linux-kernel - Re: [PATCH 4/4] usb: otg: twl4030-usb: Don't power down phy when it is in-use by charger.

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Date:	Sun, 13 May 2012 20:14:09 +0200
From:	Andi Shyti <andi.shyti@...il.com>
To:	NeilBrown <neilb@...e.de>
Cc:	Samuel Ortiz <sameo@...ux.intel.com>, Felipe Balbi <balbi@...com>,
	Anton Vorontsov <cbou@...l.ru>,
	David Woodhouse <dwmw2@...radead.org>,
	Grazvydas Ignotas <notasas@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH 4/4] usb: otg: twl4030-usb: Don't power down phy when it
 is in-use by charger.

Hi,

On Wed, May 09, 2012 at 07:40:40AM +1000, NeilBrown wrote:
> @@ -388,10 +388,16 @@ static void twl4030_phy_power(struct twl4030_usb *twl, int on)
>  					(PHY_CLK_CTRL_CLOCKGATING_EN |
>  						PHY_CLK_CTRL_CLK32K_EN));
>  	} else {
> -		__twl4030_phy_power(twl, 0);
>  		regulator_disable(twl->usb1v5);
>  		regulator_disable(twl->usb1v8);
>  		regulator_disable(twl->usb3v1);
> +		if (!regulator_is_enabled(twl->usb3v1))
> +			/* no-one else is requesting this
> +			 * so it is OK to power-down the
> +			 * phy.  Sometimes a charger might
> +			 * hold the regulator active.
> +			 */
> +			__twl4030_phy_power(twl, 0);
>  	}

Usually a regulator line is shared by more than one device and
regulator_is_enable() returns true if at least one of these
devices is holding the regulator. This means that here the check
will not work if this is your case.

Andi
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