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SubjectRe: [PATCH] USB: otg: twl4030: fix phy initialization
Hi,

On Thu, 2 Sep 2010 23:58:18 +0800, tom.leiming@gmail.com wrote:
> 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:

I'm pretty sure I verified both cases.

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

I kinda doubt it, would have to test it myself, but I'm without
enough gear to test it again.

> [1]. warnings of 'unbalanced disables' of regulators.
> [root@OMAP3EVM /]# dmesg
> ------------[ cut here ]------------
> WARNING: at drivers/regulator/core.c:1357
_regulator_disable+0x38/0x128()

this should not have been caused by that patch, though.


> Cc: Felipe Balbi <felipe.balbi@nokia.com>

this email doesn't exist anymore... I'm yet to subscribe the new one,
for now keep this one in Cc, sorry for that.

> diff --git a/drivers/usb/otg/twl4030-usb.c
b/drivers/usb/otg/twl4030-usb.c
> index 05aaac1..df6381f 100644
> --- a/drivers/usb/otg/twl4030-usb.c
> +++ b/drivers/usb/otg/twl4030-usb.c
> @@ -347,11 +347,22 @@ static void twl4030_i2c_access(struct twl4030_usb
> *twl, int on)
> }
> }
>
> -static void twl4030_phy_power(struct twl4030_usb *twl, int on)
> +static void __twl4030_phy_power(struct twl4030_usb *twl, int on)
> {
> + u8 old_pwr = twl4030_usb_read(twl, PHY_PWR_CTRL);
> u8 pwr;
>
> - pwr = twl4030_usb_read(twl, PHY_PWR_CTRL);
> + if (on)
> + pwr = old_pwr & ~PHY_PWR_PHYPWD;
> + else
> + pwr = old_pwr | PHY_PWR_PHYPWD;
> +
> + if (pwr != old_pwr)
> + WARN_ON(twl4030_usb_write_verify(twl, PHY_PWR_CTRL, pwr) < 0);

writing 1 if register is one won't cause any problems, you're just
wasting a variable.

> +static void twl4030_phy_power(struct twl4030_usb *twl, int on)
> +{
> if (on) {
> regulator_enable(twl->usb3v1);
> regulator_enable(twl->usb1v8);
> @@ -365,15 +376,13 @@ static void twl4030_phy_power(struct twl4030_usb
> *twl, int on)
> 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);
> + __twl4030_phy_power(twl, 0);
> regulator_disable(twl->usb1v5);
> regulator_disable(twl->usb1v8);
> regulator_disable(twl->usb3v1);
> @@ -387,19 +396,25 @@ static void twl4030_phy_suspend(struct twl4030_usb
> *twl, int controller_off)
>
> twl4030_phy_power(twl, 0);
> twl->asleep = 1;
> + dev_dbg(twl->dev, "%s\n", __func__);

this is noise.

> }
>
> -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__);

this is noise.

> @@ -502,6 +517,26 @@ static irqreturn_t twl4030_usb_irq(int irq, void
> *_twl)
> 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);

this might break people who are using charger detection, although I
would have to revisit some code to be sure.

> + twl->asleep = 0;
> + }
> +
> + blocking_notifier_call_chain(&twl->otg.notifier, status,
> + twl->otg.gadget);
> + }
> + sysfs_notify(&twl->dev->kobj, NULL, "vbus");

thís should only be called from IRQ handler and is duplicating
code.

> @@ -550,7 +585,6 @@ static int __devinit twl4030_usb_probe(struct
> platform_device *pdev)
> 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 +603,7 @@ static int __devinit twl4030_usb_probe(struct
> platform_device *pdev)
> 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;

and now you're lying to the driver again. What happens if
bootloader has put transceiver to sleep ??

> @@ -610,15 +641,10 @@ static int __devinit twl4030_usb_probe(struct
> platform_device *pdev)
> 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.

if you're changing the comment you might as well fix the comment style.

> */
> - twl4030_usb_irq(twl->irq, twl);
> + twl4030_usb_phy_init(twl);

now I see, this doesn't care about that flag, so why even setting
it above ??

--
balbi
--
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