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- // 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 <asm/unaligned.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;
- /* Ensure naturally aligned timestamp */
- u8 buffer[RM3100_SCAN_BYTES] __aligned(8);
- 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(get_unaligned_be24(&buffer[0]), 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,
- .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->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");
|