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    SubjectRe: [RFC 01/19] extcon: add extcon-odroid-usbotg driver
    From
    Hi Robert,

    This looks like a extcon driver based on gpio for USB.

    Roger posted a generic one a while back.
    https://lkml.org/lkml/2015/2/2/187

    Doesn't this serve the purpose rather than adding this driver?

    -George

    On Wed, Mar 18, 2015 at 7:34 PM, Robert Baldyga <r.baldyga@samsung.com> wrote:
    > This patch adds extcon driver for Odroid U3, U3+ and X boards.
    > It recognizes type of USB cable connected to Odroid board basing on
    > two signal lines VBUS_DET and OTG_ID (the second one is present only
    > on Odroid U3+ board).
    >
    > Following table of states presents relationship between this signals
    > and detected cable type:
    >
    > state | VBUS_DET | OTG_ID
    > -------------------------------
    > USB | H | H
    > USB_HOST | H | L
    > disconn. | L | H
    > USB-HOST | L | L
    >
    > This driver is based on extcon-gpio driver.
    >
    > Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
    > Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
    > ---
    > drivers/extcon/Kconfig | 4 +
    > drivers/extcon/Makefile | 1 +
    > drivers/extcon/extcon-odroid-usbotg.c | 256 ++++++++++++++++++++++++++++++++++
    > 3 files changed, 261 insertions(+)
    > create mode 100644 drivers/extcon/extcon-odroid-usbotg.c
    >
    > diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
    > index 6a1f7de..891dca3 100644
    > --- a/drivers/extcon/Kconfig
    > +++ b/drivers/extcon/Kconfig
    > @@ -93,4 +93,8 @@ config EXTCON_SM5502
    > Silicon Mitus SM5502. The SM5502 is a USB port accessory
    > detector and switch.
    >
    > +config EXTCON_ODROID_USBOTG
    > + tristate "Extcon Odroid U3, U3+, X and XU USB OTG port"
    > + depends on OF_GPIO
    > +
    > endif # MULTISTATE_SWITCH
    > diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
    > index 0370b42..514384e 100644
    > --- a/drivers/extcon/Makefile
    > +++ b/drivers/extcon/Makefile
    > @@ -12,3 +12,4 @@ obj-$(CONFIG_EXTCON_MAX8997) += extcon-max8997.o
    > obj-$(CONFIG_EXTCON_PALMAS) += extcon-palmas.o
    > obj-$(CONFIG_EXTCON_RT8973A) += extcon-rt8973a.o
    > obj-$(CONFIG_EXTCON_SM5502) += extcon-sm5502.o
    > +obj-$(CONFIG_EXTCON_ODROID_USBOTG) += extcon-odroid-usbotg.o
    > diff --git a/drivers/extcon/extcon-odroid-usbotg.c b/drivers/extcon/extcon-odroid-usbotg.c
    > new file mode 100644
    > index 0000000..7f71c48
    > --- /dev/null
    > +++ b/drivers/extcon/extcon-odroid-usbotg.c
    > @@ -0,0 +1,256 @@
    > +/*
    > + * drivers/extcon/extcon-odroid-usbotg.c
    > + *
    > + * USB cable extcon driver for Odroid U3, Odroid U3+ and Odroid X
    > + *
    > + * Copyright (C) 2014 Samsung Electronics
    > + * Author: Lukasz Stelmach <l.stelmach@samsung.com>
    > + * Author: Robert Baldyga <r.baldyga@samsung.com>
    > + *
    > + * based on drivers/extcon/extcon-gpio.c
    > + * Copyright (C) 2008 Google, Inc.
    > + * Author: Mike Lockwood <lockwood@android.com>
    > + *
    > + * This software is licensed under the terms of the GNU General Public
    > + * License version 2, as published by the Free Software Foundation, and
    > + * may be copied, distributed, and modified under those terms.
    > + *
    > + * 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/kernel.h>
    > +#include <linux/init.h>
    > +#include <linux/interrupt.h>
    > +#include <linux/platform_device.h>
    > +#include <linux/slab.h>
    > +#include <linux/gpio.h>
