iio: magnetometer: Add support for MEMSIC MMC35240 sensor
authorDaniel Baluta <daniel.baluta@intel.com>
Fri, 24 Apr 2015 15:58:30 +0000 (18:58 +0300)
committerJonathan Cameron <jic23@kernel.org>
Sun, 10 May 2015 19:31:45 +0000 (20:31 +0100)
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@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
drivers/iio/magnetometer/Kconfig
drivers/iio/magnetometer/Makefile
drivers/iio/magnetometer/mmc35240.c [new file with mode: 0644]

index 9746a2a88640ee230c42941337947be0fd500caa..dcadfc4f06619a1a147d560581bb7bfabdd3f663 100644 (file)
@@ -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
index e2c34594ff3f5ded7098ae03d14ae3f587085b57..33b1d4d54ee70a6b064c1c3aabed171e9a0b7892 100644 (file)
@@ -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 (file)
index 0000000..4672800
--- /dev/null
@@ -0,0 +1,469 @@
+/*
+ * 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;
+};
+
+static const 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));
+}
+
+static 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@intel.com>");
+MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
+MODULE_LICENSE("GPL v2");