linux-kernel - [patch 2.6.29-rc3-git 2/2] USB: disable twl4030 USB regulators when cable unplugged

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Message-Id: <200902081053.00255.david-b@pacbell.net>
Date:	Sun, 8 Feb 2009 10:52:59 -0800
From:	David Brownell <david-b@...bell.net>
To:	Liam Girdwood <lrg@...mlogic.co.uk>,
	Mark Brown <broonie@...ena.org.uk>
Cc:	lkml <linux-kernel@...r.kernel.org>, linux-usb@...r.kernel.org,
	OMAP <linux-omap@...r.kernel.org>,
	Kalle Jokiniemi <kalle.jokiniemi@...ia.com>
Subject: [patch 2.6.29-rc3-git 2/2] USB: disable twl4030 USB regulators when cable unplugged

From: Kalle Jokiniemi <kalle.jokiniemi@...ia.com>

This patch disables LDO regulators VUSB1V5, VUSB1V8, and VUSB3V1
when the USB cable is unplugged, to eliminate that source of power
waste.  (Enabled LDOs consume power at all times.)

Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@...ia.com>
Signed-off-by: David Brownell <dbrownell@...rs.sourceforge.net>
---
Depends on the twl4030 regulator driver, so I'm suggesting this
be merged (with that driver) through the regulator patch queue
to simplify things.

 drivers/usb/otg/twl4030-usb.c |   30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

--- a/drivers/usb/otg/twl4030-usb.c
+++ b/drivers/usb/otg/twl4030-usb.c
@@ -34,6 +34,7 @@
 #include <linux/delay.h>
 #include <linux/usb/otg.h>
 #include <linux/i2c/twl4030.h>
+#include <linux/regulator/consumer.h>
 
 
 /* Register defines */
@@ -246,6 +247,11 @@ struct twl4030_usb {
 	struct otg_transceiver	otg;
 	struct device		*dev;
 
+	/* TWL4030 internal USB regulator supplies */
+	struct regulator	*usb1v5;
+	struct regulator	*usb1v8;
+	struct regulator	*usb3v1;
+
 	/* for vbus reporting with irqs disabled */
 	spinlock_t		lock;
 
@@ -434,6 +440,9 @@ static void twl4030_phy_power(struct twl
 
 	pwr = twl4030_usb_read(twl, PHY_PWR_CTRL);
 	if (on) {
+		regulator_enable(twl->usb1v5);
+		regulator_enable(twl->usb1v8);
+		regulator_enable(twl->usb3v1);
 		pwr &= ~PHY_PWR_PHYPWD;
 		WARN_ON(twl4030_usb_write_verify(twl, PHY_PWR_CTRL, pwr) < 0);
 		twl4030_usb_write(twl, PHY_CLK_CTRL,
@@ -443,6 +452,9 @@ static void twl4030_phy_power(struct twl
 	} else  {
 		pwr |= PHY_PWR_PHYPWD;
 		WARN_ON(twl4030_usb_write_verify(twl, PHY_PWR_CTRL, pwr) < 0);
+		regulator_disable(twl->usb1v5);
+		regulator_disable(twl->usb1v8);
+		regulator_disable(twl->usb3v1);
 	}
 }
 
@@ -480,16 +492,19 @@ static void twl4030_usb_ldo_init(struct 
 	/* input to VUSB3V1 LDO is from VBAT, not VBUS */
 	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0x14, VUSB_DEDICATED1);
 
-	/* turn on 3.1V regulator */
-	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0x20, VUSB3V1_DEV_GRP);
+	/* Initialize 3.1V regulator */
+	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB3V1_DEV_GRP);
+	twl->usb3v1 = regulator_get(twl->dev, "usb3v1");
 	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB3V1_TYPE);
 
-	/* turn on 1.5V regulator */
-	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0x20, VUSB1V5_DEV_GRP);
+	/* Initialize 1.5V regulator */
+	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB1V5_DEV_GRP);
+	twl->usb1v5 = regulator_get(twl->dev, "usb1v5");
 	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB1V5_TYPE);
 
-	/* turn on 1.8V regulator */
-	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0x20, VUSB1V8_DEV_GRP);
+	/* Initialize 1.8V regulator */
+	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB1V8_DEV_GRP);
+	twl->usb1v8 = regulator_get(twl->dev, "usb1v8");
 	twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB1V8_TYPE);
 
 	/* disable access to power configuration registers */
@@ -688,6 +703,9 @@ static int __exit twl4030_usb_remove(str
 	twl4030_usb_clear_bits(twl, POWER_CTRL, POWER_CTRL_OTG_ENAB);
 
 	twl4030_phy_power(twl, 0);
+	regulator_put(twl->usb1v5);
+	regulator_put(twl->usb1v8);
+	regulator_put(twl->usb3v1);
 
 	kfree(twl);
 
--
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