static int wait_conversion_complete_polled(struct ak8975_data *data)
{
struct i2c_client *client = data->client;
u8 read_status;
u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
int ret;
/* Wait for the conversion to complete. */
while (timeout_ms) {
msleep(AK8975_CONVERSION_DONE_POLL_TIME);
ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
if (ret < 0) {
dev_err(&client->dev, "Error in reading ST1\n");
return ret;
}
if (read_status)
break;
timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
}
if (!timeout_ms) {
dev_err(&client->dev, "Conversion timeout happened\n");
return -EINVAL;
}
return read_status;
}
/*
* Perform some start-of-day setup, including reading the asa calibration
* values and caching them.
*/
static int ak8975_setup(struct i2c_client *client)
{
struct ak8975_data *data = i2c_get_clientdata(client);
u8 device_id;
int ret;
/* Confirm that the device we're talking to is really an AK8975. */
ret = ak8975_read_data(client, AK8975_REG_WIA, 1, &device_id);
if (ret < 0) {
dev_err(&client->dev, "Error reading WIA\n");
return ret;
}
if (device_id != AK8975_DEVICE_ID) {
dev_err(&client->dev, "Device ak8975 not found\n");
return -ENODEV;
}
/* Write the fused rom access mode. */
ret = ak8975_write_data(client,
AK8975_REG_CNTL,
AK8975_REG_CNTL_MODE_FUSE_ROM,
AK8975_REG_CNTL_MODE_MASK,
AK8975_REG_CNTL_MODE_SHIFT);
if (ret < 0) {
dev_err(&client->dev, "Error in setting fuse access mode\n");
return ret;
}
/* Get asa data and store in the device data. */
ret = ak8975_read_data(client, AK8975_REG_ASAX, 3, data->asa);
if (ret < 0) {
dev_err(&client->dev, "Not able to read asa data\n");
return ret;
}
/* Precalculate scale factor for each axis and
store in the device data. */
data->raw_to_gauss[0] = ((data->asa[0] + 128) * 30) >> 8;
data->raw_to_gauss[1] = ((data->asa[1] + 128) * 30) >> 8;
data->raw_to_gauss[2] = ((data->asa[2] + 128) * 30) >> 8;
return 0;
}
bool ak8975_get_mag(AK8975_t *structure, signed short *X_Axis, signed short *Y_Axis, signed short *Z_Axis) {
if(!ak8975_start_measure(structure))
return false;
timer(Timeout);
timer_interval(&Timeout, 11);
timer_enable(&Timeout);
while(!ak8975_ready(structure)) {
if(timer_tick(&Timeout))
return false;
}
if(!ak8975_read_data(structure, X_Axis, Y_Axis, Z_Axis))
return false;
return true;
}
bool ak8975_display_result(AK8975_t *structure) {
signed short Xg = 0;
signed short Yg = 0;
signed short Zg = 0;
if(!ak8975_start_measure(structure))
return false;
timer(Timeout);
timer_interval(&Timeout, 11);
timer_enable(&Timeout);
while(!ak8975_ready(structure)) {
if(timer_tick(&Timeout))
return false;
}
if(!ak8975_read_data(structure, &Xg, &Yg, &Zg))
return false;
uart.printf(DebugCom, "AK8975: Magnetometer: Xg = %d, Yg = %d, Zg = %d\n\r", Xg, Yg, Zg);
return true;
}
/*
* Emits the raw flux value for the x, y, or z axis.
*/
static ssize_t show_raw(struct device *dev, struct device_attribute *devattr,
char *buf)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct ak8975_data *data = indio_dev->dev_data;
struct i2c_client *client = data->client;
struct iio_dev_attr *this_attr = to_iio_dev_attr(devattr);
u16 meas_reg;
s16 raw;
u8 read_status;
int ret;
mutex_lock(&data->lock);
if (data->mode == 0) {
dev_err(&client->dev, "Operating mode is in power down mode\n");
ret = -EBUSY;
goto exit;
}
/* Set up the device for taking a sample. */
ret = ak8975_write_data(client,
AK8975_REG_CNTL,
AK8975_REG_CNTL_MODE_ONCE,
AK8975_REG_CNTL_MODE_MASK,
AK8975_REG_CNTL_MODE_SHIFT);
if (ret < 0) {
dev_err(&client->dev, "Error in setting operating mode\n");
goto exit;
}
/* Wait for the conversion to complete. */
if (data->eoc_gpio)
ret = wait_conversion_complete_gpio(data);
else
ret = wait_conversion_complete_polled(data);
if (ret < 0)
goto exit;
read_status = ret;
if (read_status & AK8975_REG_ST1_DRDY_MASK) {
ret = ak8975_read_data(client, AK8975_REG_ST2, 1, &read_status);
if (ret < 0) {
dev_err(&client->dev, "Error in reading ST2\n");
goto exit;
}
if (read_status & (AK8975_REG_ST2_DERR_MASK |
AK8975_REG_ST2_HOFL_MASK)) {
dev_err(&client->dev, "ST2 status error 0x%x\n",
read_status);
ret = -EINVAL;
goto exit;
}
}
/* Read the flux value from the appropriate register
(the register is specified in the iio device attributes). */
ret = ak8975_read_data(client, this_attr->address, 2, (u8 *)&meas_reg);
if (ret < 0) {
dev_err(&client->dev, "Read axis data fails\n");
goto exit;
}
mutex_unlock(&data->lock);
/* Endian conversion of the measured values. */
raw = (s16) (le16_to_cpu(meas_reg));
/* Clamp to valid range. */
raw = clamp_t(s16, raw, -4096, 4095);
return sprintf(buf, "%d\n", raw);
exit:
mutex_unlock(&data->lock);
return ret;
}
