Which macro to get sck, mosi and miso pin on spi master

RE: Which macro to get sck, mosi and miso pin on spi master

Simon — Thu, 30 Jun 2022 14:21:51 GMT

Hello Stéphane,

It seems like I was wrong in my first reply. The spi_nrfx_spim.c will not use the DT_PROP macros to get the sck, mosi and miso pins when pinctrl is enabled due to this check. Instead it will configure it through pin_ctrl_apply_state()-->pin_ctrl_apply_state_direct()-->pin_ctrl_configure_pins()

Please use the approach by Tristen instead: RE: Which macro to get sck, mosi and miso pin on spi master

I will get back to you if I find a better approach

Best regards,

simon

RE: Which macro to get sck, mosi and miso pin on spi master

ngbe — Wed, 29 Jun 2022 08:22:19 GMT

Hello Tristen,

Interesting, thank you for you experience sharing.

Stéphane

RE: Which macro to get sck, mosi and miso pin on spi master

Tristen — Tue, 28 Jun 2022 17:52:58 GMT

To answer your original question (for cases like mine where I use PINCTRL but also had to use the NRFX SPI driver for one of my SPI peripherals in order to utilize PPI), I did not find any DT macros that would just do this. Understanding the Device Tree, you can use a combination of other macros to access pin info. Here's an example:

dtsi file:

...

spi1_default: spi1_default {

group1 {

psels = <NRF_PSEL(SPIM_SCK, 1, 9)>,

<NRF_PSEL(SPIM_MOSI, 1, 8)>,

<NRF_PSEL(SPIM_MISO, 0, 4)>;

};

...

dts file:

...
&spi1 {
compatible = "nordic,nrf-spim"; status = "okay"; pinctrl-0 = <&spi1_default>;
pinctrl-1 = <&spi1_sleep>;
pinctrl-names = "default", "sleep"; cs-gpios = <&gpio0 31 GPIO_ACTIVE_LOW>; };
...

application:

#define SPI_NODE DT_NODELABEL(spi1)

#define SPI_PINCTRL_NODE DT_CHILD(DT_PINCTRL_0(SPI_NODE, 0), group1)

Then in your SPI Configuration structure, you can grab the property like this:

nrfx_spim_config_t xSpiConfig = {

.sck_pin = (uint8_t)DT_PROP_BY_IDX(SPI_PINCTRL_NODE, psels, 0) & 0x3F,

.mosi_pin = (uint8_t)DT_PROP_BY_IDX(SPI_PINCTRL_NODE, psels, 1) & 0x3F,

.miso_pin = (uint8_t)DT_PROP_BY_IDX(SPI_PINCTRL_NODE, psels, 2) & 0x3F,

.ss_pin = DT_GPIO_PIN_BY_IDX(SPI_NODE, cs_gpios, 0),
...

The psel property will return a 32-bit configuration (defined in nrf-pinctrl.h), but you just need the first 6 bits.

If anyone knows an easier way, please share.

RE: Which macro to get sck, mosi and miso pin on spi master

ngbe — Fri, 24 Jun 2022 08:10:35 GMT

Hello Simon,

Thank you for your reply,
I took your advice and it is all right with Zephyr API.

Note that I have to add following properties in "zephyr/dts/bindings/spi/nordic,nrf-spim.yaml"

   spi-max-frequency:
      type: int
      required: false
      default: 4000000
      description: Maximum clock frequency of device's SPI interface in Hz

    duplex:
      type: int
      default: 0
      required: false
      description: |
        Duplex mode, full or half. By default it's always full duplex thus 0
        as this is, by far, the most common mode.
        Use the macros not the actual enum value, here is the concordance
        list (see dt-bindings/spi/spi.h)
          0    SPI_FULL_DUPLEX
          2048 SPI_HALF_DUPLEX
      enum:
        - 0
        - 2048

    frame-format:
      type: int
      default: 0
      required: false
      description: |
        Motorola or TI frame format. By default it's always Motorola's,
        thus 0 as this is, by far, the most common format.
        Use the macros not the actual enum value, here is the concordance
        list (see dt-bindings/spi/spi.h)
          0     SPI_FRAME_FORMAT_MOTOROLA
          32768 SPI_FRAME_FORMAT_TI
      enum:
        - 0
        - 32768

WIthout that , SPI_CONFIG_DT fail .

struct spi_dt_spec	spi_rfid={ 
	.bus=DEVICE_DT_GET(SPI_RFID_NODE), 
	.config=SPI_CONFIG_DT(SPI_RFID_NODE,SPI_OP_MODE_MASTER | SPI_WORD_SET(8) | SPI_MODE_CPHA | SPI_MODE_CPOL,0),
};

Regards,

Stéphane

RE: Which macro to get sck, mosi and miso pin on spi master

Simon — Wed, 22 Jun 2022 16:53:22 GMT

Update 30.06.2022: Added strikethrough to an incorrect statement.

I would recommend you to use the Zephyr API. Then the information specified in DTS will automatically get picked up by the SPI drivers without you needing to do anything. It is also much less complicated to use.

However, you might have chosen to use the nrfx drivers for a specific reason, but I thought it would be nice to inform you in case you weren't aware.

To answer your question, you could take a look at the file spi_nrfx_spim.c to see how to get the pin number from the DTS pinctrl (use DT_PROP_OR or DT_PROP macros)

https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/drivers/spi/spi_nrfx_spim.c#L487-L488

https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/drivers/spi/spi_nrfx_spim.c#L511-L515

https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/drivers/spi/spi_nrfx_spim.c#L510

Best regards,

Simon