diff options
Diffstat (limited to 'drivers/iio/pressure/dps310.c')
| -rw-r--r-- | drivers/iio/pressure/dps310.c | 827 |
1 files changed, 827 insertions, 0 deletions
diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c new file mode 100644 index 000000000000..2c1943bbc433 --- /dev/null +++ b/drivers/iio/pressure/dps310.c @@ -0,0 +1,827 @@ +// SPDX-License-Identifier: GPL-2.0+ +// Copyright IBM Corp 2019 +/* + * The DPS310 is a barometric pressure and temperature sensor. + * Currently only reading a single temperature is supported by + * this driver. + * + * https://www.infineon.com/dgdl/?fileId=5546d462576f34750157750826c42242 + * + * Temperature calculation: + * c0 * 0.5 + c1 * T_raw / kT °C + * + * TODO: + * - Optionally support the FIFO + */ + +#include <linux/i2c.h> +#include <linux/limits.h> +#include <linux/math64.h> +#include <linux/module.h> +#include <linux/regmap.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define DPS310_DEV_NAME "dps310" + +#define DPS310_PRS_B0 0x00 +#define DPS310_PRS_B1 0x01 +#define DPS310_PRS_B2 0x02 +#define DPS310_TMP_B0 0x03 +#define DPS310_TMP_B1 0x04 +#define DPS310_TMP_B2 0x05 +#define DPS310_PRS_CFG 0x06 +#define DPS310_PRS_RATE_BITS GENMASK(6, 4) +#define DPS310_PRS_PRC_BITS GENMASK(3, 0) +#define DPS310_TMP_CFG 0x07 +#define DPS310_TMP_RATE_BITS GENMASK(6, 4) +#define DPS310_TMP_PRC_BITS GENMASK(3, 0) +#define DPS310_TMP_EXT BIT(7) +#define DPS310_MEAS_CFG 0x08 +#define DPS310_MEAS_CTRL_BITS GENMASK(2, 0) +#define DPS310_PRS_EN BIT(0) +#define DPS310_TEMP_EN BIT(1) +#define DPS310_BACKGROUND BIT(2) +#define DPS310_PRS_RDY BIT(4) +#define DPS310_TMP_RDY BIT(5) +#define DPS310_SENSOR_RDY BIT(6) +#define DPS310_COEF_RDY BIT(7) +#define DPS310_CFG_REG 0x09 +#define DPS310_INT_HL BIT(7) +#define DPS310_TMP_SHIFT_EN BIT(3) +#define DPS310_PRS_SHIFT_EN BIT(4) +#define DPS310_FIFO_EN BIT(5) +#define DPS310_SPI_EN BIT(6) +#define DPS310_RESET 0x0c +#define DPS310_RESET_MAGIC 0x09 +#define DPS310_COEF_BASE 0x10 + +/* Make sure sleep time is <= 20ms for usleep_range */ +#define DPS310_POLL_SLEEP_US(t) min(20000, (t) / 8) +/* Silently handle error in rate value here */ +#define DPS310_POLL_TIMEOUT_US(rc) ((rc) <= 0 ? 1000000 : 1000000 / (rc)) + +#define DPS310_PRS_BASE DPS310_PRS_B0 +#define DPS310_TMP_BASE DPS310_TMP_B0 + +/* + * These values (defined in the spec) indicate how to scale the raw register + * values for each level of precision available. + */ +static const int scale_factors[] = { + 524288, + 1572864, + 3670016, + 7864320, + 253952, + 516096, + 1040384, + 2088960, +}; + +struct dps310_data { + struct i2c_client *client; + struct regmap *regmap; + struct mutex lock; /* Lock for sequential HW access functions */ + + s32 c0, c1; + s32 c00, c10, c20, c30, c01, c11, c21; + s32 pressure_raw; + s32 temp_raw; +}; + +static const struct iio_chan_spec dps310_channels[] = { + { + .type = IIO_TEMP, + .info_mask_separate = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | + BIT(IIO_CHAN_INFO_SAMP_FREQ) | + BIT(IIO_CHAN_INFO_PROCESSED), + }, + { + .type = IIO_PRESSURE, + .info_mask_separate = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | + BIT(IIO_CHAN_INFO_SAMP_FREQ) | + BIT(IIO_CHAN_INFO_PROCESSED), + }, +}; + +/* To be called after checking the COEF_RDY bit in MEAS_CFG */ +static int dps310_get_coefs(struct dps310_data *data) +{ + int rc; + u8 coef[18]; + u32 c0, c1; + u32 c00, c10, c20, c30, c01, c11, c21; + + /* Read all sensor calibration coefficients from the COEF registers. */ + rc = regmap_bulk_read(data->regmap, DPS310_COEF_BASE, coef, + sizeof(coef)); + if (rc < 0) + return rc; + + /* + * Calculate temperature calibration coefficients c0 and c1. The + * numbers are 12-bit 2's complement numbers. + */ + c0 = (coef[0] << 4) | (coef[1] >> 4); + data->c0 = sign_extend32(c0, 11); + + c1 = ((coef[1] & GENMASK(3, 0)) << 8) | coef[2]; + data->c1 = sign_extend32(c1, 11); + + /* + * Calculate pressure calibration coefficients. c00 and c10 are 20 bit + * 2's complement numbers, while the rest are 16 bit 2's complement + * numbers. + */ + c00 = (coef[3] << 12) | (coef[4] << 4) | (coef[5] >> 4); + data->c00 = sign_extend32(c00, 19); + + c10 = ((coef[5] & GENMASK(3, 0)) << 16) | (coef[6] << 8) | coef[7]; + data->c10 = sign_extend32(c10, 19); + + c01 = (coef[8] << 8) | coef[9]; + data->c01 = sign_extend32(c01, 15); + + c11 = (coef[10] << 8) | coef[11]; + data->c11 = sign_extend32(c11, 15); + + c20 = (coef[12] << 8) | coef[13]; + data->c20 = sign_extend32(c20, 15); + + c21 = (coef[14] << 8) | coef[15]; + data->c21 = sign_extend32(c21, 15); + + c30 = (coef[16] << 8) | coef[17]; + data->c30 = sign_extend32(c30, 15); + + return 0; +} + +static int dps310_get_pres_precision(struct dps310_data *data) +{ + int rc; + int val; + + rc = regmap_read(data->regmap, DPS310_PRS_CFG, &val); + if (rc < 0) + return rc; + + return BIT(val & GENMASK(2, 0)); +} + +static int dps310_get_temp_precision(struct dps310_data *data) +{ + int rc; + int val; + + rc = regmap_read(data->regmap, DPS310_TMP_CFG, &val); + if (rc < 0) + return rc; + + /* + * Scale factor is bottom 4 bits of the register, but 1111 is + * reserved so just grab bottom three + */ + return BIT(val & GENMASK(2, 0)); +} + +/* Called with lock held */ +static int dps310_set_pres_precision(struct dps310_data *data, int val) +{ + int rc; + u8 shift_en; + + if (val < 0 || val > 128) + return -EINVAL; + + shift_en = val >= 16 ? DPS310_PRS_SHIFT_EN : 0; + rc = regmap_write_bits(data->regmap, DPS310_CFG_REG, + DPS310_PRS_SHIFT_EN, shift_en); + if (rc) + return rc; + + return regmap_update_bits(data->regmap, DPS310_PRS_CFG, + DPS310_PRS_PRC_BITS, ilog2(val)); +} + +/* Called with lock held */ +static int dps310_set_temp_precision(struct dps310_data *data, int val) +{ + int rc; + u8 shift_en; + + if (val < 0 || val > 128) + return -EINVAL; + + shift_en = val >= 16 ? DPS310_TMP_SHIFT_EN : 0; + rc = regmap_write_bits(data->regmap, DPS310_CFG_REG, + DPS310_TMP_SHIFT_EN, shift_en); + if (rc) + return rc; + + return regmap_update_bits(data->regmap, DPS310_TMP_CFG, + DPS310_TMP_PRC_BITS, ilog2(val)); +} + +/* Called with lock held */ +static int dps310_set_pres_samp_freq(struct dps310_data *data, int freq) +{ + u8 val; + + if (freq < 0 || freq > 128) + return -EINVAL; + + val = ilog2(freq) << 4; + + return regmap_update_bits(data->regmap, DPS310_PRS_CFG, + DPS310_PRS_RATE_BITS, val); +} + +/* Called with lock held */ +static int dps310_set_temp_samp_freq(struct dps310_data *data, int freq) +{ + u8 val; + + if (freq < 0 || freq > 128) + return -EINVAL; + + val = ilog2(freq) << 4; + + return regmap_update_bits(data->regmap, DPS310_TMP_CFG, + DPS310_TMP_RATE_BITS, val); +} + +static int dps310_get_pres_samp_freq(struct dps310_data *data) +{ + int rc; + int val; + + rc = regmap_read(data->regmap, DPS310_PRS_CFG, &val); + if (rc < 0) + return rc; + + return BIT((val & DPS310_PRS_RATE_BITS) >> 4); +} + +static int dps310_get_temp_samp_freq(struct dps310_data *data) +{ + int rc; + int val; + + rc = regmap_read(data->regmap, DPS310_TMP_CFG, &val); + if (rc < 0) + return rc; + + return BIT((val & DPS310_TMP_RATE_BITS) >> 4); +} + +static int dps310_get_pres_k(struct dps310_data *data) +{ + int rc = dps310_get_pres_precision(data); + + if (rc < 0) + return rc; + + return scale_factors[ilog2(rc)]; +} + +static int dps310_get_temp_k(struct dps310_data *data) +{ + int rc = dps310_get_temp_precision(data); + + if (rc < 0) + return rc; + + return scale_factors[ilog2(rc)]; +} + +static int dps310_read_pres_raw(struct dps310_data *data) +{ + int rc; + int rate; + int