From tom.leiming@gmail.com  Tue Sep  7 00:49:51 2010
From: tom.leiming@gmail.com
Date: Mon,  6 Sep 2010 23:27:09 +0800
Subject: USB: otg: twl4030: fix phy initialization(v1)
To: greg@kroah.com
Cc: linux-usb@vger.kernel.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, Ming Lei <tom.leiming@gmail.com>, David Brownell <dbrownell@users.sourceforge.net>, Felipe Balbi <me@felipebalbi.com>, Anand Gadiyar <gadiyar@ti.com>, Mike Frysinger <vapier@gentoo.org>, Sergei Shtylyov <sshtylyov@ru.mvista.com>
Message-ID: <1283786829-3564-1-git-send-email-tom.leiming@gmail.com>


From: Ming Lei <tom.leiming@gmail.com>

Commit 461c317705eca5cac09a360f488715927fd0a927(into 2.6.36-v3)
is put forward to power down phy if no usb cable is connected,
but does introduce the two issues below:

1), phy is not into work state if usb cable is connected
with PC during poweron, so musb device mode is not usable
in such case, follows the reasons:
	-twl4030_phy_resume is not called, so
		regulators are not enabled
		i2c access are not enabled
		usb mode not configurated

2), The kernel warings[1] of regulators 'unbalanced disables'
is caused if poweron without usb cable connected
with PC or b-device.

This patch fixes the two issues above:
	-power down phy only if no usb cable is connected with PC
and b-device
	-do phy initialization(via __twl4030_phy_resume) if usb cable
is connected with PC(vbus event) or another b-device(ID event) in
twl4030_usb_probe.

This patch also doesn't put VUSB3V1 LDO into active mode in
twl4030_usb_ldo_init until VBUS/ID change detected, so we can
save more power consumption than before.

This patch is verified OK on Beagle board either connected with
usb cable or not when poweron.

