linux/drivers/iio/magnetometer/rm3100-core.c
Song Qiang 121354b2ec iio: magnetometer: Add driver support for PNI RM3100
PNI RM3100 is a high resolution, large signal immunity magnetometer,
composed of 3 single sensors and a processing chip with a MagI2C
interface.

Following functions are available:
 - Single-shot measurement from
   /sys/bus/iio/devices/iio:deviceX/in_magn_{axis}_raw
 - Triggerd buffer measurement.
 - DRDY pin for data ready trigger.
 - Both i2c and spi interface are supported.
 - Both interrupt and polling measurement is supported, depends on if
   the 'interrupts' in DT is declared.

Signed-off-by: Song Qiang <songqiang1304521@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2018-11-16 18:32:31 +00:00

617 lines
16 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* PNI RM3100 3-axis geomagnetic sensor driver core.
*
* Copyright (C) 2018 Song Qiang <songqiang1304521@gmail.com>
*
* User Manual available at
* <https://www.pnicorp.com/download/rm3100-user-manual/>
*
* TODO: event generation, pm.
*/
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include "rm3100.h"
/* Cycle Count Registers. */
#define RM3100_REG_CC_X 0x05
#define RM3100_REG_CC_Y 0x07
#define RM3100_REG_CC_Z 0x09
/* Poll Measurement Mode register. */
#define RM3100_REG_POLL 0x00
#define RM3100_POLL_X BIT(4)
#define RM3100_POLL_Y BIT(5)
#define RM3100_POLL_Z BIT(6)
/* Continuous Measurement Mode register. */
#define RM3100_REG_CMM 0x01
#define RM3100_CMM_START BIT(0)
#define RM3100_CMM_X BIT(4)
#define RM3100_CMM_Y BIT(5)
#define RM3100_CMM_Z BIT(6)
/* TiMe Rate Configuration register. */
#define RM3100_REG_TMRC 0x0B
#define RM3100_TMRC_OFFSET 0x92
/* Result Status register. */
#define RM3100_REG_STATUS 0x34
#define RM3100_STATUS_DRDY BIT(7)
/* Measurement result registers. */
#define RM3100_REG_MX2 0x24
#define RM3100_REG_MY2 0x27
#define RM3100_REG_MZ2 0x2a
#define RM3100_W_REG_START RM3100_REG_POLL
#define RM3100_W_REG_END RM3100_REG_TMRC
#define RM3100_R_REG_START RM3100_REG_POLL
#define RM3100_R_REG_END RM3100_REG_STATUS
#define RM3100_V_REG_START RM3100_REG_POLL
#define RM3100_V_REG_END RM3100_REG_STATUS
/*
* This is computed by hand, is the sum of channel storage bits and padding
* bits, which is 4+4+4+12=24 in here.
*/
#define RM3100_SCAN_BYTES 24
#define RM3100_CMM_AXIS_SHIFT 4
struct rm3100_data {
struct regmap *regmap;
struct completion measuring_done;
bool use_interrupt;
int conversion_time;
int scale;
u8 buffer[RM3100_SCAN_BYTES];
struct iio_trigger *drdy_trig;
/*
* This lock is for protecting the consistency of series of i2c
* operations, that is, to make sure a measurement process will
* not be interrupted by a set frequency operation, which should
* be taken where a series of i2c operation starts, released where
* the operation ends.
*/
struct mutex lock;
};
static const struct regmap_range rm3100_readable_ranges[] = {
regmap_reg_range(RM3100_R_REG_START, RM3100_R_REG_END),
};
const struct regmap_access_table rm3100_readable_table = {
.yes_ranges = rm3100_readable_ranges,
.n_yes_ranges = ARRAY_SIZE(rm3100_readable_ranges),
};
EXPORT_SYMBOL_GPL(rm3100_readable_table);
static const struct regmap_range rm3100_writable_ranges[] = {
regmap_reg_range(RM3100_W_REG_START, RM3100_W_REG_END),
};
const struct regmap_access_table rm3100_writable_table = {
.yes_ranges = rm3100_writable_ranges,
.n_yes_ranges = ARRAY_SIZE(rm3100_writable_ranges),
};
EXPORT_SYMBOL_GPL(rm3100_writable_table);
static const struct regmap_range rm3100_volatile_ranges[] = {
regmap_reg_range(RM3100_V_REG_START, RM3100_V_REG_END),
};
const struct regmap_access_table rm3100_volatile_table = {
.yes_ranges = rm3100_volatile_ranges,
.n_yes_ranges = ARRAY_SIZE(rm3100_volatile_ranges),
};
EXPORT_SYMBOL_GPL(rm3100_volatile_table);
static irqreturn_t rm3100_thread_fn(int irq, void *d)
{
struct iio_dev *indio_dev = d;
struct rm3100_data *data = iio_priv(indio_dev);
/*
* Write operation to any register or read operation
* to first byte of results will clear the interrupt.
