[PATCH 0/2] extcon: Inform the state of both ID and VBUS pin for USB

[Chanwoo Choi]

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);
		} 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);
		...
	}

	static int extcon_usb_notifier(struct notifier_block *self,
		unsigned long event, void *ptr)
	{
		switch (event) {
		case EXTCON_DETACHED:
			printk("USB is detached\n");
			break;
		case EXTCON_ATTACHED:
			printk("USB is attached\n");
			break;

		case EXTCON_USB_ID_LOW:
			printk("USB's ID pin is low state\n");
			break;
		case EXTCON_USB_ID_HIGH:
			printk("USB's ID pin is high state\n");
			break;
		case EXTCON_USB_VBUS_LOW:
			printk("USB's VBUS pin is high state\n");
			break;
		case EXTCON_USB_VBUS_HIGH:
			printk("USB's VBUS pin is high state\n");
			break;
		default:
			return -EINVAL;
		};
	}

Chanwoo Choi (2):
  extcon: Add extcon_set_cable_line_state() to inform the additional state of external connectors
  extcon: usb-gpio: Update the ID pin state of USB when cable state is changed

 drivers/extcon/extcon-usb-gpio.c |  6 ++++
 drivers/extcon/extcon.c          | 74 +++++++++++++++++++++++++++++++++++++++-
 include/linux/extcon.h           | 24 +++++++++++++
 3 files changed, 103 insertions(+), 1 deletion(-)

-- 
1.8.5.5

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