USB: TWL: disable VUSB regulators when cable unplugged

This patch disables USB regulators VUSB1V5, VUSB1V8, and VUSB3V1
when the USB cable is unplugged to reduce power consumption.
Added a depencency from twl4030 usb driver to TWL_REGULATOR.

Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@digia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 65 insertions, 10 deletions

diff --git a/drivers/usb/otg/Kconfig b/drivers/usb/otg/Kconfig
index fc1ca03ce4da..aa884d072f0b 100644
--- a/drivers/usb/otg/Kconfig
+++ b/drivers/usb/otg/Kconfig
@@ -43,7 +43,7 @@ config ISP1301_OMAP
 
 config TWL4030_USB
         tristate "TWL4030 USB Transceiver Driver"
-        depends on TWL4030_CORE
+        depends on TWL4030_CORE && REGULATOR_TWL4030
         select USB_OTG_UTILS
         help
           Enable this to support the USB OTG transceiver on TWL4030
diff --git a/drivers/usb/otg/twl4030-usb.c b/drivers/usb/otg/twl4030-usb.c
index 416e4410be02..d9478d0e1c8b 100644
--- a/drivers/usb/otg/twl4030-usb.c
+++ b/drivers/usb/otg/twl4030-usb.c
@@ -34,6 +34,8 @@
 #include <linux/delay.h>
 #include <linux/usb/otg.h>
 #include <linux/i2c/twl4030.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
 
 
 /* Register defines */
@@ -246,6 +248,11 @@ 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 +441,18 @@ static void twl4030_phy_power(struct twl4030_usb *twl, int on)
 
         pwr = twl4030_usb_read(twl, PHY_PWR_CTRL);
         if (on) {
+                regulator_enable(twl->usb3v1);
+                regulator_enable(twl->usb1v8);
+                /*
+                 * Disabling usb3v1 regulator (= writing 0 to VUSB3V1_DEV_GRP
+                 * in twl4030) resets the VUSB_DEDICATED2 register. This reset
+                 * enables VUSB3V1_SLEEP bit that remaps usb3v1 ACTIVE state to
+                 * SLEEP. We work around this by clearing the bit after usv3v1
+                 * is re-activated. This ensures that VUSB3V1 is really active.
+                 */
+                twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0,
+                                                        VUSB_DEDICATED2);
+                regulator_enable(twl->usb1v5);
                 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 +462,9 @@ static void twl4030_phy_power(struct twl4030_usb *twl, int on)
         } 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);
         }
 }
 
@@ -468,7 +490,7 @@ static void twl4030_phy_resume(struct twl4030_usb *twl)
         twl->asleep = 0;
 }
 
-static void twl4030_usb_ldo_init(struct twl4030_usb *twl)
+static int twl4030_usb_ldo_init(struct twl4030_usb *twl)
 {
         /* Enable writing to power configuration registers */
         twl4030_i2c_write_u8(TWL4030_MODULE_PM_MASTER, 0xC0, PROTECT_KEY);
@@ -480,20 +502,45 @@ static void twl4030_usb_ldo_init(struct twl4030_usb *twl)
         /* 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");
+        if (IS_ERR(twl->usb3v1))
+                return -ENODEV;
+
         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");
+        if (IS_ERR(twl->usb1v5))
+                goto fail1;
+
         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");
+        if (IS_ERR(twl->usb1v8))
+                goto fail2;
+
         twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB1V8_TYPE);
 
         /* disable access to power configuration registers */
         twl4030_i2c_write_u8(TWL4030_MODULE_PM_MASTER, 0, PROTECT_KEY);
+
+        return 0;
+
+fail2:
+        regulator_put(twl->usb1v5);
+        twl->usb1v5 = NULL;
+fail1:
+        regulator_put(twl->usb3v1);
+        twl->usb3v1 = NULL;
+        return -ENODEV;
 }
 
 static ssize_t twl4030_usb_vbus_show(struct device *dev,
@@ -598,7 +645,7 @@ static int __init twl4030_usb_probe(struct platform_device *pdev)
 {
         struct twl4030_usb_data *pdata = pdev->dev.platform_data;
         struct twl4030_usb      *twl;
-        int                     status;
+        int                     status, err;
 
         if (!pdata) {
                 dev_dbg(&pdev->dev, "platform_data not available\n");
@@ -622,7 +669,12 @@ static int __init twl4030_usb_probe(struct platform_device *pdev)
         /* init spinlock for workqueue */
         spin_lock_init(&twl->lock);
 
-        twl4030_usb_ldo_init(twl);
+        err = twl4030_usb_ldo_init(twl);
+        if (err) {
+                dev_err(&pdev->dev, "ldo init failed\n");
+                kfree(twl);
+                return err;
+        }
         otg_set_transceiver(&twl->otg);
 
         platform_set_drvdata(pdev, twl);
@@ -688,6 +740,9 @@ static int __exit twl4030_usb_remove(struct platform_device *pdev)
         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);