hp206c: Initial support for reading sensor values
authorCrestez Dan Leonard <leonard.crestez@intel.com>
Tue, 29 Mar 2016 16:14:27 +0000 (19:14 +0300)
committerJonathan Cameron <jic23@kernel.org>
Sun, 3 Apr 2016 10:14:01 +0000 (11:14 +0100)
Signed-off-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
drivers/iio/pressure/Kconfig
drivers/iio/pressure/Makefile
drivers/iio/pressure/hp206c.c [new file with mode: 0644]

index 31c0e1fd2202d6dea587dc7fbb07cbff74397b36..8de0192adea6cde2466ee58942aef4eef457b476 100644 (file)
@@ -148,4 +148,14 @@ config T5403
          To compile this driver as a module, choose M here: the module
          will be called t5403.
 
+config HP206C
+       tristate "HOPERF HP206C precision barometer and altimeter sensor"
+       depends on I2C
+       help
+         Say yes here to build support for the HOPREF HP206C precision
+         barometer and altimeter sensor.
+
+         This driver can also be built as a module. If so, the module will
+         be called hp206c.
+
 endmenu
index d336af14f3fe8e36c7c97d59cf411f1ac5632d4f..6e60863c10867485854f1814a929c16fa79e4b5f 100644 (file)
@@ -17,6 +17,7 @@ obj-$(CONFIG_IIO_ST_PRESS) += st_pressure.o
 st_pressure-y := st_pressure_core.o
 st_pressure-$(CONFIG_IIO_BUFFER) += st_pressure_buffer.o
 obj-$(CONFIG_T5403) += t5403.o
+obj-$(CONFIG_HP206C) += hp206c.o
 
 obj-$(CONFIG_IIO_ST_PRESS_I2C) += st_pressure_i2c.o
 obj-$(CONFIG_IIO_ST_PRESS_SPI) += st_pressure_spi.o
diff --git a/drivers/iio/pressure/hp206c.c b/drivers/iio/pressure/hp206c.c
new file mode 100644 (file)
index 0000000..90f2b6e
--- /dev/null
@@ -0,0 +1,426 @@
+/*
+ * hp206c.c - HOPERF HP206C precision barometer and altimeter sensor
+ *
+ * Copyright (c) 2016, Intel Corporation.
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * (7-bit I2C slave address 0x76)
+ *
+ * Datasheet:
+ *  http://www.hoperf.com/upload/sensor/HP206C_DataSheet_EN_V2.0.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/delay.h>
+#include <linux/util_macros.h>
+#include <linux/acpi.h>
+
+/* I2C commands: */
+#define HP206C_CMD_SOFT_RST    0x06
+
+#define HP206C_CMD_ADC_CVT     0x40
+
+#define HP206C_CMD_ADC_CVT_OSR_4096    0x00
+#define HP206C_CMD_ADC_CVT_OSR_2048    0x04
+#define HP206C_CMD_ADC_CVT_OSR_1024    0x08
+#define HP206C_CMD_ADC_CVT_OSR_512     0x0c
+#define HP206C_CMD_ADC_CVT_OSR_256     0x10
+#define HP206C_CMD_ADC_CVT_OSR_128     0x14
+
+#define HP206C_CMD_ADC_CVT_CHNL_PT     0x00
+#define HP206C_CMD_ADC_CVT_CHNL_T      0x02
+
+#define HP206C_CMD_READ_P      0x30
+#define HP206C_CMD_READ_T      0x32
+
+#define HP206C_CMD_READ_REG    0x80
+#define HP206C_CMD_WRITE_REG   0xc0
+
+#define HP206C_REG_INT_EN      0x0b
+#define HP206C_REG_INT_CFG     0x0c
+
+#define HP206C_REG_INT_SRC     0x0d
+#define HP206C_FLAG_DEV_RDY    0x40
+
+#define HP206C_REG_PARA                0x0f
+#define HP206C_FLAG_CMPS_EN    0x80
+
+/* Maximum spin for DEV_RDY */
+#define HP206C_MAX_DEV_RDY_WAIT_COUNT 20
+#define HP206C_DEV_RDY_WAIT_US    20000
+
+struct hp206c_data {
+       struct mutex mutex;
+       struct i2c_client *client;
+       int temp_osr_index;
+       int pres_osr_index;
