[nRF52840] SPI data control pin definition (.dts)

[AnomalySmith]

Hi,

I'm porting my SSD1333 (Solomon IC for OLED displays) code driver to Zephyr OS drivers for ease of use along with LVGL (going from `<nrfx_spim.h>` to `<drivers/spi.h>`).

Actually, I want to know if there is way of defining custom bindings so I can define a Data Control pin into SPI device tree definition that I can retrieve from the driver code ?

Here is the current progress:

.dts file of project that wish to use this driver

&spi3 {
  status = "okay";
  device_type = "spi";
  compatible = "nordic,nrf-spim";
  sck-pin = < 5 >;
  mosi-pin = < 32 >;
  data-ctrl-pin = <&gpio0 30 GPIO_ACTIVE_LOW>;
  clock-frequency = <8000000>;
  cs-pin = < &gpio1 8 GPIO_ACTIVE_LOW >;
  reset-pin = < &gpio0 28 GPIO_ACTIVE_LOW >;

  ssd1333: ssd1333@0 {
      compatible = "solomon,ssd1333";
      status = "okay";
      reg = < 0x0 >;
      label = "OLED_DISPLAY";
      spi-max-frequency = < 0x16e3600 >;
      width = <160>;
      height = <128>;
  };
};

ssd1333.c driver definition - extraction of dts configuration :

#define DT_DRV_COMPAT solomon_ssd1333

// [Driver display's API methods definition]

static const struct ssd1333_config ssd1333_config = {
#if DT_INST_ON_BUS(0, i2c)
  .bus = I2C_DT_SPEC_INST_GET(0),
#elif DT_INST_ON_BUS(3, spi)
  .bus = SPI_DT_SPEC_INST_GET(
    3, SPI_OP_MODE_MASTER | SPI_TRANSFER_MSB | SPI_WORD_SET(8), 0),
  .dc_gpio = GPIO_DT_SPEC_INST_GET(0, data_ctrl_pin),
  .mosi_gpio = GPIO_DT_SPEC_INST_GET_OR(0, mosi_pin, { 0 })
  .sck_gpio = GPIO_DT_SPEC_INST_GET_OR(0, sck_pin, { 0 })
  .cs_gpio = GPIO_DT_SPEC_INST_GET_OR(0, cs_pin, { 0 })
#endif
  .reset_gpio = GPIO_DT_SPEC_INST_GET_OR(0, reset_pin, { 0 })
};

For now, the following error comes up:

devicetree error: 'data-ctrl-pin' appears in /soc/spi@4002f000 in /Users/x/developpement/Quantum/build/zephyr/zephyr.dts.pre, but is not declared in 'properties:' in /opt/nordic/ncs/v2.0.2/zephyr/dts/bindings/spi/nordic,nrf-spim.yaml
CMake Error at /opt/nordic/ncs/v2.0.2/zephyr/cmake/modules/dts.cmake:213 (message):
  gen_defines.py failed with return code: 1

Also, if I use this spi3 on nRF52840 that way, will I be able to set the max 32MHz clock over SPI (and Easy DMA but I think not)?

Finally, if you have tips or you think I'm going on the wrong way, let me know !

Thanks for your time.

FYI, I'm following the ssd1306 sample from nordic/ncs/v2.0.2/zephyr/drivers/display

[AnomalySmith]

Thanks, applying this logic makes more sense :)

But now, just another error comes up about the custom properties :

In file included from /opt/nordic/ncs/v2.0.2/zephyr/include/zephyr/arch/arm/aarch32/arch.h:20,
                 from /opt/nordic/ncs/v2.0.2/zephyr/include/zephyr/arch/cpu.h:19,
                 from /opt/nordic/ncs/v2.0.2/zephyr/include/zephyr/kernel_includes.h:33,
                 from /opt/nordic/ncs/v2.0.2/zephyr/include/zephyr/kernel.h:17,
                 from /opt/nordic/ncs/v2.0.2/zephyr/include/zephyr/init.h:11,
                 from /opt/nordic/ncs/v2.0.2/zephyr/include/zephyr/device.h:29,
                 from /opt/nordic/ncs/v2.0.2/zephyr/drivers/display/ssd1333.c:13:
/opt/nordic/ncs/v2.0.2/zephyr/drivers/display/ssd1333.c: In function 'ssd1333_get_capabilities':
/opt/nordic/ncs/v2.0.2/zephyr/include/zephyr/devicetree.h:305:40: error: 'DT_N_INST_3_solomon_ssd1333_P_width' undeclared (first use in this function)
  305 | #define DT_INST(inst, compat) UTIL_CAT(DT_N_INST, DT_DASH(inst, compat))
      | 

