From: Kalle Jokiniemi <kalle.jokini...@digia.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.jokini...@digia.com>
Signed-off-by: David Brownell <dbrown...@users.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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