// SPDX-License-Identifier: GPL-2.0-only /* * MMC35240 - MEMSIC 3-axis Magnetic Sensor * * Copyright (c) 2015, Intel Corporation. * * 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 MMC35240_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, ®_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(MMC35240_WAIT_SET_RESET, MMC35240_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, 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, ®_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, 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, ®); 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 const 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->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");