On 02/10/14 21:04, Peter Meerwald wrote: > >> Minimal implementation, can read temperature and data using direct mode. >> >> Datasheet available at >> <http://ae-bst.resource.bosch.com/media/products/dokumente/bmp280/BST-BMP280-DS001-09.pdf> > > minor comments below Looks pretty good to me. I've made a few little suggestions inline. Most interesting one is the question of whether it would be better to let the regmap cache deal with the various calibration parameters rather than caching them again locally. J > >> Signed-off-by: Vlad Dogaru <vlad.dogaru@xxxxxxxxx> >> --- >> drivers/iio/pressure/Kconfig | 11 ++ >> drivers/iio/pressure/Makefile | 1 + >> drivers/iio/pressure/bmp280.c | 433 ++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 445 insertions(+) >> create mode 100644 drivers/iio/pressure/bmp280.c >> >> diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig >> index 15afbc9..27ab27e 100644 >> --- a/drivers/iio/pressure/Kconfig >> +++ b/drivers/iio/pressure/Kconfig >> @@ -5,6 +5,17 @@ >> >> menu "Pressure sensors" >> >> +config BMP280 >> + tristate "Bosch Sensortec BMP280 pressure sensor driver" >> + depends on I2C >> + select REGMAP_I2C >> + help >> + Say yes here to build support for Bosch Sensortec BMP28 > > BMP280 > >> + pressure and temperature sensor. >> + >> + To compile this driver as a module, choose M here: the module >> + will be called bmp280. >> + >> config HID_SENSOR_PRESS >> depends on HID_SENSOR_HUB >> select IIO_BUFFER >> diff --git a/drivers/iio/pressure/Makefile b/drivers/iio/pressure/Makefile >> index 90a37e8..88011f2 100644 >> --- a/drivers/iio/pressure/Makefile >> +++ b/drivers/iio/pressure/Makefile >> @@ -3,6 +3,7 @@ >> # >> >> # When adding new entries keep the list in alphabetical order >> +obj-$(CONFIG_BMP280) += bmp280.o >> obj-$(CONFIG_HID_SENSOR_PRESS) += hid-sensor-press.o >> obj-$(CONFIG_MPL115) += mpl115.o >> obj-$(CONFIG_MPL3115) += mpl3115.o >> diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c >> new file mode 100644 >> index 0000000..f5764ee >> --- /dev/null >> +++ b/drivers/iio/pressure/bmp280.c >> @@ -0,0 +1,433 @@ >> +/* >> + * Copyright (c) 2014 Intel Corporation >> + * >> + * Driver for Bosch Sensortec BMP280 digital pressure sensor. >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + * >> + */ >> + >> +#define pr_fmt(fmt) "bmp280: " fmt >> + >> +#include <linux/module.h> >> +#include <linux/i2c.h> >> +#include <linux/acpi.h> >> +#include <linux/regmap.h> >> +#include <linux/iio/iio.h> >> +#include <linux/iio/sysfs.h> >> + >> +#define BMP280_REG_TEMP_XLSB 0xFC >> +#define BMP280_REG_TEMP_LSB 0xFB >> +#define BMP280_REG_TEMP_MSB 0xFA >> +#define BMP280_REG_PRESS_XLSB 0xF9 >> +#define BMP280_REG_PRESS_LSB 0xF8 >> +#define BMP280_REG_PRESS_MSB 0xF7 >> + >> +#define BMP280_REG_CONFIG 0xF5 >> +#define BMP280_REG_CTRL_MEAS 0xF4 >> +#define BMP280_REG_STATUS 0xF3 >> +#define BMP280_REG_RESET 0xE0 >> +#define BMP280_REG_ID 0xD0 >> + >> +#define BMP280_REG_COMP_START 0x88 >> +#define