[PATCH RESEND] ARM: dts: add BeagleBone Audio Cape (Rev A) dtsi

[PATCH RESEND] ARM: dts: add BeagleBone Audio Cape (Rev A) dtsi

[Jack Mitchell]

From: Jack Mitchell <jack@embed.me.uk>

Devicetree include file for setting up the am335x mcasp bus, i2c-2
bus, and audio codec required for a functioning BeagleBone Audio Cape.

Signed-off-by: Jack Mitchell <jack@embed.me.uk>
Signed-off-by: Matt Porter <mporter@linaro.org>
---
 arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi | 124 +++++++++++++++++++++
 arch/arm/boot/dts/am335x-bone-common.dtsi          |  14 +++
 2 files changed, 138 insertions(+)
 create mode 100644 arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi

diff --git a/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi b/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi
new file mode 100644
index 0000000..b8ec3dc
--- /dev/null
+++ b/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2014 Jack Mitchell <jack@embed.me.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * In order to enable the BeagleBone Audio Cape this dtsi must be
+ * incuded in the top level dts. On BeagleBone Black hardware the
+ * status of the HDMI dts node must also be set to "disabled".
+ *
+ * --- a/arch/arm/boot/dts/am335x-bone.dts
+ * +++ b/arch/arm/boot/dts/am335x-bone.dts
+ * @@ -9,6 +9,7 @@
+ *
+ *  #include "am33xx.dtsi"
+ *  #include "am335x-bone-common.dtsi"
+ * +#include "am335x-bone-audio-cape-reva.dtsi"
+ *
+ *  &ldo3_reg {
+ *  	regulator-min-microvolt = <1800000>;
+ *
+ * On BeagleBone Black hardware the status of the HDMI dts node must
+ * also be set to "disabled"
+ *
+ * --- a/arch/arm/boot/dts/am335x-boneblack.dts
+ * +++ b/arch/arm/boot/dts/am335x-boneblack.dts
+ * @@ -73,6 +74,6 @@
+ *  		pinctrl-names = "default", "off";
+ *  		pinctrl-0 = <&nxp_hdmi_bonelt_pins>;
+ *  		pinctrl-1 = <&nxp_hdmi_bonelt_off_pins>;
+ * -		status = "okay";
+ * +		status = "disabled";
+ *  	};
+ *  };
+ */
+
+/ {
+	sound {
+		compatible = "ti,da830-evm-audio";
+		ti,model = "AM335x BeagleBone Audio Cape Rev. A";
+		ti,audio-codec = <&tlv320aic3106>;
+		ti,mcasp-controller = <&mcasp0>;
+		ti,codec-clock-rate = <12000000>;
+		ti,audio-routing =
+			"Headphone Jack",       "HPLOUT",
+			"Headphone Jack",       "HPROUT",
+			"LINE1L",               "Line In",
+			"LINE1R",               "Line In";
+	};
+
+	audio-cape-gpio-leds {
+		compatible = "gpio-leds";
+		pinctrl-names = "default";
+		pinctrl-0 = <&bone_audio_cape_led_pins>;
+
+		audio-led0 {
+			label = "audio:green:usr0";
+			gpios = <&gpio1 18 GPIO_ACTIVE_HIGH>;
+			linux,default-trigger = "heartbeat";
+			default-state = "off";
+		};
+
+		audio-led1 {
+			label = "audio:green:usr1";
+			gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>;
+			linux,default-trigger = "mmc0";
+			default-state = "off";
+		};
+	};
+};
+
+&am33xx_pinmux {
+	bone_audio_cape_led_pins: pinmux_bone_audio_cape_led_pins {
+		pinctrl-single,pins = <
+			0x48 (PIN_OUTPUT_PULLDOWN | MUX_MODE7) /* gpmc_a2.gpio1_18 */
+			0x4c (PIN_OUTPUT_PULLDOWN | MUX_MODE7) /* gpmc_a3.gpio1_19 */
+		>;
+	};
+
+	bone_audio_cape_pins: bone_audio_cape_pins {
+		pinctrl-single,pins = <
+			0x190 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mcasp0_aclkx.mcasp0_aclkx */
+			0x194 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mcasp0_fsx.mcasp0_fsx */
+			0x19c (PIN_INPUT_PULLUP | MUX_MODE2)	/* mcasp0_ahclkr.mcasp0_axr2 */
+			0x1ac (PIN_INPUT_PULLUP | MUX_MODE2)	/* mcasp0_ahclkx.mcasp0_axr3 */
+		>;
+	};
+};
+
+&i2c2 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&i2c2_pins>;
+
+	status = "okay";
+	clock-frequency = <100000>;
+
+	tlv320aic3106: tlv320aic3106@1b {
+		compatible = "ti,tlv320aic3106";
+		reg = <0x1b>;
+		status = "okay";
+
+		/* Regulators */
+		AVDD-supply = <&vmmcsd_fixed>;
+		IOVDD-supply = <&vmmcsd_fixed>;
+		DRVDD-supply = <&vmmcsd_fixed>;
+		DVDD-supply = <&vdd1v8_fixed>;
+	};
+};
+
+&mcasp0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&bone_audio_cape_pins>;
+
+	status = "okay";
+
+	op-mode = <0>;      /* MCASP_IIS_MODE */
+	tdm-slots = <2>;
+	serial-dir = <      /* 0: INACTIVE, 1: TX, 2: RX */
+		0 0 2 1
+	>;
+	tx-num-evt = <1>;
+	rx-num-evt = <1>;
+};
diff --git a/arch/arm/boot/dts/am335x-bone-common.dtsi b/arch/arm/boot/dts/am335x-bone-common.dtsi
index e3f27ec..c1c0f74 100644
--- a/arch/arm/boot/dts/am335x-bone-common.dtsi
+++ b/arch/arm/boot/dts/am335x-bone-common.dtsi
@@ -62,12 +62,26 @@
 		regulator-min-microvolt = <3300000>;
 		regulator-max-microvolt = <3300000>;
 	};
+
+	vdd1v8_fixed: fixedregulator@1 {
+		compatible = "regulator-fixed";
+		regulator-name = "vdd1v8_fixed";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+	};
 };
 
