how to specify an OMAP clock in device tree?

[Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>]

Hi Rajendra,

On 02/04/2013 05:58 PM, 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
> pins.
> 
> Signed-off-by: Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>
> ---
>  arch/arm/boot/dts/omap4-panda.dts |   55 +++++++++++++++++++++++++++++++++++++
>  1 files changed, 55 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/omap4-panda.dts b/arch/arm/boot/dts/omap4-panda.dts
> index 4122efe..fe2d3d4 100644
> --- a/arch/arm/boot/dts/omap4-panda.dts
> +++ b/arch/arm/boot/dts/omap4-panda.dts
> @@ -57,6 +57,35 @@
>  			"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;
> +	};
> +
> +	/* HS USB Port 1 Power */
> +	hsusb1_power: hsusb1_power_reg {
> +		compatible = "regulator-fixed";
> +		regulator-name = "hsusb1_vbus";
> +		regulator-min-microvolt = <3300000>;
> +		regulator-max-microvolt = <3300000>;
> +		gpio = <&gpio1 1 0>;	/* gpio_1 */
> +		startup-delay-us = <70000>;
> +		enable-active-high;
> +	};
> +
> +	/* HS USB Host PHY on PORT 1 */
> +	hsusb1_phy: hsusb1_phy {
> +		compatible = "usb-nop-xceiv";
> +		reset-supply = <&hsusb1_reset>;
> +		vcc-supply = <&hsusb1_power>;
> +	};

This is the patch I was discussing with you about before.

Let me explain the problem again.

The Pandaboard has a USB PHY whose reference clock is provided by
FREF_CLK3 pin which is a clock generated by the OMAP.
The PHY driver expects a reference to this clock in the PHY device node.
See the above node hsusb1_phy. we would need something like
	hsusb1_phy {
		...
		clocks = <&fref_clk3>;
		clock-names = "main_clk";
		...
	};

Currently on OMAP, there is no way to provide a phandle to this clock.

Is it practical to provide device tree based implementation of at least
the externally accessible OMAP clocks?

cheers,
-roger

>  };
>  
>  &omap4_pmx_core {
> @@ -67,6 +96,7 @@
>  			&mcbsp1_pins
>  			&dss_hdmi_pins
>  			&tpd12s015_pins
> +			&hsusbb1_pins
>  	>;
>  
>  	twl6040_pins: pinmux_twl6040_pins {
> @@ -110,6 +140,23 @@
>  			0x58 0x10b	/* hdmi_hpd.gpio_63 INPUT PULLDOWN | MODE3 */
>  		>;
>  	};