Hi Joel, On Thu, Apr 27, 2017 at 12:03:21AM +0930, Joel Stanley wrote: > 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? >
IIO, I think. Pressure isn't really for hardware monitoring, and we would have a hard time supporting it. IIO already has the necessary infrastructure for it. Jonathan, any thoughts/comments ? Thanks, Guenter > 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 <[email protected]> > --- > 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 <[email protected]> > + * > + * 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 <[email protected]>"); > +MODULE_DESCRIPTION("Infineon DPS310 driver"); > +MODULE_LICENSE("GPL"); > -- > 2.11.0 >