ready; + int timeout; + s32 raw; + u8 val[3]; + + if (mutex_lock_interruptible(&data->lock)) + return -EINTR; + + rate = dps310_get_pres_samp_freq(data); + timeout = DPS310_POLL_TIMEOUT_US(rate); + + /* Poll for sensor readiness; base the timeout upon the sample rate. */ + rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready, + ready & DPS310_PRS_RDY, + DPS310_POLL_SLEEP_US(timeout), timeout); + if (rc) + goto done; + + rc = regmap_bulk_read(data->regmap, DPS310_PRS_BASE, val, sizeof(val)); + if (rc < 0) + goto done; + + raw = (val[0] << 16) | (val[1] << 8) | val[2]; + data->pressure_raw = sign_extend32(raw, 23); + +done: + mutex_unlock(&data->lock); + return rc; +} + +/* Called with lock held */ +static int dps310_read_temp_ready(struct dps310_data *data) +{ + int rc; + u8 val[3]; + s32 raw; + + rc = regmap_bulk_read(data->regmap, DPS310_TMP_BASE, val, sizeof(val)); + if (rc < 0) + return rc; + + raw = (val[0] << 16) | (val[1] << 8) | val[2]; + data->temp_raw = sign_extend32(raw, 23); + + return 0; +} + +static int dps310_read_temp_raw(struct dps310_data *data) +{ + int rc; + int rate; + int ready; + int timeout; + + if (mutex_lock_interruptible(&data->lock)) + return -EINTR; + + rate = dps310_get_temp_samp_freq(data); + timeout = DPS310_POLL_TIMEOUT_US(rate); + + /* Poll for sensor readiness; base the timeout upon the sample rate. */ + rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready, + ready & DPS310_TMP_RDY, + DPS310_POLL_SLEEP_US(timeout), timeout); + if (rc < 0) + goto done; + + rc = dps310_read_temp_ready(data); + +done: + mutex_unlock(&data->lock); + return rc; +} + +static bool dps310_is_writeable_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case DPS310_PRS_CFG: + case DPS310_TMP_CFG: + case DPS310_MEAS_CFG: + case DPS310_CFG_REG: + case DPS310_RESET: + /* No documentation available on the registers below */ + case 0x0e: + case 0x0f: + case 0x62: + return true; + default: + return false; + } +} + +static bool dps310_is_volatile_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case DPS310_PRS_B0: + case DPS310_PRS_B1: + case DPS310_PRS_B2: + case DPS310_TMP_B0: + case DPS310_TMP_B1: + case DPS310_TMP_B2: + case DPS310_MEAS_CFG: + case 0x32: /* No documentation available on this register */ + return true; + default: + return false; + } +} + +static int dps310_write_raw(struct iio_dev *iio, + struct iio_chan_spec const *chan, int val, + int val2, long mask) +{ + int rc; + struct dps310_data *data = iio_priv(iio); + + if (mutex_lock_interruptible(&data->lock)) + return -EINTR; + + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + switch (chan->type) { + case IIO_PRESSURE: + rc = dps310_set_pres_samp_freq(data, val); + break; + + case IIO_TEMP: + rc = dps310_set_temp_samp_freq(data, val); + break; + + default: + rc = -EINVAL; + break; + } + break; + + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + switch (chan->type) { + case IIO_PRESSURE: + rc = dps310_set_pres_precision(data, val); + break; + + case IIO_TEMP: + rc = dps310_set_temp_precision(data, val); + break; + + default: + rc = -EINVAL; + break; + } + break; + + default: + rc = -EINVAL; + break; + } + + mutex_unlock(&data->lock); + return rc; +} + +static int dps310_calculate_pressure(struct dps310_data *data) +{ + int i; + int rc; + int t_ready; + int kpi = dps310_get_pres_k(data); + int kti = dps310_get_temp_k(data); + s64 rem = 0ULL; + s64 pressure = 0ULL; + s64 p; + s64 t; + s64 denoms[7]; + s64 nums[7]; + s64 rems[7]; + s64 kp; + s64 kt; + + if (kpi < 0) + return kpi; + + if (kti < 0) + return kti; + + kp = (s64)kpi; + kt = (s64)kti; + + /* Refresh temp if it's ready, otherwise just use the latest value */ + if (mutex_trylock(&data->lock)) { + rc = regmap_read(data->regmap, DPS310_MEAS_CFG, &t_ready); + if (rc >= 