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SubjectRe: [PATCH v3 1/3] iio: Add driver for Infineon DPS310
On Wed, 15 May 2019 13:41:15 -0500
Eddie James <eajames@linux.ibm.com> wrote:

> From: Joel Stanley <joel@jms.id.au>
>
> The DPS310 is a temperature and pressure sensor. It can be accessed over
> i2c and SPI.
>
> Signed-off-by: Eddie James <eajames@linux.ibm.com>
Hi Eddie,

One spacing issue in the Kconfig file otherwise I think this looks good.

However, Joel, I would definitely prefer it if you took a look and ideally
provided a Signed-off-by as we need the Developer Certificate of Origin
stuff to be clearly correct.

Thanks,

Jonathan
> ---
> MAINTAINERS | 6 +
> drivers/iio/pressure/Kconfig | 10 +
> drivers/iio/pressure/Makefile | 1 +
> drivers/iio/pressure/dps310.c | 468 ++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 485 insertions(+)
> create mode 100644 drivers/iio/pressure/dps310.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7345e45..ea31027 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7760,6 +7760,12 @@ W: http://industrypack.sourceforge.net
> S: Maintained
> F: drivers/ipack/
>
> +INFINEON DPS310 Driver
> +M: Eddie James <eajames@linux.ibm.com>
> +L: linux-iio@vger.kernel.org
> +F: drivers/iio/pressure/dps310.c
> +S: Maintained
> +
> INFINIBAND SUBSYSTEM
> M: Doug Ledford <dledford@redhat.com>
> M: Jason Gunthorpe <jgg@mellanox.com>
> diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig
> index efeb89f..681a1cc 100644
> --- a/drivers/iio/pressure/Kconfig
> +++ b/drivers/iio/pressure/Kconfig
> @@ -52,6 +52,16 @@ config IIO_CROS_EC_BARO
> To compile this driver as a module, choose M here: the module
> will be called cros_ec_baro.
>
> +config DPS310
> + tristate "Infineon DPS310 pressure and temperature sensor"
> + depends on I2C
> + select REGMAP_I2C
> + help
Mixture of spaces and tabs here it seems. Please match the rest of the file
(which is hopefully consistent!).
> + Support for the Infineon DPS310 digital barometric pressure sensor.
> +
> + This driver can also be built as a module. If so, the module will be
> + called dps310.
> +
> config HID_SENSOR_PRESS
> depends on HID_SENSOR_HUB
> select IIO_BUFFER
> diff --git a/drivers/iio/pressure/Makefile b/drivers/iio/pressure/Makefile
> index c2058d7..d8f5ace 100644
> --- a/drivers/iio/pressure/Makefile
> +++ b/drivers/iio/pressure/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_BMP280) += bmp280.o
> bmp280-objs := bmp280-core.o bmp280-regmap.o
> obj-$(CONFIG_BMP280_I2C) += bmp280-i2c.o
> obj-$(CONFIG_BMP280_SPI) += bmp280-spi.o
> +obj-$(CONFIG_DPS310) += dps310.o
> obj-$(CONFIG_IIO_CROS_EC_BARO) += cros_ec_baro.o
> obj-$(CONFIG_HID_SENSOR_PRESS) += hid-sensor-press.o
> obj-$(CONFIG_HP03) += hp03.o
> diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c
> new file mode 100644
> index 0000000..9acfccb
> --- /dev/null
> +++ b/drivers/iio/pressure/dps310.c
> @@ -0,0 +1,468 @@
> +// 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:
> + * - Pressure sensor readings
> + * - Optionally support the FIFO
> + */
> +
> +#include <linux/i2c.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_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
> +#define DPS310_COEF_SRC 0x28
> +
> +/* 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 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),
> + },
> +};
> +
> +/* To be called after checking the COEF_RDY bit in MEAS_CFG */
> +static int dps310_get_temp_coef(struct dps310_data *data)
> +{
> + int rc;
> + u8 coef[3];
> + u32 c0, c1;
> +
> + /*
> + * Read temperature calibration coefficients c0 and c1 from the
> + * COEF register. The numbers are 12-bit 2's compliment numbers
> + */
> + rc = regmap_bulk_read(data->regmap, DPS310_COEF_BASE, coef,
> + sizeof(coef));
> + if (rc < 0)
> + return rc;
> +
> + 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);
> +
> + return 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_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_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_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_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_temp(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_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 = regmap_bulk_read(data->regmap, DPS310_TMP_BASE, val, sizeof(val));
> + if (rc < 0)
> + goto done;
> +
> + raw = (val[0] << 16) | (val[1] << 8) | val[2];
> + data->temp_raw = sign_extend32(raw, 23);
> +
> +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:
> + 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:
> + 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 (chan->type != IIO_TEMP)
> + return -EINVAL;
> +
> + if (mutex_lock_interruptible(&data->lock))
> + return -EINTR;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + rc = dps310_set_temp_samp_freq(data, val);
> + break;
> +
> + case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> + rc = dps310_set_temp_precision(data, val);
> + break;
> +
> + default:
> + rc = -EINVAL;
> + break;
> + }
> +
> + mutex_unlock(&data->lock);
> + return rc;
> +}
> +
> +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_raw(struct iio_dev *iio,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct dps310_data *data = iio_priv(iio);
> + 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(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 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 = DPS310_COEF_SRC,
> +};
> +
> +static const struct iio_info dps310_info = {
> + .read_raw = dps310_read_raw,
> + .write_raw = dps310_write_raw,
> +};
> +
> +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 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 shift is disabled when PRC <= 8 */
> + rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
> + 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 measurement in the background */
> + rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
> + DPS310_MEAS_CTRL_BITS,
> + 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_temp_coef(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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