On 26/04/17 16:13, Guenter Roeck wrote:
> 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 ?
>
Agree with you. Pressure doesn't really fit in hwmon, so IIO is best location.
> 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
>>
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