Adding extcon driver for USB ID detection to dynamically
configure USB Host/Peripheral mode.

Signed-off-by: George Cherian <george.cher...@ti.com>
---
 .../devicetree/bindings/extcon/extcon-dra7xx.txt   |  19 ++
 drivers/extcon/Kconfig                             |   7 +
 drivers/extcon/Makefile                            |   1 +
 drivers/extcon/extcon-dra7xx.c                     | 234 +++++++++++++++++++++
 4 files changed, 261 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt
 create mode 100644 drivers/extcon/extcon-dra7xx.c

diff --git a/Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt 
b/Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt
new file mode 100644
index 0000000..37e4c22
--- /dev/null
+++ b/Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt
@@ -0,0 +1,19 @@
+EXTCON FOR DRA7xx
+
+Required Properties:
+ - compatible : Should be "ti,dra7xx-usb"
+ - gpios : phandle to ID pin and interrupt gpio.
+
+Optional Properties:
+  - interrupt-parent : interrupt controller phandle
+  - interrupts : interrupt number
+
+
+dra7x_extcon1 {
+               compatible = "ti,dra7xx-usb";
+               gpios = <&pcf_usb 1 0>,
+                       <&gpio6 11 2>;
+               interrupt-parent = <&gpio6>;
+               interrupts = <11>;
+       };
+
diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index f1d54a3..b9cf0b2 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -64,4 +64,11 @@ config EXTCON_PALMAS
          Say Y here to enable support for USB peripheral and USB host
          detection by palmas usb.
 
