Hi Guenter, Below is a work in progress hwmon driver for the DPS310[1]. The device does both pressure and temperature monitoring over either I2C or SPI. There's a public datasheet available on Infineon's website. I require a driver that reads the temperature data over I2C and exposes it to userspace as a hwmon device. I wanted your opinion weather this should be an IIO driver (and we could then use the IIO HWMON bridge in our application), or if it should be a native HWMON driver? Once we've agreed on a subsystem I will clean the driver up and submit it properly. Cheers, Joel [1] https://www.infineon.com/cms/en/product/sensor/capacitive-pressure-sensor-for-consumer-applications/channel.html --- The DPS310 is a temperature and pressure sensor. It can be accessed over i2c and SPI. This driver supports continual measurement of temperature over i2c only. Signed-off-by: Joel Stanley <joel@xxxxxxxxx> --- drivers/hwmon/Kconfig | 12 ++ drivers/hwmon/Makefile | 1 + drivers/hwmon/dps310.c | 331 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 344 insertions(+) create mode 100644 drivers/hwmon/dps310.c diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 190d270b20a2..8229b2f8c591 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -1349,6 +1349,18 @@ config SENSORS_DME1737 This driver can also be built as a module. If so, the module will be called dme1737. +config SENSORS_DPS310 + tristate "Infineon DPS310" + depends on I2C + select HWMON_VID + select REGMAP_I2C + help + If you say yes here you get support for the hardware monitoring + features of 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 SENSORS_EMC1403 tristate "SMSC EMC1403/23 thermal sensor" depends on I2C diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index d2cb7e804a0f..3a5ad06d6d89 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -52,6 +52,7 @@ obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o obj-$(CONFIG_SENSORS_DELL_SMM) += dell-smm-hwmon.o obj-$(CONFIG_SENSORS_DME1737) += dme1737.o +obj-$(CONFIG_SENSORS_DPS310) += dps310.o obj-$(CONFIG_SENSORS_DS620) += ds620.o obj-$(CONFIG_SENSORS_DS1621) += ds1621.o obj-$(CONFIG_SENSORS_EMC1403) += emc1403.o diff --git a/drivers/hwmon/dps310.c b/drivers/hwmon/dps310.c new file mode 100644 index 000000000000..b014f01d0d3f --- /dev/null +++ b/drivers/hwmon/dps310.c @@ -0,0 +1,331 @@ +/* + * Copyright 2017 IBM Corporation + * + * Joel Stanley <joel@xxxxxxxxx> + * + * The DPS310 is a barometric pressure and temperature sensor. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/i2c.h> +#include <linux/regmap.h> +#include <linux/hwmon.h> +#include <linux/module.h> + +#define PRS_B2 0x00 +#define PRS_B1 0x01 +#define PRS_B0 0x02 +#define TMP_B2 0x03 +#define TMP_B1 0x04 +#define TMP_B0 0x05 +#define PRS_CFG 0x06 +#define TMP_CFG 0x07 +#define TMP_RATE_BITS GENMASK(6, 4) +#define TMP_EXT BIT(7) +#define MEAS_CFG 0x08 +#define MEAS_CTRL_BITS GENMASK(2, 0) +#define PRESSURE_EN BIT(0) +#define TEMP_EN BIT(1) +#define BACKGROUND BIT(2) +#define PRS_RDY BIT(4) +#define TMP_RDY BIT(5) +#define SENSOR_RDY BIT(6) +#define COEF_RDY BIT(7) +#define RESET 0x0c +#define RESET_MAGIC (BIT(0) | BIT(3)) +#define COEF_BASE 0x10 + +#define TMP_BASE TMP_B2 +#define PRS_BASE PRS_B2 + +#define TMP_RATE(_n) ilog2(_n) +#define TMP_PRC(_n) ilog2(_n) + +const int scale_factor[] = { + 524288, + 1572864, + 3670016, + 7864320, + 253952, + 516096, + 1040384, + 2088960, +}; + +struct dps310_data { + struct regmap *regmap; + int interval; + s32 c0, c1; +}; + +static s32 dps310_twos_compliment(u32 raw, size_t num_bits) +{ + s32 out = raw; + + if (raw & BIT(num_bits - 1)) + out = raw - BIT(num_bits); + + return out; +} + +static int dps310_get_temp_coef(struct dps310_data *data) +{ + struct regmap *regmap = data->regmap; + uint8_t coef[3] = {0}; + int ready, r; + u32 c0, c1; + + r = regmap_read(regmap, MEAS_CFG, &ready); + if (r < 0) + return r; + + if (!