display: blank display on st25dv

[everedero]

Describe the bug

The display sample shows a blank screen instead of the 4-squares thing.

• Board: st25dv_mb1283_disco
• Tested with samples/drivers/display

Git bisect says it comes from commit 011a357 (drivers: mipi-dbi-spi: fix initialization of SPI CS).

Regression

• This is a regression.

Steps to reproduce

west build -b st25dv_mb1283_disco -p always drivers/display/

Impact

Functional Limitation – Some features not working as expected, but system usable.

Environment

• Linux Mint
• Zephyr main

Additional Context

If someone else has the same target:

• For some reason this target has to be power cycled to work correctly, reset button only does not work
• Also this board can only be flashed if reset button is released 2 seconds after "west flash", as per an old ST-Link tradition

[JarmouniA]

Must be the same reason behind #97746

[JarmouniA]

Cc @jeremydick

[NickIOT72]

I did 2 tests using the samples/drivers/display with a nucleo-f44re boards and a TFT with a st7789v driver. On the file zephyr/driver/display/display_st7789v.c I added a LOG_INF in order to print the SPI configuration. Here's what I got:

First test
Zephyr version: 4.2.0
SDK: zephyr-sdk-0.17.4

[00:00:00.067,000] <inf> display_st7789v: spi_cfg-->freq:20000000, operation:256, slave:0
[00:00:00.067,000] <inf> display_st7789v: spi_cs_control-->pin:12, port:gpio@40020400
*** Booting Zephyr OS build v4.2.0 ***
[00:00:00.188,000] <inf> sample: Display sample for st7789v_tft@0
[00:00:00.693,000] <inf> sample: Display starts

Second test
Zephyr version: 4.2.99 (with commit 011a357)
SDK: zephyr-sdk-0.17.4

[00:00:00.067,000] <inf> display_st7789v: spi_cfg-->freq:20000000, operation:256, slave:0

[00:00:00.067,000] <inf> display_st7789v: spi_cs_control-->pin:0, port: 

*** Booting Zephyr OS build v4.2.0-6166-g8a72d776c5af ***
[00:00:00.188,000] <inf> sample: Display sample for st7789v_tft@0
[00:00:00.690,000] <inf> sample: Display starts

This what I used for the test.

Devicetree created: samples/drivers/display/boards/nucleo_f446re.overlay

#include <zephyr/dt-bindings/mipi_dbi/mipi_dbi.h>

/ {

	chosen {
		zephyr,display = &st7789v_tft;
	};
	
    mipi_dbi {
		compatible = "zephyr,mipi-dbi-spi";
		spi-dev = <&spi2>;
		reset-gpios = <&gpioc 1 GPIO_ACTIVE_HIGH>;
		dc-gpios = <&gpioc 0 GPIO_ACTIVE_HIGH>;
		write-only;
		#address-cells = <1>;
		#size-cells = <0>;

		st7789v_tft: st7789v_tft@0 {
			compatible = "sitronix,st7789v";
			status = "okay";

			mipi-max-frequency = <DT_FREQ_M(20)>;
			reg = <0>;
			width = <320>;
			height = <175>;
			x-offset = <0>;
			y-offset = <32>;
			vcom = <0x19>;
			gctrl = <0x35>;
			vrhs = <0x12>;
			vdvs = <0x20>;
			mdac = <0xA0>;
			gamma = <0x01>;
			colmod = <0x55>;
			lcm = <0x2c>;
			porch-param = [0c 0c 00 33 33];
			cmd2en-param = [5a 69 02 01];
			pwctrl1-param = [a4 a1];
			pvgam-param = [D0 04 0D 11 13 2B 3F 54 4C 18 0D 0B 1F 23];
			nvgam-param = [D0 04 0C 11 13 2C 3F 44 51 2F 1F 1F 20 23];
			ram-param = [00 F0];
			rgb-param = [CD 08 14];
			mipi-mode = "MIPI_DBI_MODE_SPI_4WIRE";
		};
	};
	
};

&spi2 { /* Max 20 Mbit/s */
	#address-cells = <1>;
	#size-cells = <0>;
	pinctrl-0 = <&spi2_mosi_pc3 &spi2_sck_pb13>;
	cs-gpios = <&gpiob 12 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
	pinctrl-names = "default";
	status = "okay";
};

CS initialization issue is also occurring with nucleo_f446re

[jeremydick]

Can you confirm if #98086 fixes this?