*/
regmap_write(data->regmap, RM3100_REG_POLL, 0);
return IRQ_HANDLED;
}
static irqreturn_t rm3100_irq_handler(int irq, void *d)
{
struct iio_dev *indio_dev = d;
struct rm3100_data *data = iio_priv(indio_dev);
switch (indio_dev->currentmode) {
case INDIO_DIRECT_MODE:
complete(&data->measuring_done);
break;
case INDIO_BUFFER_TRIGGERED:
iio_trigger_poll(data->drdy_trig);
break;
default:
dev_err(indio_dev->dev.parent,
"device mode out of control, current mode: %d",
indio_dev->currentmode);
}
return IRQ_WAKE_THREAD;
}
static int rm3100_wait_measurement(struct rm3100_data *data)
{
struct regmap *regmap = data->regmap;
unsigned int val;
int tries = 20;
int ret;
/*
* A read cycle of 400kbits i2c bus is about 20us, plus the time
* used for scheduling, a read cycle of fast mode of this device
* can reach 1.7ms, it may be possible for data to arrive just
* after we check the RM3100_REG_STATUS. In this case, irq_handler is
* called before measuring_done is reinitialized, it will wait
* forever for data that has already been ready.
* Reinitialize measuring_done before looking up makes sure we
* will always capture interrupt no matter when it happens.
*/
if (data->use_interrupt)
reinit_completion(&data->measuring_done);
ret = regmap_read(regmap, RM3100_REG_STATUS, &val);
if (ret < 0)
return ret;
if ((val & RM3100_STATUS_DRDY) != RM3100_STATUS_DRDY) {
if (data->use_interrupt) {
ret = wait_for_completion_timeout(&data->measuring_done,
msecs_to_jiffies(data->conversion_time));
if (!ret)
return -ETIMEDOUT;
} else {
do {
usleep_range(1000, 5000);
ret = regmap_read(regmap, RM3100_REG_STATUS,
&val);
if (ret < 0)
return ret;
if (val & RM3100_STATUS_DRDY)
break;
} while (--tries);
if (!tries)
return -ETIMEDOUT;
}
}
return 0;
}
static int rm3100_read_mag(struct rm3100_data *data, int idx, int *val)
{
struct regmap *regmap = data->regmap;
u8 buffer[3];
int ret;
mutex_lock(&data->lock);
ret = regmap_write(regmap, RM3100_REG_POLL, BIT(4 + idx));
if (ret < 0)
goto unlock_return;
ret = rm3100_wait_measurement(data);
if (ret < 0)
goto unlock_return;
ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * idx, buffer, 3);
if (ret < 0)
goto unlock_return;
mutex_unlock(&data->lock);
*val = sign_extend32((buffer[0] << 16) | (buffer[1] << 8) | buffer[2],
23);
return IIO_VAL_INT;
unlock_return:
mutex_unlock(&data->lock);
return ret;
}
#define RM3100_CHANNEL(axis, idx) \
{ \
.type = IIO_MAGN, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
BIT(IIO_CHAN_INFO_SAMP_FREQ), \
.scan_index = idx, \
.scan_type = { \
.sign = 's', \
.realbits = 24, \
.storagebits = 32, \
.shift = 8, \
.endianness = IIO_BE, \
}, \
}
static const struct iio_chan_spec rm3100_channels[] = {
RM3100_CHANNEL(X, 0),
RM3100_CHANNEL(Y, 1),
RM3100_CHANNEL(Z, 2),
IIO_CHAN_SOFT_TIMESTAMP(3),
};
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
"600 300 150 75 37 18 9 4.5 2.3 1.2 0.6 0.3 0.015 0.075"
);
static struct attribute *rm3100_attributes[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL,
};
static const struct attribute_group rm3100_attribute_group = {
.attrs = rm3100_attributes,
};
#define RM3100_SAMP_NUM 14
/*
* Frequency : rm3100_samp_rates[][0].rm3100_samp_rates[][1]Hz.
* Time between reading: rm3100_sam_rates[][2]ms.
* The first one is actually 1.7ms.
