Re: [PATCH v2 1/4] ARM: dts: omap4-panda: Add USB Host support

From: Florian Vaussard
Date: Wed Jun 19 2013 - 08:05:13 EST


On 06/19/2013 01:03 PM, Roger Quadros wrote:
On 06/19/2013 01:10 PM, Benoit Cousson wrote:
On 06/19/2013 02:46 AM, Tony Lindgren wrote:
* Roger Quadros <rogerq@xxxxxx> [130619 00:42]:
Hi Benoit,

On 06/19/2013 04:17 AM, Benoit Cousson wrote:
Hi Roger,

On 06/18/2013 11:04 AM, Roger Quadros wrote:
Provide the RESET and Power regulators for the USB PHY,
the USB Host port mode and the PHY device.

Also provide pin multiplexer information for the USB host

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
arch/arm/boot/dts/omap4-panda-common.dtsi | 62 +++++++++++++++++++++++++++++
1 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/arch/arm/boot/dts/omap4-panda-common.dtsi b/arch/arm/boot/dts/omap4-panda-common.dtsi
index 00cbaa5..7a21e8e 100644
--- a/arch/arm/boot/dts/omap4-panda-common.dtsi
+++ b/arch/arm/boot/dts/omap4-panda-common.dtsi
@@ -59,6 +59,42 @@
"AFML", "Line In",
"AFMR", "Line In";
+ /* HS USB Port 1 RESET */
+ hsusb1_reset: hsusb1_reset_reg {
+ compatible = "regulator-fixed";
+ regulator-name = "hsusb1_reset";
+ regulator-min-microvolt = <3300000>;
+ regulator-max-microvolt = <3300000>;
+ gpio = <&gpio2 30 0>; /* gpio_62 */
+ startup-delay-us = <70000>;
+ enable-active-high;
+ };

Is this really a regulator? Or just a GPIO line used to reset the USB PHY?

It is in fact a GPIO line used as reset.

If this is the case, I don't think it should be represented as a regulator.

Why not? I think it fits very well in the regulator device model.

I'm not sure fitting very well is the correct term.
It works, for sure, but it is no different than when we were trying to abuse the regulator fmwk to enable the 32k clock in phoenix.
It is just a hack.

The only difference is there is a dedicated framework for clocks. Since there is nothing specific to
handle reset lines it is left to the driver writer how he wants to manage it.

There is a proposed binding for gpio-controlled reset lines, but it is not yet merged [1].
I guess it can fit most usage patterns, and it can be an interesting move in the future.



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