linux-kernel - [PATCH 3/6] twl4030_charger: allow charging whenever VBUS is present.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 25 Apr 2012 17:33:10 +1000
From:	NeilBrown <neilb@...e.de>
To:	Samuel Ortiz <sameo@...ux.intel.com>, Felipe Balbi <balbi@...com>,
	Grazvydas Ignotas <notasas@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
	linux-omap@...r.kernel.org, NeilBrown <neilb@...e.de>
Subject: [PATCH 3/6] twl4030_charger: allow charging whenever VBUS is present.

We currently refuse to charge if the USB ID pin is grounded, even
though VBUS might be present.
However some chargers do pull the ID pin low through a resistor which
might be as low as 47Kohm (openmoko charger).

The documentation is unclear but some experimental evidence suggests
that when the charge pump provides VBUS that doesn't get reflected in
HW_CONDITIONS, so we should be safe to ignore the ID pin.

Signed-off-by: NeilBrown <neilb@...e.de>
---

 drivers/power/twl4030_charger.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/power/twl4030_charger.c b/drivers/power/twl4030_charger.c
index 0511610..684662a 100644
--- a/drivers/power/twl4030_charger.c
+++ b/drivers/power/twl4030_charger.c
@@ -155,11 +155,7 @@ static int twl4030_bci_have_vbus(struct twl4030_bci *bci)
 
 	dev_dbg(bci->dev, "check_vbus: HW_CONDITIONS %02x\n", hwsts);
 
-	/* in case we also have STS_USB_ID, VBUS is driven by TWL itself */
-	if ((hwsts & TWL4030_STS_VBUS) && !(hwsts & TWL4030_STS_USB_ID))
-		return 1;
-
-	return 0;
+	return (hwsts & TWL4030_STS_VBUS);
 }
 
 /*


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/