+};
+
+struct hp206c_osr_setting {
+       u8 osr_mask;
+       unsigned int temp_conv_time_us;
+       unsigned int pres_conv_time_us;
+};
+
+/* Data from Table 5 in datasheet. */
+static const struct hp206c_osr_setting hp206c_osr_settings[] = {
+       { HP206C_CMD_ADC_CVT_OSR_4096,  65600,  131100  },
+       { HP206C_CMD_ADC_CVT_OSR_2048,  32800,  65600   },
+       { HP206C_CMD_ADC_CVT_OSR_1024,  16400,  32800   },
+       { HP206C_CMD_ADC_CVT_OSR_512,   8200,   16400   },
+       { HP206C_CMD_ADC_CVT_OSR_256,   4100,   8200    },
+       { HP206C_CMD_ADC_CVT_OSR_128,   2100,   4100    },
+};
+static const int hp206c_osr_rates[] = { 4096, 2048, 1024, 512, 256, 128 };
+static const char hp206c_osr_rates_str[] = "4096 2048 1024 512 256 128";
+
+static inline int hp206c_read_reg(struct i2c_client *client, u8 reg)
+{
+       return i2c_smbus_read_byte_data(client, HP206C_CMD_READ_REG | reg);
+}
+
+static inline int hp206c_write_reg(struct i2c_client *client, u8 reg, u8 val)
+{
+       return i2c_smbus_write_byte_data(client,
+                       HP206C_CMD_WRITE_REG | reg, val);
+}
+
+static int hp206c_read_20bit(struct i2c_client *client, u8 cmd)
+{
+       int ret;
+       u8 values[3];
+
+       ret = i2c_smbus_read_i2c_block_data(client, cmd, 3, values);
+       if (ret < 0)
+               return ret;
+       if (ret != 3)
+               return -EIO;
+       return ((values[0] & 0xF) << 16) | (values[1] << 8) | (values[2]);
+}
+
+/* Spin for max 160ms until DEV_RDY is 1, or return error. */
+static int hp206c_wait_dev_rdy(struct iio_dev *indio_dev)
+{
+       int ret;
+       int count = 0;
+       struct hp206c_data *data = iio_priv(indio_dev);
+       struct i2c_client *client = data->client;
+
+       while (++count <= HP206C_MAX_DEV_RDY_WAIT_COUNT) {
+               ret = hp206c_read_reg(client, HP206C_REG_INT_SRC);
+               if (ret < 0) {
+                       dev_err(&indio_dev->dev, "Failed READ_REG INT_SRC: %d\n", ret);
+                       return ret;
+               }
+               if (ret & HP206C_FLAG_DEV_RDY)
+                       return 0;
+               usleep_range(HP206C_DEV_RDY_WAIT_US, HP206C_DEV_RDY_WAIT_US * 3 / 2);
+       }
+       return -ETIMEDOUT;
+}
+
+static int hp206c_set_compensation(struct i2c_client *client, bool enabled)
+{
+       int val;
+
+       val = hp206c_read_reg(client, HP206C_REG_PARA);
+       if (val < 0)
+               return val;
+       if (enabled)
+               val |= HP206C_FLAG_CMPS_EN;
+       else
+               val &= ~HP206C_FLAG_CMPS_EN;
+
+       return hp206c_write_reg(client, HP206C_REG_PARA, val);
+}
+
+/* Do a soft reset */
+static int hp206c_soft_reset(struct iio_dev *indio_dev)
+{
+       int ret;
+       struct hp206c_data *data = iio_priv(indio_dev);
+       struct i2c_client *client = data->client;
+
+       ret = i2c_smbus_write_byte(client, HP206C_CMD_SOFT_RST);
+       if (ret) {
+               dev_err(&client->dev, "Failed to reset device: %d\n", ret);
+               return ret;
+       }
+
+       usleep_range(400, 600);
+
+       ret = hp206c_wait_dev_rdy(indio_dev);
