAHVO_MODE_HOST;
+#else
+        tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
+#endif
+
+        mutex_init(&tu->serialize);
+
+        tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick");
+        if (!IS_ERR(tu->ick))
+                clk_enable(tu->ick);
+
+        /*
+         * Set initial state, so that we generate kevents only on state changes.
+         */
+        tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS;
+
+        tu->extcon.name = DRIVER_NAME;
+        tu->extcon.supported_cable = tahvo_cable;
+        tu->extcon.dev.parent = &pdev->dev;
+
+        ret = extcon_dev_register(&tu->extcon);
+        if (ret) {
+                dev_err(&pdev->dev, "could not register extcon device: %d\n",
+                        ret);
+                goto err_disable_clk;
+        }
+
+        /* Set the initial cable state. */
+        extcon_set_cable_state(&tu->extcon, "USB-HOST",
+                               tu->tahvo_mode == TAHVO_MODE_HOST);
+        extcon_set_cable_state(&tu->extcon, "USB", tu->vbus_state);
+
+        /* Create OTG interface */
+        tahvo_usb_power_off(tu);
+        tu->phy.dev = &pdev->dev;
+        tu->phy.state = OTG_STATE_UNDEFINED;
+        tu->phy.label = DRIVER_NAME;
+        tu->phy.set_suspend = tahvo_usb_set_suspend;
+
+        tu->phy.otg->phy = &tu->phy;
+        tu->phy.otg->set_host = tahvo_usb_set_host;
+        tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral;
+
+        ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "cannot register USB transceiver: %d\n",
+                        ret);
+                goto err_extcon_unreg;
+        }
+
+        dev_set_drvdata(&pdev->dev, tu);
+
+        tu->irq = platform_get_irq(pdev, 0);
+        ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt, 0,
+                                   "tahvo-vbus", tu);
+        if (ret) {
+                dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n",
+                        ret);
+                goto err_remove_phy;
+        }
+
+        /* Attributes */
+        ret = sysfs_create_group(&pdev->dev.kobj, &tahvo_attr_group);
+        if (ret) {
+                dev_err(&pdev->dev, "cannot create sysfs group: %d\n", ret);
+                goto err_free_irq;
+        }
+
+        return 0;
+
+err_free_irq:
+        free_irq(tu->irq, tu);
+err_remove_phy:
+        usb_remove_phy(&tu->phy);
+err_extcon_unreg:
+        extcon_dev_unregister(&tu->extcon);
+err_disable_clk:
+        if (!IS_ERR(tu->ick))
+                clk_disable(tu->ick);
+
+        return ret;
+}
+
+static int tahvo_usb_remove(struct platform_device *pdev)
+{
+        struct tahvo_usb *tu = platform_get_drvdata(pdev);
+
+        sysfs_remove_group(&pdev->dev.kobj, &tahvo_attr_group);
+        free_irq(tu->irq, tu);
+        usb_remove_phy(&tu->phy);
+        extcon_dev_unregister(&tu->extcon);
+        if (!IS_ERR(tu->ick))
+                clk_disable(tu->ick);
+
+        return 0;
+}
+
+static struct platform_driver tahvo_usb_driver = {
+        .probe          = tahvo_usb_probe,
+        .remove         = tahvo_usb_remove,
+        .driver         = {
+                .name   = "tahvo-usb",
+                .owner  = THIS_MODULE,
+        },
+};
+module_platform_driver(tahvo_usb_driver);
+
+MODULE_DESCRIPTION("Tahvo USB transceiver driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs");
+MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");