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    Subject[PATCH 2/2] iio: magnetometer: Add driver support for PNI RM3100
    Date
    PNI RM3100 is a high resolution, large signal immunity magnetometer,
    composed of 3 single sensors and a processing chip with MagI2C Interface.

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

    Signed-off-by: Song Qiang <songqiang1304521@gmail.com>
    ---
    Changes in v2:
    - Add scale channel.
    - Add EXPORT_SYMBOL_GPL() to export regmap confuguration
    structures.
    - Add sampling frequency available attribute.
    - Clean up headers and License declarations.
    - Change axis number to 3.
    - Remove bus specific part in compatible string.
    - Remove le32_to_cpu().
    - Check cycle count registers at *_probe().
    - Format comments.
    - Spell check.
    - Change prefix from RM_* to RM3100_*.
    - Check all error return paths.
    - Add devm_add_action() to avoid race condition when remove.

    MAINTAINERS | 7 +
    drivers/iio/magnetometer/Kconfig | 29 ++
    drivers/iio/magnetometer/Makefile | 4 +
    drivers/iio/magnetometer/rm3100-core.c | 470 +++++++++++++++++++++++++
    drivers/iio/magnetometer/rm3100-i2c.c | 58 +++
    drivers/iio/magnetometer/rm3100-spi.c | 64 ++++
    drivers/iio/magnetometer/rm3100.h | 73 ++++
    7 files changed, 705 insertions(+)
    create mode 100644 drivers/iio/magnetometer/rm3100-core.c
    create mode 100644 drivers/iio/magnetometer/rm3100-i2c.c
    create mode 100644 drivers/iio/magnetometer/rm3100-spi.c
    create mode 100644 drivers/iio/magnetometer/rm3100.h

    diff --git a/MAINTAINERS b/MAINTAINERS
    index 967ce8cdd1cc..14eeeb072403 100644
    --- a/MAINTAINERS
    +++ b/MAINTAINERS
    @@ -11393,6 +11393,13 @@ M: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
    S: Maintained
    F: drivers/pnp/

    +PNI RM3100 IIO DRIVER
    +M: Song Qiang <songqiang1304521@gmail.com>
    +L: linux-iio@vger.kernel.org
    +S: Maintained
    +F: drivers/iio/magnetometer/rm3100*
    +F: Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt
    +
    POSIX CLOCKS and TIMERS
    M: Thomas Gleixner <tglx@linutronix.de>
    L: linux-kernel@vger.kernel.org
    diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
    index ed9d776d01af..f130b866a4fc 100644
    --- a/drivers/iio/magnetometer/Kconfig
    +++ b/drivers/iio/magnetometer/Kconfig
    @@ -175,4 +175,33 @@ config SENSORS_HMC5843_SPI
    - hmc5843_core (core functions)
    - hmc5843_spi (support for HMC5983)

    +config SENSORS_RM3100
    + tristate
    + select IIO_BUFFER
    + select IIO_TRIGGERED_BUFFER
    +
    +config SENSORS_RM3100_I2C
    + tristate "PNI RM3100 9-Axis Magnetometer (I2C)"
    + depends on I2C
    + select SENSORS_RM3100
    + select REGMAP_I2C
    + help
    + Say Y here to add support for the PNI RM3100 9-Axis Magnetometer.
    +
    + This driver can also be compiled as a module.
    + To compile this driver as a module, choose M here: the module
    + will be called rm3100-i2c.
    +
    +config SENSORS_RM3100_SPI
    + tristate "PNI RM3100 9-Axis Magnetometer (SPI)"
    + depends on SPI_MASTER
    + select SENSORS_RM3100
    + select REGMAP_SPI
    + help
    + Say Y here to add support for the PNI RM3100 9-Axis Magnetometer.
    +
    + This driver can also be compiled as a module.
    + To compile this driver as a module, choose M here: the module
    + will be called rm3100-spi.