    > +#include <linux/of_gpio.h>
    > +#include <linux/extcon.h>
    > +#include <linux/extcon/extcon-gpio.h>
    > +#include <linux/delay.h>
    > +
    > +enum {
    > + EXTCON_CABLE_USB = 0,
    > + EXTCON_CABLE_USB_HOST,
    > +
    > + _EXTCON_CABLE_NUM,
    > +};
    > +
    > +static const char * const odroid_usbotg_cable[] = {
    > + [EXTCON_CABLE_USB] = "USB",
    > + [EXTCON_CABLE_USB_HOST] = "USB-HOST",
    > +
    > + NULL,
    > +};
    > +
    > +struct odroid_usbotg_data {
    > + struct extcon_dev *edev;
    > + struct gpio_desc *otg_id;
    > + struct gpio_desc *vbus_det;
    > + int otg_id_irq;
    > + int vbus_det_irq;
    > + unsigned long debounce_ms;
    > +};
    > +
    > +/*
    > + * state | VBUS_DET | OTG_ID
    > + * -------------------------------
    > + * USB | H | H
    > + * USB-HOST | H | L
    > + * disconn. | L | H
    > + * USB-HOST | L | L
    > + *
    > + * Only Odroid U3+ has OTG_ID line. U3 and X versions can detect only
    > + * USB slave cable.
    > + */
    > +
    > +static void odroid_usbotg_detect_cable(struct odroid_usbotg_data *extcon_data)
    > +{
    > + int state;
    > +
    > + mdelay(extcon_data->debounce_ms);
    > +
    > + if (extcon_data->otg_id)
    > + state = (gpiod_get_value(extcon_data->vbus_det) << 1) |
    > + gpiod_get_value(extcon_data->otg_id);
    > + else
    > + state = (gpiod_get_value(extcon_data->vbus_det) << 1) | 1;
    > +
    > + dev_dbg(&extcon_data->edev->dev, "cable state changed to %d\n", state);
    > +
    > + if (state & 0x1)
    > + extcon_set_cable_state_(extcon_data->edev,
    > + EXTCON_CABLE_USB_HOST, false);
    > + if (state != 0x3)
    > + extcon_set_cable_state_(extcon_data->edev,
    > + EXTCON_CABLE_USB, false);
    > +
    > + if (!(state & 0x1))
    > + extcon_set_cable_state_(extcon_data->edev,
    > + EXTCON_CABLE_USB_HOST, true);
    > + else if (state == 0x3)
    > + extcon_set_cable_state_(extcon_data->edev,
    > + EXTCON_CABLE_USB, true);
    > +}
    > +
    > +static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
    > +{
    > + struct odroid_usbotg_data *extcon_data = dev_id;
    > +
    > + odroid_usbotg_detect_cable(extcon_data);
    > +
    > + return IRQ_HANDLED;
    > +}
    > +
    > +static int odroid_usbotg_parse_dt(struct platform_device *pdev,
    > + struct odroid_usbotg_data *extcon_data)
    > +{
    > + struct device_node *np = pdev->dev.of_node;
    > + u32 val;
    > +
    > + if (!np)
    > + return -ENODEV;
    > +
    > + extcon_data->edev->name = np->name;
    > +
    > + if (of_property_read_u32(np, "debounce", &val) != 0)
    > + val = 50;
    > + extcon_data->debounce_ms = val;
    > +
    > + return 0;
    > +}
    > +
    > +static int odroid_usbotg_probe(struct platform_device *pdev)
    > +{
    > + struct odroid_usbotg_data *extcon_data;
    > + int ret = 0;
    > +
    > + extcon_data = devm_kzalloc(&pdev->dev,
    > + sizeof(struct odroid_usbotg_data), GFP_KERNEL);
    > + if (!extcon_data)
    > + return -ENOMEM;
    > +
    > + extcon_data->edev = devm_kzalloc(&pdev->dev, sizeof(struct extcon_dev),
    > + GFP_KERNEL);
    > + if (IS_ERR(extcon_data->edev)) {
    > + dev_err(&pdev->dev, "failed to allocate extcon device\n");
    > + return -ENOMEM;
    > + }
    > + extcon_data->edev->supported_cable = odroid_usbotg_cable;
    > +
    > + ret = odroid_usbotg_parse_dt(pdev, extcon_data);
    > + if (IS_ERR_VALUE(ret)) {
    > + dev_err(&pdev->dev, "failed to get data from device tree\n");
    > + return ret;
    > + }
    > +
    > + /* gpios */
    > + extcon_data->vbus_det = devm_gpiod_get(&pdev->dev, "vbus-det");
