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From: Markus Pargmann <mpa@pengutronix.de>
To: Tony Lindgren <tony@atomide.com>
Cc: "Benoît Cousson" <bcousson@baylibre.com>,
	linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	kernel@pengutronix.de
Subject: Re: [PATCH] arm: dtsi: am335x-bone-common, usb0 is peripheral only
Date: Fri, 14 Feb 2014 00:13:33 +0100	[thread overview]
Message-ID: <20140213231333.GK31787@pengutronix.de> (raw)
In-Reply-To: <20140213225438.GF28216@atomide.com>

Hi,

On Thu, Feb 13, 2014 at 02:54:38PM -0800, Tony Lindgren wrote:
> * Markus Pargmann <mpa@pengutronix.de> [140111 06:03]:
> > The PMIC is using usb0 vbus line as power source. It is also connected
> > to the am335x processor as vbus sense. But there is no possibility to
> > pullup usb0 vbus to operate as host. This patch fixes the dr_mode of usb0.
> 
> That's the MUSB? AFAIK it's not possible to operate MUSB in peripheral
> only mode because the hardware does what it wants based on the ID
> pin state.

Yes that's MUSB. The am335x reference manual describes that it is
possible to force peripheral/host mode by setting bit 7 (IDDIG_MUX) in
register USBnMODE to 1. Then it uses the bit written in bit 8 (IDDIG) of
register USBnMODE to set host/peripheral mode.

I am not sure if the driver supports it yet but I think the DTS should
contain the correct mode nevertheless, especially to avoid starting the
otg loops in the musb driver.

Regards,

Markus

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

WARNING: multiple messages have this Message-ID (diff)
From: mpa@pengutronix.de (Markus Pargmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm: dtsi: am335x-bone-common, usb0 is peripheral only
Date: Fri, 14 Feb 2014 00:13:33 +0100	[thread overview]
Message-ID: <20140213231333.GK31787@pengutronix.de> (raw)
In-Reply-To: <20140213225438.GF28216@atomide.com>

Hi,

On Thu, Feb 13, 2014 at 02:54:38PM -0800, Tony Lindgren wrote:
> * Markus Pargmann <mpa@pengutronix.de> [140111 06:03]:
> > The PMIC is using usb0 vbus line as power source. It is also connected
> > to the am335x processor as vbus sense. But there is no possibility to
> > pullup usb0 vbus to operate as host. This patch fixes the dr_mode of usb0.
> 
> That's the MUSB? AFAIK it's not possible to operate MUSB in peripheral
> only mode because the hardware does what it wants based on the ID
> pin state.

Yes that's MUSB. The am335x reference manual describes that it is
possible to force peripheral/host mode by setting bit 7 (IDDIG_MUX) in
register USBnMODE to 1. Then it uses the bit written in bit 8 (IDDIG) of
register USBnMODE to set host/peripheral mode.

I am not sure if the driver supports it yet but I think the DTS should
contain the correct mode nevertheless, especially to avoid starting the
otg loops in the musb driver.

Regards,

Markus

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

  reply	other threads:[~2014-02-13 23:13 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-11 14:00 [PATCH] arm: dtsi: am335x-bone-common, usb0 is peripheral only Markus Pargmann
2014-01-11 14:00 ` Markus Pargmann
2014-02-13 22:54 ` Tony Lindgren
2014-02-13 22:54   ` Tony Lindgren
2014-02-13 23:13   ` Markus Pargmann [this message]
2014-02-13 23:13     ` Markus Pargmann
2014-02-13 23:25     ` Tony Lindgren
2014-02-13 23:25       ` Tony Lindgren
2014-02-14 10:02       ` Markus Pargmann
2014-02-14 10:02         ` Markus Pargmann
2014-02-14 16:20         ` Tony Lindgren
2014-02-14 16:20           ` Tony Lindgren

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