Re: [PATCH v4] extcon: Palmas Extcon Driver

[Chanwoo Choi <cw00.choi@samsung.com>]

On 05/07/2013 03:25 PM, Kishon Vijay Abraham I wrote:
> Hi,
>
> On Tuesday 07 May 2013 11:40 AM, Chanwoo Choi wrote:
>> Hi Kishon,
>>
>> I add some opinion about this patch.
>>
>> On 05/06/2013 10:17 PM, Kishon Vijay Abraham I wrote:
>>> From: Graeme Gregory <gg@slimlogic.co.uk>
>>>
>>> This is the driver for the USB comparator built into the palmas chip. It
>>> handles the various USB OTG events that can be generated by cable
>>> insertion/removal.
>>>
>>> Signed-off-by: Graeme Gregory <gg@slimlogic.co.uk>
>>> Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
>>> Signed-off-by: Ruchika Kharwar <ruchika@ti.com>
>>> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
>>> [kishon@ti.com: adapted palmas usb driver to use the extcon framework]
>>> Signed-off-by: Sebastien Guiriec <s-guiriec@ti.com>
>>> ---
>>> Changes from v3:
>>> * adapted the driver to extcon framework (so moved to drivers/extcon)
>>> * removed palmas_usb_(write/read) and replaced all calls with
>>>    palmas_(read/write).
>>> * ignored a checkpatch warning in the line
>>>     static const char *palmas_extcon_cable[] = {
>>>    as it seemed to be incorrect?
>>> * removed all references to OMAP in this driver.
>>> * couldn't test this driver with mainline as omap5 panda is not booting
>>>    with mainline.
>>> * A comment to change to platform_get_irq from regmap is not done as I felt
>>>    the data should come from regmap in this case. Graeme?
>>> Changes from v2:
>>> * Moved the driver to drivers/usb/phy/
>>> * Added a bit more explanation in Kconfig
>>>   .../devicetree/bindings/extcon/extcon-twl.txt      |   17 +
>>>   drivers/extcon/Kconfig                             |    7 +
>>>   drivers/extcon/Makefile                            |    1 +
>>>   drivers/extcon/extcon-palmas.c                     |  389 ++++++++++++++++++++
>>>   include/linux/extcon/extcon_palmas.h               |   26 ++
>>>   include/linux/mfd/palmas.h                         |    8 +-
>>>   6 files changed, 447 insertions(+), 1 deletion(-)
>>>   create mode 100644 Documentation/devicetree/bindings/extcon/extcon-twl.txt
>>>   create mode 100644 drivers/extcon/extcon-palmas.c
>>>   create mode 100644 include/linux/extcon/extcon_palmas.h
>>>
>>> diff --git a/Documentation/devicetree/bindings/extcon/extcon-twl.txt b/Documentation/devicetree/bindings/extcon/extcon-twl.txt
>>> new file mode 100644
>>> index 0000000..a7f6527
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/extcon/extcon-twl.txt
>>> @@ -0,0 +1,17 @@
>>> +EXTCON FOR TWL CHIPS
>>> +
>>> +PALMAS USB COMPARATOR
>>> +Required Properties:
>>> + - compatible : Should be "ti,palmas-usb" or "ti,twl6035-usb"
>>> + - vbus-supply : phandle to the regulator device tree node.
>>> +
>>> +Optional Properties:
>>> + - ti,wakeup : To enable the wakeup comparator in probe
>>> + - ti,no_control_vbus: if the platform wishes its own vbus control
>>> +
>>> +palmas-usb {
>>> +       compatible = "ti,twl6035-usb", "ti,palmas-usb";
>>> +       vbus-supply = <&smps10_reg>;
>>> +       ti,wakeup;
>>> +};
>>> +
>>> diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
>>> index 5168a13..c881899 100644
>>> --- a/drivers/extcon/Kconfig
>>> +++ b/drivers/extcon/Kconfig
>>> @@ -53,4 +53,11 @@ config EXTCON_ARIZONA
>>>         with Wolfson Arizona devices. These are audio CODECs with
>>>         advanced audio accessory detection support.
>>>
>>> +config EXTCON_PALMAS
>>> +    tristate "Palmas USB EXTCON support"
