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Release 4.7 drivers/iio/magnetometer/mag3110.c

/*
 * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
 *
 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * (7-bit I2C slave address 0x0e)
 *
 * TODO: irq, user offset, oversampling, continuous mode
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/delay.h>


#define MAG3110_STATUS 0x00

#define MAG3110_OUT_X 0x01 
/* MSB first */

#define MAG3110_OUT_Y 0x03

#define MAG3110_OUT_Z 0x05

#define MAG3110_WHO_AM_I 0x07

#define MAG3110_OFF_X 0x09 
/* MSB first */

#define MAG3110_OFF_Y 0x0b

#define MAG3110_OFF_Z 0x0d

#define MAG3110_DIE_TEMP 0x0f

#define MAG3110_CTRL_REG1 0x10

#define MAG3110_CTRL_REG2 0x11


#define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))


#define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))

#define MAG3110_CTRL_DR_SHIFT 5

#define MAG3110_CTRL_DR_DEFAULT 0


#define MAG3110_CTRL_TM BIT(1) 
/* trigger single measurement */

#define MAG3110_CTRL_AC BIT(0) 
/* continuous measurements */


#define MAG3110_CTRL_AUTO_MRST_EN BIT(7) 
/* magnetic auto-reset */

#define MAG3110_CTRL_RAW BIT(5) 
/* measurements not user-offset corrected */


#define MAG3110_DEVICE_ID 0xc4

/* Each client has this additional data */

struct mag3110_data {
	
struct i2c_client *client;
	
struct mutex lock;
	
u8 ctrl_reg1;
};


static int mag3110_request(struct mag3110_data *data) { int ret, tries = 150; /* trigger measurement */ ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, data->ctrl_reg1 | MAG3110_CTRL_TM); if (ret < 0) return ret; while (tries-- > 0) { ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS); if (ret < 0) return ret; /* wait for data ready */ if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY) break; msleep(20); } if (tries < 0) { dev_err(&data->client->dev, "data not ready\n"); return -EIO; } return 0; }

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static int mag3110_read(struct mag3110_data *data, __be16 buf[3]) { int ret; mutex_lock(&data->lock); ret = mag3110_request(data); if (ret < 0) { mutex_unlock(&data->lock); return ret; } ret = i2c_smbus_read_i2c_block_data(data->client, MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf); mutex_unlock(&data->lock); return ret; }

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static ssize_t mag3110_show_int_plus_micros(char *buf, const int (*vals)[2], int n) { size_t len = 0; while (n-- > 0) len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06d ", vals[n][0], vals[n][1]); /* replace trailing space by newline */ buf[len - 1] = '\n'; return len; } static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n, int val, int val2) { while (n-- > 0) if (val == vals[n][0] && val2 == vals[n][1]) return n; return -EINVAL; } static const int mag3110_samp_freq[8][2] = { {80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000}, {1, 250000}, {0, 625000} };
static ssize_t mag3110_show_samp_freq_avail(struct device *dev, struct device_attribute *attr, char *buf) { return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8); }

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static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
static int mag3110_get_samp_freq_index(struct mag3110_data *data, int val, int val2) { return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val, val2); }

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static int mag3110_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct mag3110_data *data = iio_priv(indio_dev); __be16 buffer[3]; int i, ret; switch (mask) { case IIO_CHAN_INFO_RAW: if (iio_buffer_enabled(indio_dev)) return -EBUSY; switch (chan->type) { case IIO_MAGN: /* in 0.1 uT / LSB */ ret = mag3110_read(data, buffer); if (ret < 0) return ret; *val = sign_extend32( be16_to_cpu(buffer[chan->scan_index]), 15); return IIO_VAL_INT; case IIO_TEMP: /* in 1 C / LSB */ mutex_lock(&data->lock); ret = mag3110_request(data); if (ret < 0) { mutex_unlock(&data->lock); return ret; } ret = i2c_smbus_read_byte_data(data->client, MAG3110_DIE_TEMP); mutex_unlock(&data->lock); if (ret < 0) return ret; *val = sign_extend32(ret, 7); return IIO_VAL_INT; default: return -EINVAL; } case IIO_CHAN_INFO_SCALE: switch (chan->type) { case IIO_MAGN: *val = 0; *val2 = 1000; return IIO_VAL_INT_PLUS_MICRO; case IIO_TEMP: *val = 1000; return IIO_VAL_INT; default: return -EINVAL; } case IIO_CHAN_INFO_SAMP_FREQ: i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT; *val = mag3110_samp_freq[i][0]; *val2 = mag3110_samp_freq[i][1]; return IIO_VAL_INT_PLUS_MICRO; case IIO_CHAN_INFO_CALIBBIAS: ret = i2c_smbus_read_word_swapped(data->client, MAG3110_OFF_X + 2 * chan->scan_index); if (ret < 0) return ret; *val = sign_extend32(ret >> 1, 14); return IIO_VAL_INT; } return -EINVAL; }