+       if (ret) {
+               dev_err(&client->dev, "Device not ready after soft reset: %d\n", ret);
+               return ret;
+       }
+
+       ret = hp206c_set_compensation(client, true);
+       if (ret)
+               dev_err(&client->dev, "Failed to enable compensation: %d\n", ret);
+       return ret;
+}
+
+static int hp206c_conv_and_read(struct iio_dev *indio_dev,
+                               u8 conv_cmd, u8 read_cmd,
+                               unsigned int sleep_us)
+{
+       int ret;
+       struct hp206c_data *data = iio_priv(indio_dev);
+       struct i2c_client *client = data->client;
+
+       ret = hp206c_wait_dev_rdy(indio_dev);
+       if (ret < 0) {
+               dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
+               return ret;
+       }
+
+       ret = i2c_smbus_write_byte(client, conv_cmd);
+       if (ret < 0) {
+               dev_err(&indio_dev->dev, "Failed convert: %d\n", ret);
+               return ret;
+       }
+
+       usleep_range(sleep_us, sleep_us * 3 / 2);
+
+       ret = hp206c_wait_dev_rdy(indio_dev);
+       if (ret < 0) {
+               dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
+               return ret;
+       }
+
+       ret = hp206c_read_20bit(client, read_cmd);
+       if (ret < 0)
+               dev_err(&indio_dev->dev, "Failed read: %d\n", ret);
+
+       return ret;
+}
+
+static int hp206c_read_raw(struct iio_dev *indio_dev,
+                          struct iio_chan_spec const *chan, int *val,
+                          int *val2, long mask)
+{
+       int ret;
+       struct hp206c_data *data = iio_priv(indio_dev);
+       const struct hp206c_osr_setting *osr_setting;
+       u8 conv_cmd;
+
+       mutex_lock(&data->mutex);
+
+       switch (mask) {
+       case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+               switch (chan->type) {
+               case IIO_TEMP:
+                       *val = hp206c_osr_rates[data->temp_osr_index];
+                       ret = IIO_VAL_INT;
+                       break;
+
+               case IIO_PRESSURE:
+                       *val = hp206c_osr_rates[data->pres_osr_index];
+                       ret = IIO_VAL_INT;
+                       break;
+               default:
+                       ret = -EINVAL;
+               }
+               break;
+
+       case IIO_CHAN_INFO_RAW:
+               switch (chan->type) {
+               case IIO_TEMP:
+                       osr_setting = &hp206c_osr_settings[data->temp_osr_index];
+                       conv_cmd = HP206C_CMD_ADC_CVT |
+                                       osr_setting->osr_mask |
+                                       HP206C_CMD_ADC_CVT_CHNL_T;
+                       ret = hp206c_conv_and_read(indio_dev,
+                                       conv_cmd,
+                                       HP206C_CMD_READ_T,
+                                       osr_setting->temp_conv_time_us);
+                       if (ret >= 0) {
+                               /* 20 significant bits are provided.
+                                * Extend sign over the rest.