>>> +    depends on MFD_PALMAS
>>> +    help
>>> +      Say Y here to enable support for USB peripheral and USB host
>>> +      detection by palmas usb.
>>> +
>>>   endif # MULTISTATE_SWITCH
>>> diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
>>> index f98a3c4..540e2c3 100644
>>> --- a/drivers/extcon/Makefile
>>> +++ b/drivers/extcon/Makefile
>>> @@ -8,3 +8,4 @@ obj-$(CONFIG_EXTCON_ADC_JACK)    += extcon-adc-jack.o
>>>   obj-$(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
>>> diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c
>>> new file mode 100644
>>> index 0000000..3ef042f
>>> --- /dev/null
>>> +++ b/drivers/extcon/extcon-palmas.c
>>> @@ -0,0 +1,389 @@
>>> +/*
>>> + * Palmas USB transceiver 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: Graeme Gregory <gg@...mlogic.co.uk>
>>> + * Author: Kishon Vijay Abraham I <kishon@...com>
>>> + *
>>> + * Based on twl6030_usb.c
>>> + *
>>> + * Author: Hema HK <hemahk@...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/init.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/io.h>
>>> +#include <linux/usb/phy_companion.h>
>>> +#include <linux/regulator/consumer.h>
>>> +#include <linux/err.h>
>>> +#include <linux/notifier.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/mfd/palmas.h>
>>> +#include <linux/of.h>
>>> +#include <linux/of_platform.h>
>>> +#include <linux/extcon/extcon_palmas.h>
>>> +
>> Remove unnecessary header file. When I remove following header file,
>> I completed kernel build without any problem.
>>
>> linux/init.h
>> linux/io.h
>> linux/regulator/consumer.h
>> linux/notifier.h
>> linux/slab.h
>> linux/delay.h
>
> hmm.. ok.
>>> +static const char *palmas_extcon_cable[] = {
>>> +    [0] = "USB",
>>> +    [1] = "USB-HOST",
>>> +    NULL,
>>> +};
>>> +
>>> +static const int mutually_exclusive[] = {0x3, 0x0};
>>> +
>>> +static void palmas_usb_wakeup(struct palmas *palmas, int enable)
>>> +{
>>> +    if (enable)
>>> +        palmas_write(palmas, PALMAS_USB_OTG_BASE, PALMAS_USB_WAKEUP,
>>> +            PALMAS_USB_WAKEUP_ID_WK_UP_COMP);
>>> +    else
>>> +        palmas_write(palmas, PALMAS_USB_OTG_BASE, PALMAS_USB_WAKEUP, 0);
>>> +}
>>> +
>>> +static ssize_t palmas_usb_vbus_show(struct device *dev,
>>> +            struct device_attribute *attr, char *buf)
>>> +{
>>> +    unsigned long        flags;
>>> +    int            ret = -EINVAL;
>>> +    struct palmas_usb    *palmas_usb = dev_get_drvdata(dev);
>>> +
>>> +    spin_lock_irqsave(&palmas_usb->lock, flags);
>>> +
>>> +    switch (palmas_usb->linkstat) {
>>> +    case PALMAS_USB_STATE_VBUS:
>>> +           ret = snprintf(buf, PAGE_SIZE, "vbus\n");
>>> +           break;
>>> +    case PALMAS_USB_STATE_ID:
>>> +           ret = snprintf(buf, PAGE_SIZE, "id\n");
>>> +           break;
>>> +    case PALMAS_USB_STATE_DISCONNECT:
>>> +           ret = snprintf(buf, PAGE_SIZE, "none\n");
>>> +           break;
>>> +    default:
>>> +           ret = snprintf(buf, PAGE_SIZE, "UNKNOWN\n");
>>> +    }
>>> +    spin_unlock_irqrestore(&palmas_usb->lock, flags);
>>> +
>>> +    return ret;
>>> +}
>>> +static DEVICE_ATTR(vbus, 0444, palmas_usb_vbus_show, NULL);
>> I think that 'palmas_usb_vbus' device attribute isn't standard node
>> of extcon framework. If you want to check USB/USB-HOST state
>> on user-space, user process should use following standard node
>> of extcon instead of 'palmas_usb_vbus' node.
>
> Ok. Makes sense.
>>
>> - User can get the state of USB/USB-HOST through following node:
>> /sys/class/extcon/palmas_usb/cable.0/state