0 && t_ready & DPS310_TMP_RDY) + dps310_read_temp_ready(data); + + mutex_unlock(&data->lock); + } + + p = (s64)data->pressure_raw; + t = (s64)data->temp_raw; + + /* Section 4.9.1 of the DPS310 spec; algebra'd to avoid underflow */ + nums[0] = (s64)data->c00; + denoms[0] = 1LL; + nums[1] = p * (s64)data->c10; + denoms[1] = kp; + nums[2] = p * p * (s64)data->c20; + denoms[2] = kp * kp; + nums[3] = p * p * p * (s64)data->c30; + denoms[3] = kp * kp * kp; + nums[4] = t * (s64)data->c01; + denoms[4] = kt; + nums[5] = t * p * (s64)data->c11; + denoms[5] = kp * kt; + nums[6] = t * p * p * (s64)data->c21; + denoms[6] = kp * kp * kt; + + /* Kernel lacks a div64_s64_rem function; denoms are all positive */ + for (i = 0; i < 7; ++i) { + u64 irem; + + if (nums[i] < 0LL) { + pressure -= div64_u64_rem(-nums[i], denoms[i], &irem); + rems[i] = -irem; + } else { + pressure += div64_u64_rem(nums[i], denoms[i], &irem); + rems[i] = (s64)irem; + } + } + + /* Increase precision and calculate the remainder sum */ + for (i = 0; i < 7; ++i) + rem += div64_s64((s64)rems[i] * 1000000000LL, denoms[i]); + + pressure += div_s64(rem, 1000000000LL); + if (pressure < 0LL) + return -ERANGE; + + return (int)min_t(s64, pressure, INT_MAX); +} + +static int dps310_read_pressure(struct dps310_data *data, int *val, int *val2, + long mask) +{ + int rc; + + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + rc = dps310_get_pres_samp_freq(data); + if (rc < 0) + return rc; + + *val = rc; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_PROCESSED: + rc = dps310_read_pres_raw(data); + if (rc) + return rc; + + rc = dps310_calculate_pressure(data); + if (rc < 0) + return rc; + + *val = rc; + *val2 = 1000; /* Convert Pa to KPa per IIO ABI */ + return IIO_VAL_FRACTIONAL; + + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + rc = dps310_get_pres_precision(data); + if (rc < 0) + return rc; + + *val = rc; + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static int dps310_calculate_temp(struct dps310_data *data) +{ + s64 c0; + s64 t; + int kt = dps310_get_temp_k(data); + + if (kt < 0) + return kt; + + /* Obtain inverse-scaled offset */ + c0 = div_s64((s64)kt * (s64)data->c0, 2); + + /* Add the offset to the unscaled temperature */ + t = c0 + ((s64)data->temp_raw * (s64)data->c1); + + /* Convert to milliCelsius and scale the temperature */ + return (int)div_s64(t * 1000LL, kt); +} + +static int dps310_read_temp(struct dps310_data *data, int *val, int *val2, + long mask) +{ + int rc; + + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + rc = dps310_get_temp_samp_freq(data); + if (rc < 0) + return rc; + + *val = rc; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_PROCESSED: + rc = dps310_read_temp_raw(data); + if (rc) + return rc; + + rc = dps310_calculate_temp(data); + if (rc < 0) + return rc; + + *val = rc; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + rc = dps310_get_temp_precision(data); + if (rc < 0) + return rc; + + *val = rc; + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static int dps310_read_raw(struct iio_dev *iio, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct dps310_data *data = iio_priv(iio); + + switch (chan->type) { + case IIO_PRESSURE: + return dps310_read_pressure(data, val, val2, mask); + + case IIO_TEMP: + return dps310_read_temp(data, val, val2, mask); + + default: + return -EINVAL; + } +} + +static void dps310_reset(void *action_data) +{ + struct dps310_data *data = action_data; + + regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC); +} + +static const struct regmap_config dps310_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .writeable_reg = dps310_is_writeable_reg, + .volatile_reg = dps310_is_volatile_reg, + .cache_type = REGCACHE_RBTREE, + .max_register = 0x62, /* No documentation available