    +
    endmenu
    diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
    index 664b2f866472..ba1bc34b82fa 100644
    --- a/drivers/iio/magnetometer/Makefile
    +++ b/drivers/iio/magnetometer/Makefile
    @@ -24,3 +24,7 @@ obj-$(CONFIG_IIO_ST_MAGN_SPI_3AXIS) += st_magn_spi.o
    obj-$(CONFIG_SENSORS_HMC5843) += hmc5843_core.o
    obj-$(CONFIG_SENSORS_HMC5843_I2C) += hmc5843_i2c.o
    obj-$(CONFIG_SENSORS_HMC5843_SPI) += hmc5843_spi.o
    +
    +obj-$(CONFIG_SENSORS_RM3100) += rm3100-core.o
    +obj-$(CONFIG_SENSORS_RM3100_I2C) += rm3100-i2c.o
    +obj-$(CONFIG_SENSORS_RM3100_SPI) += rm3100-spi.o
    diff --git a/drivers/iio/magnetometer/rm3100-core.c b/drivers/iio/magnetometer/rm3100-core.c
    new file mode 100644
    index 000000000000..5d28b53b7a04
    --- /dev/null
    +++ b/drivers/iio/magnetometer/rm3100-core.c
    @@ -0,0 +1,470 @@
    +// 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 generaton, pm.
    + */
    +
    +#include <linux/module.h>
    +#include <linux/delay.h>
    +#include <linux/interrupt.h>
    +#include <linux/slab.h>
    +
    +#include <linux/iio/iio.h>
    +#include <linux/iio/sysfs.h>
    +#include <linux/iio/triggered_buffer.h>
    +#include <linux/iio/trigger_consumer.h>
    +#include <linux/iio/buffer.h>
    +#include <linux/iio/kfifo_buf.h>
    +
    +#include "rm3100.h"
    +
    +static const struct regmap_range rm3100_readable_ranges[] = {
    + regmap_reg_range(RM3100_W_REG_START, RM3100_W_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_R_REG_START, RM3100_R_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_irq_handler(int irq, void *d)
    +{
    + struct rm3100_data *data = d;
    +
    + complete(&data->measuring_done);
    +
    + return IRQ_HANDLED;
    +}
    +
    +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 happened.
    + */
    + 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 < 0)
    + 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 = rm3100_wait_measurement(data);
    + if (ret < 0) {
    + mutex_unlock(&data->lock);
    + return ret;
    + }
    +
    + ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * idx, buffer, 3);
    + mutex_unlock(&data->lock);
    + if (ret < 0)
    + return ret;
    +
    + *val = sign_extend32((buffer[0] << 16) | (buffer[1] << 8) | buffer[2],
    + 23);
    +
    + return IIO_VAL_INT;
    +}
    +
    +#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_LE, \
    + }, \
    + }
    +
    +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 const unsigned long rm3100_scan_masks[] = {GENMASK(2, 0), 0};
    +
    +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)
    +{
    + int ret;
    + int tmp;
    +
    + 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, 100);
    + if (ret < 0)
    + return ret;
    + }
    + if (val == 50)
    + data->cycle_count_index = 0;
    + else if (val == 100)
    + data->cycle_count_index = 1;
    + else
    + data->cycle_count_index = 2;
    +
    + return 0;
    +}
    +
    +static int rm3100_set_samp_freq(struct rm3100_data *data, int val, int val2)
    +{
    + struct regmap *regmap = data->regmap;
    + 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;
    + }
    +
    + /* Writing TMRC registers requires CMM reset. */
    + ret = regmap_write(regmap, RM3100_REG_CMM, 0);
    + if (ret < 0)
    + goto unlock_return;
    + ret = regmap_write(regmap, RM3100_REG_CMM,
    + RM3100_CMM_X | RM3100_CMM_Y | RM3100_CMM_Z | RM3100_CMM_START);
    + mutex_unlock(&data->lock);
    + if (ret < 0)
    + return ret;
    +
    + data->conversion_time = rm3100_samp_rates[i][2] + 3000;
    + return 0;
    +
    +unlock_return:
    + mutex_unlock(&data->lock);
    + return ret;
    +}
    +
    +/*
    + * Scale of this sensor depends on cycle count value, these three values
    + * are corresponding to cycle count value 50, 100, 200.
