Re: [PATCH v2 1/3] iio: magnetometer: Add support for MEMSIC MMC35240 sensor

From: Jonathan Cameron
Date: Fri May 08 2015 - 14:30:33 EST

On 24/04/15 11:58, Daniel Baluta wrote:
> Minimal implementation for MMC35240 3-axis magnetometer
> sensor. It provides processed readings and possiblity to change
> the sampling frequency.
>
> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>
Applied with a couple of statics and a const that were suggested
by compiler warnings.

Jonathan
> ---
> drivers/iio/magnetometer/Kconfig | 11 +
> drivers/iio/magnetometer/Makefile | 1 +
> drivers/iio/magnetometer/mmc35240.c | 468 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 480 insertions(+)
> create mode 100644 drivers/iio/magnetometer/mmc35240.c
>
> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
> index a5d6de7..7aba685 100644
> --- a/drivers/iio/magnetometer/Kconfig
> +++ b/drivers/iio/magnetometer/Kconfig
> @@ -47,6 +47,17 @@ config HID_SENSOR_MAGNETOMETER_3D
> Say yes here to build support for the HID SENSOR
> Magnetometer 3D.
>
> +config MMC35240
> + tristate "MEMSIC MMC35240 3-axis magnetic sensor"
> + select REGMAP_I2C
> + depends on I2C
> + help
> + Say yes here to build support for the MEMSIC MMC35240 3-axis
> + magnetic sensor.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called mmc35240.
> +
> config IIO_ST_MAGN_3AXIS
> tristate "STMicroelectronics magnetometers 3-Axis Driver"
> depends on (I2C || SPI_MASTER) && SYSFS
> diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
> index 0f5d3c9..696a429 100644
> --- a/drivers/iio/magnetometer/Makefile
> +++ b/drivers/iio/magnetometer/Makefile
> @@ -6,6 +6,7 @@
> obj-$(CONFIG_AK8975) += ak8975.o
> obj-$(CONFIG_MAG3110) += mag3110.o
> obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o
> +obj-$(CONFIG_MMC35240) += mmc35240.o
>
> obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o
> st_magn-y := st_magn_core.o
> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
> new file mode 100644
> index 0000000..beefebc
> --- /dev/null
> +++ b/drivers/iio/magnetometer/mmc35240.c
> @@ -0,0 +1,468 @@
> +/*
> + * MMC35240 - MEMSIC 3-axis Magnetic Sensor
> + *
> + * Copyright (c) 2015, Intel Corporation.
> + *
> + * 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.
> + *
> + * IIO driver for MMC35240 (7-bit I2C slave address 0x30).
> + *
> + * TODO: offset, ACPI, continuous measurement mode, PM
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/delay.h>
> +#include <linux/regmap.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define MMC35240_DRV_NAME "mmc35240"
> +#define MMC35240_REGMAP_NAME "mmc35240_regmap"
> +
> +#define MMC35240_REG_XOUT_L 0x00
> +#define MMC35240_REG_XOUT_H 0x01
> +#define MMC35240_REG_YOUT_L 0x02
> +#define MMC35240_REG_YOUT_H 0x03
> +#define MMC35240_REG_ZOUT_L 0x04
> +#define MMC35240_REG_ZOUT_H 0x05