[1]. warnings of 'unbalanced disables' of regulators.
[root@OMAP3EVM /]# dmesg
------------[ cut here ]------------
WARNING: at drivers/regulator/core.c:1357 _regulator_disable+0x38/0x128()
unbalanced disables for VUSB1V8
Modules linked in:
Backtrace:
[<c0030c48>] (dump_backtrace+0x0/0x110) from [<c034f5a8>] (dump_stack+0x18/0x1c)
 r7:c78179d8 r6:c01ed6b8 r5:c0410822 r4:0000054d
[<c034f590>] (dump_stack+0x0/0x1c) from [<c0057da8>] (warn_slowpath_common+0x54/0x6c)
[<c0057d54>] (warn_slowpath_common+0x0/0x6c) from [<c0057e64>] (warn_slowpath_fmt+0x38/0x40)
 r9:00000000 r8:00000000 r7:c78e6608 r6:00000000 r5:fffffffb
 r4:c78e6c00
[<c0057e2c>] (warn_slowpath_fmt+0x0/0x40) from [<c01ed6b8>] (_regulator_disable+0x38/0x128)
 r3:c0410e53 r2:c0410ad5
[<c01ed680>] (_regulator_disable+0x0/0x128) from [<c01ed87c>] (regulator_disable+0x24/0x38)
 r7:c78e6608 r6:00000000 r5:c78e6c40 r4:c78e6c00
[<c01ed858>] (regulator_disable+0x0/0x38) from [<c02382dc>] (twl4030_phy_power+0x15c/0x17c)
 r5:c78595c0 r4:00000000
[<c0238180>] (twl4030_phy_power+0x0/0x17c) from [<c023831c>] (twl4030_phy_suspend+0x20/0x2c)
 r6:00000000 r5:c78595c0 r4:c78595c0
[<c02382fc>] (twl4030_phy_suspend+0x0/0x2c) from [<c0238638>] (twl4030_usb_irq+0x11c/0x16c)
 r5:c78595c0 r4:00000040
[<c023851c>] (twl4030_usb_irq+0x0/0x16c) from [<c034ec18>] (twl4030_usb_probe+0x2c4/0x32c)
 r6:00000000 r5:00000000 r4:c78595c0
[<c034e954>] (twl4030_usb_probe+0x0/0x32c) from [<c02152a0>] (platform_drv_probe+0x20/0x24)
 r7:00000000 r6:c047d49c r5:c78e6608 r4:c047d49c
[<c0215280>] (platform_drv_probe+0x0/0x24) from [<c0214244>] (driver_probe_device+0xd0/0x190)
[<c0214174>] (driver_probe_device+0x0/0x190) from [<c02143d4>] (__device_attach+0x44/0x48)
 r7:00000000 r6:c78e6608 r5:c78e6608 r4:c047d49c
[<c0214390>] (__device_attach+0x0/0x48) from [<c0213694>] (bus_for_each_drv+0x50/0x90)
 r5:c0214390 r4:00000000
[<c0213644>] (bus_for_each_drv+0x0/0x90) from [<c0214474>] (device_attach+0x70/0x94)
 r6:c78e663c r5:c78e6608 r4:c78e6608
[<c0214404>] (device_attach+0x0/0x94) from [<c02134fc>] (bus_probe_device+0x2c/0x48)
 r7:00000000 r6:00000002 r5:c78e6608 r4:c78e6600
[<c02134d0>] (bus_probe_device+0x0/0x48) from [<c0211e48>] (device_add+0x340/0x4b4)
[<c0211b08>] (device_add+0x0/0x4b4) from [<c021597c>] (platform_device_add+0x110/0x16c)
[<c021586c>] (platform_device_add+0x0/0x16c) from [<c0220cb0>] (add_numbered_child+0xd8/0x118)
 r7:00000000 r6:c045f15c r5:c78e6600 r4:00000000
[<c0220bd8>] (add_numbered_child+0x0/0x118) from [<c001c618>] (twl_probe+0x3a4/0x72c)
[<c001c274>] (twl_probe+0x0/0x72c) from [<c02601ac>] (i2c_device_probe+0x7c/0xa4)
[<c0260130>] (i2c_device_probe+0x0/0xa4) from [<c0214244>] (driver_probe_device+0xd0/0x190)
 r5:c7856e20 r4:c047c860
[<c0214174>] (driver_probe_device+0x0/0x190) from [<c02143d4>] (__device_attach+0x44/0x48)
 r7:c7856e04 r6:c7856e20 r5:c7856e20 r4:c047c860
[<c0214390>] (__device_attach+0x0/0x48) from [<c0213694>] (bus_for_each_drv+0x50/0x90)
 r5:c0214390 r4:00000000
[<c0213644>] (bus_for_each_drv+0x0/0x90) from [<c0214474>] (device_attach+0x70/0x94)
 r6:c7856e54 r5:c7856e20 r4:c7856e20
[<c0214404>] (device_attach+0x0/0x94) from [<c02134fc>] (bus_probe_device+0x2c/0x48)
 r7:c7856e04 r6:c78fd048 r5:c7856e20 r4:c7856e20
[<c02134d0>] (bus_probe_device+0x0/0x48) from [<c0211e48>] (device_add+0x340/0x4b4)
[<c0211b08>] (device_add+0x0/0x4b4) from [<c0211fd8>] (device_register+0x1c/0x20)
[<c0211fbc>] (device_register+0x0/0x20) from [<c0260aa8>] (i2c_new_device+0xec/0x150)
 r5:c7856e00 r4:c7856e20
[<c02609bc>] (i2c_new_device+0x0/0x150) from [<c0260dc0>] (i2c_register_adapter+0xa0/0x1c4)
 r7:00000000 r6:c78fd078 r5:c78fd048 r4:c781d5c0
[<c0260d20>] (i2c_register_adapter+0x0/0x1c4) from [<c0260f80>] (i2c_add_numbered_adapter+0x9c/0xb4)
 r7:00000a28 r6:c04600a8 r5:c78fd048 r4:00000000
[<c0260ee4>] (i2c_add_numbered_adapter+0x0/0xb4) from [<c034efa4>] (omap_i2c_probe+0x324/0x3e8)
 r5:00000000 r4:c78fd000
[<c034ec80>] (omap_i2c_probe+0x0/0x3e8) from [<c02152a0>] (platform_drv_probe+0x20/0x24)
[<c0215280>] (platform_drv_probe+0x0/0x24) from [<c0214244>] (driver_probe_device+0xd0/0x190)
[<c0214174>] (driver_probe_device+0x0/0x190) from [<c021436c>] (__driver_attach+0x68/0x8c)
 r7:c78b2140 r6:c047e214 r5:c04600e4 r4:c04600b0
[<c0214304>] (__driver_attach+0x0/0x8c) from [<c021399c>] (bus_for_each_dev+0x50/0x84)
 r7:c78b2140 r6:c047e214 r5:c0214304 r4:00000000
[<c021394c>] (bus_for_each_dev+0x0/0x84) from [<c0214068>] (driver_attach+0x20/0x28)
 r6:c047e214 r5:c047e214 r4:c00270d0
[<c0214048>] (driver_attach+0x0/0x28) from [<c0213274>] (bus_add_driver+0xa8/0x228)
[<c02131cc>] (bus_add_driver+0x0/0x228) from [<c02146a4>] (driver_register+0xb0/0x13c)
[<c02145f4>] (driver_register+0x0/0x13c) from [<c0215744>] (platform_driver_register+0x4c/0x60)
 r9:00000000 r8:c001f688 r7:00000013 r6:c005b6fc r5:c00083dc
r4:c00270d0
[<c02156f8>] (platform_driver_register+0x0/0x60) from [<c001f69c>] (omap_i2c_init_driver+0x14/0x1c)
[<c001f688>] (omap_i2c_init_driver+0x0/0x1c) from [<c002c460>] (do_one_initcall+0xd0/0x1a4)
[<c002c390>] (do_one_initcall+0x0/0x1a4) from [<c0008478>] (kernel_init+0x9c/0x154)
[<c00083dc>] (kernel_init+0x0/0x154) from [<c005b6fc>] (do_exit+0x0/0x688)
 r5:c00083dc r4:00000000
---[ end trace 1b75b31a2719ed1d ]---