    + * scale = output / gain * 10e4.
    + */
    +const static int rm3100_scale[] = {500, 263, 133};
    +
    +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) {
    + iio_device_release_direct_mode(indio_dev);
    + 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 = rm3100_scale[data->cycle_count_index];
    +
    + 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)
    +{
    + struct rm3100_data *data = iio_priv(indio_dev);
    +
    + switch (mask) {
    + case IIO_CHAN_INFO_SAMP_FREQ:
    + return rm3100_set_samp_freq(data, 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 irqreturn_t rm3100_trigger_handler(int irq, void *p)
    +{
    + struct iio_poll_func *pf = p;
    + struct iio_dev *indio_dev = pf->indio_dev;
    + struct rm3100_data *data = iio_priv(indio_dev);
    + struct regmap *regmap = data->regmap;
    + u8 buffer[9];
    + int ret;
    + int i;
    +
    + mutex_lock(&data->lock);
    + ret = rm3100_wait_measurement(data);
    + if (ret < 0) {
    + mutex_unlock(&data->lock);
    + goto done;
    + }
    +
    + ret = regmap_bulk_read(regmap, RM3100_REG_MX2, buffer, sizeof(buffer));
    + mutex_unlock(&data->lock);
    + if (ret < 0)
    + goto done;
    +
    + /* Convert XXXYYYZZZxxx to XXXxYYYxZZZx. x for padding. */
    + for (i = 0; i < 3; i++)
    + memcpy(data->buffer + i * 4, buffer + i * 3, 3);
    +
    + iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
    + iio_get_time_ns(indio_dev));
    +
    +done:
    + iio_trigger_notify_done(indio_dev->trig);
    +
    + return IRQ_HANDLED;
    +}
    +
    +static void rm3100_remove(void *dh)
    +{
    + struct rm3100_data *data = (struct rm3100_data *)dh;
    + int ret;
    +
    + ret = regmap_write(data->regmap, RM3100_REG_CMM, 0x00);
    + if (ret < 0)
    + dev_err(data->dev, "failed to stop device.\n");
    +}
    +
    +int rm3100_common_probe(struct device *dev, struct regmap *regmap, int irq)
    +{
    + struct iio_dev *indio_dev;
    + struct rm3100_data *data;
    + int tmp;
    + int ret;
    +
    + indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
    + if (!indio_dev)
    + return -ENOMEM;
    +
    + data = iio_priv(indio_dev);
    + data->dev = dev;
    + data->regmap = regmap;
    + data->buffer = devm_kzalloc(dev, RM3100_SCAN_BYTES, GFP_KERNEL);
    + if (!data->buffer)
    + return -ENOMEM;
    +
    + 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_dev->available_scan_masks = rm3100_scan_masks;
    +
    + if (!irq)
    + data->use_interrupt = false;
    + else {
    + data->use_interrupt = true;
    + ret = devm_request_irq(dev,
    + irq,
    + rm3100_irq_handler,
    + IRQF_TRIGGER_RISING,
    + indio_dev->name,
    + data);
    + if (ret < 0) {
    + dev_err(dev, "request irq line failed.\n");
    + return ret;
    + }
    + init_completion(&data->measuring_done);
    + }
    +
    + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
    + rm3100_trigger_handler, NULL);
    + if (ret < 0)
    + return ret;
    +
    + /* 3sec more wait time. */
    + ret = regmap_read(regmap, RM3100_REG_TMRC, &tmp);
    + if (ret < 0)
    + return ret;
    + data->conversion_time =
    + rm3100_samp_rates[tmp-RM3100_TMRC_OFFSET][2] + 3000;
    +
    + /* Cycle count values may not be what we want. */
    + ret = regmap_read(data->regmap, RM3100_REG_TMRC, &tmp);
    + if (ret < 0)
    + return ret;
    + if ((tmp - RM3100_TMRC_OFFSET) == 0)
    + rm3100_set_cycle_count(data, 100);
    + else
    + rm3100_set_cycle_count(data, 200);
    +
    + /* Starting all channels' conversion. */
    + ret = regmap_write(regmap, RM3100_REG_CMM,
    + RM3100_CMM_X | RM3100_CMM_Y | RM3100_CMM_Z | RM3100_CMM_START);
    + if (ret < 0)
    + return ret;
    +
    + ret = devm_iio_device_register(dev, indio_dev);
    + if (ret < 0)
    + return ret;
    +
    + return devm_add_action(dev, rm3100_remove, data);
    +}
    +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");
    diff --git a/drivers/iio/magnetometer/rm3100-i2c.c b/drivers/iio/magnetometer/rm3100-i2c.c
    new file mode 100644
    index 000000000000..e8b84fac771b
    --- /dev/null
    +++ b/drivers/iio/magnetometer/rm3100-i2c.c
    @@ -0,0 +1,58 @@
    +// SPDX-License-Identifier: GPL-2.0
    +/*
    + * Support for PNI RM3100 3-axis geomagnetic sensor a i2c bus.