 &am33xx_pinmux {
 	pinctrl-names = "default";
 	pinctrl-0 = <&clkout2_pin>;
 
+	i2c2_pins: pinmux_i2c2_pins {
+		pinctrl-single,pins = <
+			0x178 (PIN_INPUT_PULLUP | MUX_MODE3)  /* uart1_ctsn.i2c2_sda */
+			0x17c (PIN_INPUT_PULLUP | MUX_MODE3)  /* uart1_rtsn.i2c2_scl */
+		>;
+	};
+
 	user_leds_s0: user_leds_s0 {
 		pinctrl-single,pins = <
 			0x54 (PIN_OUTPUT_PULLDOWN | MUX_MODE7)	/* gpmc_a5.gpio1_21 */
-- 
1.8.5.3

Re: [PATCH RESEND] ARM: dts: add BeagleBone Audio Cape (Rev A) dtsi

[Nishanth Menon]

On 02/05/2014 07:48 AM, Jack Mitchell wrote:
> From: Jack Mitchell <jack@embed.me.uk>
> 
> Devicetree include file for setting up the am335x mcasp bus, i2c-2
> bus, and audio codec required for a functioning BeagleBone Audio Cape.
> 
> Signed-off-by: Jack Mitchell <jack@embed.me.uk>
> Signed-off-by: Matt Porter <mporter@linaro.org>
> ---
>  arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi | 124 +++++++++++++++++++++
>  arch/arm/boot/dts/am335x-bone-common.dtsi          |  14 +++
>  2 files changed, 138 insertions(+)
>  create mode 100644 arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi
> 
> diff --git a/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi b/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi
> new file mode 100644
> index 0000000..b8ec3dc
> --- /dev/null
> +++ b/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi
> @@ -0,0 +1,124 @@
> +/*
> + * Copyright (C) 2014 Jack Mitchell <jack@embed.me.uk>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * In order to enable the BeagleBone Audio Cape this dtsi must be
> + * incuded in the top level dts. On BeagleBone Black hardware the
> + * status of the HDMI dts node must also be set to "disabled".
> + *
> + * --- a/arch/arm/boot/dts/am335x-bone.dts
> + * +++ b/arch/arm/boot/dts/am335x-bone.dts
> + * @@ -9,6 +9,7 @@
> + *
> + *  #include "am33xx.dtsi"
> + *  #include "am335x-bone-common.dtsi"
> + * +#include "am335x-bone-audio-cape-reva.dtsi"
> + *
> + *  &ldo3_reg {
> + *  	regulator-min-microvolt = <1800000>;
> + *
> + * On BeagleBone Black hardware the status of the HDMI dts node must
> + * also be set to "disabled"
> + *
> + * --- a/arch/arm/boot/dts/am335x-boneblack.dts
> + * +++ b/arch/arm/boot/dts/am335x-boneblack.dts
> + * @@ -73,6 +74,6 @@
> + *  		pinctrl-names = "default", "off";
> + *  		pinctrl-0 = <&nxp_hdmi_bonelt_pins>;
> + *  		pinctrl-1 = <&nxp_hdmi_bonelt_off_pins>;
> + * -		status = "okay";
> + * +		status = "disabled";
> + *  	};
> + *  };
> + */
> +
how about making the audio-cape-reva.dts which includes and overrides
parameters of boneblack.dts?


Further, I see a bunch of capes in
http://elinux.org/Beagleboard:BeagleBone_Capes

Assuming that we dont want to discuss capebus all over again, is this
the approach we'd like to consider in the interim?

> +/ {
> +	sound {
> +		compatible = "ti,da830-evm-audio";
> +		ti,model = "AM335x BeagleBone Audio Cape Rev. A";
> +		ti,audio-codec = <&tlv320aic3106>;
> +		ti,mcasp-controller = <&mcasp0>;
> +		ti,codec-clock-rate = <12000000>;
> +		ti,audio-routing =
> +			"Headphone Jack",       "HPLOUT",
