linux-kernel - [PATCH 4/4] usb: otg: twl4030-usb: Don't power down phy when it is in-use by charger.

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Message-ID: <20120508214040.2844.81364.stgit@notabene.brown>
Date:	Wed, 09 May 2012 07:40:40 +1000
From:	NeilBrown <neilb@...e.de>
To:	Samuel Ortiz <sameo@...ux.intel.com>, Felipe Balbi <balbi@...com>,
	Anton Vorontsov <cbou@...l.ru>,
	David Woodhouse <dwmw2@...radead.org>
Cc:	Grazvydas Ignotas <notasas@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
	NeilBrown <neilb@...e.de>
Subject: [PATCH 4/4] usb: otg: twl4030-usb: Don't power down phy when it is
 in-use by charger.

The USB phy is used both for data transfer and to charge the battery.
If the charger is active it will hold a reference to
usb3v1.  In that case we don't want to power-down the phy.

This allows charging to continue while the device is suspended.

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

 drivers/usb/otg/twl4030-usb.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/otg/twl4030-usb.c b/drivers/usb/otg/twl4030-usb.c
index c4a86da..bd8fe9b 100644
--- a/drivers/usb/otg/twl4030-usb.c
+++ b/drivers/usb/otg/twl4030-usb.c
@@ -388,10 +388,16 @@ static void twl4030_phy_power(struct twl4030_usb *twl, int on)
 					(PHY_CLK_CTRL_CLOCKGATING_EN |
 						PHY_CLK_CTRL_CLK32K_EN));
 	} else {
-		__twl4030_phy_power(twl, 0);
 		regulator_disable(twl->usb1v5);
 		regulator_disable(twl->usb1v8);
 		regulator_disable(twl->usb3v1);
+		if (!regulator_is_enabled(twl->usb3v1))
+			/* no-one else is requesting this
+			 * so it is OK to power-down the
+			 * phy.  Sometimes a charger might
+			 * hold the regulator active.
+			 */
+			__twl4030_phy_power(twl, 0);
 	}
 }
 


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