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.koski...@iki.fi>
---
 Documentation/ABI/testing/sysfs-platform-tahvo-usb |  16 +
 drivers/usb/phy/Kconfig                            |  15 +
 drivers/usb/phy/Makefile                           |   1 +
 drivers/usb/phy/phy-tahvo.c                        | 461 +++++++++++++++++++++
 4 files changed, 493 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-tahvo-usb
 create mode 100644 drivers/usb/phy/phy-tahvo.c

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.koski...@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.koski...@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 95d0acc117cc..e0d11c227dd7 100644
--- a/drivers/usb/phy/Kconfig
+++ b/drivers/usb/phy/Kconfig
@@ -164,6 +164,21 @@ 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 ca5bcad49da2..5359489891de 100644
--- a/drivers/usb/phy/Makefile
+++ b/drivers/usb/phy/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_FSL_USB2_OTG)            += phy-fsl-usb2.o
 obj-$(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..7cf1766e1106
--- /dev/null
+++ b/drivers/usb/phy/phy-tahvo.c
@@ -0,0 +1,461 @@
+/*
+ * 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;
+       ret = extcon_dev_register(&tu->extcon, &pdev->dev);
+       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.koski...@iki.fi>");
-- 
1.8.4.4

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