There are some devices which have D+ pullup GPIO, but no VBUS sensing
support. As such they can't be supported by gpio-vbus transceiver but
would benefit from OTG transceiver interface support. Provide simple
driver that would just handle OTG API for gadgete drivers and provide a
way to toggle D+ pullup.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx>
---
drivers/usb/otg/Kconfig | 8 ++
drivers/usb/otg/Makefile | 1 +
drivers/usb/otg/gpio_pullup.c | 159 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 168 insertions(+), 0 deletions(-)
create mode 100644 drivers/usb/otg/gpio_pullup.c
diff --git a/drivers/usb/otg/Kconfig b/drivers/usb/otg/Kconfig
index cf3a245..18b9183 100644
--- a/drivers/usb/otg/Kconfig
+++ b/drivers/usb/otg/Kconfig
@@ -140,4 +140,12 @@ config FSL_USB2_OTG
help
Enable this to support Freescale USB OTG transceiver.
+config USB_GPIO_PULLUP
+ tristate "GPIO based peripheral-only D+ pullup handling"
+ depends on GENERIC_GPIO
+ select USB_OTG_UTILS
+ help
+ Provides simple GPIO D+ pullup handling for controllers with
+ internal transceiver via the otg_transceiver interface.
+
endif # USB || OTG
diff --git a/drivers/usb/otg/Makefile b/drivers/usb/otg/Makefile
index 24d4e63..b482e79 100644
--- a/drivers/usb/otg/Makefile
+++ b/drivers/usb/otg/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_AB8500_USB) += ab8500-usb.o
obj-$(CONFIG_LUBBOCK_USB) += lubbock-usb.o
fsl_usb2_otg-objs := fsl_otg.o otg_fsm.o
obj-$(CONFIG_FSL_USB2_OTG) += fsl_usb2_otg.o
+obj-$(CONFIG_USB_GPIO_PULLUP) += gpio_pullup.o
diff --git a/drivers/usb/otg/gpio_pullup.c b/drivers/usb/otg/gpio_pullup.c
new file mode 100644
index 0000000..075d269
--- /dev/null
+++ b/drivers/usb/otg/gpio_pullup.c
@@ -0,0 +1,159 @@
+/*
+ * gpio_pullup.c - simple GPIO D+ pullup handling for B peripheral devices
+ *
+ * Copyright (c) 2011 Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx>
+ *
+ * Heavily based on gpio_vbus driver:
+ *
+ * Copyright (c) 2008 Philipp Zabel <philipp.zabel@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/usb.h>
+
+#include <linux/usb/gadget.h>
+#include <linux/usb/gpio_vbus.h>
+#include <linux/usb/otg.h>
+
+struct gpio_pullup_data {
+ struct otg_transceiver otg;
+ struct device *dev;
+};
+
+/* OTG transceiver interface */
+
+/* bind/unbind the peripheral controller */
+static int gpio_pullup_set_peripheral(struct otg_transceiver *otg,
+ struct usb_gadget *gadget)
+{
+ struct gpio_pullup_data *gpio_pullup;
+ struct gpio_vbus_mach_info *pdata;
+ struct platform_device *pdev;
+ int gpio;
+
+ gpio_pullup = container_of(otg, struct gpio_pullup_data, otg);
+ pdev = to_platform_device(gpio_pullup->dev);
+ pdata = gpio_pullup->dev->platform_data;
+ gpio = pdata->gpio_pullup;
+
+ if (!gadget) {
+ dev_dbg(&pdev->dev, "unregistering gadget '%s'\n",
+ otg->gadget->name);
+
+ /* optionally disable D+ pullup */
+ gpio_set_value(pdata->gpio_pullup, pdata->gpio_pullup_inverted);
+
+ usb_gadget_vbus_disconnect(otg->gadget);
+ otg->state = OTG_STATE_UNDEFINED;
+
+ otg->gadget = NULL;
+ return 0;
+ }
+
+ otg->gadget = gadget;
+ dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
+
+ /* initialize connection state */
+ gpio_pullup->otg.state = OTG_STATE_B_PERIPHERAL;
+ usb_gadget_vbus_connect(gpio_pullup->otg.gadget);
+
+ gpio_set_value(pdata->gpio_pullup, !pdata->gpio_pullup_inverted);
+
+ return 0;
+}
+
+/* platform driver interface */
+
+static int __devinit gpio_pullup_probe(struct platform_device *pdev)
+{
+ struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
+ struct gpio_pullup_data *gpio_pullup;
+ int err, gpio;
+
+ if (!pdata || !gpio_is_valid(pdata->gpio_pullup))
+ return -EINVAL;
+
+ gpio_pullup = kzalloc(sizeof(struct gpio_pullup_data), GFP_KERNEL);
+ if (!gpio_pullup)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, gpio_pullup);
+ gpio_pullup->dev = &pdev->dev;
+ gpio_pullup->otg.label = "gpio-pullup";
+ gpio_pullup->otg.state = OTG_STATE_UNDEFINED;
+ gpio_pullup->otg.set_peripheral = gpio_pullup_set_peripheral;
+
+ /* if data line pullup is in use, initialize it to "not pulling up" */
+ gpio = pdata->gpio_pullup;
+ err = gpio_request(gpio, "udc_pullup");
+ if (err) {
+ dev_err(&pdev->dev,
+ "can't request pullup gpio %d, err: %d\n",
+ gpio, err);
+ gpio_free(pdata->gpio_pullup);
+ goto err_gpio;
+ }
+ gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
+
+ /* only active when a gadget is registered */
+ err = otg_set_transceiver(&gpio_pullup->otg);
+ if (err) {
+ dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
+ err);
+ goto err_otg;
+ }
+
+ return 0;
+err_otg:
+ gpio_free(pdata->gpio_pullup);
+err_gpio:
+ platform_set_drvdata(pdev, NULL);
+ kfree(gpio_pullup);
+ return err;
+}
+
+static int __devexit gpio_pullup_remove(struct platform_device *pdev)
+{
+ struct gpio_pullup_data *gpio_pullup = platform_get_drvdata(pdev);
+ struct gpio_vbus_mach_info *pdata = pdev->dev.platform_data;
+
+ otg_set_transceiver(NULL);
+
+ gpio_free(pdata->gpio_pullup);
+ platform_set_drvdata(pdev, NULL);
+ kfree(gpio_pullup);
+
+ return 0;
+}
+
+static struct platform_driver gpio_pullup_driver = {
+ .driver = {
+ .name = "gpio-pullup",
+ .owner = THIS_MODULE,
+ },
+ .probe = gpio_pullup_probe,
+ .remove = __devexit_p(gpio_pullup_remove),
+};
+MODULE_ALIAS("platform:gpio-pullup");
+
+static int __init gpio_pullup_init(void)
+{
+ return platform_driver_register(&gpio_pullup_driver);
+}
+module_init(gpio_pullup_init);
+
+static void __exit gpio_pullup_exit(void)
+{
+ platform_driver_unregister(&gpio_pullup_driver);
+}
+module_exit(gpio_pullup_exit);
+
+MODULE_DESCRIPTION("simple GPIO D+ pulllup OTG transceiver driver");
+MODULE_AUTHOR("Dmitry Eremin-Solenikov");
+MODULE_LICENSE("GPL");
--
1.7.5.4
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