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path: root/drivers/iio/magnetometer/mmc35240.c
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-rw-r--r--drivers/iio/magnetometer/mmc35240.c594
1 files changed, 594 insertions, 0 deletions
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
new file mode 100644
index 000000000..6b640c633
--- /dev/null
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -0,0 +1,594 @@
+/*
+ * 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/acpi.h>
+#include <linux/pm.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 */
+
+/*
+ * Memsic OTP process code piece is put here for reference:
+ *
+ * #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006
+ * 1) For X axis, the COEFFICIENT is always 1.
+ * 2) For Y axis, the COEFFICIENT is as below:
+ * f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) |
+ * (reg_data[2] >> 4)) + 1.0;
+ * 3) For Z axis, the COEFFICIENT is as below:
+ * f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35;
+ * We implemented the OTP logic into driver.
+ */
+
+/* scale = 1000 here for Y otp */
+#define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
+
+/* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */
+#define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81)
+
+#define MMC35240_X_COEFF(x) (x)
+#define MMC35240_Y_COEFF(y) (y + 1000)
+#define MMC35240_Z_COEFF(z) (z + 13500)
+
+#define MMC35240_OTP_START_ADDR 0x1B
+
+enum mmc35240_resolution {
+ MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */
+ MMC35240_16_BITS_FAST, /* 4.08 ms */
+ MMC35240_14_BITS, /* 2.16 ms */
+ MMC35240_12_BITS, /* 1.20 ms */
+};
+
+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, 125Hz ODR */
+ {
+ {1024, 1024, 1024},
+ 32768,
+ },
+ /* 16 bits, 250Hz ODR */
+ {
+ {1024, 1024, 770},
+ 32768,
+ },
+ /* 14 bits, 450Hz ODR */
+ {
+ {256, 256, 193},
+ 8192,
+ },
+ /* 12 bits, 800Hz ODR */
+ {
+ {64, 64, 48},
+ 2048,
+ },
+};
+
+struct mmc35240_data {
+ struct i2c_client *client;
+ struct mutex mutex;
+ struct regmap *regmap;
+ enum mmc35240_resolution res;
+
+ /* OTP compensation */
+ int axis_coef[3];
+ int axis_scale[3];
+};
+
+static const struct {
+ int val;
+ int val2;
+} mmc35240_samp_freq[] = { {1, 500000},
+ {13, 0},
+ {25, 0},
+ {50, 0} };
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50");
+
+#define MMC35240_CHANNEL(_axis) { \
+ .type = IIO_MAGN, \
+ .modified = 1, \
+ .channel2 = IIO_MOD_ ## _axis, \
+ .address = AXIS_ ## _axis, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+}
+
+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,
+ NULL
+};
+
+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 == val &&
+ mmc35240_samp_freq[i].val2 == val2)
+ 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,
+ coil_bit, coil_bit);
+
+}
+
+static int mmc35240_init(struct mmc35240_data *data)
+{
+ int ret, y_convert, z_convert;
+ unsigned int reg_id;
+ u8 otp_data[6];
+
+ 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 SET/RESET sequence, the axis polarity being naturally
+ * aligned after RESET
+ */
+ ret = mmc35240_hw_set(data, true);
+ if (ret < 0)
+ return ret;
+ usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);
+
+ ret = mmc35240_hw_set(data, false);
+ if (ret < 0)
+ return ret;
+
+ /* set default sampling frequency */
+ ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
+ MMC35240_CTRL1_BW_MASK,
+ data->res << MMC35240_CTRL1_BW_SHIFT);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
+ (u8 *)otp_data, sizeof(otp_data));
+ if (ret < 0)
+ return ret;
+
+ y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
+ (otp_data[2] >> 4));
+ z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
+
+ data->axis_coef[0] = MMC35240_X_COEFF(1);
+ data->axis_coef[1] = MMC35240_Y_COEFF(y_convert);
+ data->axis_coef[2] = MMC35240_Z_COEFF(z_convert);
+
+ data->axis_scale[0] = 1;
+ data->axis_scale[1] = 1000;
+ data->axis_scale[2] = 10000;
+
+ return 0;
+}
+
+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;
+ /* minimum wait time to complete measurement is 10 ms */
+ usleep_range(10000, 11000);
+ }
+
+ 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));
+}
+
+/**
+ * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
+ compensation for output value.
+ *
+ * @data: device private data
+ * @index: axis index for which we want the conversion
+ * @buf: raw data to be converted, 2 bytes in little endian format
+ * @val: compensated output reading (unit is milli gauss)
+ *
+ * Returns: 0 in case of success, -EINVAL when @index is not valid
+ */
+static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
+ __le16 buf[], int *val)
+{
+ int raw[3];
+ int sens[3];
+ int nfo;
+
+ raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]);
+ raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]);
+ raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]);
+
+ sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X];
+ sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y];
+ sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z];
+
+ nfo = mmc35240_props_table[data->res].nfo;
+
+ switch (index) {
+ case AXIS_X:
+ *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
+ break;
+ case AXIS_Y:
+ *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
+ (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
+ break;
+ case AXIS_Z:
+ *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
+ (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
+ break;
+ default:
+ return -EINVAL;
+ }
+ /* apply OTP compensation */
+ *val = (*val) * data->axis_coef[index] / data->axis_scale[index];
+
+ 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_RAW:
+ mutex_lock(&data->mutex);
+ ret = mmc35240_read_measurement(data, buf);
+ mutex_unlock(&data->mutex);
+ if (ret < 0)
+ return ret;
+ ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
+ if (ret < 0)
+ return ret;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = 0;
+ *val2 = 1000;
+ 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].val;
+ *val2 = mmc35240_samp_freq[i].val2;
+ return IIO_VAL_INT_PLUS_MICRO;
+ 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 = {
+ .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);
+ i2c_set_clientdata(client, 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);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mmc35240_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mmc35240_data *data = iio_priv(indio_dev);
+
+ regcache_cache_only(data->regmap, true);
+
+ return 0;
+}
+
+static int mmc35240_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mmc35240_data *data = iio_priv(indio_dev);
+ int ret;
+
+ regcache_mark_dirty(data->regmap);
+ ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0,
+ MMC35240_REG_CTRL1);
+ if (ret < 0)
+ dev_err(dev, "Failed to restore control registers\n");
+
+ regcache_cache_only(data->regmap, false);
+
+ return 0;
+}
+#endif
+
+static const struct dev_pm_ops mmc35240_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume)
+};
+
+static const struct of_device_id mmc35240_of_match[] = {
+ { .compatible = "memsic,mmc35240", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, mmc35240_of_match);
+
+static const struct acpi_device_id mmc35240_acpi_match[] = {
+ {"MMC35240", 0},
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
+
+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,
+ .of_match_table = mmc35240_of_match,
+ .pm = &mmc35240_pm_ops,
+ .acpi_match_table = ACPI_PTR(mmc35240_acpi_match),
+ },
+ .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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-18 21:45:37 +0000