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static int mag3110_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) { struct mag3110_data *data = iio_priv(indio_dev); int rate; if (iio_buffer_enabled(indio_dev)) return -EBUSY; switch (mask) { case IIO_CHAN_INFO_SAMP_FREQ: rate = mag3110_get_samp_freq_index(data, val, val2); if (rate < 0) return -EINVAL; data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK; data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT; return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, data->ctrl_reg1); case IIO_CHAN_INFO_CALIBBIAS: if (val < -10000 || val > 10000) return -EINVAL; return i2c_smbus_write_word_swapped(data->client, MAG3110_OFF_X + 2 * chan->scan_index, val << 1); default: return -EINVAL; } }

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static irqreturn_t mag3110_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct mag3110_data *data = iio_priv(indio_dev); u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */ int ret; ret = mag3110_read(data, (__be16 *) buffer); if (ret < 0) goto done; if (test_bit(3, indio_dev->active_scan_mask)) { ret = i2c_smbus_read_byte_data(data->client, MAG3110_DIE_TEMP); if (ret < 0) goto done; buffer[6] = ret; } iio_push_to_buffers_with_timestamp(indio_dev, buffer, iio_get_time_ns()); done: iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; }

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#define MAG3110_CHANNEL(axis, idx) { \ .type = IIO_MAGN, \ .modified = 1, \ .channel2 = IIO_MOD_##axis, \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ BIT(IIO_CHAN_INFO_CALIBBIAS), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ BIT(IIO_CHAN_INFO_SCALE), \ .scan_index = idx, \ .scan_type = { \ .sign = 's', \ .realbits = 16, \ .storagebits = 16, \ .endianness = IIO_BE, \ }, \ } static const struct iio_chan_spec mag3110_channels[] = { MAG3110_CHANNEL(X, 0), MAG3110_CHANNEL(Y, 1), MAG3110_CHANNEL(Z, 2), { .type = IIO_TEMP, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), .scan_index = 3, .scan_type = { .sign = 's', .realbits = 8, .storagebits = 8, }, }, IIO_CHAN_SOFT_TIMESTAMP(4), }; static struct attribute *mag3110_attributes[] = { &iio_dev_attr_sampling_frequency_available.dev_attr.attr, NULL }; static const struct attribute_group mag3110_group = { .attrs = mag3110_attributes, }; static const struct iio_info mag3110_info = { .attrs = &mag3110_group, .read_raw = &mag3110_read_raw, .write_raw = &mag3110_write_raw, .driver_module = THIS_MODULE, }; static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
static int mag3110_standby(struct mag3110_data *data) { return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, data->ctrl_reg1 & ~MAG3110_CTRL_AC); }

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static int mag3110_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct mag3110_data *data; struct iio_dev *indio_dev; int ret; ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I); if (ret < 0) return ret; if (ret != MAG3110_DEVICE_ID) return -ENODEV; indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; data = iio_priv(indio_dev); data->client = client; mutex_init(&data->lock); i2c_set_clientdata(client, indio_dev); indio_dev->info = &mag3110_info; indio_dev->name = id->name; indio_dev->dev.parent = &client->dev; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->channels = mag3110_channels; indio_dev->num_channels = ARRAY_SIZE(mag3110_channels); indio_dev->available_scan_masks = mag3110_scan_masks; data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT; ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1, data->ctrl_reg1); if (ret < 0) return ret; ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2, MAG3110_CTRL_AUTO_MRST_EN); if (ret < 0) goto standby_on_error; ret = iio_triggered_buffer_setup(indio_dev, NULL, mag3110_trigger_handler, NULL); if (ret < 0) goto standby_on_error; ret = iio_device_register(indio_dev); if (ret < 0) goto buffer_cleanup; return 0; buffer_cleanup: iio_triggered_buffer_cleanup(indio_dev); standby_on_error: mag3110_standby(iio_priv(indio_dev)); return ret; }

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static int mag3110_remove(struct i2c_client *client) { struct iio_dev *indio_dev = i2c_get_clientdata(client); iio_device_unregister(indio_dev); iio_triggered_buffer_cleanup(indio_dev); mag3110_standby(iio_priv(indio_dev)); return 0; }

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#ifdef CONFIG_PM_SLEEP
static int mag3110_suspend(struct device *dev) { return mag3110_standby(iio_priv(i2c_get_clientdata( to_i2c_client(dev)))); }

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static int mag3110_resume(struct device *dev) { struct mag3110_data *data = iio_priv(i2c_get_clientdata( to_i2c_client(dev))); return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, data->ctrl_reg1); }

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static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume); #define MAG3110_PM_OPS (&mag3110_pm_ops) #else #define MAG3110_PM_OPS NULL #endif static const struct i2c_device_id mag3110_id[] = { { "mag3110", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, mag3110_id); static struct i2c_driver mag3110_driver = { .driver = { .name = "mag3110", .pm = MAG3110_PM_OPS, }, .probe = mag3110_probe, .remove = mag3110_remove, .id_table = mag3110_id, }; module_i2c_driver(mag3110_driver); MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver"); MODULE_LICENSE("GPL");

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