SPI working! when using SPI, the order of writing out ctrl_reg's matters....but seemingly not when using i2c

README.md

@@ -21,7 +21,7 @@ See the `examples/` dir for complete code examples
 ## Implementation
 This driver requires the user to implement the following interface functions:
 
-This project has example interface code for I2C and SPI (broken) used on Raspberry Pi 4.
+This project has example interface code for I2C and SPI used on Raspberry Pi 4.
 ```c
 /* initialise the "interface" */
 int init(void);
@@ -52,6 +52,9 @@ int i2c_write(uint8_t reg, uint8_t value) {
 }
 
 int i2c_read(uint8_t reg, uint8_t *dst, uint32_t size) {
+    if (size > 1) {
+        reg |= 0x80; /* auto-increment bit */
+    }
     uint8_t send[2] = { reg, 0x00 };
     HAL_I2C_Master_Transmit(&hi2c2, LIS3DH_I2C_ADDR << 1, send, 2, HAL_MAX_DELAY);
     HAL_I2C_Master_Receive(&hi2c2, LIS3DH_I2C_ADDR << 1, dst, size, HAL_MAX_DELAY);

i2c.c

@@ -24,19 +24,19 @@ Example I2C use on linux/raspberry pi
  */
 
 #define I2C_DEVICE "/dev/i2c-1"
-#define I2C_LIS3DH_ADDRESS 0x18
+#define I2C_LIS3DH_ADDRESS 0x18 /* Can also be 0x19 */
 
 static int fd;
 
 int i2c_init(void) {
 	fd = open(I2C_DEVICE, O_RDWR);
 	if (fd < 0) {
-		fprintf(stderr, "[i2c] could not open device: %s\n", I2C_DEVICE);
+		fprintf(stderr, "i2c_init(): could not open device: %s\n", I2C_DEVICE);
 		return 1;
 	}
 
 	if (ioctl(fd, I2C_SLAVE, I2C_LIS3DH_ADDRESS) < 0) {
-		fprintf(stderr, "[i2c] failed to acquire bus/talk to slave\n");
+		fprintf(stderr, "i2c_init(): failed to acquire bus/talk to slave\n");
 		close(fd);
 		return 1;
 	}
@@ -44,7 +44,6 @@ int i2c_init(void) {
 	return 0;
 }
 
-
 int i2c_read(uint8_t reg, uint8_t *dst, uint32_t size) {
 	uint8_t cmd[2];
 
@@ -55,10 +54,13 @@ int i2c_read(uint8_t reg, uint8_t *dst, uint32_t size) {
 	cmd[0] = reg;
 	cmd[1] = 0x00;
 
-	write(fd, cmd, 2);
+	if (write(fd, cmd, 2) != 2) {
+		fprintf(stderr, "i2c_read(): error write()\n");
+		return 1;
+	}
 	
-	if (read(fd, dst, size) != (ssize_t)size) {
+	if (read(fd, dst, size) != (int)size) {
-		fprintf(stderr, "[i2c] error read()\n");
+		fprintf(stderr, "i2c_read(): error read()\n");
 		return 1;
 	
 	}
@@ -66,7 +68,6 @@ int i2c_read(uint8_t reg, uint8_t *dst, uint32_t size) {
 	return 0;
 }
 
-
 int i2c_write(uint8_t reg, uint8_t value) {
 	uint8_t cmd[2];
 
@@ -74,7 +75,7 @@ int i2c_write(uint8_t reg, uint8_t value) {
 	cmd[1] = value;
 	
 	if (write(fd, cmd, 2) != 2) {
-		fprintf(stderr, "[i2c] error write()\n");
+		fprintf(stderr, "i2c_write(): error write()\n");
 		return 1;
 	}
 

lis3dh.c

@@ -175,7 +175,9 @@ int lis3dh_configure(lis3dh_t *lis3dh) {
     ctrl_reg0 |= 0x10;
     ctrl_reg0 |= (lis3dh->cfg.sdo_pullup & 1) << 7;
 
-    /* write these before the control regs that start the device */
+    err |= lis3dh->dev.write(REG_CTRL_REG4, ctrl_reg4);
+    err |= lis3dh->dev.write(REG_CTRL_REG5, ctrl_reg5);
+    
     err |= lis3dh->dev.write(REG_FIFO_CTRL_REG, fifo_ctrl_reg);
