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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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