[PATCH v2] dt-bindings: display: atmel,lcdc: convert to dtschema

Dharma Balasubiramani
2024-03-04T05:37:13Z

Convert the atmel,lcdc bindings to DT schema.
Changes during conversion: add missing clocks and clock-names properties.

Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
---
This patch converts the existing lcdc display text binding to JSON schema.
The binding is split into two namely
lcdc.yaml
- Holds the frame buffer properties
lcdc-display.yaml
- Holds the display panel properties which is a phandle to the display
property in lcdc fb node.

These bindings are tested against the existing at91 dts files using
dtbs_check.
---
Changes in v2:
- Run checkpatch and remove whitespace errors.
- Add the standard interrupt flags.
- Split the binding into two, namely lcdc.yaml and lcdc-display.yaml.
- Link to v1: https://lore.kernel.org/r/20240223-lcdc-fb-v1-1-4c64cb6277df@microchip.com
---
.../bindings/display/atmel,lcdc-display.yaml | 98 ++++++++++++++++++++++
.../devicetree/bindings/display/atmel,lcdc.txt | 87 -------------------
.../devicetree/bindings/display/atmel,lcdc.yaml | 70 ++++++++++++++++
3 files changed, 168 insertions(+), 87 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/atmel,lcdc-display.yaml b/Documentation/devicetree/bindings/display/atmel,lcdc-display.yaml
new file mode 100644
index 000000000000..ea4fd34b9e2c
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/atmel,lcdc-display.yaml
@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/atmel,lcdc-display.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip's LCDC Display
+
+maintainers:
+ - Nicolas Ferre <nicolas.ferre@microchip.com>
+ - Dharma Balasubiramani <dharma.b@microchip.com>
+
+description:
+ The LCD Controller (LCDC) consists of logic for transferring LCD image data
+ from an external display buffer to a TFT LCD panel. The LCDC has one display
+ input buffer per layer that fetches pixels through the single bus host
+ interface and a look-up table to allow palletized display configurations. The
+ LCDC is programmable on a per layer basis, and supports different LCD
+ resolutions, window sizes, image formats and pixel depths.
+
+# We need a select here since this schema is applicable only for nodes with the
+# following properties
+
+select:
+ anyOf:
+ - required: [ 'atmel,dmacon' ]
+ - required: [ 'atmel,lcdcon2' ]
+ - required: [ 'atmel,guard-time' ]
+ - required: [ bits-per-pixel ]
+
+properties:
+ atmel,dmacon:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: dma controller configuration
+
+ atmel,lcdcon2:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: lcd controller configuration
+
+ atmel,guard-time:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: lcd guard time (Delay in frame periods)
+
+ bits-per-pixel:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: lcd panel bit-depth.
+
+ atmel,lcdcon-backlight:
+ $ref: /schemas/types.yaml#/definitions/flag
+ description: enable backlight
+
+ atmel,lcdcon-backlight-inverted:
+ $ref: /schemas/types.yaml#/definitions/flag
+ description: invert backlight PWM polarity
+
+ atmel,lcd-wiring-mode:
+ $ref: /schemas/types.yaml#/definitions/non-unique-string-array
+ description: lcd wiring mode "RGB" or "BRG"
+
+ atmel,power-control-gpio:
+ description: gpio to power on or off the LCD (as many as needed)
+
+ display-timings:
+ $ref: panel/display-timings.yaml#
+
+required:
+ - atmel,dmacon
+ - atmel,lcdcon2
+ - atmel,guard-time
+ - bits-per-pixel
+
+additionalProperties: false
+
+examples:
+ - |
+ display: panel {
+ bits-per-pixel = <32>;
+ atmel,lcdcon-backlight;
+ atmel,dmacon = <0x1>;
+ atmel,lcdcon2 = <0x80008002>;
+ atmel,guard-time = <9>;
+ atmel,lcd-wiring-mode = <1>;
+
+ display-timings {
+ native-mode = <&timing0>;
+ timing0: timing0 {
+ clock-frequency = <9000000>;
+ hactive = <480>;
+ vactive = <272>;
+ hback-porch = <1>;
+ hfront-porch = <1>;
+ vback-porch = <40>;
+ vfront-porch = <1>;
+ hsync-len = <45>;
+ vsync-len = <1>;
+ };
+ };
+ };
diff --git a/Documentation/devicetree/bindings/display/atmel,lcdc.txt b/Documentation/devicetree/bindings/display/atmel,lcdc.txt
deleted file mode 100644
index b5e355ada2fa..000000000000
--- a/Documentation/devicetree/bindings/display/atmel,lcdc.txt
+++ /dev/null
@@ -1,87 +0,0 @@
-Atmel LCDC Framebuffer