    > + if (IS_ERR(extcon_data->vbus_det)) {
    > + dev_err(&pdev->dev, "failed to get vbus_det gpio\n");
    > + return PTR_ERR(extcon_data->vbus_det);
    > + }
    > + extcon_data->otg_id = devm_gpiod_get_optional(&pdev->dev, "otg-id");
    > +
    > + extcon_data->edev->dev.parent = &pdev->dev;
    > + ret = extcon_dev_register(extcon_data->edev);
    > + if (ret < 0)
    > + return ret;
    > +
    > + /* irq */
    > + extcon_data->vbus_det_irq = gpiod_to_irq(extcon_data->vbus_det);
    > + if (extcon_data->vbus_det_irq < 0) {
    > + dev_err(&pdev->dev, "failed to get irq from vbus_det\n");
    > + ret = extcon_data->vbus_det_irq;
    > + goto err;
    > + }
    > + ret = request_threaded_irq(extcon_data->vbus_det_irq, NULL,
    > + gpio_irq_handler, IRQF_ONESHOT |
    > + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
    > + pdev->name, extcon_data);
    > + if (ret < 0) {
    > + dev_err(&pdev->dev, "failed to request vbus_det irq\n");
    > + goto err;
    > + }
    > +
    > + if (extcon_data->otg_id) {
    > + extcon_data->otg_id_irq = gpiod_to_irq(extcon_data->otg_id);
    > + if (extcon_data->otg_id_irq < 0) {
    > + dev_err(&pdev->dev, "failed to get irq from otg_id\n");
    > + ret = extcon_data->otg_id_irq;
    > + goto err;
    > + }
    > + ret = request_threaded_irq(extcon_data->otg_id_irq, NULL,
    > + gpio_irq_handler, IRQF_ONESHOT |
    > + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
    > + pdev->name, extcon_data);
    > + if (ret < 0) {
    > + dev_err(&pdev->dev, "failed to request otg_id irq\n");
    > + goto err;
    > + }
    > + }
    > +
    > + platform_set_drvdata(pdev, extcon_data);
    > + /* Perform initial detection */
    > + odroid_usbotg_detect_cable(extcon_data);
    > +
    > + dev_dbg(&pdev->dev, "probe: success\n");
    > +
    > + return 0;
    > +
    > +err:
    > + extcon_dev_unregister(extcon_data->edev);
    > +
    > + return ret;
    > +}
    > +
    > +static int odroid_usbotg_remove(struct platform_device *pdev)
    > +{
    > + struct odroid_usbotg_data *extcon_data = platform_get_drvdata(pdev);
    > +
    > + free_irq(extcon_data->vbus_det_irq, extcon_data);
    > + if (extcon_data->otg_id)
    > + free_irq(extcon_data->otg_id_irq, extcon_data);
    > + extcon_dev_unregister(extcon_data->edev);
    > +
    > + return 0;
    > +}
    > +
    > +static const struct of_device_id odroid_usbotg_of_match[] = {
    > + { .compatible = "extcon-odroid-usbotg" },
    > + { },
    > +};
    > +MODULE_DEVICE_TABLE(of, odroid_usbotg_of_match);
    > +
    > +static struct platform_driver odroid_usbotg_driver = {
    > + .probe = odroid_usbotg_probe,
    > + .remove = odroid_usbotg_remove,
    > + .driver = {
    > + .name = "odroid-usbotg",
    > + .owner = THIS_MODULE,
    > + .of_match_table = of_match_ptr(odroid_usbotg_of_match)
    > + },
    > +};
    > +
    > +static int __init odroid_usbotg_init(void)
    > +{
    > + return platform_driver_register(&odroid_usbotg_driver);
    > +}
    > +
    > +subsys_initcall(odroid_usbotg_init);
    > +
    > +static void __exit odroid_usbotg_cleanup(void)
    > +{
    > + platform_driver_unregister(&odroid_usbotg_driver);
    > +}
    > +
    > +module_exit(odroid_usbotg_cleanup);
    > +
    > +MODULE_AUTHOR("Lukasz Stelmach <l.stelmach@samsung.com>, Robert Baldyga <r.baldyga@samsung.com>");
    > +MODULE_DESCRIPTION("USB OTG extcon driver for Odroid U3, U3+ and X");
    > +MODULE_LICENSE("GPL");
    > --
    > 1.9.1
    >
    > --
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