--- /dev/null
+// 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");
projects / platform / kernel / linux-rpi.git / commitdiff