------------------------------------------------------
-
-Required properties:
-- compatible :
- "atmel,at91sam9261-lcdc" ,
- "atmel,at91sam9263-lcdc" ,
- "atmel,at91sam9g10-lcdc" ,
- "atmel,at91sam9g45-lcdc" ,
- "atmel,at91sam9g45es-lcdc" ,
- "atmel,at91sam9rl-lcdc" ,
-- reg : Should contain 1 register ranges(address and length).
- Can contain an additional register range(address and length)
- for fixed framebuffer memory. Useful for dedicated memories.
-- interrupts : framebuffer controller interrupt
-- display: a phandle pointing to the display node
-
-Required nodes:
-- display: a display node is required to initialize the lcd panel
- This should be in the board dts.
-- default-mode: a videomode within the display with timing parameters
- as specified below.
-
-Optional properties:
-- lcd-supply: Regulator for LCD supply voltage.
-
-Example:
-
- fb0: fb@00500000 {
- compatible = "atmel,at91sam9g45-lcdc";
- reg = <0x00500000 0x1000>;
- interrupts = <23 3 0>;
- pinctrl-names = "default";
- pinctrl-0 = <&pinctrl_fb>;
- display = <&display0>;
- #address-cells = <1>;
- #size-cells = <1>;
-
- };
-
-Example for fixed framebuffer memory:
-
- fb0: fb@00500000 {
- compatible = "atmel,at91sam9263-lcdc";
- reg = <0x00700000 0x1000 0x70000000 0x200000>;
- [...]
- };
-
-Atmel LCDC Display
------------------------------------------------------
-Required properties (as per of_videomode_helper):
-
- - atmel,dmacon: dma controller configuration
- - atmel,lcdcon2: lcd controller configuration
- - atmel,guard-time: lcd guard time (Delay in frame periods)
- - bits-per-pixel: lcd panel bit-depth.
-
-Optional properties (as per of_videomode_helper):
- - atmel,lcdcon-backlight: enable backlight
- - atmel,lcdcon-backlight-inverted: invert backlight PWM polarity
- - atmel,lcd-wiring-mode: lcd wiring mode "RGB" or "BRG"
- - atmel,power-control-gpio: gpio to power on or off the LCD (as many as needed)
-
-Example:
- display0: display {
- bits-per-pixel = <32>;
- atmel,lcdcon-backlight;
- atmel,dmacon = <0x1>;
- atmel,lcdcon2 = <0x80008002>;
- atmel,guard-time = <9>;
- atmel,lcd-wiring-mode = <1>;
-
- display-timings {
- native-mode = <&timing0>;
- timing0: timing0 {
- clock-frequency = <9000000>;
- hactive = <480>;
- vactive = <272>;
- hback-porch = <1>;
- hfront-porch = <1>;
- vback-porch = <40>;
- vfront-porch = <1>;
- hsync-len = <45>;
- vsync-len = <1>;
- };
- };
- };
diff --git a/Documentation/devicetree/bindings/display/atmel,lcdc.yaml b/Documentation/devicetree/bindings/display/atmel,lcdc.yaml
new file mode 100644
index 000000000000..1b6f7e395006
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/atmel,lcdc.yaml
@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/atmel,lcdc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip's LCDC Framebuffer
+
+maintainers:
+ - Nicolas Ferre <nicolas.ferre@microchip.com>
+ - Dharma Balasubiramani <dharma.b@microchip.com>
+
+description:
+ The LCDC works with a framebuffer, which is a section of memory that contains
+ a complete frame of data representing pixel values for the display. The LCDC
+ reads the pixel data from the framebuffer and sends it to the LCD panel to
+ render the image.
+
+properties:
+ compatible:
+ enum:
+ - atmel,at91sam9261-lcdc
+ - atmel,at91sam9263-lcdc
+ - atmel,at91sam9g10-lcdc
+ - atmel,at91sam9g45-lcdc
+ - atmel,at91sam9g45es-lcdc
+ - atmel,at91sam9rl-lcdc
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ clocks:
+ maxItems: 2
+
+ clock-names:
+ items:
+ - const: hclk
+ - const: lcdc_clk
+
+ display:
+ $ref: /schemas/types.yaml#/definitions/phandle
+ description: A phandle pointing to the display node.
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - clocks
+ - clock-names
+ - display
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/clock/at91.h>
+ #include <dt-bindings/interrupt-controller/irq.h>
+ fb@500000 {
+ compatible = "atmel,at91sam9g45-lcdc";
+ reg = <0x00500000 0x1000>;
+ interrupts = <23 IRQ_TYPE_LEVEL_HIGH 0>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_fb>;
+ clocks = <&pmc PMC_TYPE_PERIPHERAL 23>, <&pmc PMC_TYPE_PERIPHERAL 23>;
+ clock-names = "hclk", "lcdc_clk";
+ display = <&display>;
+ };

---
base-commit: 90d35da658da8cff0d4ecbb5113f5fac9d00eb72
change-id: 20240223-lcdc-fb-b8d2e2f3c914

Best regards,
--
Dharma Balasubiramani <dharma.b@microchip.com>