*/
static const int rm3100_samp_rates[RM3100_SAMP_NUM][3] = {
{600, 0, 2}, {300, 0, 3}, {150, 0, 7}, {75, 0, 13}, {37, 0, 27},
{18, 0, 55}, {9, 0, 110}, {4, 500000, 220}, {2, 300000, 440},
{1, 200000, 800}, {0, 600000, 1600}, {0, 300000, 3300},
{0, 15000, 6700}, {0, 75000, 13000}
};
static int rm3100_get_samp_freq(struct rm3100_data *data, int *val, int *val2)
{
unsigned int tmp;
int ret;
mutex_lock(&data->lock);
ret = regmap_read(data->regmap, RM3100_REG_TMRC, &tmp);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][0];
*val2 = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][1];
return IIO_VAL_INT_PLUS_MICRO;
}
static int rm3100_set_cycle_count(struct rm3100_data *data, int val)
{
int ret;
u8 i;
for (i = 0; i < 3; i++) {
ret = regmap_write(data->regmap, RM3100_REG_CC_X + 2 * i, val);
if (ret < 0)
return ret;
}
/*
* The scale of this sensor depends on the cycle count value, these
* three values are corresponding to the cycle count value 50, 100,
* 200. scale = output / gain * 10^4.
*/
switch (val) {
case 50:
data->scale = 500;
break;
case 100:
data->scale = 263;
break;
/*
* case 200:
* This function will never be called by users' code, so here we
* assume that it will never get a wrong parameter.
*/
default:
data->scale = 133;
}
return 0;
}
static int rm3100_set_samp_freq(struct iio_dev *indio_dev, int val, int val2)
{
struct rm3100_data *data = iio_priv(indio_dev);
struct regmap *regmap = data->regmap;
unsigned int cycle_count;
int ret;
int i;
mutex_lock(&data->lock);
/* All cycle count registers use the same value. */
ret = regmap_read(regmap, RM3100_REG_CC_X, &cycle_count);
if (ret < 0)
goto unlock_return;
for (i = 0; i < RM3100_SAMP_NUM; i++) {
if (val == rm3100_samp_rates[i][0] &&
val2 == rm3100_samp_rates[i][1])
break;
}
if (i == RM3100_SAMP_NUM) {
ret = -EINVAL;
goto unlock_return;
}
ret = regmap_write(regmap, RM3100_REG_TMRC, i + RM3100_TMRC_OFFSET);
if (ret < 0)
goto unlock_return;
/* Checking if cycle count registers need changing. */
if (val == 600 && cycle_count == 200) {
ret = rm3100_set_cycle_count(data, 100);
if (ret < 0)
goto unlock_return;
} else if (val != 600 && cycle_count == 100) {
ret = rm3100_set_cycle_count(data, 200);
if (ret < 0)
goto unlock_return;
}
if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
/* Writing TMRC registers requires CMM reset. */
ret = regmap_write(regmap, RM3100_REG_CMM, 0);
if (ret < 0)
goto unlock_return;
ret = regmap_write(data->regmap, RM3100_REG_CMM,
(*indio_dev->active_scan_mask & 0x7) <<
RM3100_CMM_AXIS_SHIFT | RM3100_CMM_START);
if (ret < 0)
goto unlock_return;
}
mutex_unlock(&data->lock);
data->conversion_time = rm3100_samp_rates[i][2] * 2;
return 0;
unlock_return:
mutex_unlock(&data->lock);
return ret;
}
static int rm3100_read_raw(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
int *val, int *val2, long mask)
{
struct rm3100_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = iio_device_claim_direct_mode(indio_dev);
if (ret < 0)
return ret;
ret = rm3100_read_mag(data, chan->scan_index, val);
iio_device_release_direct_mode(indio_dev);
return ret;
case IIO_CHAN_INFO_SCALE:
*val = 0;
*val2 = data->scale;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SAMP_FREQ:
return rm3100_get_samp_freq(data, val, val2);
default:
return -EINVAL;
}
}
static int rm3100_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
switch (mask) {
case IIO_CHAN_INFO_SAMP_FREQ:
return rm3100_set_samp_freq(indio_dev, val, val2);
default:
return -EINVAL;
}
}
static const struct iio_info rm3100_info = {
.attrs = &rm3100_attribute_group,
.read_raw = rm3100_read_raw,
.write_raw = rm3100_write_raw,
};
static int rm3100_buffer_preenable(struct iio_dev *indio_dev)
{
struct rm3100_data *data = iio_priv(indio_dev);
/* Starting channels enabled. */
return regmap_write(data->regmap, RM3100_REG_CMM,
(*indio_dev->active_scan_mask & 0x7) << RM3100_CMM_AXIS_SHIFT |
RM3100_CMM_START);
}