> +			"Headphone Jack",       "HPROUT",
> +			"LINE1L",               "Line In",
> +			"LINE1R",               "Line In";
> +	};
> +
> +	audio-cape-gpio-leds {
> +		compatible = "gpio-leds";
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&bone_audio_cape_led_pins>;
> +
> +		audio-led0 {
> +			label = "audio:green:usr0";
> +			gpios = <&gpio1 18 GPIO_ACTIVE_HIGH>;
> +			linux,default-trigger = "heartbeat";
> +			default-state = "off";
> +		};
> +
> +		audio-led1 {
> +			label = "audio:green:usr1";
> +			gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>;
> +			linux,default-trigger = "mmc0";
> +			default-state = "off";
> +		};
> +	};
> +};
> +
> +&am33xx_pinmux {
> +	bone_audio_cape_led_pins: pinmux_bone_audio_cape_led_pins {
> +		pinctrl-single,pins = <
> +			0x48 (PIN_OUTPUT_PULLDOWN | MUX_MODE7) /* gpmc_a2.gpio1_18 */
> +			0x4c (PIN_OUTPUT_PULLDOWN | MUX_MODE7) /* gpmc_a3.gpio1_19 */
> +		>;
> +	};
> +
> +	bone_audio_cape_pins: bone_audio_cape_pins {
> +		pinctrl-single,pins = <
> +			0x190 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mcasp0_aclkx.mcasp0_aclkx */
> +			0x194 (PIN_INPUT_PULLUP | MUX_MODE0)	/* mcasp0_fsx.mcasp0_fsx */
> +			0x19c (PIN_INPUT_PULLUP | MUX_MODE2)	/* mcasp0_ahclkr.mcasp0_axr2 */
> +			0x1ac (PIN_INPUT_PULLUP | MUX_MODE2)	/* mcasp0_ahclkx.mcasp0_axr3 */
> +		>;
> +	};
> +};
> +
> +&i2c2 {
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&i2c2_pins>;
> +
> +	status = "okay";
> +	clock-frequency = <100000>;
> +
> +	tlv320aic3106: tlv320aic3106@1b {
> +		compatible = "ti,tlv320aic3106";
> +		reg = <0x1b>;
> +		status = "okay";
> +
> +		/* Regulators */
> +		AVDD-supply = <&vmmcsd_fixed>;
> +		IOVDD-supply = <&vmmcsd_fixed>;
> +		DRVDD-supply = <&vmmcsd_fixed>;
> +		DVDD-supply = <&vdd1v8_fixed>;
> +	};
> +};
> +
> +&mcasp0 {
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&bone_audio_cape_pins>;
> +
> +	status = "okay";
> +
> +	op-mode = <0>;      /* MCASP_IIS_MODE */
> +	tdm-slots = <2>;
> +	serial-dir = <      /* 0: INACTIVE, 1: TX, 2: RX */
> +		0 0 2 1
> +	>;
> +	tx-num-evt = <1>;
> +	rx-num-evt = <1>;
> +};
> diff --git a/arch/arm/boot/dts/am335x-bone-common.dtsi b/arch/arm/boot/dts/am335x-bone-common.dtsi
> index e3f27ec..c1c0f74 100644
> --- a/arch/arm/boot/dts/am335x-bone-common.dtsi
> +++ b/arch/arm/boot/dts/am335x-bone-common.dtsi
> @@ -62,12 +62,26 @@
>  		regulator-min-microvolt = <3300000>;
>  		regulator-max-microvolt = <3300000>;
>  	};
> +
> +	vdd1v8_fixed: fixedregulator@1 {
> +		compatible = "regulator-fixed";
> +		regulator-name = "vdd1v8_fixed";
> +		regulator-min-microvolt = <1800000>;
> +		regulator-max-microvolt = <1800000>;
> +	};
>  };
>  
>  &am33xx_pinmux {
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&clkout2_pin>;
>  
> +	i2c2_pins: pinmux_i2c2_pins {
> +		pinctrl-single,pins = <
> +			0x178 (PIN_INPUT_PULLUP | MUX_MODE3)  /* uart1_ctsn.i2c2_sda */
> +			0x17c (PIN_INPUT_PULLUP | MUX_MODE3)  /* uart1_rtsn.i2c2_scl */
> +		>;
> +	};
> +
>  	user_leds_s0: user_leds_s0 {
>  		pinctrl-single,pins = <
>  			0x54 (PIN_OUTPUT_PULLDOWN | MUX_MODE7)	/* gpmc_a5.gpio1_21 */
> 