    + *
    + * Copyright (C) 2018 Song Qiang <songqiang1304521@gmail.com>
    + *
    + * i2c slave address 0x20 + SA1 << 1 + SA0.
    + */
    +
    +#include <linux/module.h>
    +#include <linux/i2c.h>
    +
    +#include "rm3100.h"
    +
    +static const struct regmap_config rm3100_regmap_config = {
    + .reg_bits = 8,
    + .val_bits = 8,
    +
    + .rd_table = &rm3100_readable_table,
    + .wr_table = &rm3100_writable_table,
    + .volatile_table = &rm3100_volatile_table,
    +
    + .cache_type = REGCACHE_RBTREE,
    +};
    +
    +static int rm3100_probe(struct i2c_client *client)
    +{
    + struct regmap *regmap;
    +
    + if (!i2c_check_functionality(client->adapter,
    + I2C_FUNC_SMBUS_READ_I2C_BLOCK | I2C_FUNC_SMBUS_BYTE_DATA))
    + return -EOPNOTSUPP;
    +
    + regmap = devm_regmap_init_i2c(client, &rm3100_regmap_config);
    + if (IS_ERR(regmap))
    + return PTR_ERR(regmap);
    +
    + return rm3100_common_probe(&client->dev, regmap, client->irq);
    +}
    +
    +static const struct of_device_id rm3100_dt_match[] = {
    + { .compatible = "pni,rm3100", },
    + { }
    +};
    +MODULE_DEVICE_TABLE(of, rm3100_dt_match);
    +
    +static struct i2c_driver rm3100_driver = {
    + .driver = {
    + .name = "rm3100-i2c",
    + .of_match_table = rm3100_dt_match,
    + },
    + .probe_new = rm3100_probe,
    +};
    +module_i2c_driver(rm3100_driver);
    +
    +MODULE_AUTHOR("Song Qiang <songqiang1304521@gmail.com>");
    +MODULE_DESCRIPTION("PNI RM3100 3-axis magnetometer i2c driver");
    +MODULE_LICENSE("GPL v2");
    diff --git a/drivers/iio/magnetometer/rm3100-spi.c b/drivers/iio/magnetometer/rm3100-spi.c
    new file mode 100644
    index 000000000000..1a7a69fb9872
    --- /dev/null
    +++ b/drivers/iio/magnetometer/rm3100-spi.c
    @@ -0,0 +1,64 @@
    +// SPDX-License-Identifier: GPL-2.0
    +/*
    + * Support for PNI RM3100 3-axis geomagnetic sensor a spi bus.