+config EXTCON_DRA7XX
+       tristate "DRA7XX EXTCON support"
+       help
+         Say Y here to enable support for USB peripheral and USB host
+         detection by pcf8575 using DRA7XX extcon.
+
+
 endif # MULTISTATE_SWITCH
diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
index e4fa8ba..e4778f9 100644
--- a/drivers/extcon/Makefile
+++ b/drivers/extcon/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_EXTCON_MAX77693) += extcon-max77693.o
 obj-$(CONFIG_EXTCON_MAX8997)   += extcon-max8997.o
 obj-$(CONFIG_EXTCON_ARIZONA)   += extcon-arizona.o
 obj-$(CONFIG_EXTCON_PALMAS)    += extcon-palmas.o
+obj-$(CONFIG_EXTCON_DRA7XX)    += extcon-dra7xx.o
diff --git a/drivers/extcon/extcon-dra7xx.c b/drivers/extcon/extcon-dra7xx.c
new file mode 100644
index 0000000..268c25e
--- /dev/null
+++ b/drivers/extcon/extcon-dra7xx.c
@@ -0,0 +1,234 @@
+/*
+ * DRA7XX USB ID pin detection driver
+ *
+ * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Author: George Cherian <george.cher...@ti.com>
+ *
+ * Based on extcon-palmas.c
+ *
+ * Author: Kishon Vijay Abraham I <kis...@ti.com>
+ *
+ * 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/module.h>
+#include <linux/interrupt.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/platform_device.h>
+#include <linux/extcon.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+
+struct dra7xx_usb {
+       struct device *dev;
+
+       struct extcon_dev edev;
+       struct task_struct *thread_task;
+
+       /*GPIO pin */
+       int id_gpio;
+       int irq_gpio;
+
+       int id_prev;
+       int id_current;
+
+};
+
+static const char *dra7xx_extcon_cable[] = {
+       [0] = "USB",
+       [1] = "USB-HOST",
+       NULL,
+};
+
+static const int mutually_exclusive[] = {0x3, 0x0};
+
+static int id_poll_func(void *data)
+{
+       struct dra7xx_usb *dra7xx_usb = (struct dra7xx_usb *) data;
+
+       allow_signal(SIGINT);
+       allow_signal(SIGTERM);
+       allow_signal(SIGKILL);
+       allow_signal(SIGUSR1);
+
+       set_freezable();
+
+       while (!kthread_should_stop()) {
+               dra7xx_usb->id_current = gpio_get_value_cansleep
+                                               (dra7xx_usb->id_gpio);
+               if (dra7xx_usb->id_current == dra7xx_usb->id_prev) {
+                       schedule_timeout_interruptible
+                                               (msecs_to_jiffies(2*1000));
+                       continue;
+               } else if (dra7xx_usb->id_current == 0) {
+                       extcon_set_cable_state(&dra7xx_usb->edev, "USB", false);
+                       extcon_set_cable_state(&dra7xx_usb->edev,
+                                               "USB-HOST", true);
+               } else {
+                       extcon_set_cable_state(&dra7xx_usb->edev,
+                                               "USB-HOST", false);
+                       extcon_set_cable_state(&dra7xx_usb->edev, "USB", true);
+               }
+               dra7xx_usb->id_prev = dra7xx_usb->id_current;
+       }
+
+       return 0;
+}
+
+static irqreturn_t id_irq_handler(int irq, void *data)
+{
+       struct dra7xx_usb *dra7xx_usb = (struct dra7xx_usb *) data;
+
+       dra7xx_usb->id_current = gpio_get_value_cansleep(dra7xx_usb->id_gpio);
+
+       if (dra7xx_usb->id_current == dra7xx_usb->id_prev) {
+               return IRQ_NONE;
+       } else if (dra7xx_usb->id_current == 0) {
+               extcon_set_cable_state(&dra7xx_usb->edev, "USB", false);
+               extcon_set_cable_state(&dra7xx_usb->edev, "USB-HOST", true);
+       } else {
+               extcon_set_cable_state(&dra7xx_usb->edev, "USB-HOST", false);
+               extcon_set_cable_state(&dra7xx_usb->edev, "USB", true);
+       }
+
+       dra7xx_usb->id_prev = dra7xx_usb->id_current;
+       return IRQ_HANDLED;
+
+}
+
+static int dra7xx_usb_probe(struct platform_device *pdev)
+{
+       struct device_node *node = pdev->dev.of_node;
+       struct dra7xx_usb *dra7xx_usb;
+       int status;
+       int irq_num;
+       int gpio;
+
+       dra7xx_usb = devm_kzalloc(&pdev->dev, sizeof(*dra7xx_usb), GFP_KERNEL);
+       if (!dra7xx_usb)
+               return -ENOMEM;
+
+
+       dra7xx_usb->dev  = &pdev->dev;
+
+       platform_set_drvdata(pdev, dra7xx_usb);
+
+       dra7xx_usb->edev.name = dev_name(&pdev->dev);
+       dra7xx_usb->edev.supported_cable = dra7xx_extcon_cable;
+       dra7xx_usb->edev.mutually_exclusive = mutually_exclusive;
+
+       gpio = of_get_gpio(node, 0);
+       if (gpio_is_valid(gpio)) {
+               dra7xx_usb->id_gpio = gpio;
+               status = gpio_request(dra7xx_usb->id_gpio, "id_gpio");
+               if (status)
+                       return status;
+       } else {
+               dev_err(&pdev->dev, "failed to get id gpio\n");
+               return -ENODEV;
+       }
+
+       gpio = of_get_gpio(node, 1);
+       if (gpio_is_valid(gpio)) {
+               dra7xx_usb->irq_gpio = gpio;
+               irq_num = gpio_to_irq(dra7xx_usb->irq_gpio);
+               if (irq_num < 0)
+                       dra7xx_usb->irq_gpio = 0;
+       } else {
+               dev_err(&pdev->dev, "failed to get irq gpio\n");
+       }
+
+
+       status = extcon_dev_register(&dra7xx_usb->edev, dra7xx_usb->dev);
+       if (status) {
+               dev_err(&pdev->dev, "failed to register extcon device\n");
+               return status;
+       }
+
+       dra7xx_usb->id_prev = gpio_get_value_cansleep(dra7xx_usb->id_gpio);
+       if (dra7xx_usb->id_prev) {
+               extcon_set_cable_state(&dra7xx_usb->edev, "USB-HOST", false);
+               extcon_set_cable_state(&dra7xx_usb->edev, "USB", true);
+       } else {
+               extcon_set_cable_state(&dra7xx_usb->edev, "USB", false);
+               extcon_set_cable_state(&dra7xx_usb->edev, "USB-HOST", true);
+       }
+
+       if (dra7xx_usb->irq_gpio) {
+               status = devm_request_threaded_irq(dra7xx_usb->dev, irq_num,
+                               NULL, id_irq_handler, IRQF_SHARED |
+                               IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
+                               dev_name(&pdev->dev), (void *) dra7xx_usb);
+               if (status)
+                       dev_err(dra7xx_usb->dev, "failed to request irq #%d\n",
+                                               irq_num);
+               else
+                       return 0;
+       }
+
+       dra7xx_usb->thread_task = kthread_create(id_poll_func, dra7xx_usb,
+                                                dev_name(&pdev->dev));
+       if (!dra7xx_usb->thread_task) {
+               dev_err(dra7xx_usb->dev, "failed to create thread for %s\n"
+                                       , dev_name(&pdev->dev));
+               goto err0;
+       }
+
+       wake_up_process(dra7xx_usb->thread_task);
+
+       return 0;
+
+err0:
+       gpio_free(dra7xx_usb->id_gpio);
+       extcon_dev_unregister(&dra7xx_usb->edev);
+
+       return status;
+}
+
+static int dra7xx_usb_remove(struct platform_device *pdev)
+{
+       struct dra7xx_usb *dra7xx_usb = platform_get_drvdata(pdev);
+
+       if (!dra7xx_usb->irq_gpio)
+               kthread_stop(dra7xx_usb->thread_task);
+
+       gpio_free(dra7xx_usb->id_gpio);
+       extcon_dev_unregister(&dra7xx_usb->edev);
+
+       return 0;
+}
+
+static struct of_device_id of_dra7xx_match_tbl[] = {
+       { .compatible = "ti,dra7xx-usb", },
+       { /* end */ }
+};
+
+static struct platform_driver dra7xx_usb_driver = {
+       .probe = dra7xx_usb_probe,
+       .remove = dra7xx_usb_remove,
+       .driver = {
+               .name = "dra7xx-usb",
+               .of_match_table = of_dra7xx_match_tbl,
+               .owner = THIS_MODULE,
+       },
+};
+
+module_platform_driver(dra7xx_usb_driver);
+
+MODULE_ALIAS("platform:dra7xx-usb");
+MODULE_AUTHOR("George Cherian <george.cher...@ti.com>");
+MODULE_DESCRIPTION("DRA7x USB Connector driver");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, of_dra7xx_match_tbl);
-- 
1.8.1.4

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