>>      if state is 1, PALMAS_USB_STATE_VBUS
>>      if state is 0, PALMAS_USB_STATE_DISCONNECT
>>
>> /sys/class/extcon/palmas_usb/cable.1/state
>>      if state is 1, PALMAS_USB_STATE_ID
>>      if state is 0, PALMAS_USB_STATE_DISCONNECT
>>
>> Certainly, extcon driver have to provide specific information of external connector through
>> standard sysfs entry.
>>> +
>>> +static irqreturn_t palmas_vbus_wakeup_irq(int irq, void *_palmas_usb)
>>> +{
>>> +    int ret;
>>> +    struct palmas_usb *palmas_usb = _palmas_usb;
>>> +    unsigned int vbus_line_state;
>>> +
>>> +    palmas_read(palmas_usb->palmas, PALMAS_INTERRUPT_BASE,
>>> +        PALMAS_INT3_LINE_STATE, &vbus_line_state);
>>> +
>>> +    if (vbus_line_state & PALMAS_INT3_LINE_STATE_VBUS) {
>>> +        if (palmas_usb->linkstat != PALMAS_USB_STATE_VBUS) {
>>> +            if (palmas_usb->vbus_reg) {
>>> +                ret = regulator_enable(palmas_usb->vbus_reg);
>>> +                if (ret) {
>>> +                    dev_dbg(palmas_usb->dev,
>>> +                        "regulator enable failed\n");
>>> +                    goto ret0;
>>> +                }
>>> +            }
>>> +            palmas_usb->linkstat = PALMAS_USB_STATE_VBUS;
>>> +            extcon_set_cable_state(&palmas_usb->edev, "USB", true);
>>> +        } else {
>>> +            dev_dbg(palmas_usb->dev,
>>> +                "Spurious connect event detected\n");
>>> +        }
>>> +    } else if (!(vbus_line_state & PALMAS_INT3_LINE_STATE_VBUS)) {
>>> +        if (palmas_usb->linkstat == PALMAS_USB_STATE_VBUS) {
>>> +            if (palmas_usb->vbus_reg)
>>> +                regulator_disable(palmas_usb->vbus_reg);
>>> +            palmas_usb->linkstat = PALMAS_USB_STATE_DISCONNECT;
>>> +            extcon_set_cable_state(&palmas_usb->edev, "USB", false);
>>> +        } else {
>>> +            dev_dbg(palmas_usb->dev,
>>> +                "Spurious disconnect event detected\n");
>>> +        }
>>> +    }
>>> +
>>> +ret0:
>>> +    return IRQ_HANDLED;
>>> +}
>>> +
>>> +static irqreturn_t palmas_id_wakeup_irq(int irq, void *_palmas_usb)
>>> +{
>>> +    int            ret;
>>> +    unsigned int        set;
>>> +    struct palmas_usb    *palmas_usb = _palmas_usb;
>>> +
>>> +    palmas_read(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +        PALMAS_USB_ID_INT_LATCH_SET, &set);
>>> +
>>> +    if (set & PALMAS_USB_ID_INT_SRC_ID_GND) {
>>> +        if (palmas_usb->vbus_reg) {
>>> +            ret = regulator_enable(palmas_usb->vbus_reg);
>>> +            if (ret) {
>>> +                dev_dbg(palmas_usb->dev,
>>> +                    "regulator enable failed\n");
>>> +                goto ret0;
>>> +            }
>>> +        }
>>> +        palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +            PALMAS_USB_ID_INT_EN_HI_SET,
>>> +            PALMAS_USB_ID_INT_EN_HI_SET_ID_FLOAT);
>>> +        palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +            PALMAS_USB_ID_INT_EN_HI_CLR,
>>> +            PALMAS_USB_ID_INT_EN_HI_CLR_ID_GND);
>>> +        palmas_usb->linkstat = PALMAS_USB_STATE_ID;
>>> +        extcon_set_cable_state(&palmas_usb->edev, "USB-HOST", true);
>>> +    } else if (set & PALMAS_USB_ID_INT_SRC_ID_FLOAT) {
>>> +        palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +            PALMAS_USB_ID_INT_EN_HI_SET,
>>> +            PALMAS_USB_ID_INT_EN_HI_SET_ID_GND);
>>> +        palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +            PALMAS_USB_ID_INT_EN_HI_CLR,
>>> +            PALMAS_USB_ID_INT_EN_HI_CLR_ID_FLOAT);