on this register */ +}; + +static const struct iio_info dps310_info = { + .read_raw = dps310_read_raw, + .write_raw = dps310_write_raw, +}; + +/* + * Some verions of chip will read temperatures in the ~60C range when + * its actually ~20C. This is the manufacturer recommended workaround + * to correct the issue. The registers used below are undocumented. + */ +static int dps310_temp_workaround(struct dps310_data *data) +{ + int rc; + int reg; + + rc = regmap_read(data->regmap, 0x32, ®); + if (rc < 0) + return rc; + + /* + * If bit 1 is set then the device is okay, and the workaround does not + * need to be applied + */ + if (reg & BIT(1)) + return 0; + + rc = regmap_write(data->regmap, 0x0e, 0xA5); + if (rc < 0) + return rc; + + rc = regmap_write(data->regmap, 0x0f, 0x96); + if (rc < 0) + return rc; + + rc = regmap_write(data->regmap, 0x62, 0x02); + if (rc < 0) + return rc; + + rc = regmap_write(data->regmap, 0x0e, 0x00); + if (rc < 0) + return rc; + + return regmap_write(data->regmap, 0x0f, 0x00); +} + +static int dps310_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct dps310_data *data; + struct iio_dev *iio; + int rc, ready; + + iio = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!iio) + return -ENOMEM; + + data = iio_priv(iio); + data->client = client; + mutex_init(&data->lock); + + iio->dev.parent = &client->dev; + iio->name = id->name; + iio->channels = dps310_channels; + iio->num_channels = ARRAY_SIZE(dps310_channels); + iio->info = &dps310_info; + iio->modes = INDIO_DIRECT_MODE; + + data->regmap = devm_regmap_init_i2c(client, &dps310_regmap_config); + if (IS_ERR(data->regmap)) + return PTR_ERR(data->regmap); + + /* Register to run the device reset when the device is removed */ + rc = devm_add_action_or_reset(&client->dev, dps310_reset, data); + if (rc) + return rc; + + /* + * Set up pressure sensor in single sample, one measurement per second + * mode + */ + rc = regmap_write(data->regmap, DPS310_PRS_CFG, 0); + + /* + * Set up external (MEMS) temperature sensor in single sample, one + * measurement per second mode + */ + rc = regmap_write(data->regmap, DPS310_TMP_CFG, DPS310_TMP_EXT); + if (rc < 0) + return rc; + + /* Temp and pressure shifts are disabled when PRC <= 8 */ + rc = regmap_write_bits(data->regmap, DPS310_CFG_REG, + DPS310_PRS_SHIFT_EN | DPS310_TMP_SHIFT_EN, 0); + if (rc < 0) + return rc; + + /* MEAS_CFG doesn't update correctly unless first written with 0 */ + rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG, + DPS310_MEAS_CTRL_BITS, 0); + if (rc < 0) + return rc; + + /* Turn on temperature and pressure measurement in the background */ + rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG, + DPS310_MEAS_CTRL_BITS, DPS310_PRS_EN | + DPS310_TEMP_EN | DPS310_BACKGROUND); + if (rc < 0) + return rc; + + /* + * Calibration coefficients required for reporting temperature. + * They are available 40ms after the device has started + */ + rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready, + ready & DPS310_COEF_RDY, 10000, 40000); + if (rc < 0) + return rc; + + rc = dps310_get_coefs(data); + if (rc < 0) + return rc; + + rc = dps310_temp_workaround(data); + if (rc < 0) + return rc; + + rc = devm_iio_device_register(&client->dev, iio); + if (rc) + return rc; + + i2c_set_clientdata(client, iio); + + return 0; +} + +static const struct i2c_device_id dps310_id[] = { + { DPS310_DEV_NAME, 0 }, + {} +}; +MODULE_DEVICE_TABLE(i2c, dps310_id); + +static struct i2c_driver dps310_driver = { + .driver = { + .name = DPS310_DEV_NAME, + }, + .probe = dps310_probe, + .id_table = dps310_id, +}; +module_i2c_driver(dps310_driver); + +MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>"); +MODULE_DESCRIPTION("Infineon DPS310 pressure and temperature sensor"); +MODULE_LICENSE("GPL v2"); |