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SubjectRe: [PATCH 1/3] iio: Add driver for Infineon DPS310
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On 5/6/19 4:18 PM, Peter Meerwald-Stadler wrote:
> On Mon, 6 May 2019, Eddie James wrote:
>
>> From: Joel Stanley <joel@jms.id.au>
> some comments below


Thanks for the quick review! Will get these in for v2, I did have a
couple of questions below though.

Eddie


>
>> 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>
>> ---
>> MAINTAINERS | 6 +
>> drivers/iio/pressure/Kconfig | 10 +
>> drivers/iio/pressure/Makefile | 1 +
>> drivers/iio/pressure/dps310.c | 429 ++++++++++++++++++++++++++++++++++++++++++
>> 4 files changed, 446 insertions(+)
>> create mode 100644 drivers/iio/pressure/dps310.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index c61c49d..a91dfa9 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -7743,6 +7743,12 @@ 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
>> + 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..21d5dcb
>> --- /dev/null
>> +++ b/drivers/iio/pressure/dps310.c
>> @@ -0,0 +1,429 @@
>> +// 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_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 (BIT(0) | BIT(3))
>> +#define DPS310_COEF_BASE 0x10
>> +
>> +#define DPS310_PRS_BASE DPS310_PRS_B0
>> +#define DPS310_TMP_BASE DPS310_TMP_B0
>> +
>> +#define DPS310_CALC_RATE(_n) ilog2(_n)
>> +#define DPS310_CALC_PRC(_n) ilog2(_n)
>> +
>> +const int scale_factor[] = {
> static
> maybe plural, scale_factors?
> maybe some comment would be good what these values relate to
>
>> + 524288,
>> + 1572864,
>> + 3670016,
>> + 7864320,
>> + 253952,
>> + 516096,
>> + 1040384,
>> + 2088960,
>> +};
>> +
>> +struct dps310_data {
>> + struct i2c_client *client;
>> + struct regmap *regmap;
>> +
>> + s32 c0, c1;
>> + s32 temp_raw;
>> +};
>> +
>> +static const struct iio_chan_spec dps310_channels[] = {
>> + {
>> + .type = IIO_TEMP,
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_OFFSET) |
>> + BIT(IIO_CHAN_INFO_SCALE) |
>> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
>> + BIT(IIO_CHAN_INFO_SAMP_FREQ) |
>> + BIT(IIO_CHAN_INFO_RAW),
>> + },
>> +};
>> +
>> +/* To be called after checking the TMP_RDY bit in MEAS_CFG */
>> +static int dps310_get_temp_coef(struct dps310_data *data)
>> +{
>> + struct regmap *regmap = data->regmap;
>> + u8 coef[3] = {0};
> initialization needed?
>
>> + int r;
>> + u32 c0, c1;
>> +
>> + /*
>> + * Read temperature calibration coefficients c0 and c1 from the
>> + * COEF register. The numbers are 12-bit 2's compliment numbers
>> + */
>> + r = regmap_bulk_read(regmap, DPS310_COEF_BASE, coef, 3);
> sizeof(coef) instead of 3
>
>> + if (r < 0)
>> + return r;
>> +
>> + 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 val, r;
>> +
>> + r = regmap_read(data->regmap, DPS310_TMP_CFG, &val);
>> + if (r < 0)
>> + return r;
>> +
>> + /*
>> + * Scale factor is bottom 4 bits of the register, but 1111 is
>> + * reserved so just grab bottom three
>> + */
>> + return BIT(val & GENMASK(2, 0));
>> +}
>> +
>> +static int dps310_set_temp_precision(struct dps310_data *data, int val)
>> +{
>> + int ret;
>> + u8 shift_en;
>> +
>> + if (val < 0 || val > 128)
>> + return -EINVAL;
>> +
>> + shift_en = val >= 16 ? DPS310_TMP_SHIFT_EN : 0;
>> + ret = regmap_write_bits(data->regmap, DPS310_CFG_REG,
>> + DPS310_TMP_SHIFT_EN, shift_en);
>> + if (ret)
>> + return ret;
>> +
>> + return regmap_update_bits(data->regmap, DPS310_TMP_CFG,
>> + DPS310_TMP_PRC_BITS, DPS310_CALC_PRC(val));
>> +}
>> +
>> +static int dps310_set_temp_samp_freq(struct dps310_data *data, int freq)
>> +{
>> + u8 val;
>> +
>> + if (freq < 0 || freq > 128)
>> + return -EINVAL;
>> +
>> + val = DPS310_CALC_RATE(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 val, r;
>> +
>> + r = regmap_read(data->regmap, DPS310_TMP_CFG, &val);
>> + if (r < 0)
>> + return r;
>> +
>> + return BIT((val & DPS310_TMP_RATE_BITS) >> 4);
>> +}
>> +
>> +static int dps310_get_temp_k(struct dps310_data *data)
>> +{
>> + int r = dps310_get_temp_precision(data);
>> +
>> + if (r < 0)
>> + return r;
>> +
>> + return scale_factor[DPS310_CALC_PRC(r)];
>> +}
>> +
>> +static int dps310_read_temp(struct dps310_data *data)
>> +{
>> + struct device *dev = &data->client->dev;
>> + struct regmap *regmap = data->regmap;
>> + u8 val[3] = {0};
> initialization needed?
>
>> + int r, ready;
>> + int T_raw;
>> +
>> + r = regmap_read(regmap, DPS310_MEAS_CFG, &ready);
>> + if (r < 0)
>> + return r;
>> + if (!(ready & DPS310_TMP_RDY)) {
>> + dev_dbg(dev, "temperature not ready\n");
> most drivers wait for the results to become ready\


OK, this may have to wait up to a second then, since the background
measurement rate can be as low as 1 HZ... I can base the timeout on the
sample rate. Would that be OK?


