Linux-ARM-Kernel Archive on lore.kernel.org

* [PATCH RFC] ARM: dts: add Raspberry Pi Compute Module and IO board
From: Stefan Wahren @ 2018-05-21 19:28 UTC (permalink / raw)
  To: linux-arm-kernel
In-Reply-To: <87d0xouapx.fsf@anholt.net>

> Eric Anholt <eric@anholt.net> hat am 21. Mai 2018 um 20:26 geschrieben:
> 
> 
> Stefan Wahren <stefan.wahren@i2se.com> writes:
> 
> > The Raspberry Pi Compute Module (CM1) is a SoM which contains a
> > BCM2835 processor, 512 MB RAM and a 4 GB eMMC. There is also a carrier
> > board which is called Compute Module IO Board.
> >
> > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
> > ---
> >  arch/arm/boot/dts/Makefile                |  1 +
> >  arch/arm/boot/dts/bcm2835-rpi-cm1-io1.dts | 92 +++++++++++++++++++++++++++++++
> >  arch/arm/boot/dts/bcm2835-rpi-cm1.dtsi    | 34 ++++++++++++
> >  3 files changed, 127 insertions(+)
> >  create mode 100644 arch/arm/boot/dts/bcm2835-rpi-cm1-io1.dts
> >  create mode 100644 arch/arm/boot/dts/bcm2835-rpi-cm1.dtsi
> >
> > diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
> > index ec2024e..a9883e8 100644
> > --- a/arch/arm/boot/dts/Makefile
> > +++ b/arch/arm/boot/dts/Makefile
> > @@ -73,6 +73,7 @@ dtb-$(CONFIG_ARCH_BCM2835) += \
> >  	bcm2835-rpi-b-rev2.dtb \
> >  	bcm2835-rpi-b-plus.dtb \
> >  	bcm2835-rpi-a-plus.dtb \
> > +	bcm2835-rpi-cm1-io1.dtb \
> >  	bcm2836-rpi-2-b.dtb \
> >  	bcm2837-rpi-3-b.dtb \
> >  	bcm2837-rpi-3-b-plus.dtb \
> > diff --git a/arch/arm/boot/dts/bcm2835-rpi-cm1-io1.dts b/arch/arm/boot/dts/bcm2835-rpi-cm1-io1.dts
> > new file mode 100644
> > index 0000000..4d9aa22
> > --- /dev/null
> > +++ b/arch/arm/boot/dts/bcm2835-rpi-cm1-io1.dts
> > @@ -0,0 +1,92 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/dts-v1/;
> > +#include "bcm2835-rpi-cm1.dtsi"
> > +#include "bcm283x-rpi-usb-host.dtsi"
> > +
> > +/ {
> > +	compatible = "raspberrypi,compute-module", "brcm,bcm2835";
> > +	model = "Raspberry Pi Compute Module IO board rev1";
> > +};
> > +
> > +&dsi1 {
> > +	status = "okay";
> > +};
> > +
> > +&gpio {
> > +	/*
> > +	 * This is based on the official GPU firmware DT blob.
> > +	 *
> > +	 * Legend:
> > +	 * "NC" = not connected (no rail from the SoC)
> > +	 * "FOO" = GPIO line named "FOO" on the schematic
> > +	 * "FOO_N" = GPIO line named "FOO" on schematic, active low
> > +	 */
> > +	gpio-line-names = "GPIO0",
> > +			  "GPIO1",
> > +			  "GPIO2",
> > +			  "GPIO3",
> > +			  "GPIO4",
> > +			  "GPIO5",
> > +			  "GPIO6",
> > +			  "GPIO7",
> > +			  "GPIO8",
> > +			  "GPIO9",
> > +			  "GPIO10",
> > +			  "GPIO11",
> > +			  "GPIO12",
> > +			  "GPIO13",
> > +			  "GPIO14",
> > +			  "GPIO15",
> > +			  "GPIO16",
> > +			  "GPIO17",
> > +			  "GPIO18",
> > +			  "GPIO19",
> > +			  "GPIO20",
> > +			  "GPIO21",
> > +			  "GPIO22",
> > +			  "GPIO23",
> > +			  "GPIO24",
> > +			  "GPIO25",
> > +			  "GPIO26",
> > +			  "GPIO27",
> > +			  "GPIO28",
> > +			  "GPIO29",
> > +			  "GPIO30",
> > +			  "GPIO31",
> > +			  "GPIO32",
> > +			  "GPIO33",
> > +			  "GPIO34",
> > +			  "GPIO35",
> > +			  "GPIO36",
> > +			  "GPIO37",
> > +			  "GPIO38",
> > +			  "GPIO39",
> > +			  "GPIO40",
> > +			  "GPIO41",
> > +			  "GPIO42",
> > +			  "GPIO43",
> > +			  "GPIO44",
> > +			  "GPIO45",
> > +			  "HDMI_HPD_N",
> > +			  /* Also used as ACT LED */
> > +			  "EMMC_EN_N",
> > +			  /* Used by eMMC */
> > +			  "SD_CLK_R",
> > +			  "SD_CMD_R",
> > +			  "SD_DATA0_R",
> > +			  "SD_DATA1_R",
> > +			  "SD_DATA2_R",
> > +			  "SD_DATA3_R";
> > +
> > +	pinctrl-0 = <&gpioout &alt0>;
> > +};
> > +
> > +&hdmi {
> > +	hpd-gpios = <&gpio 46 GPIO_ACTIVE_HIGH>;
> > +};
> 
> I think this should be ACTIVE_LOW, since it's "HDMI_HPD_N_1V8", right?

