+++ /dev/null
-/* Copyright (c) 2010 Christoph Mair <christoph.mair@gmail.com>
- * Copyright (c) 2012 Bosch Sensortec GmbH
- * Copyright (c) 2012 Unixphere AB
- *
- * This driver supports the bmp085 and bmp18x digital barometric pressure
- * and temperature sensors from Bosch Sensortec. The datasheets
- * are available from their website:
- * http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP085-DS000-05.pdf
- * http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP180-DS000-07.pdf
- *
- * A pressure measurement is issued by reading from pressure0_input.
- * The return value ranges from 30000 to 110000 pascal with a resulution
- * of 1 pascal (0.01 millibar) which enables measurements from 9000m above
- * to 500m below sea level.
- *
- * The temperature can be read from temp0_input. Values range from
- * -400 to 850 representing the ambient temperature in degree celsius
- * multiplied by 10.The resolution is 0.1 celsius.
- *
- * Because ambient pressure is temperature dependent, a temperature
- * measurement will be executed automatically even if the user is reading
- * from pressure0_input. This happens if the last temperature measurement
- * has been executed more then one second ago.
- *
- * To decrease RMS noise from pressure measurements, the bmp085 can
- * autonomously calculate the average of up to eight samples. This is
- * set up by writing to the oversampling sysfs file. Accepted values
- * are 0, 1, 2 and 3. 2^x when x is the value written to this file
- * specifies the number of samples used to calculate the ambient pressure.
- * RMS noise is specified with six pascal (without averaging) and decreases
- * down to 3 pascal when using an oversampling setting of 3.
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-#include <linux/module.h>
-#include <linux/device.h>
-#include <linux/slab.h>
-#include <linux/of.h>
-#include "bmp085.h"
-#include <linux/interrupt.h>
-#include <linux/completion.h>
-#include <linux/gpio.h>
-
-#define BMP085_CHIP_ID 0x55
-#define BMP085_CALIBRATION_DATA_START 0xAA
-#define BMP085_CALIBRATION_DATA_LENGTH 11 /* 16 bit values */
-#define BMP085_CHIP_ID_REG 0xD0
-#define BMP085_CTRL_REG 0xF4
-#define BMP085_TEMP_MEASUREMENT 0x2E
-#define BMP085_PRESSURE_MEASUREMENT 0x34
-#define BMP085_CONVERSION_REGISTER_MSB 0xF6
-#define BMP085_CONVERSION_REGISTER_LSB 0xF7
-#define BMP085_CONVERSION_REGISTER_XLSB 0xF8
-#define BMP085_TEMP_CONVERSION_TIME 5
-
-struct bmp085_calibration_data {
- s16 AC1, AC2, AC3;
- u16 AC4, AC5, AC6;
- s16 B1, B2;
- s16 MB, MC, MD;
-};
-
-struct bmp085_data {
- struct device *dev;
- struct regmap *regmap;
- struct mutex lock;
- struct bmp085_calibration_data calibration;
- u8 oversampling_setting;
- u32 raw_temperature;
- u32 raw_pressure;
- u32 temp_measurement_period;
- unsigned long last_temp_measurement;
- u8 chip_id;
- s32 b6; /* calculated temperature correction coefficient */
- int irq;
- struct completion done;
-};
-
-static irqreturn_t bmp085_eoc_isr(int irq, void *devid)
-{
- struct bmp085_data *data = devid;
-
- complete(&data->done);
-
- return IRQ_HANDLED;
-}
-
-static s32 bmp085_read_calibration_data(struct bmp085_data *data)
-{
- u16 tmp[BMP085_CALIBRATION_DATA_LENGTH];
- struct bmp085_calibration_data *cali = &(data->calibration);
- s32 status = regmap_bulk_read(data->regmap,
- BMP085_CALIBRATION_DATA_START, (u8 *)tmp,
- (BMP085_CALIBRATION_DATA_LENGTH << 1));
- if (status < 0)
- return status;
-
- cali->AC1 = be16_to_cpu(tmp[0]);
- cali->AC2 = be16_to_cpu(tmp[1]);
- cali->AC3 = be16_to_cpu(tmp[2]);
- cali->AC4 = be16_to_cpu(tmp[3]);
- cali->AC5 = be16_to_cpu(tmp[4]);
- cali->AC6 = be16_to_cpu(tmp[5]);
- cali->B1 = be16_to_cpu(tmp[6]);
- cali->B2 = be16_to_cpu(tmp[7]);
- cali->MB = be16_to_cpu(tmp[8]);