     err |= lis3dh->dev.write(REG_INT1_CFG, int1_cfg);
     err |= lis3dh->dev.write(REG_INT1_THS, int1_ths);
@@ -193,16 +195,15 @@ int lis3dh_configure(lis3dh_t *lis3dh) {
     err |= lis3dh->dev.write(REG_TEMP_CFG_REG, temp_cfg_reg);
     err |= lis3dh->dev.write(REG_REFERENCE, lis3dh->cfg.reference);
 
-    err |= lis3dh->dev.write(REG_CTRL_REG0, ctrl_reg0);
     err |= lis3dh->dev.write(REG_CTRL_REG1, ctrl_reg1);
+
+    err |= lis3dh->dev.write(REG_CTRL_REG6, ctrl_reg6);
+    err |= lis3dh->dev.write(REG_CTRL_REG0, ctrl_reg0);
     err |= lis3dh->dev.write(REG_CTRL_REG2, ctrl_reg2);
     err |= lis3dh->dev.write(REG_CTRL_REG3, ctrl_reg3);
-    err |= lis3dh->dev.write(REG_CTRL_REG4, ctrl_reg4);
-    err |= lis3dh->dev.write(REG_CTRL_REG5, ctrl_reg5);
-    err |= lis3dh->dev.write(REG_CTRL_REG6, ctrl_reg6);
 
     /* sleep for a period TBD ~ ODR */
-    lis3dh->dev.sleep(50000); /* 50 ms */
+    lis3dh->dev.sleep(1000); /* 50 ms */
     return err;
 }
 
@@ -335,6 +336,9 @@ int lis3dh_reset(lis3dh_t *lis3dh) {
     /* set BOOT bit so device reloads internal trim parameters */
     err |= lis3dh->dev.write(REG_CTRL_REG5, 0x80);
 
+    /* wait 30 ms */
+    lis3dh->dev.sleep(30000);
+
     /* write default values to rw regs */
     err |= lis3dh->dev.write(REG_CTRL_REG0, 0x10);
     err |= lis3dh->dev.write(REG_CTRL_REG1, 0x07);
@@ -357,6 +361,12 @@ int lis3dh_reset(lis3dh_t *lis3dh) {
     err |= lis3dh->dev.write(REG_TIME_WINDOW, 0x00);
     err |= lis3dh->dev.write(REG_ACT_THS, 0x00);
     err |= lis3dh->dev.write(REG_ACT_DUR, 0x00);
+
+    /* set BOOT bit again so device reloads internal trim parameters */
+    err |= lis3dh->dev.write(REG_CTRL_REG5, 0x80);
+
+    /* wait 30 ms */
+    lis3dh->dev.sleep(30000);
     
     return err;
 }

main.c

@@ -1,107 +1,65 @@
 #define _GNU_SOURCE
-#include <stdio.h>
-#include <stdlib.h>
 #include <unistd.h>
-#include <math.h>
+#include <stdio.h>
 #include "lis3dh.h"
-#include "interrupt.h"
 #include "i2c.h"
-
+#include "spi.h"
-/* GPIO 12 or Pin 32 */
-#define GPIO_INTERRUPT_PIN 12
-
-static void quit(const char *msg, lis3dh_t *lis) {
-    lis->dev.deinit();
-    fprintf(stderr, "%s\n", msg);
-    exit(1);
-}
-
-static float mag(float x, float y, float z) {
-    return (float) sqrt(x*x + y*y + z*z);
-}
 
 int main() {
 
     lis3dh_t lis;
-    struct lis3dh_fifo_data fifo;
+    struct lis3dh_fifo_data data;
-    int k;
+    int i;
 
-    lis.dev.init = i2c_init;
+    lis.dev.init = spi_init;
-    lis.dev.read = i2c_read;
+    lis.dev.read = spi_read;
-    lis.dev.write = i2c_write;
+    lis.dev.write = spi_write;
     lis.dev.sleep = usleep;
-    lis.dev.deinit = i2c_deinit;
+    lis.dev.deinit = spi_deinit;
 
-    /* initalise LIS3DH struct */
+    /* initialise LIS3DH struct */
     if (lis3dh_init(&lis)) {
-        quit("init()", &lis);
+        puts("init()");
     }
 
     /* reset device just in case */
     if (lis3dh_reset(&lis)) {
-        quit("reset()", &lis);
+        puts("reset()");
-    }
-
