[RFC PATCH] hwmon: Add driver for Infineon DPS310
From: Joel Stanley
Date: Wed Apr 26 2017 - 10:33:52 EST
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 mÂC */
+ *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