Re: [PATCH 4/4] usb: phy: twl4030: test ID resistance to see if charger is present.

Pavel Machek
2015-03-02T21:04:48Z

On Tue 2015-02-24 14:40:37, NeilBrown wrote:
> If an 'A' plug is inserted, ID should be pulled to ground.
> If a 'B' plug, then ID should be floating.
>
> If an Accessory Charger Adapter is inserted, then ID will
> be neither grounded nor floating. In this case tell the
> USB subsystem that it is an A plug, and the battery
> charging subsystem that it is a charger.

> Fortunately, this will treat the Openmoko charger (and
> other similar chargers) as a charger.
>
> Signed-off-by: NeilBrown <neilb@suse.de>

I guess signed-off-by should be "real name", so I'd add a space..

Acked-by: Pavel Machek <pavel@ucw.cz>

> --- a/drivers/phy/phy-twl4030-usb.c
> +++ b/drivers/phy/phy-twl4030-usb.c
> @@ -596,9 +596,31 @@ static irqreturn_t twl4030_usb_irq(int irq, void *_twl)
> struct twl4030_usb *twl = _twl;
> enum omap_musb_vbus_id_status status;
> bool status_changed = false;
> + bool found_charger = false;
>
> status = twl4030_usb_linkstat(twl);
>
> + if (status == OMAP_MUSB_ID_GROUND ||
> + status == OMAP_MUSB_VBUS_VALID) {
> + /* We should check the resistance on the ID pin.
> + * If not a Ground or Floating, then this is
> + * likely a charger

"charger.", and I guess kernel comments should have /* on separate line.

So it will draw .5A from the charger? 1A? 2A?

Pavel
--
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