-- 
Regards,
Nishanth Menon

Re: [PATCH RESEND] ARM: dts: add BeagleBone Audio Cape (Rev A) dtsi

[Matt Porter]

On Wed, Feb 05, 2014 at 08:09:16AM -0600, Nishanth Menon wrote:
> On 02/05/2014 07:48 AM, Jack Mitchell wrote:
> > From: Jack Mitchell <jack-psbXN780rFT10XsdtD+oqA@public.gmane.org>
> > 
> > Devicetree include file for setting up the am335x mcasp bus, i2c-2
> > bus, and audio codec required for a functioning BeagleBone Audio Cape.
> > 
> > Signed-off-by: Jack Mitchell <jack-psbXN780rFT10XsdtD+oqA@public.gmane.org>
> > Signed-off-by: Matt Porter <mporter-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> > ---
> >  arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi | 124 +++++++++++++++++++++
> >  arch/arm/boot/dts/am335x-bone-common.dtsi          |  14 +++
> >  2 files changed, 138 insertions(+)
> >  create mode 100644 arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi
> > 
> > diff --git a/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi b/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi
> > new file mode 100644
> > index 0000000..b8ec3dc
> > --- /dev/null
> > +++ b/arch/arm/boot/dts/am335x-bone-audio-cape-reva.dtsi
> > @@ -0,0 +1,124 @@
> > +/*
> > + * Copyright (C) 2014 Jack Mitchell <jack-psbXN780rFT10XsdtD+oqA@public.gmane.org>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + *
> > + * In order to enable the BeagleBone Audio Cape this dtsi must be
> > + * incuded in the top level dts. On BeagleBone Black hardware the
> > + * status of the HDMI dts node must also be set to "disabled".
> > + *
> > + * --- a/arch/arm/boot/dts/am335x-bone.dts
> > + * +++ b/arch/arm/boot/dts/am335x-bone.dts
> > + * @@ -9,6 +9,7 @@
> > + *
> > + *  #include "am33xx.dtsi"
> > + *  #include "am335x-bone-common.dtsi"
> > + * +#include "am335x-bone-audio-cape-reva.dtsi"
> > + *
> > + *  &ldo3_reg {
> > + *  	regulator-min-microvolt = <1800000>;
> > + *
> > + * On BeagleBone Black hardware the status of the HDMI dts node must
> > + * also be set to "disabled"
> > + *
> > + * --- a/arch/arm/boot/dts/am335x-boneblack.dts
> > + * +++ b/arch/arm/boot/dts/am335x-boneblack.dts
> > + * @@ -73,6 +74,6 @@
> > + *  		pinctrl-names = "default", "off";
> > + *  		pinctrl-0 = <&nxp_hdmi_bonelt_pins>;
> > + *  		pinctrl-1 = <&nxp_hdmi_bonelt_off_pins>;
> > + * -		status = "okay";
> > + * +		status = "disabled";
> > + *  	};
> > + *  };
> > + */
> > +
> how about making the audio-cape-reva.dts which includes and overrides
> parameters of boneblack.dts?

