Filling out init function and adding an API for applying settings dyn…

…amically

inc/icm20948_api.h

@@ -29,11 +29,56 @@
 #ifndef _ICM20948_API_H_
 #define _ICM20948_API_H_
 
+#include <stdint.h>
+#include <stdbool.h>
+
+#define ICM20948_GYRO_ENABLE    (true)
+#define ICM20948_GYRO_DISABLE   (false)
+
+#define ICM20948_ACCEL_ENABLE   (true)
+#define ICM20948_ACCEL_DISABLE  (false)
+
+#define ICM20948_MAG_ENABLE     (true)
+#define ICM20948_MAG_DISABLE    (false)
+
 typedef int8_t(*icm20948_read_fptr_t)(uint8_t addr, uint8_t *data, uint32_t len);
 typedef int8_t(*icm20948_write_fptr_t)(uint8_t addr, uint8_t *data, uint32_t len);
 typedef void(*icm20948_delay_us_fptr_t)(uint32_t period);
 
-int8_t icm20948_intf_init(icm20948_read_fptr_t r, icm20948_write_fptr_t w, icm20948_delay_us_fptr_t delay);
-int8_t icm20948_writeRegs(void);
+typedef enum {
+    ICM20948_RET_OK = 0,
+    ICM20948_RET_GEN_FAIL = -1,
+    ICM20948_RET_INV_PARAM  = -2,
+    ICM20948_RET_NULL_PTR   = -3,
+    ICM20948_RET_INV_CONFIG = -4,
+    ICM20948_RET_TIMEOUT   = -5
+} icm20948_return_code_t;
+
+typedef struct {
+    bool gyro_en;
+    bool accel_en;
+    bool mag_en;
+} icm20948_settings_t;
+
+typedef struct {
+    uint16_t x;
+    uint16_t y;
+    uint16_t z;
+} icm20948_gyro_t;
+
+typedef struct {
+    uint16_t x;
+    uint16_t y;
+    uint16_t z;
+} icm20948_accel_t;
+
+typedef struct {
+    uint16_t x;
+    uint16_t y;
+    uint16_t z;
+} icm20948_mag_t;
+
+icm20948_return_code_t icm20948_init(icm20948_read_fptr_t r, icm20948_write_fptr_t w, icm20948_delay_us_fptr_t delay);
+icm20948_return_code_t icm20948_applySettings(icm20948_settings_t *newSettings);
 
 #endif // _ICM20948_API_H_

src/icm20948.c

@@ -26,32 +26,70 @@
  * @brief Source file for the ICM20948 9-Axis MEMS device driver.
  */
 
+#include <string.h>
 #include "icm20948.h"
 #include "icm20948_api.h"
 
 static icm20948_dev_t dev;
+static icm20948_settings_t settings;
 
-int8_t icm20948_intf_init(icm20948_read_fptr_t r, icm20948_write_fptr_t w, icm20948_delay_us_fptr_t delay) {
+icm20948_return_code_t icm20948_init(icm20948_read_fptr_t r, icm20948_write_fptr_t w, icm20948_delay_us_fptr_t delay) {
 
-    uint8_t reg[5];
-    // Store the interface passed in to us. This has pointer references
-    // for our read, write, and delay functions.
+    icm20948_return_code_t ret = ICM20948_RET_OK;
+
+    // Verify that the function pointers given to us are not invalid
+    if( (r == NULL) || (w == NULL) || (delay == NULL) ) {
+        // One of the functions given to us was a NULL pointer, return with a
+        // NULL PTR return code
+        ret = ICM20948_RET_NULL_PTR;
+    }
+
+    // Store the interface functions passed in to us to be used to
+    // communicate with the IC.
     dev.intf.read = r;
     dev.intf.write = w;
     dev.intf.delay_us = delay;
 
-    dev.intf.read(0x01, dev.usr_bank.bank0.arr, sizeof(dev.usr_bank.bank0.arr));
-    dev.intf.write(0x01, dev.usr_bank.bank0.arr, sizeof(dev.usr_bank.bank0.arr));
-    dev.intf.delay_us(56);
+    // Select user register bank 0
+    dev.usr_bank.reg_bank_sel = ICM20948_USER_BANK_0;
 