+                                */
+                               *val = sign_extend32(ret, 19);
+                               ret = IIO_VAL_INT;
+                       }
+                       break;
+
+               case IIO_PRESSURE:
+                       osr_setting = &hp206c_osr_settings[data->pres_osr_index];
+                       conv_cmd = HP206C_CMD_ADC_CVT |
+                                       osr_setting->osr_mask |
+                                       HP206C_CMD_ADC_CVT_CHNL_PT;
+                       ret = hp206c_conv_and_read(indio_dev,
+                                       conv_cmd,
+                                       HP206C_CMD_READ_P,
+                                       osr_setting->pres_conv_time_us);
+                       if (ret >= 0) {
+                               *val = ret;
+                               ret = IIO_VAL_INT;
+                       }
+                       break;
+               default:
+                       ret = -EINVAL;
+               }
+               break;
+
+       case IIO_CHAN_INFO_SCALE:
+               switch (chan->type) {
+               case IIO_TEMP:
+                       *val = 0;
+                       *val2 = 10000;
+                       ret = IIO_VAL_INT_PLUS_MICRO;
+                       break;
+
+               case IIO_PRESSURE:
+                       *val = 0;
+                       *val2 = 1000;
+                       ret = IIO_VAL_INT_PLUS_MICRO;
+                       break;
+               default:
+                       ret = -EINVAL;
+               }
+               break;
+
+       default:
+               ret = -EINVAL;
+       }
+
+       mutex_unlock(&data->mutex);
+       return ret;
+}
+
+static int hp206c_write_raw(struct iio_dev *indio_dev,
+                           struct iio_chan_spec const *chan,
+                           int val, int val2, long mask)
+{
+       int ret = 0;
+       struct hp206c_data *data = iio_priv(indio_dev);
+
+       if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
+               return -EINVAL;
+       mutex_lock(&data->mutex);
+       switch (chan->type) {
+       case IIO_TEMP:
+               data->temp_osr_index = find_closest_descending(val,
+                       hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
+               break;
+       case IIO_PRESSURE:
+               data->pres_osr_index = find_closest_descending(val,
+                       hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
+               break;
+       default:
+               ret = -EINVAL;
+       }
+       mutex_unlock(&data->mutex);
+       return ret;
+}
+
+static const struct iio_chan_spec hp206c_channels[] = {
+       {
+               .type = IIO_TEMP,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                                     BIT(IIO_CHAN_INFO_SCALE) |
+                                     BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+       },
+       {
+               .type = IIO_PRESSURE,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                                     BIT(IIO_CHAN_INFO_SCALE) |
+                                     BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+       }
+};
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(hp206c_osr_rates_str);
+
+static struct attribute *hp206c_attributes[] = {
+       &iio_const_attr_sampling_frequency_available.dev_attr.attr,
+       NULL,
+};
+
+static const struct attribute_group hp206c_attribute_group = {
+       .attrs = hp206c_attributes,
+};
+
+static const struct iio_info hp206c_info = {
+       .attrs = &hp206c_attribute_group,
+       .read_raw = hp206c_read_raw,
+       .write_raw = hp206c_write_raw,
+       .driver_module = THIS_MODULE,
+};
+
+static int hp206c_probe(struct i2c_client *client,
+                       const struct i2c_device_id *id)
+{
+       struct iio_dev *indio_dev;
+       struct hp206c_data *data;
+       int ret;
+
+       if (!i2c_check_functionality(client->adapter,
+                                    I2C_FUNC_SMBUS_BYTE |
+                                    I2C_FUNC_SMBUS_BYTE_DATA |
+                                    I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+               dev_err(&client->dev, "Adapter does not support "
+                               "all required i2c functionality\n");
+               return -ENODEV;
+       }
+
+       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+       if (!indio_dev)
+               return -ENOMEM;
+
+       data = iio_priv(indio_dev);
+       data->client = client;
+       mutex_init(&data->mutex);
+
+       indio_dev->info = &hp206c_info;
+       indio_dev->name = id->name;
+       indio_dev->dev.parent = &client->dev;
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->channels = hp206c_channels;
+       indio_dev->num_channels = ARRAY_SIZE(hp206c_channels);
+
+       i2c_set_clientdata(client, indio_dev);
+
+       /* Do a soft reset on probe */
+       ret = hp206c_soft_reset(indio_dev);
+       if (ret) {
+               dev_err(&client->dev, "Failed to reset on startup: %d\n", ret);
+               return -ENODEV;
+       }
+
+       return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id hp206c_id[] = {
+       {"hp206c"},
+       {}
+};
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id hp206c_acpi_match[] = {
+       {"HOP206C", 0},
+       { },
+};
+MODULE_DEVICE_TABLE(acpi, hp206c_acpi_match);
+#endif
+
+static struct i2c_driver hp206c_driver = {
+       .probe = hp206c_probe,
+       .id_table = hp206c_id,
+       .driver = {
+               .name = "hp206c",
+               .acpi_match_table = ACPI_PTR(hp206c_acpi_match),
+       },
+};
+
+module_i2c_driver(hp206c_driver);
+
+MODULE_DESCRIPTION("HOPERF HP206C precision barometer and altimeter sensor");
+MODULE_AUTHOR("Leonard Crestez <leonard.crestez@intel.com>");
+MODULE_LICENSE("GPL v2");