> +
> +#define MMC35240_REG_STATUS 0x06
> +#define MMC35240_REG_CTRL0 0x07
> +#define MMC35240_REG_CTRL1 0x08
> +
> +#define MMC35240_REG_ID 0x20
> +
> +#define MMC35240_STATUS_MEAS_DONE_BIT BIT(0)
> +
> +#define MMC35240_CTRL0_REFILL_BIT BIT(7)
> +#define MMC35240_CTRL0_RESET_BIT BIT(6)
> +#define MMC35240_CTRL0_SET_BIT BIT(5)
> +#define MMC35240_CTRL0_CMM_BIT BIT(1)
> +#define MMC35240_CTRL0_TM_BIT BIT(0)
> +
> +/* output resolution bits */
> +#define MMC35240_CTRL1_BW0_BIT BIT(0)
> +#define MMC35240_CTRL1_BW1_BIT BIT(1)
> +
> +#define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \
> + MMC35240_CTRL1_BW1_BIT)
> +#define MMC35240_CTRL1_BW_SHIFT 0
> +
> +#define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */
> +#define MMC53240_WAIT_SET_RESET 1000 /* us */
> +
> +enum mmc35240_resolution {
> + MMC35240_16_BITS_SLOW = 0, /* 100 Hz */
> + MMC35240_16_BITS_FAST, /* 200 Hz */
> + MMC35240_14_BITS, /* 333 Hz */
> + MMC35240_12_BITS, /* 666 Hz */
> +};
> +
> +enum mmc35240_axis {
> + AXIS_X = 0,
> + AXIS_Y,
> + AXIS_Z,
> +};
> +
> +static const struct {
> + int sens[3]; /* sensitivity per X, Y, Z axis */
> + int nfo; /* null field output */
> +} mmc35240_props_table[] = {
> + /* 16 bits, 100Hz ODR */
> + {
> + {1024, 1024, 770},
> + 32768,
> + },
> + /* 16 bits, 200Hz ODR */
> + {
> + {1024, 1024, 770},
> + 32768,
> + },
> + /* 14 bits, 333Hz ODR */
> + {
> + {256, 256, 193},
> + 8192,
> + },
> + /* 12 bits, 666Hz ODR */
> + {
> + {64, 64, 48},
> + 2048,
> + },
> +};
> +
> +struct mmc35240_data {
> + struct i2c_client *client;
> + struct mutex mutex;
> + struct regmap *regmap;
> + enum mmc35240_resolution res;
> +};
> +
> +int mmc35240_samp_freq[] = {100, 200, 333, 666};
> +
> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100 200 333 666");
> +
> +#define MMC35240_CHANNEL(_axis) { \
> + .type = IIO_MAGN, \
> + .modified = 1, \
> + .channel2 = IIO_MOD_ ## _axis, \
> + .address = AXIS_ ## _axis, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> +}
> +
> +static const struct iio_chan_spec mmc35240_channels[] = {
> + MMC35240_CHANNEL(X),
> + MMC35240_CHANNEL(Y),
> + MMC35240_CHANNEL(Z),
> +};
> +
> +static struct attribute *mmc35240_attributes[] = {
> + &iio_const_attr_sampling_frequency_available.dev_attr.attr,
> +};
> +
> +static const struct attribute_group mmc35240_attribute_group = {
> + .attrs = mmc35240_attributes,
> +};
> +
> +static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
> + int val, int val2)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)
> + if (mmc35240_samp_freq[i] == val)
> + return i;
> + return -EINVAL;
> +}
> +
> +static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
> +{
> + int ret;
> + u8 coil_bit;
> +
> + /*
> + * Recharge the capacitor at VCAP pin, requested to be issued
> + * before a SET/RESET command.