    + *
    + * Copyright (C) 2018 Song Qiang <songqiang1304521@gmail.com>
    + */
    +
    +#include <linux/module.h>
    +#include <linux/spi/spi.h>
    +
    +#include "rm3100.h"
    +
    +static const struct regmap_config rm3100_regmap_config = {
    + .reg_bits = 8,
    + .val_bits = 8,
    +
    + .rd_table = &rm3100_readable_table,
    + .wr_table = &rm3100_writable_table,
    + .volatile_table = &rm3100_volatile_table,
    +
    + .read_flag_mask = 0x80,
    +
    + .cache_type = REGCACHE_RBTREE,
    +};
    +
    +static int rm3100_probe(struct spi_device *spi)
    +{
    + struct regmap *regmap;
    + int ret;
    +
    + /* Actually this device supports both mode 0 and mode 3. */
    + spi->mode = SPI_MODE_0;
    + /* Data rates cannot exceed 1Mbits. */
    + spi->max_speed_hz = 1000000;
    + spi->bits_per_word = 8;
    + ret = spi_setup(spi);
    + if (ret)
    + return ret;
    +
    + regmap = devm_regmap_init_spi(spi, &rm3100_regmap_config);
    + if (IS_ERR(regmap))
    + return PTR_ERR(regmap);
    +
    + return rm3100_common_probe(&spi->dev, regmap, spi->irq);
    +}
    +
    +static const struct of_device_id rm3100_dt_match[] = {
    + { .compatible = "pni,rm3100", },
    + { }
    +};
    +MODULE_DEVICE_TABLE(of, rm3100_dt_match);
    +
    +static struct spi_driver rm3100_driver = {
    + .driver = {
    + .name = "rm3100-spi",
    + .of_match_table = rm3100_dt_match,
    + },
    + .probe = rm3100_probe,
    +};
    +module_spi_driver(rm3100_driver);
    +
    +MODULE_AUTHOR("Song Qiang <songqiang1304521@gmail.com>");
    +MODULE_DESCRIPTION("PNI RM3100 3-axis magnetometer spi driver");
    +MODULE_LICENSE("GPL v2");
    diff --git a/drivers/iio/magnetometer/rm3100.h b/drivers/iio/magnetometer/rm3100.h
    new file mode 100644
    index 000000000000..673647574add
    --- /dev/null
    +++ b/drivers/iio/magnetometer/rm3100.h
    @@ -0,0 +1,73 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +/*
    + * Header file for PNI RM3100 driver
    + *
    + * Copyright (C) 2018 Song Qiang <songqiang1304521@gmail.com>
    + */
    +
    +#ifndef RM3100_CORE_H
    +#define RM3100_CORE_H
    +
    +#include <linux/regmap.h>
    +
    +#define RM3100_REG_REV_ID 0x36
    +
    +/* Cycle Count Registers. */
    +#define RM3100_REG_CC_X 0x05
    +#define RM3100_REG_CC_Y 0x07
    +#define RM3100_REG_CC_Z 0x09
    +
    +/* Continues 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_CMM
    +#define RM3100_W_REG_END RM3100_REG_REV_ID
    +#define RM3100_R_REG_START RM3100_REG_CMM
    +#define RM3100_R_REG_END RM3100_REG_STATUS
    +#define RM3100_V_REG_START RM3100_REG_MX2
    +#define RM3100_V_REG_END RM3100_REG_STATUS
    +
    +#define RM3100_SCAN_BYTES 24
    +
    +struct rm3100_data {
    + struct device *dev;
    + struct regmap *regmap;
    + struct completion measuring_done;
    + bool use_interrupt;
    +
    + int conversion_time;
    + int cycle_count_index;
    +
    + u8 *buffer;
    +
    + /*
    + * To protect consistency of every measurement and sampling
    + * frequency change operations.
    + */
    + struct mutex lock;
    +};
    +
    +extern const struct regmap_access_table rm3100_readable_table;
    +extern const struct regmap_access_table rm3100_writable_table;
    +extern const struct regmap_access_table rm3100_volatile_table;
    +
    +int rm3100_common_probe(struct device *dev, struct regmap *regmap, int irq);
    +
    +#endif /* RM3100_CORE_H */
    --
    2.17.1
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      Last update: 2018-09-25 05:18    [W:3.145 / U:0.560 seconds]
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