-    return 1;
-}
+    if( ret == ICM20948_RET_OK ) {
+        // Write to the reg bank select to select bank 0
+        ret = dev.intf.write(ICM20948_ADDR_REG_BANK_SEL, (uint8_t *)&dev.usr_bank.reg_bank_sel, 0x01);
+    }
 
-int8_t icm20948_writeRegs(void) {
-    dev.intf.write(0x00, dev.usr_bank.bank0.arr, sizeof(dev.usr_bank.bank0.arr));
-    dev.intf.write(0x01, dev.usr_bank.bank1.arr, sizeof(dev.usr_bank.bank1.arr));
-    dev.intf.write(0x02, dev.usr_bank.bank2.arr, sizeof(dev.usr_bank.bank2.arr));
-    dev.intf.write(0x03, dev.usr_bank.bank3.arr, sizeof(dev.usr_bank.bank3.arr));
+    if( ret == ICM20948_RET_OK) {
+        // If the bank was selected, read the WHO_AM_I register
+        ret = dev.intf.read(ICM20948_ADDR_WHO_AM_I, &dev.usr_bank.bank0.bytes.WHO_AM_I, 0x01);
 
-    return 1;
+        // If we read the register, and the ID doesn't match, return with a general failure
+        if( (ret == ICM20948_RET_OK) && (dev.usr_bank.bank0.bytes.WHO_AM_I != ICM20948_WHO_AM_I_DEFAULT) ) {
+            // The WHO_AM_I ID was incorrect.
+            ret = ICM20948_RET_GEN_FAIL;
+        }
+        else {
+            // We read the ID and it matched to what we expected. All is good.
+            ret = ICM20948_RET_OK;
+        }
+    }
+
+    // Return our init status
+    return ret;
 }
+
+icm20948_return_code_t icm20948_applySettings(icm20948_settings_t *newSettings) {
+
+    // Copy over the new settings
+    memcpy(&settings, newSettings, sizeof(settings));
+
+    // Act upon and apply the new settings
+
+    if( settings.accel_en == ICM20948_ACCEL_ENABLE ) {
+        // Enable the accelerometer
+    }
+    else {
+        // Disable the accelerometer
+    }
+
+    return ICM20948_RET_OK;
+}

src/icm20948.h

@@ -37,14 +37,22 @@
 #define ICM20948_BANK2_REG_COUNT            (20)
 #define ICM20948_BANK3_REG_COUNT            (25)
 
-#define ICM20948_USER_BANK_0                (0)
-#define ICM20948_USER_BNAK_1                (1)
-#define ICM20948_USER_BANK_2                (2)
-#define ICM20948_USER_BANK_3                (3)
-
 #define ICM20948_WHO_AM_I_DEFAULT           (0xEA)
 #define ICM20948_EXT_SLV_SENS_DATA_COUNT    (25)
 
+typedef enum {
+    ICM20948_USER_BANK_0 = 0x00,
+    ICM20948_USER_BANK_1 = 0x01,
+    ICM20948_USER_BANK_2 = 0x02,
+    ICM20948_USER_BANK_3 = 0x03
+} icm20948_reg_bank_sel_t;
+
+typedef enum {
+    ICM20948_ADDR_WHO_AM_I = 0x00,
+    ICM20948_ADDR_REG_BANK_SEL = 0x7F
+} icm20948_reg_bank0_addr_t;
+
+
 typedef union {
     struct {
         uint8_t WHO_AM_I;
@@ -621,6 +629,7 @@ typedef struct {
     icm20948_reg_bank_1_t bank1;
     icm20948_reg_bank_2_t bank2;
     icm20948_reg_bank_3_t bank3;
+    icm20948_reg_bank_sel_t reg_bank_sel;
 } icm20948_usr_bank_t;
 
 typedef struct {

template/main.c

@@ -51,10 +51,7 @@ void usr_delay_us(uint32_t period) {
 int main(void) {
 
     // Init the ICM20948 dev SPI interface
-    icm20948_intf_init(usr_write, usr_read, usr_delay_us);
-
-    // Write the regs
-    icm20948_writeRegs();
+    icm20948_init(usr_write, usr_read, usr_delay_us);
 
     return 0;
 }