> + */
> + ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
> + MMC35240_CTRL0_REFILL_BIT,
> + MMC35240_CTRL0_REFILL_BIT);
> + if (ret < 0)
> + return ret;
> + usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
> +
> + if (set)
> + coil_bit = MMC35240_CTRL0_SET_BIT;
> + else
> + coil_bit = MMC35240_CTRL0_RESET_BIT;
> +
> + return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
> + MMC35240_CTRL0_REFILL_BIT,
> + coil_bit);
> +}
> +
> +static int mmc35240_init(struct mmc35240_data *data)
> +{
> + int ret;
> + unsigned int reg_id;
> +
> + ret = regmap_read(data->regmap, MMC35240_REG_ID, &reg_id);
> + if (ret < 0) {
> + dev_err(&data->client->dev, "Error reading product id\n");
> + return ret;
> + }
> +
> + dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
> +
> + /*
> + * make sure we restore sensor characteristics, by doing
> + * a RESET/SET sequence
> + */
> + ret = mmc35240_hw_set(data, false);
> + if (ret < 0)
> + return ret;
> + usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);
> +
> + ret = mmc35240_hw_set(data, true);
> + if (ret < 0)
> + return ret;
> +
> + /* set default sampling frequency */
> + return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
> + MMC35240_CTRL1_BW_MASK,
> + data->res << MMC35240_CTRL1_BW_SHIFT);
> +}
> +
> +static int mmc35240_take_measurement(struct mmc35240_data *data)
> +{
> + int ret, tries = 100;
> + unsigned int reg_status;
> +
> + ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,
> + MMC35240_CTRL0_TM_BIT);
> + if (ret < 0)
> + return ret;
> +
> + while (tries-- > 0) {
> + ret = regmap_read(data->regmap, MMC35240_REG_STATUS,
> + &reg_status);
> + if (ret < 0)
> + return ret;
> + if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
> + break;
> + msleep(20);
> + }
> +
> + if (tries < 0) {
> + dev_err(&data->client->dev, "data not ready\n");
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
> +{
> + int ret;
> +
> + ret = mmc35240_take_measurement(data);
> + if (ret < 0)
> + return ret;
> +
> + return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf,
> + 3 * sizeof(__le16));
> +}
> +
> +int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index, __le16 buf[],
> + int *val, int *val2)
> +{
> + int raw_x, raw_y, raw_z;
> + int sens_x, sens_y, sens_z;
> + int nfo;
> +
> + raw_x = le16_to_cpu(buf[AXIS_X]);
> + raw_y = le16_to_cpu(buf[AXIS_Y]);
> + raw_z = le16_to_cpu(buf[AXIS_Z]);
> +
> + sens_x = mmc35240_props_table[data->res].sens[AXIS_X];
> + sens_y = mmc35240_props_table[data->res].sens[AXIS_Y];
> + sens_z = mmc35240_props_table[data->res].sens[AXIS_Z];
> +
> + nfo = mmc35240_props_table[data->res].nfo;
> +
> + switch (index) {
> + case AXIS_X:
> + *val = (raw_x - nfo) / sens_x;
> + *val2 = ((raw_x - nfo) % sens_x) * 1000000;
> + break;
> + case AXIS_Y:
> + *val = (raw_y - nfo) / sens_y - (raw_z - nfo) / sens_z;
> + *val2 = (((raw_y - nfo) % sens_y - (raw_z - nfo) % sens_z))
> + * 1000000;
> + break;
> + case AXIS_Z:
> + *val = (raw_y - nfo) / sens_y + (raw_z - nfo) / sens_z;
> + *val2 = (((raw_y - nfo) % sens_y + (raw_z - nfo) % sens_z))
> + * 1000000;
> + break;
> + default:
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> +static int mmc35240_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val,
> + int *val2, long mask)
> +{
> + struct mmc35240_data *data = iio_priv(indio_dev);
> + int ret, i;
> + unsigned int reg;
> + __le16 buf[3];
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_PROCESSED:
> + mutex_lock(&data->mutex);
> + ret = mmc35240_read_measurement(data, buf);
> + mutex_unlock(&data->mutex);
> + if (ret < 0)
> + return ret;
> + ret = mmc35240_raw_to_gauss(data, chan->address,
> + buf, val, val2);
> + if (ret < 0)
> + return ret;
> + return IIO_VAL_INT_PLUS_MICRO;
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + mutex_lock(&data->mutex);
> + ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, &reg);
> + mutex_unlock(&data->mutex);
> + if (ret < 0)
> + return ret;
> +
> + i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
> + if (i < 0 || i > ARRAY_SIZE(mmc35240_samp_freq))
> + return -EINVAL;
> +
> + *val = mmc35240_samp_freq[i];
> + *val2 = 0;
> + return IIO_VAL_INT;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int mmc35240_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int val,
> + int val2, long mask)
> +{
> + struct mmc35240_data *data = iio_priv(indio_dev);
> + int i, ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + i = mmc35240_get_samp_freq_index(data, val, val2);
> + if (i < 0)
> + return -EINVAL;
> + mutex_lock(&data->mutex);
> + ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
> + MMC35240_CTRL1_BW_MASK,
> + i << MMC35240_CTRL1_BW_SHIFT);
> + mutex_unlock(&data->mutex);
> + return ret;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct iio_info mmc35240_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = mmc35240_read_raw,
> + .write_raw = mmc35240_write_raw,
> + .attrs = &mmc35240_attribute_group,
> +};
> +
> +static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case MMC35240_REG_CTRL0:
> + case MMC35240_REG_CTRL1:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case MMC35240_REG_XOUT_L:
> + case MMC35240_REG_XOUT_H:
> + case MMC35240_REG_YOUT_L:
> + case MMC35240_REG_YOUT_H:
> + case MMC35240_REG_ZOUT_L:
> + case MMC35240_REG_ZOUT_H:
> + case MMC35240_REG_STATUS:
> + case MMC35240_REG_ID:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case MMC35240_REG_CTRL0:
> + case MMC35240_REG_CTRL1:
> + return false;
> + default:
> + return true;
> + }
> +}
> +
> +static struct reg_default mmc35240_reg_defaults[] = {
> + { MMC35240_REG_CTRL0, 0x00 },
> + { MMC35240_REG_CTRL1, 0x00 },
> +};
> +
> +static const struct regmap_config mmc35240_regmap_config = {
> + .name = MMC35240_REGMAP_NAME,
> +
> + .reg_bits = 8,
> + .val_bits = 8,
> +
> + .max_register = MMC35240_REG_ID,
> + .cache_type = REGCACHE_FLAT,
> +
> + .writeable_reg = mmc35240_is_writeable_reg,
> + .readable_reg = mmc35240_is_readable_reg,
> + .volatile_reg = mmc35240_is_volatile_reg,
> +
> + .reg_defaults = mmc35240_reg_defaults,
> + .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
> +};
> +
> +static int mmc35240_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct mmc35240_data *data;
> + struct iio_dev *indio_dev;
> + struct regmap *regmap;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
> + if (IS_ERR(regmap)) {
> + dev_err(&client->dev, "regmap initialization failed\n");
> + return PTR_ERR(regmap);
> + }
> +
> + data = iio_priv(indio_dev);
> + data->client = client;
> + data->regmap = regmap;
> + data->res = MMC35240_16_BITS_SLOW;
> +
> + mutex_init(&data->mutex);
> +
> + indio_dev->dev.parent = &client->dev;
> + indio_dev->info = &mmc35240_info;
> + indio_dev->name = MMC35240_DRV_NAME;
> + indio_dev->channels = mmc35240_channels;
> + indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
> + indio_dev->modes = INDIO_DIRECT_MODE;
> +
> + ret = mmc35240_init(data);
> + if (ret < 0) {
> + dev_err(&client->dev, "mmc35240 chip init failed\n");
> + return ret;
> + }
> + return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static const struct i2c_device_id mmc35240_id[] = {
> + {"MMC35240", 0},
> + {}
> +};
> +MODULE_DEVICE_TABLE(i2c, mmc35240_id);
> +
> +static struct i2c_driver mmc35240_driver = {
> + .driver = {
> + .name = MMC35240_DRV_NAME,
> + },
> + .probe = mmc35240_probe,
> + .id_table = mmc35240_id,
> +};
> +
> +module_i2c_driver(mmc35240_driver);
> +
> +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@xxxxxxxxx>");
> +MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
> +MODULE_LICENSE("GPL v2");
>

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