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

[Chanwoo Choi <cwchoi00@gmail.com>]

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;
                };
        }

Changes from v1:
- Use dev_warn() instead of dev_info() if set the same extcon_line_state value.

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(-)

-- 
2.2.0.GIT