>>> +        if (palmas_usb->vbus_reg)
>>> +            regulator_disable(palmas_usb->vbus_reg);
>>> +        palmas_usb->linkstat = PALMAS_USB_STATE_DISCONNECT;
>>> +        extcon_set_cable_state(&palmas_usb->edev, "USB-HOST", false);
>>> +    }
>>> +
>>> +ret0:
>>> +    return IRQ_HANDLED;
>>> +}
>>> +
>>> +static void palmas_enable_irq(struct palmas_usb *palmas_usb)
>>> +{
>>> +    palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +        PALMAS_USB_VBUS_CTRL_SET,
>>> +        PALMAS_USB_VBUS_CTRL_SET_VBUS_ACT_COMP);
>>> +
>>> +    palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +        PALMAS_USB_ID_CTRL_SET, PALMAS_USB_ID_CTRL_SET_ID_ACT_COMP);
>>> +
>>> +    palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +        PALMAS_USB_ID_INT_EN_HI_SET,
>>> +        PALMAS_USB_ID_INT_EN_HI_SET_ID_GND);
>>> +
>>> +    palmas_vbus_wakeup_irq(palmas_usb->irq4, palmas_usb);
>>> +    palmas_id_wakeup_irq(palmas_usb->irq2, palmas_usb);
>>> +}
>>> +
>>> +static void palmas_set_vbus_work(struct work_struct *data)
>>> +{
>>> +    int ret;
>>> +    struct palmas_usb *palmas_usb = container_of(data, struct palmas_usb,
>>> +                                set_vbus_work);
>>> +
>>> +    if (IS_ERR_OR_NULL(palmas_usb->vbus_reg)) {
>>> +        dev_err(palmas_usb->dev, "invalid regulator\n");
>>> +        return;
>>> +    }
>>> +
>>> +    /*
>>> +     * Start driving VBUS. Set OPA_MODE bit in CHARGERUSB_CTRL1
>>> +     * register. This enables boost mode.
>>> +     */
>>> +
>>> +    if (palmas_usb->vbus_enable) {
>>> +        ret = regulator_enable(palmas_usb->vbus_reg);
>>> +        if (ret)
>>> +            dev_dbg(palmas_usb->dev, "regulator enable failed\n");
>>> +    } else {
>>> +        regulator_disable(palmas_usb->vbus_reg);
>>> +    }
>>> +}
>>> +
>>> +static int palmas_set_vbus(struct phy_companion *comparator, bool enabled)
>>> +{
>>> +    struct palmas_usb *palmas_usb = comparator_to_palmas(comparator);
>>> +
>>> +    palmas_usb->vbus_enable = enabled;
>>> +    schedule_work(&palmas_usb->set_vbus_work);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int palmas_start_srp(struct phy_companion *comparator)
>>> +{
>>> +    struct palmas_usb *palmas_usb = comparator_to_palmas(comparator);
>>> +
>>> +    palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +        PALMAS_USB_VBUS_CTRL_SET, PALMAS_USB_VBUS_CTRL_SET_VBUS_DISCHRG
>>> +        | PALMAS_USB_VBUS_CTRL_SET_VBUS_IADP_SINK);
>>> +    palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +        PALMAS_USB_VBUS_CTRL_SET,
>>> +        PALMAS_USB_VBUS_CTRL_SET_VBUS_CHRG_VSYS |
>>> +        PALMAS_USB_VBUS_CTRL_SET_VBUS_IADP_SINK);
>>> +
>>> +    mdelay(100);
>>> +
>>> +    palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
>>> +        PALMAS_USB_VBUS_CTRL_CLR,
>>> +        PALMAS_USB_VBUS_CTRL_SET_VBUS_CHRG_VSYS |
>>> +        PALMAS_USB_VBUS_CTRL_SET_VBUS_CHRG_VSYS);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static void palmas_dt_to_pdata(struct device_node *node,
>>> +        struct palmas_usb_platform_data *pdata)
>>> +{
>>> +    pdata->no_control_vbus = of_property_read_bool(node,
>>> +                    "ti,no_control_vbus");
>>> +    pdata->wakeup = of_property_read_bool(node, "ti,wakeup");
>>> +}
>>> +
>>> +static int palmas_usb_probe(struct platform_device *pdev)
>>> +{
>>> +    u32 ret;
>>> +    struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
>>> +    struct palmas_usb_platform_data    *pdata = pdev->dev.platform_data;
>>> +    struct device_node *node = pdev->dev.of_node;