Yeah, that might be a little cleaner. Black makes things unfortunately
messy for these capes that were really intended for BBW :(

> Further, I see a bunch of capes in
> http://elinux.org/Beagleboard:BeagleBone_Capes
> 
> Assuming that we dont want to discuss capebus all over again, is this
> the approach we'd like to consider in the interim?

I think that's a fair assumption...I'll note that there is work slowly
in progress on a very minimal implementation DT overlays upstream. But
that doesn't exist. We are simply interested in a sane way to use the
hardware we own in mainline and this approach makes it possible to build
a kernel+dtb from mainline that works for this configuration. If
there's a better way to support this hardware *today* let's discuss it.
One of the big benefits to having this upstream is that it's no longer
out of sight out of mind. It should be managed alongside all the other
am335x dts data.

Incidentally, I'm hoping to contribute a similar patch for the DVI cape
I have here.

-Matt
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Re: [PATCH RESEND] ARM: dts: add BeagleBone Audio Cape (Rev A) dtsi

[Nishanth Menon]

On 02/05/2014 08:38 AM, Matt Porter wrote:
> On Wed, Feb 05, 2014 at 08:09:16AM -0600, Nishanth Menon wrote:
>> On 02/05/2014 07:48 AM, Jack Mitchell wrote:
[...]
>>> + * --- a/arch/arm/boot/dts/am335x-boneblack.dts
>>> + * +++ b/arch/arm/boot/dts/am335x-boneblack.dts
>>> + * @@ -73,6 +74,6 @@
>>> + *  		pinctrl-names = "default", "off";
>>> + *  		pinctrl-0 = <&nxp_hdmi_bonelt_pins>;
>>> + *  		pinctrl-1 = <&nxp_hdmi_bonelt_off_pins>;
>>> + * -		status = "okay";
>>> + * +		status = "disabled";
>>> + *  	};
>>> + *  };
>>> + */
>>> +
>> how about making the audio-cape-reva.dts which includes and overrides
>> parameters of boneblack.dts?
> 
> Yeah, that might be a little cleaner. Black makes things unfortunately
> messy for these capes that were really intended for BBW :(

yes indeed - we might have to live with more dts in such a case.
> 
>> Further, I see a bunch of capes in
>> http://elinux.org/Beagleboard:BeagleBone_Capes
>>
>> Assuming that we dont want to discuss capebus all over again, is this
>> the approach we'd like to consider in the interim?
> 
> I think that's a fair assumption...I'll note that there is work slowly
> in progress on a very minimal implementation DT overlays upstream. But
> that doesn't exist. We are simply interested in a sane way to use the
> hardware we own in mainline and this approach makes it possible to build
> a kernel+dtb from mainline that works for this configuration. If
> there's a better way to support this hardware *today* let's discuss it.
> One of the big benefits to having this upstream is that it's no longer
> out of sight out of mind. It should be managed alongside all the other
> am335x dts data.
> 
> Incidentally, I'm hoping to contribute a similar patch for the DVI cape
> I have here.

