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

On 27/05/15 15:15, 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);

Now that all USB line states can be captured by a single cable type
can we get rid of EXTCON_USB_HOST?

That way the extcon driver doesn't need to make any decisions as to
what mode we're in (host/cable) and this is best left to the USB driver.

cheers,
-roger

> 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(-)
>


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