441 lines
10 KiB
C
441 lines
10 KiB
C
/*
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* mag3110.c - Support for Freescale MAG3110 magnetometer sensor
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*
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* Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
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*
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* This file is subject to the terms and conditions of version 2 of
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* the GNU General Public License. See the file COPYING in the main
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* directory of this archive for more details.
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*
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* (7-bit I2C slave address 0x0e)
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*
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* TODO: irq, user offset, oversampling, continuous mode
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/triggered_buffer.h>
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#include <linux/delay.h>
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#define MAG3110_STATUS 0x00
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#define MAG3110_OUT_X 0x01 /* MSB first */
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#define MAG3110_OUT_Y 0x03
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#define MAG3110_OUT_Z 0x05
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#define MAG3110_WHO_AM_I 0x07
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#define MAG3110_OFF_X 0x09 /* MSB first */
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#define MAG3110_OFF_Y 0x0b
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#define MAG3110_OFF_Z 0x0d
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#define MAG3110_DIE_TEMP 0x0f
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#define MAG3110_CTRL_REG1 0x10
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#define MAG3110_CTRL_REG2 0x11
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#define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
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#define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
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#define MAG3110_CTRL_DR_SHIFT 5
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#define MAG3110_CTRL_DR_DEFAULT 0
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#define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
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#define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
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#define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
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#define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */
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#define MAG3110_DEVICE_ID 0xc4
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/* Each client has this additional data */
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struct mag3110_data {
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struct i2c_client *client;
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struct mutex lock;
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u8 ctrl_reg1;
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};
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static int mag3110_request(struct mag3110_data *data)
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{
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int ret, tries = 150;
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/* trigger measurement */
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ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
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data->ctrl_reg1 | MAG3110_CTRL_TM);
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if (ret < 0)
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return ret;
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while (tries-- > 0) {
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ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
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if (ret < 0)
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return ret;
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/* wait for data ready */
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if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
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break;
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msleep(20);
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}
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if (tries < 0) {
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dev_err(&data->client->dev, "data not ready\n");
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return -EIO;
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}
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return 0;
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}
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static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
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{
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int ret;
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mutex_lock(&data->lock);
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ret = mag3110_request(data);
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if (ret < 0) {
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mutex_unlock(&data->lock);
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return ret;
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}
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ret = i2c_smbus_read_i2c_block_data(data->client,
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MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
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mutex_unlock(&data->lock);
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return ret;
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}
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static ssize_t mag3110_show_int_plus_micros(char *buf,
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const int (*vals)[2], int n)
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{
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size_t len = 0;
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while (n-- > 0)
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len += scnprintf(buf + len, PAGE_SIZE - len,
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"%d.%06d ", vals[n][0], vals[n][1]);
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/* replace trailing space by newline */
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buf[len - 1] = '\n';
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return len;
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}
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static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
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int val, int val2)
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{
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while (n-- > 0)
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if (val == vals[n][0] && val2 == vals[n][1])
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return n;
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return -EINVAL;
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}
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static const int mag3110_samp_freq[8][2] = {
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{80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
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{1, 250000}, {0, 625000}
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};
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static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
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}
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static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
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static int mag3110_get_samp_freq_index(struct mag3110_data *data,
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int val, int val2)
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{
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return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
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val2);
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}
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static int mag3110_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct mag3110_data *data = iio_priv(indio_dev);
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__be16 buffer[3];
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int i, ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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if (iio_buffer_enabled(indio_dev))
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return -EBUSY;
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switch (chan->type) {
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case IIO_MAGN: /* in 0.1 uT / LSB */
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ret = mag3110_read(data, buffer);
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if (ret < 0)
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return ret;
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*val = sign_extend32(
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be16_to_cpu(buffer[chan->scan_index]), 15);
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return IIO_VAL_INT;
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case IIO_TEMP: /* in 1 C / LSB */
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mutex_lock(&data->lock);
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ret = mag3110_request(data);
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if (ret < 0) {
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mutex_unlock(&data->lock);
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return ret;
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}
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ret = i2c_smbus_read_byte_data(data->client,
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MAG3110_DIE_TEMP);
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mutex_unlock(&data->lock);
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if (ret < 0)
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return ret;
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*val = sign_extend32(ret, 7);
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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case IIO_CHAN_INFO_SCALE:
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switch (chan->type) {
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case IIO_MAGN:
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*val = 0;
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*val2 = 1000;
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_TEMP:
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*val = 1000;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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case IIO_CHAN_INFO_SAMP_FREQ:
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i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
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*val = mag3110_samp_freq[i][0];
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*val2 = mag3110_samp_freq[i][1];
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_CHAN_INFO_CALIBBIAS:
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ret = i2c_smbus_read_word_swapped(data->client,
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MAG3110_OFF_X + 2 * chan->scan_index);
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if (ret < 0)
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return ret;
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*val = sign_extend32(ret >> 1, 14);
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return IIO_VAL_INT;
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}
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return -EINVAL;
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}
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static int mag3110_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int val, int val2, long mask)
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{
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struct mag3110_data *data = iio_priv(indio_dev);
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int rate;
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if (iio_buffer_enabled(indio_dev))
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return -EBUSY;
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switch (mask) {
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case IIO_CHAN_INFO_SAMP_FREQ:
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rate = mag3110_get_samp_freq_index(data, val, val2);