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Felipe Balbi <me@felipebalbi.com>
Cc: Anand Gadiyar <gadiyar@ti.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/usb/otg/twl4030-usb.c |   78 +++++++++++++++++++++++++++---------------
 1 file changed, 51 insertions(+), 27 deletions(-)

--- a/drivers/usb/otg/twl4030-usb.c
+++ b/drivers/usb/otg/twl4030-usb.c
@@ -347,11 +347,20 @@ static void twl4030_i2c_access(struct tw
 	}
 }
 
-static void twl4030_phy_power(struct twl4030_usb *twl, int on)
+static void __twl4030_phy_power(struct twl4030_usb *twl, int on)
 {
-	u8 pwr;
+	u8 pwr = twl4030_usb_read(twl, PHY_PWR_CTRL);
+
+	if (on)
+		pwr &= ~PHY_PWR_PHYPWD;
+	else
+		pwr |= PHY_PWR_PHYPWD;
 
-	pwr = twl4030_usb_read(twl, PHY_PWR_CTRL);
+	WARN_ON(twl4030_usb_write_verify(twl, PHY_PWR_CTRL, pwr) < 0);
+}
+
+static void twl4030_phy_power(struct twl4030_usb *twl, int on)
+{
 	if (on) {
 		regulator_enable(twl->usb3v1);
 		regulator_enable(twl->usb1v8);
@@ -365,15 +374,13 @@ static void twl4030_phy_power(struct twl
 		twl_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_phy_power(twl, 1);
 		twl4030_usb_write(twl, PHY_CLK_CTRL,
 				  twl4030_usb_read(twl, PHY_CLK_CTRL) |
 					(PHY_CLK_CTRL_CLOCKGATING_EN |
 						PHY_CLK_CTRL_CLK32K_EN));
-	} else  {
-		pwr |= PHY_PWR_PHYPWD;
-		WARN_ON(twl4030_usb_write_verify(twl, PHY_PWR_CTRL, pwr) < 0);
+	} else {
+		__twl4030_phy_power(twl, 0);
 		regulator_disable(twl->usb1v5);
 		regulator_disable(twl->usb1v8);
 		regulator_disable(twl->usb3v1);
@@ -387,19 +394,25 @@ static void twl4030_phy_suspend(struct t
 
 	twl4030_phy_power(twl, 0);
 	twl->asleep = 1;
+	dev_dbg(twl->dev, "%s\n", __func__);
 }
 