-    /* register interrupt */
-    if (int_register(GPIO_INTERRUPT_PIN)) {
-        quit("int_register()", &lis);
     }
 
     lis.cfg.mode = LIS3DH_MODE_HR;
     lis.cfg.range = LIS3DH_FS_2G;
     lis.cfg.rate = LIS3DH_ODR_400_HZ;
-
     lis.cfg.fifo.mode = LIS3DH_FIFO_MODE_STREAM_TO_FIFO;
-    lis.cfg.fifo.trig = LIS3DH_FIFO_TRIG_INT1; /* trigger interrupt into int pin1 */
+    lis.cfg.fifo.size = 20;
-    lis.cfg.pin1.wtm = 1; /* trigger upon FIFO watermark level reached */
 
-    lis.cfg.en_adc =1;
-    lis.cfg.en_temp = 1;
-    
     /* write device config */
     if (lis3dh_configure(&lis)) {
-       quit("configure()", &lis);
+        puts("configure()");
     }
-    
+
-    /* wait for interrupt from LIS3DH */
+A:
-    if (int_poll(GPIO_INTERRUPT_PIN)) {
+    /* poll fifo register until it reports that the watermark level has 
-     
+       been reached, or that it has overwritten old data, whichever 
-        quit("int_poll()", &lis);
+       happens first. */
+    if (lis3dh_poll_fifo(&lis)) {
+        puts("poll_fifo()");
     }
 
     /* read as many [x y z] sets as specified by watermark level (fth) */
     /* copy them to the fifo data struct given below as `fifo' */
-    if (lis3dh_read_fifo(&lis, &fifo)) {
+    if (lis3dh_read_fifo(&lis, &data)) {
-       quit("read_fifo()", &lis);
+        puts("read_fifo()");
     }
 
-    /* above function also writes out the qty of [x y z] sets stored in `fifo' */
+    /* read out fifo buffer data */
-    for(k=0; k<fifo.size; k++) {
+    for(i=0; i<data.size; i++) {
-        printf("x: %d, y: %d z: %d\n",
+        printf("x: %d mg, y: %d mg, z: %d mg\n", data.x[i], data.y[i], data.z[i]);
-            fifo.x[k], fifo.y[k], fifo.z[k]);
     }
-
+goto A;
-    printf("mag: %04.04f\n", mag(100.0, 45.0, 120.0));
+    /* deinitialise struct */
-
-
-    if (lis3dh_read_adc(&lis)) {
-        quit("adc()", &lis);
-    }
-
-    if (lis3dh_read_temp(&lis)) {
-        quit("temp()", &lis);
-    }
-
-    printf("ADC1: %d mV, temp: %d\n", lis.adc.adc1, lis.adc.adc3);
-    
-    /* unregister interrupt */
-    if (int_unregister(GPIO_INTERRUPT_PIN)) {
-       quit("int_unregister()", &lis);
-    }
-
-    /* deinitalise struct */
     if (lis3dh_deinit(&lis)) {
-        quit("deinit()", &lis);
+       puts("deinit()");
     }
 
     return 0;

spi.c

@@ -16,81 +16,68 @@ Example SPI use on linux/raspberry pi
 #include "spi.h"
 
 #define SPI_DEVICE "/dev/spidev0.0"
-
+#define SPI_SPEED 1000 * 1000 /* 1 MHz */
 
 /*
  * Pinout config for this example
  *
  * MOSI - GPIO 10 (physical pin 19) => LIS3DH "SDA" or "SDI"
  * MISO - GPIO 9  (physical pin 21) => LIS3DH "SDO"
- * SCLK - GPIO 11 (physical pin 23) => LIS3DH "SCK"
+ * SCLK - GPIO 11 (physical pin 23) => LIS3DH "SCL"
  * CE0  - GPIO 8  (physical pin 24) => LIS3DH "!CS"
- * 
- * Broken for unknown reason on Pi 4
  *
  */
 
-#define SPI_SPEED 500 * 1000 /* 500 KHz */
-
 static int fd;
-static uint8_t rx[256];
-static uint8_t tx[256];
 
 int spi_init(void) {