BMP280_COMP_REG_COUNT 24 >> + >> +#define BMP280_FILTER_MASK (BIT(4) | BIT(3) | BIT(2)) >> +#define BMP280_FILTER_OFF 0 >> +#define BMP280_FILTER_2X BIT(2) >> +#define BMP280_FILTER_4X BIT(3) >> +#define BMP280_FILTER_8X (BIT(3) | BIT(2)) >> +#define BMP280_FILTER_16X BIT(4) >> + >> +#define BMP280_OSRS_TEMP_MASK (BIT(7) | BIT(6) | BIT(5)) >> +#define BMP280_OSRS_TEMP_SKIP 0 >> +#define BMP280_OSRS_TEMP_1X BIT(5) >> +#define BMP280_OSRS_TEMP_2X BIT(6) >> +#define BMP280_OSRS_TEMP_4X (BIT(6) | BIT(5)) >> +#define BMP280_OSRS_TEMP_8X BIT(7) >> +#define BMP280_OSRS_TEMP_16X (BIT(7) | BIT(5)) >> + >> +#define BMP280_OSRS_PRESS_MASK (BIT(4) | BIT(3) | BIT(2)) >> +#define BMP280_OSRS_PRESS_SKIP 0 >> +#define BMP280_OSRS_PRESS_1X BIT(2) >> +#define BMP280_OSRS_PRESS_2X BIT(3) >> +#define BMP280_OSRS_PRESS_4X (BIT(3) | BIT(2)) >> +#define BMP280_OSRS_PRESS_8X BIT(4) >> +#define BMP280_OSRS_PRESS_16X (BIT(4) | BIT(2)) >> + >> +#define BMP280_MODE_MASK (BIT(1) | BIT(0)) >> +#define BMP280_MODE_SLEEP 0 >> +#define BMP280_MODE_FORCED BIT(0) >> +#define BMP280_MODE_NORMAL (BIT(1) | BIT(0)) >> + >> +#define BMP280_CHIP_ID 0x58 >> +#define BMP280_SOFT_RESET_VAL 0xB6 >> + >> +struct bmp280_data { >> + struct i2c_client *client; >> + struct mutex lock; >> + struct regmap *regmap; >> + >> + /* >> + * Carryover value from temperature conversion, used in pressure >> + * calculation. >> + */ >> + s32 t_fine; >> + >> + /* Compensation parameters. */ >> + u16 dig_t1; >> + s16 dig_t2, dig_t3; >> + u16 dig_p1; >> + s16 dig_p2, dig_p3, dig_p4, dig_p5, dig_p6, dig_p7, dig_p8, dig_p9; >> +}; >> + >> +static const struct iio_chan_spec bmp280_channels[] = { >> + { >> + .type = IIO_PRESSURE, >> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | >> + BIT(IIO_CHAN_INFO_SCALE), >> + }, >> + { >> + .type = IIO_TEMP, >> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | >> + BIT(IIO_CHAN_INFO_SCALE), > > should probably be _PROCESSED, not _RAW > >> + }, >> +}; >> + >> +static bool bmp280_is_writeable_reg(struct device *dev, unsigned int reg) >> +{ >> + switch (reg) { >> + case BMP280_REG_CONFIG: >> + case BMP280_REG_CTRL_MEAS: >> + case BMP280_REG_RESET: >> + return true; >> + default: >> + return false; >> + }; >> +} >> + >> +static bool bmp280_is_volatile_reg(struct device *dev, unsigned int reg) >> +{ >> + switch (reg) { >> + case BMP280_REG_TEMP_XLSB: >> + case BMP280_REG_TEMP_LSB: >> + case BMP280_REG_TEMP_MSB: >> + case BMP280_REG_PRESS_XLSB: >> + case BMP280_REG_PRESS_LSB: >> + case BMP280_REG_PRESS_MSB: >> + case BMP280_REG_STATUS: >> + return true; >> + default: >> + return false; >> + } >> +} >> + >> +static const struct regmap_config bmp280_regmap_config = { >> + .reg_bits = 8, >> + .val_bits = 8, >> + >> + .max_register = BMP280_REG_TEMP_XLSB, >> + .cache_type = REGCACHE_RBTREE, >> + >> + .writeable_reg = bmp280_is_writeable_reg, >> + .volatile_reg = bmp280_is_volatile_reg, >> +}; >> + >> +/* >> + * Returns temperature in DegC, resolution is 0.01 DegC. Output value of >> + * "5123" equals 51.23 DegC. t_fine carries fine temperature as global >> + * value. >> + * >> + * Taken from datasheet, Section 3.11.3, "Compensation formula". >> + */ >> +static s32 bmp280_compensate_temp(struct bmp280_data *data, >> + s32 adc_temp) >> +{ >> + s32 var1, var2, T; > > use lowercase t? > >> + >> + var1 = (((adc_temp >> 3) - ((s32) data->dig_t1 << 1)) * >> + ((s32) data->dig_t2)) >> 11; >> + var2 = (((((adc_temp >> 4) - ((s32) data->dig_t1)) * >> + ((adc_temp >> 4) - ((s32) data->dig_t1))) >> 12) * >> + ((s32) data->dig_t3)) >> 14; >> + >> + data->t_fine = var1 + var2; >> + T = (data->t_fine * 5 + 128) >> 8; >> + >> + return T; >> +} >> + >> +/* >> + * Returns pressure in Pa as unsigned 32 bit integer in Q24.8 format (24 >> + * integer bits and 8 fractional bits). Output value of "24674867" >> + * represents 24674867/256 = 96386.2 Pa = 963.862 hPa >> + * >> + * Taken from datasheet, Section 3.11.3, "Compensation formula". >> + */ >> +static u32 bmp280_compensate_press(struct bmp280_data *data, >> + s32 adc_press) >> +{ >> + s64 var1, var2, p; >> + >> + var1 = ((s64) data->t_fine) - 128000; >> + var2 = var1 * var1 * (s64) data->dig_p6; >> + var2 = var2 + ((var1 * (s64) data->dig_p5) << 17); >> + var2 = var2 + (((s64) data->dig_p4) << 35); >> + var1 = ((var1 * var1 * (s64) data->dig_p3) >> 8) + >> + ((var1 * (s64) data->dig_p2) << 12); >> + var1 = (((((s64) 1) << 47) + var1)) * ((s64) data->dig_p1) >> 33; >> + >> + if (var1 == 0) >> + return 0; >> + >> + p = 1048576 - adc_press; >> + p = (((p << 31) - var2) * 3125) / var1; >> + var1 = (((s64) data->dig_p9) * (p >> 13) * (p >> 13)) >> 25; >> + var2 = (((s64) data->dig_p8) * p) >> 19; >> + p = ((p + var1 + var2) >> 8) + (((s64) data->dig_p7) << 4); >> + >> + return (u32) p; >> +} >> + >> +static int bmp280_read_temp(struct bmp280_data *data, >> + int *val, int *val2) >> +{ > > val2 is not used > >> + int ret; >> + __be32 tmp; >> + s32 adc_temp, comp_temp; >> + >> + ret = regmap_bulk_read(data->regmap, BMP280_REG_TEMP_MSB, >> + (u8 *) &tmp, 3); > > tmp should be initialized, only 3 bytes out of 4 read > >> + if (ret < 0) { >> + dev_err(&data->client->dev, "failed to read temperature\n"); >> + return ret; >> + } >> + >> + adc_temp = be32_to_cpu(tmp) >> 12; >> + comp_temp = bmp280_compensate_temp(data, adc_temp); >> + >> + /* >> + * val might be NULL if we're called by the read_press routine, >> + * who only cares about the carry over t_fine value. >> + */ >> + if (val) { >> + *val = comp_temp; >> + return IIO_VAL_INT; >> + } >> + >> + return 0; >> +} >> + >> +static int bmp280_read_press(struct bmp280_data *data, >> + int *val, int *val2) >> +{ > val2 is not used > >> + int ret; >> + __be32 tmp; >> + s32 adc_press; >> + u32 comp_press; >> + >> + /* Read and compensate temperature so we get a reading of t_fine. */ >> + ret = bmp280_read_temp(data, NULL, NULL); >> + if (ret < 0) >> + return ret; >> + >> + ret = regmap_bulk_read(data->regmap, BMP280_REG_PRESS_MSB, >> + (u8 *) &tmp, 3); > > I