If I am not mistaken, the capes are stackable (within reason), and are
not exactly hotpluggable.. question pops up as to how do we handle
multiple cape descriptions on the same board without having the user
to create custom dts which includes each relevant cape dts he has on
his/her bone? I wonder(without proper research, just thinking aloud)
if u-boot can do some sort of merge of dtbs - assuming ofcourse eeprom
data is used to detect the capes plugged on board?

-- 
Regards,
Nishanth Menon

Re: [PATCH RESEND] ARM: dts: add BeagleBone Audio Cape (Rev A) dtsi

[Matt Porter]

On Wed, Feb 05, 2014 at 08:56:34AM -0600, Nishanth Menon wrote:
> On 02/05/2014 08:38 AM, Matt Porter wrote:
> > On Wed, Feb 05, 2014 at 08:09:16AM -0600, Nishanth Menon wrote:
> >> On 02/05/2014 07:48 AM, Jack Mitchell wrote:
> [...]
> >>> + * --- a/arch/arm/boot/dts/am335x-boneblack.dts
> >>> + * +++ b/arch/arm/boot/dts/am335x-boneblack.dts
> >>> + * @@ -73,6 +74,6 @@
> >>> + *  		pinctrl-names = "default", "off";
> >>> + *  		pinctrl-0 = <&nxp_hdmi_bonelt_pins>;
> >>> + *  		pinctrl-1 = <&nxp_hdmi_bonelt_off_pins>;
> >>> + * -		status = "okay";
> >>> + * +		status = "disabled";
> >>> + *  	};
> >>> + *  };
> >>> + */
> >>> +
> >> how about making the audio-cape-reva.dts which includes and overrides
> >> parameters of boneblack.dts?
> > 
> > Yeah, that might be a little cleaner. Black makes things unfortunately
> > messy for these capes that were really intended for BBW :(
> 
> yes indeed - we might have to live with more dts in such a case.
> > 
> >> Further, I see a bunch of capes in
> >> http://elinux.org/Beagleboard:BeagleBone_Capes
> >>
> >> Assuming that we dont want to discuss capebus all over again, is this
> >> the approach we'd like to consider in the interim?
> > 
> > I think that's a fair assumption...I'll note that there is work slowly
> > in progress on a very minimal implementation DT overlays upstream. But
> > that doesn't exist. We are simply interested in a sane way to use the
> > hardware we own in mainline and this approach makes it possible to build
> > a kernel+dtb from mainline that works for this configuration. If
> > there's a better way to support this hardware *today* let's discuss it.
> > One of the big benefits to having this upstream is that it's no longer
> > out of sight out of mind. It should be managed alongside all the other
> > am335x dts data.
> > 
> > Incidentally, I'm hoping to contribute a similar patch for the DVI cape
> > I have here.
> 
> If I am not mistaken, the capes are stackable (within reason), and are
> not exactly hotpluggable.. question pops up as to how do we handle
> multiple cape descriptions on the same board without having the user
> to create custom dts which includes each relevant cape dts he has on
> his/her bone? I wonder(without proper research, just thinking aloud)
> if u-boot can do some sort of merge of dtbs - assuming ofcourse eeprom
> data is used to detect the capes plugged on board?

Well covered in the original discussion. gcl summarizes options in
https://lkml.org/lkml/2012/11/5/615

Since then, the basic overlay support for the kernel is pretty much a
done deal. It has a wide variety of users (FPGA folks) beyond this board
specific case. The problem you describe about resource management and
conflicts would probably need to be built on top of that. Pantelis
had a PoC implementation with capebus/not-a-capebus but that's not part
of what is being upstreamed. I'm not sure if there's anybody with enough
time out of the Beagleboard community to upstream a resource manager on
top of the basic overlay support that's in progress. However, it might
make a nice GSoC2014 project. :)

-Matt