SPI slave configuration & overlay

[Ubaid_M]

Hi,

I am using BL653 dvk to write an application for SPI,

In my prj.conf, I added below parameters:

CONFIG_SPI=y
CONFIG_SPI_ASYNC=y

Now when I am debugging SPI master code, execution enters the file "spi_nrfx_spi.c", and transfers data & rest is fine.

But when I try to use SPI slave configuration, execution enters the same file "spi_nrfx_spi.c", into the function:

static inline nrf_spi_bit_order_t get_nrf_spi_bit_order(uint16_t operation)
{
	if (operation & SPI_TRANSFER_LSB) {
		return NRF_SPI_BIT_ORDER_LSB_FIRST;
	} else {
		return NRF_SPI_BIT_ORDER_MSB_FIRST;
	}
}

static int configure(const struct device *dev,
		     const struct spi_config *spi_cfg)
{
	struct spi_nrfx_data *dev_data = get_dev_data(dev);
	const struct spi_nrfx_config *dev_config = get_dev_config(dev);
	struct spi_context *ctx = &dev_data->ctx;
	nrfx_spi_config_t config;
	nrfx_err_t result;

	if (dev_data->initialized && spi_context_configured(ctx, spi_cfg)) {
		/* Already configured. No need to do it again. */
		return 0;
	}

	if (SPI_OP_MODE_GET(spi_cfg->operation) != SPI_OP_MODE_MASTER) {
		LOG_ERR("Slave mode is not supported on %s", dev->name);
		return -EINVAL;
	}

& logs an error saying "Slave mode is not supported on".

I understand that I need to make changes to prj.conf &  also write an overlay file for bl653.

1. But I do not know how to write overlay for this case, I am using SPI_1 and wrote an overlay as:

&spi1 {
	compatible = "nordic,nrf-spis";
	status = "okay";
	sck-pin = <41>;
	mosi-pin = <40>;
	miso-pin = <4>;
	cs-gpios = <&gpio1 23 0>;
};

But is still not working,

2. Kindly also help me on what changes to be done in prj.conf to have SPI_0 in slave mode.



Thanks,

[Sigurd]

Hi,

Did you set this?

CONFIG_SPI_SLAVE=y

and 

.slave = 1 in spi_config ? Snippet:

static const struct spi_config spi_cfg = {
	.operation = SPI_WORD_SET(8) | SPI_TRANSFER_MSB | SPI_OP_MODE_SLAVE |
		     SPI_MODE_CPOL | SPI_MODE_CPHA,
	.frequency = 4000000,
	.slave = 1,
};

Some sample code: https://github.com/sigurdnev/ncs-playground/blob/master/samples/spis_thread_test/src/main.c

[Ubaid_M]

Hello Sigurd,

Sigurd said:

.slave = 1 in spi_config ?

.slave =1 i have set.

Yet it execution is entering to  the same file "spi_nrfx_spi.c":

Ubaid_M said:

xecution enters the same file "spi_nrfx_spi.c

I also noticed that, maybe something is wrong with my overlay, my overlay name is "bl653_dvk.overlay" & it is placed in project directory with the configuration as:

&spi1 {
	compatible = "nordic,nrf-spis";
	status = "okay";
	sck-pin = <41>;
	mosi-pin = <40>;
	miso-pin = <4>;
};

1. I am saying this as I do not see overlay being included, in project dts structure as in below, is the name "bl653_dvk.overlay" proper..?

2. In "prj.conf", I have the following configurations, do I need to add anything more..?

#SPI
CONFIG_SPI=y
CONFIG_SPI_ASYNC=y
CONFIG_SPI_SLAVE=y

Kindly suggest where I am mistaken.

Attaching the bl653_dvk.dts & bl653_dvk.overlay for your reference.bl653_dvk.dts

bl653_dvk.overlay

Thanks,

Ubaid

[Ubaid_M]

Also, I am wondering about including overlay in CMakeLists.txt, Do i need to add "DTC_OVERLAY_FILE"..?
Because whenever I am trying to include overlay file, I am getting boiler plate error,

[Ubaid_M]

Please find build errors when i include overlay file:

[0/1] Re-running CMake...
Including boilerplate (Zephyr base (cached)): D:/Nordic_Sample_App/Nordic_SDK/v1.8.0/zephyr/cmake/app/boilerplate.cmake
-- Application: D:/PXZ_Sample_App
-- Zephyr version: 2.7.0 (D:/Nordic_Sample_App/Nordic_SDK/v1.8.0/zephyr), build: v2.7.0-ncs1
-- Found west (found suitable version "0.12.0", minimum required is "0.7.1")
-- Board: bl653_dvk
-- Cache files will be written to: D:/Nordic_Sample_App/Nordic_SDK/v1.8.0/zephyr/.cache
-- Found dtc: D:/Nordic_Sample_App/Nordic_SDK/v1.8.0/toolchain/opt/bin/dtc.exe (found suitable version "1.4.7", minimum required is "1.4.6")
-- Found toolchain: gnuarmemb (d:/Nordic_Sample_App/Nordic_SDK/v1.8.0/toolchain/opt)
-- Found BOARD.dts: D:/Nordic_Sample_App/Nordic_SDK/v1.8.0/zephyr/boards/arm/bl653_dvk/bl653_dvk.dts
-- Found devicetree overlay: D:/PXZ_Sample_App/bl653_dvk.overlay
devicetree error: 'def-char' is marked as required in 'properties:' in D:/Nordic_Sample_App/Nordic_SDK/v1.8.0/zephyr/dts/bindings\spi\nordic,nrf-spis.yaml, but does not appear in <Node /soc/spi@40004000 in 'bl653_dvk.dts.pre.tmp'>
CMake Error at D:\Nordic_Sample_App\Nordic_SDK\v1.8.0\zephyr\cmake\dts.cmake:251 (message):
  gen_defines.py failed with return code: 1
Call Stack (most recent call first):
  D:\Nordic_Sample_App\Nordic_SDK\v1.8.0\zephyr\cmake\app\boilerplate.cmake:545 (include)
  D:\Nordic_Sample_App\Nordic_SDK\v1.8.0\zephyr\share\zephyr-package\cmake\ZephyrConfig.cmake:24 (include)
  D:\Nordic_Sample_App\Nordic_SDK\v1.8.0\zephyr\share\zephyr-package\cmake\ZephyrConfig.cmake:40 (include_boilerplate)
  d:\PXZ_Sample_App\build\CMakeLists.txt:4 (find_package)

[Ubaid_M]

Hi Sigurd,

Sorry for the chain of updates, I was able to solve it,
Now execution is entering the slave driver file "spi_nrfx_spis.c"

I had to define extra properties in spi1 node in bl653_dvk.dts as:

&spi1 {
	compatible = "nordic,nrf-spis";
	status = "okay";
	sck-pin = <41>;
	mosi-pin = <40>;
	miso-pin = <4>;
	cs-gpios = <&gpio1 23 0>;
	csn-pin = <23>; #extra property defined
	def-char = <0xFF>;#extra property defined
};

Now Please help me with

1. what do csn-pin & def-char attributes do..?
2. I need to define slave chip select on gpio0, pin:23.,

    csn-pin = <23>;

    def-char = <0xFF>;

so is my definition right..?

[Sigurd]

Ubaid_M said:

1. what do csn-pin & def-char attributes do..?

Here is the documentation for these attributes:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.8.0/zephyr/reference/devicetree/bindings/spi/nordic,nrf-spis.html

https://github.com/nrfconnect/sdk-zephyr/blob/v2.7.0-ncs1/dts/bindings/spi/nordic,nrf-spis.yaml

Ubaid_M said:

so is my definition right..?

Looks correct

[Ubaid_M]

Hello Sigurd,

Thanks for the kind help,

Now the code execution is on track on bl653 running spi slave driver.

But the spi_read always returns -116, that is  -ETIMEDOUT.

But I do not understand why slave driver always returns -ETIMEDOUT. Master board is sending data, i checked on USB logic analyzer for the same.

I traced the flow of execution all the way to the source of the error and here is what I found

spi_read( ) -> transceive (in file "spi_nrfx_spis.c") -> spi_context_wait_for_completion( in file "spi_context.h") -> and the source of error is as attached in the below snap in #else part

Without debug mode as well I am getting the same -ETIMEDOUT.

Kindly suggest on if I have missed out on configuring something.

adding my overlay file details for your reference:

&spi1 {
	compatible = "nordic,nrf-spis";
	status = "okay";
	sck-pin = <41>;
	mosi-pin = <40>;
	miso-pin = <4>;
	cs-gpios = <&gpio1 23 0>;
	csn-pin = <23>;
	def-char = <0xFF>;
};

Kindly suggest

[Sigurd]

This new issue will be handled in this new case: https://devzone.nordicsemi.com/f/nordic-q-a/83583/spi-slave-always-returns--etimedout

Closing this case.