static int rm3100_buffer_postdisable(struct iio_dev *indio_dev)
{
struct rm3100_data *data = iio_priv(indio_dev);
return regmap_write(data->regmap, RM3100_REG_CMM, 0);
}
static const struct iio_buffer_setup_ops rm3100_buffer_ops = {
.preenable = rm3100_buffer_preenable,
.postenable = iio_triggered_buffer_postenable,
.predisable = iio_triggered_buffer_predisable,
.postdisable = rm3100_buffer_postdisable,
};
static irqreturn_t rm3100_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
unsigned long scan_mask = *indio_dev->active_scan_mask;
unsigned int mask_len = indio_dev->masklength;
struct rm3100_data *data = iio_priv(indio_dev);
struct regmap *regmap = data->regmap;
int ret, i, bit;
mutex_lock(&data->lock);
switch (scan_mask) {
case BIT(0) | BIT(1) | BIT(2):
ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9);
mutex_unlock(&data->lock);
if (ret < 0)
goto done;
/* Convert XXXYYYZZZxxx to XXXxYYYxZZZx. x for paddings. */
for (i = 2; i > 0; i--)
memmove(data->buffer + i * 4, data->buffer + i * 3, 3);
break;
case BIT(0) | BIT(1):
ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 6);
mutex_unlock(&data->lock);
if (ret < 0)
goto done;
memmove(data->buffer + 4, data->buffer + 3, 3);
break;
case BIT(1) | BIT(2):
ret = regmap_bulk_read(regmap, RM3100_REG_MY2, data->buffer, 6);
mutex_unlock(&data->lock);
if (ret < 0)
goto done;
memmove(data->buffer + 4, data->buffer + 3, 3);
break;
case BIT(0) | BIT(2):
ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9);
mutex_unlock(&data->lock);
if (ret < 0)
goto done;
memmove(data->buffer + 4, data->buffer + 6, 3);
break;
default:
for_each_set_bit(bit, &scan_mask, mask_len) {
ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * bit,
data->buffer, 3);
if (ret < 0) {
mutex_unlock(&data->lock);
goto done;
}
}
mutex_unlock(&data->lock);
}
/*
* Always using the same buffer so that we wouldn't need to set the
* paddings to 0 in case of leaking any data.
*/
iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
pf->timestamp);
done:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
int rm3100_common_probe(struct device *dev, struct regmap *regmap, int irq)
{
struct iio_dev *indio_dev;
struct rm3100_data *data;
unsigned int tmp;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
data->regmap = regmap;
mutex_init(&data->lock);
indio_dev->dev.parent = dev;
indio_dev->name = "rm3100";
indio_dev->info = &rm3100_info;
indio_dev->channels = rm3100_channels;
indio_dev->num_channels = ARRAY_SIZE(rm3100_channels);
indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
indio_dev->currentmode = INDIO_DIRECT_MODE;
if (!irq)
data->use_interrupt = false;
else {
data->use_interrupt = true;
init_completion(&data->measuring_done);
ret = devm_request_threaded_irq(dev,
irq,
rm3100_irq_handler,
rm3100_thread_fn,
IRQF_TRIGGER_HIGH |
IRQF_ONESHOT,
indio_dev->name,
indio_dev);
if (ret < 0) {
dev_err(dev, "request irq line failed.\n");
return ret;
}
data->drdy_trig = devm_iio_trigger_alloc(dev, "%s-drdy%d",
indio_dev->name,
indio_dev->id);
if (!data->drdy_trig)
return -ENOMEM;
data->drdy_trig->dev.parent = dev;
ret = devm_iio_trigger_register(dev, data->drdy_trig);
if (ret < 0)
return ret;
}
ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
&iio_pollfunc_store_time,
rm3100_trigger_handler,
&rm3100_buffer_ops);
if (ret < 0)
return ret;
ret = regmap_read(regmap, RM3100_REG_TMRC, &tmp);
if (ret < 0)
return ret;
/* Initializing max wait time, which is double conversion time. */
data->conversion_time = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][2]
* 2;
/* Cycle count values may not be what we want. */
if ((tmp - RM3100_TMRC_OFFSET) == 0)
rm3100_set_cycle_count(data, 100);
else
rm3100_set_cycle_count(data, 200);
return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL_GPL(rm3100_common_probe);
MODULE_AUTHOR("Song Qiang <songqiang1304521@gmail.com>");
MODULE_DESCRIPTION("PNI RM3100 3-axis magnetometer i2c driver");
MODULE_LICENSE("GPL v2");