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if (rate < 0)
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return -EINVAL;
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data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
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data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
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return i2c_smbus_write_byte_data(data->client,
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MAG3110_CTRL_REG1, data->ctrl_reg1);
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case IIO_CHAN_INFO_CALIBBIAS:
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if (val < -10000 || val > 10000)
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return -EINVAL;
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return i2c_smbus_write_word_swapped(data->client,
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MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
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default:
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return -EINVAL;
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}
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}
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static irqreturn_t mag3110_trigger_handler(int irq, void *p)
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{
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struct iio_poll_func *pf = p;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct mag3110_data *data = iio_priv(indio_dev);
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u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
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int ret;
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ret = mag3110_read(data, (__be16 *) buffer);
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if (ret < 0)
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goto done;
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if (test_bit(3, indio_dev->active_scan_mask)) {
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ret = i2c_smbus_read_byte_data(data->client,
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MAG3110_DIE_TEMP);
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if (ret < 0)
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goto done;
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buffer[6] = ret;
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}
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iio_push_to_buffers_with_timestamp(indio_dev, buffer,
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iio_get_time_ns());
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done:
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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}
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#define MAG3110_CHANNEL(axis, idx) { \
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.type = IIO_MAGN, \
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.modified = 1, \
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.channel2 = IIO_MOD_##axis, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
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BIT(IIO_CHAN_INFO_CALIBBIAS), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
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BIT(IIO_CHAN_INFO_SCALE), \
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.scan_index = idx, \
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.scan_type = { \
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.sign = 's', \
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.realbits = 16, \
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.storagebits = 16, \
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.endianness = IIO_BE, \
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}, \
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}
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static const struct iio_chan_spec mag3110_channels[] = {
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MAG3110_CHANNEL(X, 0),
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MAG3110_CHANNEL(Y, 1),
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MAG3110_CHANNEL(Z, 2),
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{
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.type = IIO_TEMP,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_SCALE),
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.scan_index = 3,
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.scan_type = {
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.sign = 's',
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.realbits = 8,
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.storagebits = 8,
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},
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},
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IIO_CHAN_SOFT_TIMESTAMP(4),
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};
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static struct attribute *mag3110_attributes[] = {
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&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
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NULL
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};
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static const struct attribute_group mag3110_group = {
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.attrs = mag3110_attributes,
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};
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static const struct iio_info mag3110_info = {
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.attrs = &mag3110_group,
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.read_raw = &mag3110_read_raw,
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.write_raw = &mag3110_write_raw,
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.driver_module = THIS_MODULE,
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};
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static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
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static int mag3110_standby(struct mag3110_data *data)
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{
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return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
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data->ctrl_reg1 & ~MAG3110_CTRL_AC);
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}
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static int mag3110_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct mag3110_data *data;
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struct iio_dev *indio_dev;
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int ret;
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ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
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if (ret < 0)
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return ret;
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if (ret != MAG3110_DEVICE_ID)
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return -ENODEV;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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data = iio_priv(indio_dev);
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data->client = client;
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mutex_init(&data->lock);
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i2c_set_clientdata(client, indio_dev);
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indio_dev->info = &mag3110_info;
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indio_dev->name = id->name;
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indio_dev->dev.parent = &client->dev;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = mag3110_channels;
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indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
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indio_dev->available_scan_masks = mag3110_scan_masks;
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data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
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ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
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data->ctrl_reg1);
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if (ret < 0)
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return ret;
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ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
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MAG3110_CTRL_AUTO_MRST_EN);
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if (ret < 0)
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goto standby_on_error;
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ret = iio_triggered_buffer_setup(indio_dev, NULL,
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mag3110_trigger_handler, NULL);
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if (ret < 0)
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goto standby_on_error;
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ret = iio_device_register(indio_dev);
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if (ret < 0)
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goto buffer_cleanup;
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return 0;
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buffer_cleanup:
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iio_triggered_buffer_cleanup(indio_dev);
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standby_on_error:
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mag3110_standby(iio_priv(indio_dev));
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return ret;
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}
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static int mag3110_remove(struct i2c_client *client)
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{
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struct iio_dev *indio_dev = i2c_get_clientdata(client);
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iio_device_unregister(indio_dev);
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iio_triggered_buffer_cleanup(indio_dev);
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mag3110_standby(iio_priv(indio_dev));
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int mag3110_suspend(struct device *dev)
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{
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return mag3110_standby(iio_priv(i2c_get_clientdata(
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to_i2c_client(dev))));
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}
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static int mag3110_resume(struct device *dev)
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{
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struct mag3110_data *data = iio_priv(i2c_get_clientdata(
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to_i2c_client(dev)));
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return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
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data->ctrl_reg1);
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}
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static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
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#define MAG3110_PM_OPS (&mag3110_pm_ops)
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#else
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#define MAG3110_PM_OPS NULL
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#endif
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static const struct i2c_device_id mag3110_id[] = {
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{ "mag3110", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, mag3110_id);
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static struct i2c_driver mag3110_driver = {
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.driver = {
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.name = "mag3110",
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.pm = MAG3110_PM_OPS,
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},
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.probe = mag3110_probe,
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.remove = mag3110_remove,
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.id_table = mag3110_id,
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};
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module_i2c_driver(mag3110_driver);
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MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
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MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
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MODULE_LICENSE("GPL");
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