sorry for this

but in python spidev its not working as it should be i have to change sending bytes .but in raspberry pi its working without any change. and according to documents of lora chip its half-duplex.

@SpiderKenny

I am sharing code can you tell me whats wrong with it. this similar code works with raspberry pi.

#define READ_ACCESS 0x00
#define WRITE_ACCESS 0x80
#define LGW_SPI_MUX_TARGET_SX1302 0x0000
#define SX1302_REG_COMMON 0x5600
my spi is spidev 0.1

//Function to Read Register for chip version...

x = lgw_spi_r(LGW_COM_SPI,LGW_SPI_MUX_TARGET_SX1302, SX1302_REG_COMMON + 6, &data);
if (x != 0) {
    printf("ERROR (%d): failed to read register\n", __LINE__);
    exit_failure();
}
printf("SX1302 version: 0x%02X\n", data);

int lgw_spi_r(void *com_target, uint8_t spi_mux_target, uint16_t address, uint8_t *data) {
int spi_device;
uint8_t out_buf[5];
uint8_t command_size;
uint8_t in_buf[ARRAY_SIZE(out_buf)];
struct spi_ioc_transfer k;
int a;

/* check input variables */
CHECK_NULL(com_target);
CHECK_NULL(data);

spi_device = *(int *)com_target; /* must check that com_target is not null beforehand*/

/* prepare frame to be sent */
out_buf[0] = spi_mux_target;   //spi_mux_target 0x00
out_buf[1] = READ_ACCESS | ((address >> 8) & 0x7F);    //addrress=0x5600 //READ_ACCESS = 0x00

out_buf[2] =  ((address >> 0) & 0xFF);
out_buf[3] = 0x00;
out_buf[4] = 0x00;
command_size = 5;

/* I/O transaction */
memset(&k, 0, sizeof(k)); /* clear k */
k.tx_buf = (unsigned long) out_buf;
k.rx_buf = (unsigned long) in_buf;
k.len = command_size;
k.cs_change = 0;
a = ioctl(spi_device, SPI_IOC_MESSAGE(1), &k);

/* determine return code */
if (a != (int)k.len) {
    DEBUG_MSG("ERROR: SPI READ FAILURE\n");
    return LGW_SPI_ERROR;
} else {
    DEBUG_MSG("Note: SPI read success\n");
    *data = in_buf[command_size - 1];
    return LGW_SPI_SUCCESS;
}

}

the output is "SX1302 version: 0x00" output should be 0x12
I am also sharing datasheet information

I

it will work on onion omega 2s+ or not

no its not solved I am just reading the single register value of lora chip using python spidev by modified some bytes but I have to run this application on C language that is not working because full stack of lora gateway is available on C language so that's why I want run it. i want to know that if there is some problem in spidev.

I double checked it. its half duplex communication and same happens with python spidev .when I try to read single register value using xfer3 function it is reading 0x00 and it should be 0x12 but when i run it on raspberry pi using same function it gives the result and when i checked it on usb analyser with onion it shows that it reads 0x12.but not in same index but in [index-1] so when i try to read previous index using xfer3 it reads correctly.

e.g.
spi.max_speed_hz = 1000000
spi.mode = 0b00
spi.open(0, 1)
addr=0x5600+6
(its five byte transmit)
readVals = spi.xfer3([0x00,(0x00 | ((addr >>8) & 0x7F)),((addr >> 0) &0xFF),0x00,0x00],2) when i try to read using this it gives 0x00. and in rpi it gives result as expected.

(its four byte transmit)
readVals = spi.xfer3([0x00,(0x00 | ((addr >>8) & 0x7F)),((addr >> 0) &0xFF),0x00],2)
this gives result 0x12.

but according to datasheet of lora IC five byte transmit is the way its given..

Hello Everyone,

I am trying to run SPI half-duplex for my gateway(LORA) and when I run (Spi_test) utility of gateway it shows some random data read and when I connect it to USB analyzer it works as expected.it shows all data read on MOSI is correct. but in software it is not as expected. and when I run same SPI utility with Raspberry pi it works perfectly.
kindly help me.

Regards

Hello Guys,

I am new to omega ..i have omega development kit with omega 2s+ i have compiled spidev test utility for testing spi . and when i run the test by calling (./spidev -v) it reads garbage value.
as a given below

[[[[ [spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D | ......@....▒..................▒.
RX | 00 A0 02 87 E8 26 E8 7F 00 00 00 00 00 00 00 00 2F 6C 69 62 2F 6C 69 62 67 63 63 5F 73 2E 73 6F | .▒.▒▒&......../lib/libgcc_s.so ]]]]]]]]

I have connected MOSI with MISO for loopback test. but its not reading properly.
please help me.