(ready & COEF_RDY)) + return -EAGAIN; + + /* + * 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, COEF_BASE, coef, 3); + if (r < 0) + return r; + + c0 = (coef[0] << 4) | (coef[1] >> 4); + data->c0 = dps310_twos_compliment(c0, 12); + + c1 = ((coef[1] & GENMASK(3, 0)) << 8) | coef[2]; + data->c1 = dps310_twos_compliment(c1, 12); + + return 0; +} + +static int dps310_get_scale_factor(struct device *dev) +{ + struct dps310_data *data = dev_get_drvdata(dev); + int val, r; + + r = regmap_read(data->regmap, TMP_CFG, &val); + if (r < 0) + return r; + + /* Scale factor is bottom 4 bits of the register */ + val = val & GENMASK(3, 0); + if (val < 0 || val > ARRAY_SIZE(scale_factor)) + return -EINVAL; + + return scale_factor[val]; +} + +static int dps310_read_temp(struct device *dev, u32 attr, int channel, + long *temp) +{ + struct dps310_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; + uint8_t val[3] = {0}; + int r, ready; + int kT, T_raw; + + switch (attr) { + case hwmon_temp_input: + r = regmap_read(regmap, MEAS_CFG, &ready); + if (r < 0) + return r; + if (!(ready & TMP_RDY)) { + dev_err(dev, "tmp not ready\n"); + return -EAGAIN; + } + + /* Choose scaling factor kT based on chosen precision rate */ + kT = dps310_get_scale_factor(dev); + + r = regmap_bulk_read(regmap, TMP_BASE, val, 3); + if (r < 0) + return r; + T_raw = (val[0] << 16) | (val[1] << 8) | val[2]; + T_raw = dps310_twos_compliment(T_raw, 24); + + /* (c0 * 0.5 + c1 * T_raw / kT) * 1000 m°C */ + *temp = ((data->c0 >> 1) + (data->c1 * T_raw) / kT) * 1000; + + return 0; + default: + return -EOPNOTSUPP; + } +} + +static int dps310_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + switch (type) { + case hwmon_temp: + return dps310_read_temp(dev, attr, channel, val); + default: + return -EOPNOTSUPP; + } +} + +static int dps310_write(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long val) +{ + switch (type) { + case hwmon_temp: + /* Fall through */ + default: + return -EOPNOTSUPP; + } +} + +static umode_t dps310_is_visible(const void *data, + enum hwmon_sensor_types type, + u32 attr, int channel) +{ + switch (type) { + case hwmon_temp: + switch (attr) { + case hwmon_temp_input: + return 0444; + default: + return 0; + } + default: + return 0; + } +} + + +static const u32 dps310_temp_config[] = { + HWMON_T_INPUT, + 0 +}; + +static const struct hwmon_channel_info dps310_temp = { + .type = hwmon_temp, + .config = dps310_temp_config, +}; + +static const struct hwmon_channel_info *dps310_info[] = { + &dps310_temp, + NULL +}; + +static const struct hwmon_ops dps310_hwmon_ops = { + .is_visible = dps310_is_visible, + .read = dps310_read, + .write = dps310_write, +}; + +static const struct hwmon_chip_info dps310_chip_info = { + .ops = &dps310_hwmon_ops, + .info = dps310_info, +}; + +static bool dps310_is_writeable_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case PRS_CFG: + case TMP_CFG: + case MEAS_CFG: + case RESET: + return true; + default: + return false; + } +} + +static bool dps310_is_volatile_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case PRS_B2: + case PRS_B1: + case PRS_B0: + case TMP_B2: + case TMP_B1: + case TMP_B0: + case MEAS_CFG: + return true; + default: + return false; + } +} + +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, + .use_single_rw = true, +}; + +static int dps310_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct dps310_data *data; + struct device *hwmon_dev; + int r; + + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->regmap = devm_regmap_init_i2c(client, &dps310_regmap_config); + if (IS_ERR(data->regmap)) + return PTR_ERR(data->regmap); + + r = regmap_write(data->regmap, TMP_CFG, TMP_EXT | TMP_PRC(128)); + if (r < 0) + return r; + + /* Turn on background temperature measurement */ + r = regmap_update_bits(data->regmap, MEAS_CFG, MEAS_CTRL_BITS, + TEMP_EN); + if (r < 0) + return r; + + /* Get calibration coefficients required for reporting temperature */ + r = dps310_get_temp_coef(data); + if (r == -EAGAIN) + return -EPROBE_DEFER; + if (r < 0) + return r; + + hwmon_dev = devm_hwmon_device_register_with_info(&client->dev, + client->name, data, &dps310_chip_info, NULL); + + if (IS_ERR(hwmon_dev)) + return PTR_ERR(hwmon_dev); + + dev_info(&client->dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), + client->name); + + return 0; +} + +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 = { + .class = I2C_CLASS_HWMON, + .driver = { + .name = "dps310", + }, + .probe = dps310_probe, + .address_list = normal_i2c, + .id_table = dps310_id, +}; +module_i2c_driver(dps310_driver); + +MODULE_AUTHOR("Joel Stanley <joel@xxxxxxxxx>"); +MODULE_DESCRIPTION("Infineon DPS310 driver"); +MODULE_LICENSE("GPL"); -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
