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    SubjectRe: [PATCH v2 0/2] extcon: Inform the state of both ID and VBUS pin for USB
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    Hi Chanwoo,

    On Wed, 2015-05-27 at 21:15 +0900, Chanwoo Choi wrote:
    > Previously, I discussed how to inform the changed state of both ID
    > and VBUS pin for USB connector on patch-set[1].
    > [1] https://lkml.org/lkml/2015/4/2/310
    >
    > So, this patch adds the extcon_set_cable_line_state() function to inform
    > the additional state of external connectors without additional register/
    > unregister functions. This function uses the existing notifier chain
    > which is registered by extcon_register_notifier() / extcon_register_interest().
    >
    > The extcon_set_cable_line_state() can inform the new state of both
    > ID and VBUS pin state through extcon_set_cable_line_state().
    >
    > For exmaple:
    > - On extcon-usb-gpio.c as extcon provider driver as following:
    > static void usb_extcon_detect_cable(struct work_struct *work)
    > {
    > ...
    > /* check ID and update cable state */
    > id = gpiod_get_value_cansleep(info->id_gpiod);
    > if (id) {
    > extcon_set_cable_state_(info->edev, EXTCON_USB_HOST, false);
    > extcon_set_cable_state_(info->edev, EXTCON_USB, true);
    >
    > extcon_set_cable_line_state(info->edev, EXTCON_USB,
    > EXTCON_USB_ID_HIGH);

    I am getting more and more confused :-). Why EXTCON_USB is now used for ID notifications?
    It should be EXTCON_USB_HOST, no? Why we need another function, framework already have
    required information from the function one line above, do I miss something?

    > } else {
    > extcon_set_cable_state_(info->edev, EXTCON_USB, false);
    > extcon_set_cable_state_(info->edev, EXTCON_USB_HOST, true);
    >
    > extcon_set_cable_line_state(info->edev, EXTCON_USB,
    > EXTCON_USB_ID_LOW);
    > }
    > }
    >
    > - On specific extcon consumder driver as following:
    > static int xxx_probe(struct platform_device *pdev)
    > {
    > struct notifier_chain nh;
    >
    > nb.notifier_call = extcon_usb_notifier;
    > ret = extcon_register_notifier(edev, EXTCON_USB, &nb);

    This is bit misleading. 'nb' could not be in stack.

    Regards,
    Ivan



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