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OpenCloudOS-Kernel/drivers/iio/pressure/dps310.c

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// 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, &reg);
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");
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