Use of Zephyr inbuilt APIs to Use External Flash with nRF9160

[AKO]

I am using MX25 external flash with nRF9160. I am unable to find the configuration to use the Zephyr APIs to access the flash. I am able to access it when I am using 

spi_write_dt funtion but for this I have to do some SPI configuration using the following structs

struct spi_config spi_cfg;

struct spi_cs_control cs_control;

My configuration for Flash in prj.conf

# SPI

CONFIG_SPI=y

CONFIG_SPI_NOR=y

# FLASH

CONFIG_FLASH=y

CONFIG_FLASH_MAP=y

Need some insight on how to use the zephyr-based APIs without doing any other configuration other than DT.

[Naeem Maroof]

Hi

You might want to look at Zephyr Flash sample that demonstrates the use of flash API:

Zephyr Flash Sample

[AKO]

I have checked this example but it didn't worked for me. When I was calling the flash_erase I was getting some wierd observation. 

This functions calls the following code:

static inline int z_impl_flash_erase(const struct device *dev, off_t offset,

                     size_t size)

{

    const struct flash_driver_api *api =

        (const struct flash_driver_api *)dev->api;

    int rc;

    rc = api->erase(dev, offset, size);

    return rc;

}

but here I see that no function is assigned to api->erase 

[AKO]

I am using the following to the flash device from DT:

#define SPI_FLASH DEVICE_DT_GET(DT_ALIAS(ext_flash))

The aliases where I have used ext_flash:

[AKO]

My Device Tree:

[Naeem Maroof]

what error you are getting now?

defining aliases for instances is fine.

you can do the debugging to see what is causing the issue.

[AKO]

. You can see in the above image when I execute line 242, I am getting exceptions and that could be because of the erase is not pointing to any valid function (as seen in watch)

[Naeem Maroof]

Hi Amit,

I have tested on nrf52840dk, and I do not get any problem

I can see the correct functionality as well.

Just for reference, I am putting the nrf52840DK overlay here which is based on your overlay, the sample output dts, and the information from the DK guide.

/delete-node/ &mx25r64;
&qspi{
    status = "disabled";
    
};
&spi3{
    compatible = "nordic,nrf-spim";
    status = "okay";
    pinctrl-0 = < &spi3_default >;
    pinctrl-1 = < &spi3_sleep >;
    pinctrl-names = "default", "sleep";
    cs-gpios = <&gpio0 17 GPIO_ACTIVE_LOW>; /* D10 */
    mx25r64: mx25r6435f@0 {
        compatible = "jedec,spi-nor";
        reg = < 0x0 >;
        spi-max-frequency = < 8000000 >;
        status = "okay";
        jedec-id = [ C2 28 17 ];
        sfdp-bfp = [ E5 20 F1 FF FF FF FF 03 44 EB 08 6B 08 3B 04 BB EE FF FF FF FF FF 00 FF FF FF 00 FF 0C 20 0F 52 10 D8 00 FF 23 72 F5 00 82 ED 04 CC 44 83 68 44 30 B0 30 B0 F7 C4 D5 5C 00 BE 29 FF F0 D0 FF FF ];
        size = < 0x4000000 >;
        has-dpd;
        t-enter-dpd = < 0x2710 >;
        t-exit-dpd = < 0x88b8 >;
    };
};

&pinctrl{
    spi3_default: spi3_default {
		group1 {
			psels = <NRF_PSEL(SPIM_SCK, 0, 19)>,
				<NRF_PSEL(SPIM_MISO, 0, 21)>,
				<NRF_PSEL(SPIM_MOSI, 0, 20)>;
		};
	};

	spi3_sleep: spi3_sleep {
		group1 {
			psels = <NRF_PSEL(SPIM_SCK, 0, 19)>,
				<NRF_PSEL(SPIM_MISO, 0, 21)>,
				<NRF_PSEL(SPIM_MOSI, 0, 20)>;
			low-power-enable;
		};
	};
};

/{
    aliases{
        spi-flash0 = &mx25r64;
    };
};

I am using the exact sample without modifying anything in the main except including a header file for the spi.

In the project configurations, SPI is enabled and QSPI is disabled; similarly in the overlay.