>>> +    struct palmas_usb *palmas_usb;
>>> +    int status;
>>> +
>>> +    if (node && !pdata) {
>>> +        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
>>> +
>>> +        if (!pdata)
>>> +            return -ENOMEM;
>>> +
>>> +        palmas_dt_to_pdata(node, pdata);
>>> +    }
>>> +
>>> +    if (!pdata)
>>> +        return -EINVAL;
>>> +
>>> +    palmas_usb = devm_kzalloc(&pdev->dev, sizeof(*palmas_usb), GFP_KERNEL);
>>> +    if (!palmas_usb)
>>> +        return -ENOMEM;
>>> +
>>> +    palmas->usb        = palmas_usb;
>>> +    palmas_usb->palmas    = palmas;
>>> +
>>> +    palmas_usb->dev        = &pdev->dev;
>>> +
>>> +    palmas_usb->irq1 = regmap_irq_get_virq(palmas->irq_data,
>>> +                        PALMAS_ID_OTG_IRQ);
>>> +    palmas_usb->irq2 = regmap_irq_get_virq(palmas->irq_data,
>>> +                        PALMAS_ID_IRQ);
>>> +    palmas_usb->irq3 = regmap_irq_get_virq(palmas->irq_data,
>>> +                        PALMAS_VBUS_OTG_IRQ);
>>> +    palmas_usb->irq4 = regmap_irq_get_virq(palmas->irq_data,
>>> +                        PALMAS_VBUS_IRQ);
>>> +
>>> +    palmas_usb->comparator.set_vbus    = palmas_set_vbus;
>>> +    palmas_usb->comparator.start_srp = palmas_start_srp;
>>> +
>>> +    palmas_usb_wakeup(palmas, pdata->wakeup);
>>> +
>>> +    /* init spinlock for workqueue */
>>> +    spin_lock_init(&palmas_usb->lock);
>>> +
>>> +    if (!pdata->no_control_vbus) {
>>> +        palmas_usb->vbus_reg = devm_regulator_get(&pdev->dev, "vbus");
>>> +        if (IS_ERR(palmas_usb->vbus_reg)) {
>>> +            dev_err(&pdev->dev, "vbus init failed\n");
>>> +            return PTR_ERR(palmas_usb->vbus_reg);
>>> +        }
>>> +    }
>>> +
>>> +    platform_set_drvdata(pdev, palmas_usb);
>>> +
>>> +    if (device_create_file(&pdev->dev, &dev_attr_vbus))
>>> +        dev_warn(&pdev->dev, "could not create sysfs file\n");
>> device_create_file() isn't needed if remove 'palmas_usb_vbus' sysfs entry.
>
> right.
>
>>> +
>>> +    palmas_usb->edev.name = "palmas_usb";
>> I prefer '-' instead of '_'. change from "palmas_usb" to "palmas-usb".
>>> +    palmas_usb->edev.supported_cable = palmas_extcon_cable;
>>> +    palmas_usb->edev.mutually_exclusive = mutually_exclusive;
>>> +
>>> +    ret = extcon_dev_register(&palmas_usb->edev, palmas_usb->dev);
>>> +    if (ret) {
>>> +        dev_err(&pdev->dev, "failed to register extcon device\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    /* init spinlock for workqueue */
>>> +    spin_lock_init(&palmas_usb->lock);
>>> +
>>> +    INIT_WORK(&palmas_usb->set_vbus_work, palmas_set_vbus_work);
>>> +
>>> +    status = devm_request_threaded_irq(palmas_usb->dev, palmas_usb->irq2,
>>> +            NULL, palmas_id_wakeup_irq,
>>> +            IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
>>> +            "palmas_usb", palmas_usb);
>>> +    if (status < 0) {
>>> +        dev_err(&pdev->dev, "can't get IRQ %d, err %d\n",
>>> +                    palmas_usb->irq2, status);
>>> +        goto fail_irq;
>>> +    }
>>> +
>>> +    status = devm_request_threaded_irq(palmas_usb->dev, palmas_usb->irq4,
>>> +            NULL, palmas_vbus_wakeup_irq,
>>> +            IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
>>> +            "palmas_usb", palmas_usb);
>>> +    if (status < 0) {
>>> +        dev_err(&pdev->dev, "can't get IRQ %d, err %d\n",
>>> +                    palmas_usb->irq4, status);
>>> +        goto fail_irq;
>>> +    }
>>> +
>>> +    palmas_enable_irq(palmas_usb);
>>> +
>>> +    return 0;
>>> +
>>> +fail_irq:
>>> +    cancel_work_sync(&palmas_usb->set_vbus_work);
>>> +    device_remove_file(palmas_usb->dev, &dev_attr_vbus);
>> ditto.
>>> +
>>> +    return status;
>>> +}
>>> +
>>> +static int palmas_usb_remove(struct platform_device *pdev)
>>> +{
>>> +    struct palmas_usb *palmas_usb = platform_get_drvdata(pdev);
>>> +
>>> +    device_remove_file(palmas_usb->dev, &dev_attr_vbus);
>> ditto.
>>> +    cancel_work_sync(&palmas_usb->set_vbus_work);
>>> +    extcon_dev_unregister(&palmas_usb->edev);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static struct of_device_id of_palmas_match_tbl[] = {
>>> +    { .compatible = "ti,palmas-usb", },
>>> +    { .compatible = "ti,twl6035-usb", },
>>> +    { /* end */ }
>>> +};
>>> +
>>> +static struct platform_driver palmas_usb_driver = {
>>> +    .probe = palmas_usb_probe,
>>> +    .remove = palmas_usb_remove,
>>> +    .driver = {
>>> +        .name = "palmas-usb",
>>> +        .of_match_table = of_palmas_match_tbl,
>>> +        .owner = THIS_MODULE,
>>> +    },
>>> +};
>>> +
>>> +module_platform_driver(palmas_usb_driver);
>>> +
>>> +MODULE_ALIAS("platform:palmas-usb");
>>> +MODULE_AUTHOR("Graeme Gregory <gg@...mlogic.co.uk>");
>>> +MODULE_DESCRIPTION("Palmas USB transceiver driver");
>>> +MODULE_LICENSE("GPL");
>>> +MODULE_DEVICE_TABLE(of, of_palmas_match_tbl);
>>> diff --git a/include/linux/extcon/extcon_palmas.h b/include/linux/extcon/extcon_palmas.h
>>> new file mode 100644
>>> index 0000000..a5119c9
>>> --- /dev/null
>>> +++ b/include/linux/extcon/extcon_palmas.h
>>> @@ -0,0 +1,26 @@
>>> +/*
>>> + * extcon_palmas.h - palmas extcon driver to detect VBUS or ID events
>>> + *
>>> + * 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: Kishon Vijay Abraham I <kishon@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.
>>> + *
>>> + */
>>> +
>>> +#ifndef __EXTCON_PALMAS_H__
>>> +#define __EXTCON_PALMAS_H__
>>> +
>>> +#define    PALMAS_USB_STATE_DISCONNECT    0x0
>>> +#define    PALMAS_USB_STATE_VBUS        BIT(0)
>>> +#define    PALMAS_USB_STATE_ID        BIT(1)
>>> +
>> The defined variable in extcon_palmas.h is used only on extcon-palmas.c.
>> So, I would like to move definition from extcon_palmas.h to extcon-palmas.c
>> and remove extcon_palmas.h header file.
>
> Actually it has to be used in dwc3-omap.c (that was in a different patch).
>

Should detect the state of USB/USB-HOST on dwc3-omap driver?

If yes, dwc3-omap driver can immediately detect the changed state of USB/USB-HOST
by using excon_register_interest() function which is defined in extcon-class.c

I explain simple usage of extcon_register_interest()
to receive newly state of USB cable on dwc3-omap driver.
-----------
    struct extcon_specific_cable_nb extcon_notifier
    struct notifier_block extcon_notifier;

     /* ... */

    extcon_notifier.notifier_call = omap_extcon_notifier;
    ret = extcon_register_interest(&extcon_dev, "USB", &extcon_notifier);
    /* ... */

    int omap_extcon_notifier(struct notifier_block *self,
                                                unsigned long event, void *ptr)
    {
            int usb_state;

            usb_state = event;                                   

            /* if usb_state is 1, PALMAS_USB_STATE_VBUS  */
            /* if usb_state is 0, PALMAS_USB_STATE_DISCONNECT */

            /* TODO */

    }
-----------

If dwc3-omap driver use extcon_register_interest(), following defined variables
are able to be removed.
    PALMAS_USB_STATE_DISCONNECT
    PALMAS_USB_STATE_VBUS
    PALMAS_USB_STATE_ID

Thanks,
Chanwoo Choi