I just copy & paste from the rpi-4.14/bcm2708-rpi-cm.dts. I thought the HDMI interface on my IO board is broken, but maybe this is a downstream issue.

> 
> > +
> > +&uart0 {
> > +	pinctrl-names = "default";
> > +	pinctrl-0 = <&uart0_gpio14>;
> > +	status = "okay";
> > +};
> > diff --git a/arch/arm/boot/dts/bcm2835-rpi-cm1.dtsi b/arch/arm/boot/dts/bcm2835-rpi-cm1.dtsi
> > new file mode 100644
> > index 0000000..ef22c2d
> > --- /dev/null
> > +++ b/arch/arm/boot/dts/bcm2835-rpi-cm1.dtsi
> > @@ -0,0 +1,34 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/dts-v1/;
> > +#include "bcm2835.dtsi"
> > +#include "bcm2835-rpi.dtsi"
> > +
> > +/ {
> > +	leds {
> > +		act {
> > +			gpios = <&gpio 47 GPIO_ACTIVE_LOW>;
> > +		};
> > +	};
> > +
> > +	reg_3v3: fixed-regulator {
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "3V3";
> > +		regulator-min-microvolt = <3300000>;
> > +		regulator-max-microvolt = <3300000>;
> > +		regulator-always-on;
> > +	};
> > +
> > +	reg_1v8: fixed-regulator {
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "1V8";
> > +		regulator-min-microvolt = <1800000>;
> > +		regulator-max-microvolt = <1800000>;
> > +		regulator-always-on;
> > +	};
> > +};
> > +
> > +&sdhost {
> > +	non-removable;
> > +	vmmc-supply = <&reg_3v3>;
> > +	vqmmc-supply = <&reg_1v8>;
> > +};
> 
> Also, looking at some datasheets I have laying around, it says "eMMC I/O
> Voltage fixed at 1V8" -- is this regulator setup right, in that case?

Usually an eMMC has 2 different voltage sources:
vqmmc-supply -> supply node for IO line power (usually switchable, but fixed on Compute Module)
vmmc-supply -> supply node for card's power (usually fixed)

Do you have a specific concern (voltage, naming)?

Does this conversation help [1]?

Please also look at the CM schematics page 1 and 3.

[1] - https://www.raspberrypi.org/forums/viewtopic.php?f=107&t=213772

> 
> With answers for these two issues, it will be:
> 
> Reviewed-by: Eric Anholt <eric@anholt.net>
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