spi_write() is not working in lpc5536

[aravinth-kalai]

Hello everyone,

I configured board file for SPI functionality , I'm getting device ready, but if I try to write something , it's showing write successful but I'm not getting any data from that MOSI pin , the logic analyzer shows some square pulses in both MOSI and CLK pins, I'm sharing my configuration please help me to fix this issue.

Microcontroller : LPC5536
zephyr version : 3.2.0

.dts file

#include <nxp/nxp_lpc55S36_ns.dtsi>
#include <nxp/lpc/LPC55S36JBD100-pinctrl.h>

display_logic {
		compatible = "display_logic";
		display = <&display1>;
	};
&flexcomm6 {
    compatible = "nxp,lpc-spi";
    status = "okay";
    #address-cells = <1>;
    #size-cells = <0>;
    pinctrl-0 = <&pinmux_flexcomm6_spi>;
    pinctrl-names = "default";

    display1: oled@0 {
        compatible = "screen,oled";
        reg = <0>;
        spi-max-frequency = <8000000>;
        height = <64>;
        width = <256>;
    };
};

&pinctrl {
	pinmux_flexcomm6_spi: pinmux_flexcomm6_spi {
		group0 {
			pinmux = <FC6_RXD_SDA_MOSI_DATA_PIO0_29>,
				 <FC6_SCK_PIO1_12>;
			bias-pull-up;
			slew-rate = "standard";
		};
};

oled.c

#include <zephyr/drivers/spi.h>
#include <zephyr/sys/util.h>
#include <zephyr/kernel.h>

#include <zephyr/drivers/display.h>
#include <zephyr/drivers/gpio.h>

#include <zephyr/logging/log.h>

#define DT_DRV_COMPAT screen_oled

struct oled_data {
    uint8_t buffer[DISPLAY_BUFFER_SIZE];
    uint8_t page_buffer[DISPLAY_WIDTH + 1];
};


struct oled_config {
	struct spi_dt_spec spi;
	uint16_t width;
	uint16_t height;
};

static int oled_send_command(const struct device *dev, uint8_t command)
{
    static const struct spi_config spi_cfg = {
        .operation = SPI_WORD_SET(8) | SPI_OP_MODE_MASTER,
        .frequency = 8000000,
        .slave = 0,
        .cs = 0
    };
    int status = 1;
    uint8_t buff = command;
    int len = 1;

   struct spi_buf tx_buf = { .buf = &buff, .len = len };

   struct spi_buf_set tx_bufs = { .buffers = &tx_buf, .count = 1 };

   status = spi_write(dev,&spi_cfg, &tx_bufs);

    if (status) {
        printk("send command failed: %i\n", status);
    } else {
        printk("sent command: %02x\n", command);
    }
    return status;
}


static int oled_init(const struct device *dev)
{
   const struct oled_config *config = dev->config;
   int status;
    if (!spi_is_ready(&config->spi)) {
        printk(" SPI device is not ready!");
		return -ENODEV;
	}
    else
    {
            printk(" SPI device is ready \n");
    }
   status = n096pw_send_command(dev, 0XAA);
   if (status) {
        return status;
    }
}

static const struct display_driver_api oled_display_api = {
        .blanking_on = oled_blanking_on,
        .blanking_off = oled_blanking_off,
        .write = oled_write,
        .read = oled_read,
        .get_framebuffer = oled_get_framebuffer,
        .set_brightness = oled_set_brightness,
        .set_contrast = oled_set_contrast,
        .get_capabilities = oled_get_capabilities,
        .set_pixel_format = oled_set_pixel_format,
};


#define DEFINE_OLED(n)					\
	static struct oled_data data_##n;				\
	static struct oled_config config_##n = {			\
		.spi = SPI_DT_SPEC_GET(					\
				DT_DRV_INST(n),				\
				SPI_OP_MODE_MASTER | SPI_WORD_SET(8),	\
				0),					\
		.width = DT_PROP(DT_DRV_INST(n), width),		\
		.height = DT_PROP(DT_DRV_INST(n), height)		\
	};								\
	DEVICE_DT_INST_DEFINE(						\
		n, &oled_init, NULL, &data_##n, &config_##n,		\
		POST_KERNEL, CONFIG_OLED_INIT_PRIORITY,		\
		&oled_display_api);

DT_INST_FOREACH_STATUS_OKAY(DEFINE_OLED)

prj.config

I'm not sure about priority before setting the priority flag even I'm not getting device ready , after setting the flag only I got device ready

CONFIG_SPI=y
CONFIG_SPI_SLAVE=y
CONFIG_SPI_COMMUNICATION=y
CONFIG_SPI_INIT_PRIORITY=2

dts/bindings/screen,oled.yaml

description: oled display binding

include: [spi-device.yaml, display-controller.yaml]

compatible: "screen,oled"

dts/bindings/display_logic.yaml

description: Display logic module for oled

compatible: "display_logic"

properties:
  display:
    type: phandle
    required: true
    description: Display to use for drawing

or if I'm doing any configuration wrongly, help me to change the configuration ,

Thanks in advance !

[DerekSnell]

Hi @aravinth-kalai ,
Unfortunately, SPI is not yet supported on the LPCXpresso55S36 board. You can find the Supported Features for each board on the doc page, like this LPCXpresso55S36 table.

The good news is other similar boards have the same SPI peripheral supported, including the LPCXPRESSO55S69. This SPI support can be ported to the LPCXpresso55S36 board, but someone needs to do the port and test it. We typically test the SPI driver on a board using the spi_loopback test. And this test has overlay files for the LPCXPRESSO55S69 board, see the boards folder.

Something else that comes to mind when enabling a new peripheral on a board, the peripheral clock needs to be enabled. The soc.c has some code you can use as a reference for enabling Flexcomm clocks on the LPC55S36.

Best regards

[DerekSnell]

Hi @aravinth-kalai ,
As I stated, the SPI driver is not yet supported on the LPCXpresso55S36 board. You can review the LPCXpresso55S69 board, and run the SPI tests on that board, to see how the same SPI peripheral was enabled on that board.

Best regards

[aravinth-kalai]

Hi @DerekSnell ,

yes, I'm working on it, now I'm enabling the clock for flexcomm6, once if I finished I'll update, if I'm facing issue during the development I'll let you know , please help me to fix it.

Thanks in advance !