On 15/04/16 18:53, Akinobu Mita wrote: > This adds support for the BMP180 to the bmp280 iio driver. > > The BMP180 has already been supported by misc/bmp085 driver but it > doesn't use iio framework. This change adds the kconfig dependency > not to be selected both of them in order to avoid any issues. > > Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx> > Cc: Vlad Dogaru <vlad.dogaru@xxxxxxxxx> > Cc: Christoph Mair <christoph.mair@xxxxxxxxx> > Cc: Jonathan Cameron <jic23@xxxxxxxxxx> > Cc: Hartmut Knaack <knaack.h@xxxxxx> > Cc: Lars-Peter Clausen <lars@xxxxxxxxxx> > Cc: Peter Meerwald <pmeerw@xxxxxxxxxx> A few comments inline - some on things that could have been done slightly better in the original driver but which we are now stuck with for ABI compatibility reasons.. Ah well. Jonathan > --- > drivers/iio/pressure/Kconfig | 5 +- > drivers/iio/pressure/bmp280.c | 385 ++++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 374 insertions(+), 16 deletions(-) > > diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig > index e8f60db..31e5d36 100644 > --- a/drivers/iio/pressure/Kconfig > +++ b/drivers/iio/pressure/Kconfig > @@ -6,11 +6,12 @@ > menu "Pressure sensors" > > config BMP280 > - tristate "Bosch Sensortec BMP280 pressure sensor driver" > + tristate "Bosch Sensortec BMP180 and BMP280 pressure sensor driver" > depends on I2C > + depends on !(BMP085_I2C=y || BMP085_I2C=m) > select REGMAP_I2C > help > - Say yes here to build support for Bosch Sensortec BMP280 > + Say yes here to build support for Bosch Sensortec BMP180 and BMP280 > pressure and temperature sensor. > > To compile this driver as a module, choose M here: the module > diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c > index a2602d8..28daa74 100644 > --- a/drivers/iio/pressure/bmp280.c > +++ b/drivers/iio/pressure/bmp280.c > @@ -1,12 +1,15 @@ > /* > * Copyright (c) 2014 Intel Corporation > * > - * Driver for Bosch Sensortec BMP280 digital pressure sensor. > + * Driver for Bosch Sensortec BMP180 and 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. > * > + * Datasheet: > + * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP180-DS000-121.pdf > + * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP280-DS001-12.pdf > */ > > #define pr_fmt(fmt) "bmp280: " fmt > @@ -15,9 +18,13 @@ > #include <linux/i2c.h> > #include <linux/acpi.h> > #include <linux/regmap.h> > +#include <linux/delay.h> > #include <linux/iio/iio.h> > #include <linux/iio/sysfs.h> > > +/* > + * BMP280 specific registers > + */ single line comment syntax preferred. > #define BMP280_REG_TEMP_XLSB 0xFC > #define BMP280_REG_TEMP_LSB 0xFB > #define BMP280_REG_TEMP_MSB 0xFA > @@ -26,10 +33,7 @@ > #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_TEMP_START 0x88 > #define BMP280_COMP_TEMP_REG_COUNT 6 > @@ -65,6 +69,32 @@ > #define BMP280_MODE_FORCED BIT(0) > #define BMP280_MODE_NORMAL (BIT(1) | BIT(0)) > > +/* > + * BMP180 specific registers > + */ > +#define BMP180_REG_OUT_XLSB 0xF8 > +#define BMP180_REG_OUT_LSB 0xF7 > +#define BMP180_REG_OUT_MSB 0xF6 > + > +#define BMP180_REG_CALIB_START 0xAA > +#define BMP180_REG_CALIB_COUNT 22 > + > +#define BMP180_MEAS_SCO BIT(5) > +#define BMP180_MEAS_TEMP (0x0E | BMP180_MEAS_SCO) > +#define BMP180_MEAS_PRESS_X(oss) ((oss) << 6 | 0x14 | BMP180_MEAS_SCO) > +#define BMP180_MEAS_PRESS_1X BMP180_MEAS_PRESS_X(0) > +#define BMP180_MEAS_PRESS_2X BMP180_MEAS_PRESS_X(1) > +#define BMP180_MEAS_PRESS_4X BMP180_MEAS_PRESS_X(2) > +#define BMP180_MEAS_PRESS_8X BMP180_MEAS_PRESS_X(3) > + > +/* > + * BMP180 and BMP280 common registers > + */ > +#define BMP280_REG_CTRL_MEAS 0xF4 > +#define BMP280_REG_RESET 0xE0 > +#define BMP280_REG_ID 0xD0 > + > +#define BMP180_CHIP_ID 0x55 > #define BMP280_CHIP_ID 0x58 > #define BMP280_SOFT_RESET_VAL 0xB6 > > @@ -72,6 +102,7 @@ struct bmp280_data { > struct i2c_client *client; > struct mutex lock; > struct regmap *regmap; > + const struct bmp280_chip_info *chip_info; > > /* > * Carryover value from temperature conversion, used in pressure > @@ -80,9 +111,17 @@ struct bmp280_data { > s32 t_fine; > }; > > +struct bmp280_chip_info { > + const struct regmap_config *regmap_config; > + > + int (*chip_config)(struct bmp280_data *); > + int (*read_temp)(struct bmp280_data *, int *); > + int (*read_press)(struct bmp280_data *, int *, int *); > +}; > + > /* > * These enums are used for indexing into the array of compensation > - * parameters. > + * parameters for BMP280. > */ > enum { T1, T2, T3 }; > enum { P1, P2, P3, P4, P5, P6, P7, P8, P9 }; > @@ -290,10 +329,10 @@ static int bmp280_read_raw(struct iio_dev *indio_dev, > case IIO_CHAN_INFO_PROCESSED: > switch (chan->type) { > case IIO_PRESSURE: > - ret = bmp280_read_press(data, val, val2); > + ret = data->chip_info->read_press(data, val, val2); > break; > case IIO_TEMP: > - ret = bmp280_read_temp(data, val); > + ret = data->chip_info->read_temp(data, val); > break; > default: > ret = -EINVAL; > @@ -315,7 +354,7 @@ static const struct iio_info bmp280_info = { > .read_raw = &bmp280_read_raw, > }; > > -static int bmp280_chip_init(struct bmp280_data *data) > +static int bmp280_chip_config(struct bmp280_data *data) > { > int ret; > > @@ -344,6 +383,308 @@ static int bmp280_chip_init(struct bmp280_data *data) > return ret; > } > > +static const struct bmp280_chip_info bmp280_chip_info = { > + .regmap_config = &bmp280_regmap_config, > + .chip_config = bmp280_chip_config, > + .read_temp = bmp280_read_temp, > + .read_press = bmp280_read_press, > +}; > + > +static bool bmp180_is_writeable_reg(struct device *dev, unsigned int reg) > +{ > + switch (reg) { > + case BMP280_REG_CTRL_MEAS: > + case BMP280_REG_RESET: > + return true; > + default: > + return false; > + }; > +} > + > +static bool bmp180_is_volatile_reg(struct device *dev, unsigned int reg) > +{ > + switch (reg) { > + case BMP180_REG_OUT_XLSB: > + case BMP180_REG_OUT_LSB: > + case BMP180_REG_OUT_MSB: > + case BMP280_REG_CTRL_MEAS: > + return true; > + default: > + return false; > + } > +} > + > +static const struct regmap_config bmp180_regmap_config = { > + .reg_bits = 8, > + .val_bits = 8, > + > + .max_register = BMP180_REG_OUT_XLSB, > + .cache_type = REGCACHE_RBTREE, > + > + .writeable_reg = bmp180_is_writeable_reg, > + .volatile_reg = bmp180_is_volatile_reg, > +}; > + > +static int bmp180_measure(struct bmp280_data *data, u8 ctrl_meas) > +{ > + int ret; > + const int conversion_time_max[] = { 4500, 7500, 13500, 25500 }; > + unsigned int delay_us; > + unsigned int ctrl; > + > + ret = regmap_write(data->regmap, BMP280_REG_CTRL_MEAS, ctrl_meas); > + if (ret) > + return ret; > + > + if (ctrl_meas == BMP180_MEAS_TEMP) > + delay_us = 4500; > + else > + delay_us = conversion_time_max[ilog2(8)]; > + > + usleep_range(delay_us, delay_us + 1000); > + > + ret = regmap_read(data->regmap, BMP280_REG_CTRL_MEAS, &ctrl); > + if (ret) > + return ret; > + > + /* > + * The value of this bit reset to "0" after conversion is complete > + */ Single line comment syntax... > + if (ctrl & BMP180_MEAS_SCO) > + return -EIO; > + > + return 0; > +} > + > +static int bmp180_read_adc_temp(struct bmp280_data *data, int *val) > +{ > + int ret; > + __be16 tmp = 0; > + > + ret = bmp180_measure(data, BMP180_MEAS_TEMP); > + if (ret) > + return ret; > + > + ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, (u8 *)&tmp, 2); > + if (ret) > + return ret; > + > + *val = be16_to_cpu(tmp); > + > + return 0; > +} > + > +/* > + * These enums are used for indexing into the array of calibration > + * coefficients for BMP180. > + */ > +enum { AC1, AC2, AC3, AC4, AC5, AC6, B1, B2, MB, MC, MD }; > + > +struct bmp180_calib { > + s32 AC1; > + s32 AC2; > + s32 AC3; > + u32 AC4; > + u32 AC5; > + u32 AC6; > + s32 B1; > + s32 B2; > + s32 MB; > + s32 MC; > + s32 MD; > +}; > + > +static int bmp180_read_calib(struct bmp280_data *data, > + struct bmp180_calib *calib) > +{ > + int ret; > + int i; > + __be16 buf[BMP180_REG_CALIB_COUNT / 2]; > + > + ret = regmap_bulk_read(data->regmap, BMP180_REG_CALIB_START, buf, > + sizeof(buf)); > + > + if (ret < 0) > + return ret; > + > + /* > + * None of the words has the value 0 or 0xFFFF > + */ Single line comment, so single line comment syntax please (nitpick!) > + for (i = 0; i < ARRAY_SIZE(buf); i++) { > + if (buf[i] == cpu_to_be16(0) || buf[i] == cpu_to_be16(0xffff)) > + return -EIO; > + } > + > + /* > + * The double casts are necessary because be16_to_cpu returns an > + * unsigned 16-bit value. Casting that value directly to a > + * signed 32-bit will not do proper sign extension. > + * Would using sign_extend32 perhaps make this clear without the need for the comment? I think you'd need calib->AC1 = sign_extend32(be16_to_cpu(buf[AC1]), 16); etc. Compiler should optimize that to end up with similar assembler.. Or alternatively just define them as s16 if that is what they are... > + * Conversely, AC4, AC5 and AC6 are unsigned values, so they can be > + * cast straight to the larger type. > + */ > + calib->AC1 = (s32)(s16)be16_to_cpu(buf[AC1]); > + calib->AC2 = (s32)(s16)be16_to_cpu(buf[AC2]); > + calib->AC3 = (s32)(s16)be16_to_cpu(buf[AC3]); > + calib->AC4 = be16_to_cpu(buf[AC4]); > + calib->AC5 = be16_to_cpu(buf[AC5]); > + calib->AC6 = be16_to_cpu(buf[AC6]); > + calib->B1 = (s32)(s16)be16_to_cpu(buf[B1]); > + calib->B2 = (s32)(s16)be16_to_cpu(buf[B2]); > + calib->MB = (s32)(s16)be16_to_cpu(buf[MB]); > + calib->MC = (s32)(s16)be16_to_cpu(buf[MC]); > + calib->MD = (s32)(s16)be16_to_cpu(buf[MD]); > + > + return 0; > +} > + > +/* > + * Returns temperature in DegC, resolution is 0.1 DegC. > + * t_fine carries fine temperature as global value. > + * > + * Taken from datasheet, Section 3.5, "Calculating pressure and temperature". > + */ > +static s32 bmp180_compensate_temp(struct bmp280_data *data, s32 adc_temp) > +{ > + int ret; > + s32 x1, x2; > + struct bmp180_calib calib; > + > + ret = bmp180_read_calib(data, &calib); > + if (ret < 0) { > + dev_err(&data->client->dev, > + "failed to read calibration coefficients\n"); > + return ret; > + } > + > + x1 = ((adc_temp - calib.AC6) * calib.AC5) >> 15; > + x2 = (calib.MC << 11) / (x1 + calib.MD); > + data->t_fine = x1 + x2; > + > + return (data->t_fine + 8) >> 4; > +} > + > +static int bmp180_read_temp(struct bmp280_data *data, int *val) > +{ > + int ret; > + s32 adc_temp, comp_temp; > + > + ret = bmp180_read_adc_temp(data, &adc_temp); > + if (ret) > + return ret; > + > + comp_temp = bmp180_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 * 100; > + return IIO_VAL_INT; > + } > + > + return 0; > +} > + > +static int bmp180_read_adc_press(struct bmp280_data *data, int *val) > +{ > + int ret; > + __be32 tmp = 0; > + u8 oss = ilog2(8); > + > + ret = bmp180_measure(data, BMP180_MEAS_PRESS_X(oss)); > + if (ret) > + return ret; > + > + ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, (u8 *)&tmp, 3); > + if (ret) > + return ret; > + > + *val = (be32_to_cpu(tmp) >> 8) >> (8 - oss); > + > + return 0; > +} > + > +/* > + * Returns pressure in Pa, resolution is 1 Pa. > + * > + * Taken from datasheet, Section 3.5, "Calculating pressure and temperature". > + */ > +static u32 bmp180_compensate_press(struct bmp280_data *data, s32 adc_press) > +{ > + int ret; > + s32 x1, x2, x3, p; > + s32 b3, b6; > + u32 b4, b7; > + s32 oss = ilog2(8); > + struct bmp180_calib calib; > + > + ret = bmp180_read_calib(data, &calib); > + if (ret < 0) { > + dev_err(&data->client->dev, > + "failed to read calibration coefficients\n"); > + return ret; > + } > + > + b6 = data->t_fine - 4000; > + x1 = (calib.B2 * (b6 * b6 >> 12)) >> 11; > + x2 = calib.AC2 * b6 >> 11; > + x3 = x1 + x2; > + b3 = (((calib.AC1 * 4 + x3) << oss) + 2) / 4; > + x1 = calib.AC3 * b6 >> 13; > + x2 = (calib.B1 * ((b6 * b6) >> 12)) >> 16; > + x3 = (x1 + x2 + 2) >> 2; > + b4 = calib.AC4 * (u32)(x3 + 32768) >> 15; > + b7 = ((u32)adc_press - b3) * (50000 >> oss); > + if (b7 < 0x80000000) > + p = (b7 * 2) / b4; > + else > + p = (b7 / b4) * 2; > + > + x1 = (p >> 8) * (p >> 8); > + x1 = (x1 * 3038) >> 16; > + x2 = (-7357 * p) >> 16; > + > + return p + ((x1 + x2 + 3791) >> 4); > +} > + > +static int bmp180_read_press(struct bmp280_data *data, > + int *val, int *val2) > +{ > + int ret; > + s32 adc_press; > + u32 comp_press; > + > + /* Read and compensate temperature so we get a reading of t_fine. */ > + ret = bmp180_read_temp(data, NULL); > + if (ret) > + return ret; > + > + ret = bmp180_read_adc_press(data, &adc_press); > + if (ret) > + return ret; > + > + comp_press = bmp180_compensate_press(data, adc_press); > + > + *val = comp_press; > + *val2 = 1000; This would be better done using a _scale info_mask element to handle the divide by 1000. That lets the decision on whether the conversion is even needed be moved to userspace. Unfortunately that's also true for the bmp280 as it stands which is annoying as that makes it ABI which we shouldn't be changing. Ah well, the device is slow anyway so not terrible to leave this as it is. I should have picked that up when reviewing that driver originally - sometimes we have live with our mistakes! > + > + return IIO_VAL_FRACTIONAL; > +} > + > +static int bmp180_chip_config(struct bmp280_data *data) > +{ > + return 0; > +} > + > +static const struct bmp280_chip_info bmp180_chip_info = { > + .regmap_config = &bmp180_regmap_config, > + .chip_config = bmp180_chip_config, > + .read_temp = bmp180_read_temp, > + .read_press = bmp180_read_press, > +}; > + > static int bmp280_probe(struct i2c_client *client, > const struct i2c_device_id *id) > { > @@ -367,7 +708,19 @@ static int bmp280_probe(struct i2c_client *client, > indio_dev->info = &bmp280_info; > indio_dev->modes = INDIO_DIRECT_MODE; > > - data->regmap = devm_regmap_init_i2c(client, &bmp280_regmap_config); > + switch (id->driver_data) { > + case BMP180_CHIP_ID: > + data->chip_info = &bmp180_chip_info; > + break; > + case BMP280_CHIP_ID: > + data->chip_info = &bmp280_chip_info; > + break; > + default: > + return -EINVAL; > + } > + > + data->regmap = devm_regmap_init_i2c(client, > + data->chip_info->regmap_config); > if (IS_ERR(data->regmap)) { > dev_err(&client->dev, "failed to allocate register map\n"); > return PTR_ERR(data->regmap); > @@ -376,13 +729,13 @@ static int bmp280_probe(struct i2c_client *client, > ret = regmap_read(data->regmap, BMP280_REG_ID, &chip_id); > if (ret < 0) > return ret; > - if (chip_id != BMP280_CHIP_ID) { > + if (chip_id != id->driver_data) { > dev_err(&client->dev, "bad chip id. expected %x got %x\n", > BMP280_CHIP_ID, chip_id); > return -EINVAL; > } > > - ret = bmp280_chip_init(data); > + ret = data->chip_info->chip_config(data); > if (ret < 0) > return ret; > > @@ -390,13 +743,17 @@ static int bmp280_probe(struct i2c_client *client, > } > > static const struct acpi_device_id bmp280_acpi_match[] = { > - {"BMP0280", 0}, > + {"BMP0280", BMP280_CHIP_ID }, > + {"BMP0180", BMP180_CHIP_ID }, > + {"BMP0085", BMP180_CHIP_ID }, > { }, > }; > MODULE_DEVICE_TABLE(acpi, bmp280_acpi_match); > > static const struct i2c_device_id bmp280_id[] = { > - {"bmp280", 0}, > + {"bmp280", BMP280_CHIP_ID }, > + {"bmp180", BMP180_CHIP_ID }, > + {"bmp085", BMP180_CHIP_ID }, > { }, > }; > MODULE_DEVICE_TABLE(i2c, bmp280_id); > @@ -412,5 +769,5 @@ static struct i2c_driver bmp280_driver = { > module_i2c_driver(bmp280_driver); > > MODULE_AUTHOR("Vlad Dogaru <vlad.dogaru@xxxxxxxxx>"); > -MODULE_DESCRIPTION("Driver for Bosch Sensortec BMP280 pressure and temperature sensor"); > +MODULE_DESCRIPTION("Driver for Bosch Sensortec BMP180/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