-static void twl4030_phy_resume(struct twl4030_usb *twl)
+static void __twl4030_phy_resume(struct twl4030_usb *twl)
 {
-	if (!twl->asleep)
-		return;
-
 	twl4030_phy_power(twl, 1);
 	twl4030_i2c_access(twl, 1);
 	twl4030_usb_set_mode(twl, twl->usb_mode);
 	if (twl->usb_mode == T2_USB_MODE_ULPI)
 		twl4030_i2c_access(twl, 0);
+}
+
+static void twl4030_phy_resume(struct twl4030_usb *twl)
+{
+	if (!twl->asleep)
+		return;
+	__twl4030_phy_resume(twl);
 	twl->asleep = 0;
+	dev_dbg(twl->dev, "%s\n", __func__);
 }
 
 static int twl4030_usb_ldo_init(struct twl4030_usb *twl)
@@ -408,8 +421,8 @@ static int twl4030_usb_ldo_init(struct t
 	twl_i2c_write_u8(TWL4030_MODULE_PM_MASTER, 0xC0, PROTECT_KEY);
 	twl_i2c_write_u8(TWL4030_MODULE_PM_MASTER, 0x0C, PROTECT_KEY);
 
-	/* put VUSB3V1 LDO in active state */
-	twl_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB_DEDICATED2);
+	/* Keep VUSB3V1 LDO in sleep state until VBUS/ID change detected*/
+	/*twl_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0, VUSB_DEDICATED2);*/
 
 	/* input to VUSB3V1 LDO is from VBAT, not VBUS */
 	twl_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, 0x14, VUSB_DEDICATED1);
@@ -502,6 +515,26 @@ static irqreturn_t twl4030_usb_irq(int i
 	return IRQ_HANDLED;
 }
 
+static void twl4030_usb_phy_init(struct twl4030_usb *twl)
+{
+	int status;
+
+	status = twl4030_usb_linkstat(twl);
+	if (status >= 0) {
+		if (status == USB_EVENT_NONE) {
+			__twl4030_phy_power(twl, 0);
+			twl->asleep = 1;
+		} else {
+			__twl4030_phy_resume(twl);
+			twl->asleep = 0;
+		}
+
+		blocking_notifier_call_chain(&twl->otg.notifier, status,
+				twl->otg.gadget);
+	}
+	sysfs_notify(&twl->dev->kobj, NULL, "vbus");
+}
+
 static int twl4030_set_suspend(struct otg_transceiver *x, int suspend)
 {
 	struct twl4030_usb *twl = xceiv_to_twl(x);
@@ -550,7 +583,6 @@ static int __devinit twl4030_usb_probe(s
 	struct twl4030_usb_data *pdata = pdev->dev.platform_data;
 	struct twl4030_usb	*twl;
 	int			status, err;
-	u8			pwr;
 
 	if (!pdata) {
 		dev_dbg(&pdev->dev, "platform_data not available\n");
@@ -569,10 +601,7 @@ static int __devinit twl4030_usb_probe(s
 	twl->otg.set_peripheral	= twl4030_set_peripheral;
 	twl->otg.set_suspend	= twl4030_set_suspend;
 	twl->usb_mode		= pdata->usb_mode;
-
-	pwr = twl4030_usb_read(twl, PHY_PWR_CTRL);
-
-	twl->asleep		= (pwr & PHY_PWR_PHYPWD);
+	twl->asleep = 1;
 
 	/* init spinlock for workqueue */
 	spin_lock_init(&twl->lock);
@@ -610,15 +639,10 @@ static int __devinit twl4030_usb_probe(s
 		return status;
 	}
 
-	/* The IRQ handler just handles changes from the previous states
-	 * of the ID and VBUS pins ... in probe() we must initialize that
-	 * previous state.  The easy way:  fake an IRQ.
-	 *
-	 * REVISIT:  a real IRQ might have happened already, if PREEMPT is
-	 * enabled.  Else the IRQ may not yet be configured or enabled,
-	 * because of scheduling delays.
+	/* Power down phy or make it work according to
+	 * current link state.
 	 */
-	twl4030_usb_irq(twl->irq, twl);
+	twl4030_usb_phy_init(twl);
 
 	dev_info(&pdev->dev, "Initialized TWL4030 USB module\n");
 	return 0;