think tmp should be initialized, only 3 bytes out of 4 are set here > >> + if (ret < 0) { >> + dev_err(&data->client->dev, "failed to read pressure\n"); >> + return ret; >> + } >> + >> + adc_press = be32_to_cpu(tmp) >> 12; Nice, so some of the registers on this part are little endian and some are big ;) What fun. >> + comp_press = bmp280_compensate_press(data, adc_press); > > variable comp_press could probably be saved > >> + *val = comp_press; >> + >> + return IIO_VAL_INT; >> +} >> + >> +static int bmp280_read_raw(struct iio_dev *indio_dev, >> + struct iio_chan_spec const *chan, >> + int *val, int *val2, long mask) >> +{ >> + int ret; >> + struct bmp280_data *data = iio_priv(indio_dev); >> + >> + mutex_lock(&data->lock); > > locking is only needed for _RAW > >> + >> + switch (mask) { >> + case IIO_CHAN_INFO_RAW: > > I think this should be _PROCESSED, not _RAW; > there is calibration and all kind of scaling done internally > >> + switch (chan->type) { >> + case IIO_PRESSURE: >> + ret = bmp280_read_press(data, val, val2); >> + break; >> + case IIO_TEMP: >> + ret = bmp280_read_temp(data, val, val2); >> + break; >> + default: >> + ret = -EINVAL; >> + break; >> + } >> + break; >> + case IIO_CHAN_INFO_SCALE: >> + switch (chan->type) { >> + case IIO_PRESSURE: >> + /* Each LSB is 1/256 Pa. We need kPa. */ >> + *val = 1; >> + *val2 = 256000; >> + ret = IIO_VAL_FRACTIONAL; >> + break; >> + case IIO_TEMP: >> + /* Each LSB is 0.01 degC. We need milli degC. */ >> + *val = 10; >> + ret = IIO_VAL_INT; >> + break; >> + default: >> + ret = -EINVAL; >> + break; >> + } >> + break; >> + default: >> + ret = -EINVAL; >> + break; >> + } >> + >> + mutex_unlock(&data->lock); >> + >> + return ret; >> +} >> + >> +static const struct iio_info bmp280_info = { >> + .driver_module = THIS_MODULE, >> + .read_raw = &bmp280_read_raw, >> +}; >> + >> +static int bmp280_read_calibration_regs(struct iio_dev *indio_dev) >> +{ >> + struct bmp280_data *data = iio_priv(indio_dev); >> + int ret; >> + u8 buf[BMP280_COMP_REG_COUNT]; >> + __le16 *buf16; >> + >> + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_START, buf, >> + BMP280_COMP_REG_COUNT); >> + if (ret < 0) { >> + dev_err(&data->client->dev, >> + "failed to read calibration parameters\n"); >> + return ret; >> + } >> + >> + buf16 = (__le16 *) buf; Perhaps make buf a le16 in the first place which will make this a little bit cleaner (and make it explicit from the start that it is le16) >> + >> + data->dig_t1 = (u16) le16_to_cpu(buf16[0]); >> + data->dig_t2 = (s16) le16_to_cpu(buf16[1]); >> + data->dig_t3 = (s16) le16_to_cpu(buf16[2]); >> + >> + data->dig_p1 = (s16) le16_to_cpu(buf16[3]); >> + data->dig_p2 = (u16) le16_to_cpu(buf16[4]); >> + data->dig_p3 = (u16) le16_to_cpu(buf16[5]); >> + data->dig_p4 = (u16) le16_to_cpu(buf16[6]); >> + data->dig_p5 = (u16) le16_to_cpu(buf16[7]); >> + data->dig_p6 = (u16) le16_to_cpu(buf16[8]); >> + data->dig_p7 = (u16) le16_to_cpu(buf16[9]); >> + data->dig_p8 = (u16) le16_to_cpu(buf16[10]); >> + data->dig_p9 = (u16) le16_to_cpu(buf16[11]); I slightly wonder if you wouldn't be better off not caching these locally but relying directly on the regmap cache of these registers. There isn't a whole lot of point of having a regmap cache otherwise! >> + >> + return 0; >> +} >> + >> +static int bmp280_chip_init(struct bmp280_data *data) >> +{ >> + int ret; >> + >> + ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_MEAS, >> + BMP280_OSRS_TEMP_MASK | >> + BMP280_OSRS_PRESS_MASK | >> + BMP280_MODE_MASK, >> + BMP280_OSRS_TEMP_2X | >> + BMP280_OSRS_PRESS_16X | >> + BMP280_MODE_NORMAL); >> + if (ret < 0) { >> + dev_err(&data->client->dev, >> + "failed to write config register\n"); >> + return ret; >> + } >> + >> + ret = regmap_update_bits(data->regmap, BMP280_REG_CONFIG, >> + BMP280_FILTER_MASK, >> + BMP280_FILTER_4X); >> + if (ret < 0) { >> + dev_err(&data->client->dev, >> + "failed to write config register\n"); >> + return ret; >> + } >> + >> + return ret; >> +} >> + >> +static int bmp280_probe(struct i2c_client *client, >> + const struct i2c_device_id *id) >> +{ >> + int ret; >> + struct iio_dev *indio_dev; >> + struct bmp280_data *data; >> + >> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); >> + if (!indio_dev) >> + return -ENOMEM; >> + >> + i2c_set_clientdata(client, indio_dev); >> + data = iio_priv(indio_dev); >> + mutex_init(&data->lock); >> + data->client = client; >> + >> + indio_dev->dev.parent = &client->dev; >> + indio_dev->name = id->name; >> + indio_dev->channels = bmp280_channels; >> + indio_dev->num_channels = ARRAY_SIZE(bmp280_channels); >> + indio_dev->info = &bmp280_info; >> + indio_dev->modes = INDIO_DIRECT_MODE; >> + >> + data->regmap = devm_regmap_init_i2c(client, &bmp280_regmap_config); >> + if (IS_ERR(data->regmap)) { >> + dev_err(&client->dev, "failed to allocate register map\n"); >> + return PTR_ERR(data->regmap); >> + } >> + > > the BMP280 has a nice CHIP_ID which is already #define, why not check it? > >> + ret = bmp280_read_calibration_regs(indio_dev); >> + if (ret < 0) >> + return ret; >> + >> + ret = bmp280_chip_init(data); >> + if (ret < 0) >> + return ret; >> + >> + return devm_iio_device_register(&client->dev, indio_dev); >> +} >> + >> +static const struct acpi_device_id bmp280_acpi_match[] = { >> + {"BMP0280", 0}, >> + { }, >> +}; >> +MODULE_DEVICE_TABLE(acpi, bmp280_acpi_match); >> + >> +static const struct i2c_device_id bmp280_id[] = { >> + {"bmp280", 0}, >> + { }, >> +}; >> +MODULE_DEVICE_TABLE(i2c, bmp280_id); >> + >> +static struct i2c_driver bmp280_driver = { >> + .driver = { >> + .name = "bmp280", >> + .acpi_match_table = ACPI_PTR(bmp280_acpi_match), >> + }, >> + .probe = bmp280_probe, >> + .id_table = bmp280_id, >> +}; >> +module_i2c_driver(bmp280_driver); >> + >> +MODULE_AUTHOR("Vlad Dogaru <vlad.dogaru@xxxxxxxxx>"); >> +MODULE_DESCRIPTION("Driver for Bosch Sensortec BMP280 pressure and temperature sensor"); >> +MODULE_LICENSE("GPL v2"); >> > -- 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