On the related driver's function : 

static void ssd1333_get_capabilities(const struct device *dev, struct display_capabilities *caps) {
  memset(caps, 0, sizeof(struct display_capabilities));
  caps->x_resolution = DT_INST_PROP(3, width);
  caps->y_resolution = DT_INST_PROP(3, height);
  caps->supported_pixel_formats = PIXEL_FORMAT_RGB_565;
  caps->current_pixel_format = PIXEL_FORMAT_RGB_565;
  caps->screen_info = 0;
  caps->current_orientation = DISPLAY_ORIENTATION_NORMAL;
}

I'm trying to see any difference between the ssd1306 sample but still can't find any :/

Do you have an idea ? Where should I also define those ? 

EDIT: I've changed slightly the driver file to align with the ssd16xx one and the error is gone for now :

caps->x_resolution = config->width; // instead of DT_INST_PROP(0, width);...
caps->y_resolution = config->height;

Still others error but will go into it and let you know the final outcome

[Håkon Alseth]

Have you checked that "width" and "height" is described in your ssd1333-common.yaml file?

Can you share your build-folder/zephyr/zephyr.dts file?

 

Kind regards,

Håkon

[AnomalySmith]

Sure, I've got an overlay file that describes:

/*
* nRF52840_dk      SSD1333 (160x128)
* 
* P0.28 (RESET)   RES
* P0.30 (D5)      DC (DATA/CMD)
* P0.5 (SCK)      SCL
* P1.0 (MOSI)     SDA
* P1.08 (CS)      SDA
*/

/ {
  chosen {
    zephyr,display = &ssd1333;
  };
};

&pinctrl {
 spi3_default: spi3_default {
   group1 {
     psels = <NRF_PSEL(SPIM_SCK, 0, 5)>,
       <NRF_PSEL(SPIM_MOSI, 0, 32)>,
       <NRF_PSEL(SPIM_MISO, 0, 31)>;
   };
 };

 spi3_sleep: spi3_sleep {
   group1 {
     psels = <NRF_PSEL(SPIM_SCK, 0, 5)>,
       <NRF_PSEL(SPIM_MOSI, 0, 32)>,
       <NRF_PSEL(SPIM_MISO, 0, 31)>;
     low-power-enable;
   };
 };
};

&spi3 {
  compatible = "nordic,nrf-spim";
  status = "okay";
  pinctrl-0 = <&spi3_default>;
  pinctrl-1 = <&spi3_sleep>;
  cs-gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
  pinctrl-names = "default", "sleep";

  ssd1333: ssd1333@0 {
    compatible = "solomon,ssd1333";
    label = "SSD1333";
    spi-max-frequency = <20000000>;
    reg = <0>;
    cmd-data-pin = <&gpio0 30 GPIO_ACTIVE_LOW>;
    reset-pin = < &gpio0 28 GPIO_ACTIVE_LOW >;
    width = <160>;
    height = <128>;
    x-offset = <0>;
    y-offset = <0>;
    vcom = <0x19>;
    gctrl = <0x35>;
  };
};

Otherwise, I don't have any ssd1333-common.yaml file (as I don't see any on displays drivers and samples)

[Håkon Alseth]

Hi,

 

It is hard to test on my end, as you're developing your own driver, and I do not have the build artifacts to look at.

What you can try is to rather address the variable like this and see if this helps?

DT_PROP(DT_NODELABEL(ssd1333), width)

 

Kind regards,

Håkon