>
>> + return -EAGAIN;
>> + }
>> +
>> + r = regmap_bulk_read(regmap, DPS310_TMP_BASE, val, 3);
> sizeof(val)
>
>> + if (r < 0)
>> + return r;
>> +
>> + T_raw = (val[0] << 16) | (val[1] << 8) | val[2];
>> + data->temp_raw = sign_extend32(T_raw, 23);
>> +
>> + return 0;
>> +}
>> +
>> +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)
>> +{
>> + struct dps310_data *data = iio_priv(iio);
>> +
>> + if (chan->type != IIO_TEMP)
>> + return -EINVAL;
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_SAMP_FREQ:
>> + return dps310_set_temp_samp_freq(data, val);
>> + case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
>> + return dps310_set_temp_precision(data, val);
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + return -EINVAL;
> not needed, dead code
>
>> +}
>> +
>> +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 ret;
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_SAMP_FREQ:
>> + *val = dps310_get_temp_samp_freq(data);
>> + return IIO_VAL_INT;
>> +
>> + case IIO_CHAN_INFO_RAW:
>> + ret = dps310_read_temp(data);
>> + if (ret)
>> + return ret;
>> +
>> + *val = data->temp_raw * data->c1;
> one could try to avoid the multipliation here and somehow mangle it into
> _SCALE/_OFFSET


Don't think it's worth it? Would have to divide the offset by c1 and
then multiply by c1 again in the scale...


>
>> + return IIO_VAL_INT;
>> +
>> + case IIO_CHAN_INFO_OFFSET:
>> + ret = dps310_get_temp_k(data);
>> + if (ret < 0)
>> + return ret;
>> +
>> + *val = (data->c0 >> 1) * ret;
>> + return IIO_VAL_INT;
>> +
>> + case IIO_CHAN_INFO_SCALE:
>> + ret = dps310_get_temp_k(data);
>> + if (ret < 0)
>> + return ret;
>> +
>> + *val = 1000; /* milliCelsius per Celsius */
>> + *val2 = ret;
>> + return IIO_VAL_FRACTIONAL;
>> +
>> + case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
>> + *val = dps310_get_temp_precision(data);
>> + return IIO_VAL_INT;
>> +
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + return -EINVAL;
> not needed, dead code
>
>> +}
>> +
>> +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 = 0x29,
>> +};
>> +
>> +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 r, ready;
>> +
>> + iio = devm_iio_device_alloc(&client->dev, sizeof(*data));
>> + if (!iio)
>> + return -ENOMEM;
>> +
>> + data = iio_priv(iio);
>> + data->client = client;
>> +
>> + 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);
>> +
>> + /*
>> + * Set up external (MEMS) temperature sensor in single sample, one
>> + * measurement per second mode
>> + */
>> + r = regmap_write(data->regmap, DPS310_TMP_CFG,
>> + DPS310_TMP_EXT | DPS310_CALC_RATE(1) |
>> + DPS310_CALC_PRC(1));
>> + if (r < 0)
>> + goto err;
>> +
>> + /* Temp shift is disabled when PRC <= 8 */
>> + r = regmap_write_bits(data->regmap, DPS310_CFG_REG,
>> + DPS310_TMP_SHIFT_EN, 0);
>> + if (r < 0)
>> + goto err;
>> +
>> + /* Turn on temperature measurement in the background */
>> + r = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
>> + DPS310_MEAS_CTRL_BITS,
>> + DPS310_TEMP_EN | DPS310_BACKGROUND);
>> + if (r < 0)
>> + goto err;
>> +
>> + /*
>> + * Calibration coefficients required for reporting temperature.
>> + * They are available 40ms after the device has started
>> + */
>> + r = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
>> + ready & DPS310_COEF_RDY, 10000, 40000);
>> + if (r < 0)
>> + goto err;
>> +
>> + r = dps310_get_temp_coef(data);
>> + if (r < 0)
>> + goto err;
>> +
>> + r = devm_iio_device_register(&client->dev, iio);
>> + if (r)
>> + goto err;
>> +
>> + i2c_set_clientdata(client, iio);
>> +
>> + dev_info(&client->dev, "%s: sensor '%s'\n", dev_name(&iio->dev),
>> + client->name);
> don't clutter the log
>
>> +
>> + return 0;
>> +
>> +err:
>> + regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC);
>> + return r;
>> +}
>> +
>> +static int dps310_remove(struct i2c_client *client)
>> +{
>> + struct dps310_data *data = i2c_get_clientdata(client);
>> +
>> + return regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC);
>> +}
>> +
>> +static const struct i2c_device_id dps310_id[] = {
>> + { "dps310", 0 },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(i2c, dps310_id);
>> +
>> +static const unsigned short normal_i2c[] = {
>> + 0x77, 0x76, I2C_CLIENT_END
>> +};
>> +
>> +static struct i2c_driver dps310_driver = {
>> + .driver = {
>> + .name = "dps310",
>> + },
>> + .probe = dps310_probe,
>> + .remove = dps310_remove,
>> + .address_list = normal_i2c,
>> + .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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