-	uint8_t mode = SPI_MODE_3;
+	uint8_t mode = SPI_MODE_0;
 	uint8_t bits = 8;
 	uint32_t speed = SPI_SPEED;
 
 	if ((fd = open(SPI_DEVICE, O_RDWR)) < 0) {
-		fprintf(stderr, "spi open(%s)\n", SPI_DEVICE);
+		fprintf(stderr, "spi_init(): open(%s)\n", SPI_DEVICE);
 		return 1;
 	}
 
 	if (ioctl(fd, SPI_IOC_RD_MODE, &mode) == -1) {
-		fprintf(stderr, "SPI_IOC_RD_MODE\n");
+		fprintf(stderr, "spi_init(): SPI_IOC_RD_MODE\n");
 		return 1;
 	}
 
 	if (ioctl(fd, SPI_IOC_WR_MODE, &mode) == -1) {
-		fprintf(stderr, "SPI_IOC_WR_MODE\n");
+		fprintf(stderr, "spi_init(): SPI_IOC_WR_MODE\n");
 		return 1;
 	}
 
 	if (ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits) == -1) {
-		fprintf(stderr, "SPI_IOC_WR_BITS_PER_WORD\n");
+		fprintf(stderr, "spi_init(): SPI_IOC_WR_BITS_PER_WORD\n");
 		return 1;
 	}
 
 	if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) == -1) {
-		fprintf(stderr, "SPI_IOC_RD_BITS_PER_WORD\n");
+		fprintf(stderr, "spi_init(): SPI_IOC_RD_BITS_PER_WORD\n");
 		return 1;
 	}
 
 	if (ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) == -1) {
-		fprintf(stderr, "SPI_IOC_WR_MAX_SPEED_HZ\n");
+		fprintf(stderr, "spi_init(): SPI_IOC_WR_MAX_SPEED_HZ\n");
 		return 1;
 	}
 
 	if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) == -1) {
-		fprintf(stderr, "SPI_IOC_RD_MAX_SPEED_HZ\n");
+		fprintf(stderr, "spi_init(): SPI_IOC_RD_MAX_SPEED_HZ\n");
 		return 1;
 	}
 	
 	return 0;
 }
 
-static int spi_transaction(uint8_t *tx, uint8_t *rx, uint32_t size) {
-	struct spi_ioc_transfer tr = {0};
-
-	tr.tx_buf = (unsigned long) tx;
-	tr.rx_buf = (unsigned long) rx;
-	tr.len = size;
-
-	return ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
-}
-
 int spi_read(uint8_t reg, uint8_t *dst, uint32_t size) {
 
+	uint8_t send[2];
+	struct spi_ioc_transfer tr[2] = {0};
+
 	/* clear 2 MSbits */
 	reg &= 0x3F;
 
@@ -102,28 +89,41 @@ int spi_read(uint8_t reg, uint8_t *dst, uint32_t size) {
         reg |= 0x40;
     }
 
-	tx[0] = reg;
+	send[0] = reg;
+	send[1] = 0x00;
 
-	if (spi_transaction(tx, rx, size + 1) < 0) {
+	tr[0].tx_buf = (unsigned long) send;
-		fprintf(stderr, "spi_read()\n");
+	tr[0].rx_buf = (unsigned long) 0;
+	tr[0].len = 2;
+
+	tr[1].tx_buf = (unsigned long) 0;
+	tr[1].rx_buf = (unsigned long) dst;
+	tr[1].len = size;
+
+	if (ioctl(fd, SPI_IOC_MESSAGE(2), tr) < 0) {
+		fprintf(stderr, "spi_read(): error ioctl()\n");
 		return 1;
 	}
 
-	memcpy(dst, rx + 1, size);
-
 	return 0;
 }
 
 int spi_write(uint8_t reg, uint8_t value) {
+	struct spi_ioc_transfer tr[2] = {0};
 
 	/* clear 2 MSbits */
 	reg &= 0x3F;
 
-	tx[0] = reg;
+	tr[0].tx_buf = (unsigned long) &reg;
-	tx[1] = value;
+	tr[0].rx_buf = (unsigned long) 0;
+	tr[0].len = 1;
 
-	if (spi_transaction(tx, rx, 2) < 0) {
+	tr[1].tx_buf = (unsigned long) &value;
-		fprintf(stderr, "spi_write()\n");
+	tr[1].rx_buf = (unsigned long) 0;
+	tr[1].len = 1;
+
+	if (ioctl(fd, SPI_IOC_MESSAGE(2), tr) < 0) {
+		fprintf(stderr, "spi_write(): error ioctl()\n");
 		return 1;
 	}