Re: [PATCH 1/2] arm64: dts: ti: Add overlay for OLDI-LCD1EVM Display and touch screen

[Andrew Davis <afd@ti.com>]

On 4/25/23 12:12 AM, Aradhya Bhatia wrote:
> From: Jyri Sarha <jsarha@ti.com>
> 
> The OLDI-LCD1EVM add on board has Rocktech RK101II01D-CT panel with
> integrated touch screen. The integrated touch screen is Goodix GT928.
> Add DT nodes for these and connect the endpoint nodes with DSS.
> 
> This patch was picked from TI's public tree based on 5.10 LTS kernel.
> 
> Signed-off-by: Jyri Sarha <jsarha@ti.com>
> Signed-off-by: Nikhil Devshatwar <nikhil.nd@ti.com>
> [abhatia1@ti.com: Make syntax changes to support 6.1 DTSO format]
> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
> ---
>   arch/arm64/boot/dts/ti/Makefile               |  2 +
>   .../dts/ti/k3-am654-evm-oldi-lcd1evm.dtso     | 70 +++++++++++++++++++
>   2 files changed, 72 insertions(+)
>   create mode 100644 arch/arm64/boot/dts/ti/k3-am654-evm-oldi-lcd1evm.dtso
> 
> diff --git a/arch/arm64/boot/dts/ti/Makefile b/arch/arm64/boot/dts/ti/Makefile
> index 6acd12409d59..8956b19e587a 100644
> --- a/arch/arm64/boot/dts/ti/Makefile
> +++ b/arch/arm64/boot/dts/ti/Makefile
> @@ -26,6 +26,7 @@ dtb-$(CONFIG_ARCH_K3) += k3-am6548-iot2050-advanced.dtb
>   dtb-$(CONFIG_ARCH_K3) += k3-am6548-iot2050-advanced-m2.dtb
>   dtb-$(CONFIG_ARCH_K3) += k3-am6548-iot2050-advanced-pg2.dtb
>   dtb-$(CONFIG_ARCH_K3) += k3-am654-base-board.dtb
> +dtb-$(CONFIG_ARCH_K3) += k3-am654-evm-oldi-lcd1evm.dtbo

This name is a bit odd, why "evm" twice? Looks like the first instance
is the redundant one as most of the documents on this LCD board call it
the "LCD1EVM". How about:

k3-am654-lcd1evm.dtbo

I would like the overlay names to give some hint to what base DTB they
apply to, or better yet, apply them here in the build which will check
that they apply cleanly. Plus you can drop the silly "+= -@" below.

Let's see how this should be called, from the AM65x GP EVM doc[0] we
get a nice picture on page 5 and the following:

"The AM65x GP EVM consists of a common processor board, an LCD adapter,
and a one-lane PCIe/USB3 personality card."

So, this would translate to:

k3-am654-gp-evm-dtbs := k3-am654-base-board.dtb k3-am654-lcd1evm.dtbo k3-am654-pcie-usb3.dtbo
dtb-$(CONFIG_ARCH_K3) += k3-am654-gp-evm.dtb

Next, from the AM65x IDK doc[1] also with a nice image on page 5:

"The AM65x IDK consists of a common processor board, IDK application board,
and a two-lane PCIe personality card.:

So:

k3-am654-idk-dtbs := k3-am654-base-board.dtb k3-am654-idk.dtbo k3-am654-pcie-usb2.dtbo
dtb-$(CONFIG_ARCH_K3) += k3-am654-idk.dtb

Note that we do have all those missing dtso files in our evil vendor tree[2]
and will be upstreaming them next, so this naming should all work out nicely.

Andrew

[0] https://www.ti.com/lit/ug/spruim7/spruim7.pdf
[1] https://www.ti.com/lit/ug/spruim6a/spruim6a.pdf
[2] https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti?h=ti-linux-5.10.y

>   
>   # Boards with J7200 SoC
>   dtb-$(CONFIG_ARCH_K3) += k3-j7200-common-proc-board.dtb
> @@ -45,3 +46,4 @@ dtb-$(CONFIG_ARCH_K3) += k3-j784s4-evm.dtb
>   
>   # Enable support for device-tree overlays
>   DTC_FLAGS_k3-am6548-iot2050-advanced-m2 += -@
> +DTC_FLAGS_k3-am654-base-board += -@
> diff --git a/arch/arm64/boot/dts/ti/k3-am654-evm-oldi-lcd1evm.dtso b/arch/arm64/boot/dts/ti/k3-am654-evm-oldi-lcd1evm.dtso
> new file mode 100644
> index 000000000000..b2c790b314cf
> --- /dev/null
> +++ b/arch/arm64/boot/dts/ti/k3-am654-evm-oldi-lcd1evm.dtso
> @@ -0,0 +1,70 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * OLDI-LCD1EVM Rocktech integrated panel and touch DT overlay for AM654-EVM.
> + *
> + * Copyright (C) 2023 Texas Instruments Incorporated - http://www.ti.com/
> + */
> +
> +/dts-v1/;
> +/plugin/;
> +
> +#include <dt-bindings/pwm/pwm.h>
> +#include <dt-bindings/gpio/gpio.h>
> +#include <dt-bindings/interrupt-controller/irq.h>
> +
> +&{/} {
> +	display0 {
> +		compatible = "rocktech,rk101ii01d-ct";
> +		backlight = <&lcd_bl>;
> +		enable-gpios = <&pca9555 8 GPIO_ACTIVE_HIGH>;
> +		port {
> +			lcd_in0: endpoint {
> +				remote-endpoint = <&oldi_out0>;
> +			};
> +		};
> +	};
> +
> +	lcd_bl: backlight {
> +		compatible = "pwm-backlight";
> +		pwms = <&ecap0 0 50000 PWM_POLARITY_INVERTED>;
> +		brightness-levels =
> +			<0 32 64 96 128 160 192 224 255>;
> +		default-brightness-level = <8>;
> +	};
> +};
> +
> +&dss {
> +	status = "okay";
> +};
> +
> +&dss_ports {
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	port@0 {
> +		reg = <0>;
> +
> +		oldi_out0: endpoint {
> +			remote-endpoint = <&lcd_in0>;
> +		};
> +	};
> +};
> +
> +&main_i2c1 {
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	gt928: touchscreen@14 {
> +		status = "okay";
> +		compatible = "goodix,gt928";
> +		reg = <0x14>;
> +
> +		interrupt-parent = <&pca9554>;
> +		interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
> +		touchscreen-size-x = <1280>;
> +		touchscreen-size-y = <800>;
> +
> +		reset-gpios = <&pca9555 9 GPIO_ACTIVE_HIGH>;
> +		irq-gpios = <&pca9554 3 GPIO_ACTIVE_HIGH>;
> +	};
> +};