- cali->MC = be16_to_cpu(tmp[9]);
- cali->MD = be16_to_cpu(tmp[10]);
- return 0;
-}
-
-static s32 bmp085_update_raw_temperature(struct bmp085_data *data)
-{
- u16 tmp;
- s32 status;
-
- mutex_lock(&data->lock);
-
- init_completion(&data->done);
-
- status = regmap_write(data->regmap, BMP085_CTRL_REG,
- BMP085_TEMP_MEASUREMENT);
- if (status < 0) {
- dev_err(data->dev,
- "Error while requesting temperature measurement.\n");
- goto exit;
- }
- wait_for_completion_timeout(&data->done, 1 + msecs_to_jiffies(
- BMP085_TEMP_CONVERSION_TIME));
-
- status = regmap_bulk_read(data->regmap, BMP085_CONVERSION_REGISTER_MSB,
- &tmp, sizeof(tmp));
- if (status < 0) {
- dev_err(data->dev,
- "Error while reading temperature measurement result\n");
- goto exit;
- }
- data->raw_temperature = be16_to_cpu(tmp);
- data->last_temp_measurement = jiffies;
- status = 0; /* everything ok, return 0 */
-
-exit:
- mutex_unlock(&data->lock);
- return status;
-}
-
-static s32 bmp085_update_raw_pressure(struct bmp085_data *data)
-{
- u32 tmp = 0;
- s32 status;
-
- mutex_lock(&data->lock);
-
- init_completion(&data->done);
-
- status = regmap_write(data->regmap, BMP085_CTRL_REG,
- BMP085_PRESSURE_MEASUREMENT +
- (data->oversampling_setting << 6));
- if (status < 0) {
- dev_err(data->dev,
- "Error while requesting pressure measurement.\n");
- goto exit;
- }
-
- /* wait for the end of conversion */
- wait_for_completion_timeout(&data->done, 1 + msecs_to_jiffies(
- 2+(3 << data->oversampling_setting)));
- /* copy data into a u32 (4 bytes), but skip the first byte. */
- status = regmap_bulk_read(data->regmap, BMP085_CONVERSION_REGISTER_MSB,
- ((u8 *)&tmp)+1, 3);
- if (status < 0) {
- dev_err(data->dev,
- "Error while reading pressure measurement results\n");
- goto exit;
- }
- data->raw_pressure = be32_to_cpu((tmp));
- data->raw_pressure >>= (8-data->oversampling_setting);
- status = 0; /* everything ok, return 0 */
-
-exit:
- mutex_unlock(&data->lock);
- return status;
-}
-
-/*
- * This function starts the temperature measurement and returns the value
- * in tenth of a degree celsius.
- */
-static s32 bmp085_get_temperature(struct bmp085_data *data, int *temperature)
-{
- struct bmp085_calibration_data *cali = &data->calibration;
- long x1, x2;
- int status;
-
- status = bmp085_update_raw_temperature(data);
- if (status < 0)
- goto exit;
-
- x1 = ((data->raw_temperature - cali->AC6) * cali->AC5) >> 15;
- x2 = (cali->MC << 11) / (x1 + cali->MD);
- data->b6 = x1 + x2 - 4000;
- /* if NULL just update b6. Used for pressure only measurements */
- if (temperature != NULL)
- *temperature = (x1+x2+8) >> 4;
-
-exit:
- return status;
-}
-
-/*
- * This function starts the pressure measurement and returns the value
- * in millibar. Since the pressure depends on the ambient temperature,
- * a temperature measurement is executed according to the given temperature
- * measurement period (default is 1 sec boundary). This period could vary
- * and needs to be adjusted according to the sensor environment, i.e. if big
- * temperature variations then the temperature needs to be read out often.
- */
-static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure)
-{
- struct bmp085_calibration_data *cali = &data->calibration;
- s32 x1, x2, x3, b3;
- u32 b4, b7;
- s32 p;
- int status;
-
- /* alt least every second force an update of the ambient temperature */
- if ((data->last_temp_measurement == 0) ||
- time_is_before_jiffies(data->last_temp_measurement + 1*HZ)) {
- status = bmp085_get_temperature(data, NULL);
- if (status < 0)
- return status;
- }
-
- status = bmp085_update_raw_pressure(data);
- if (status < 0)
- return status;
-
- x1 = (data->b6 * data->b6) >> 12;
- x1 *= cali->B2;
- x1 >>= 11;
-
- x2 = cali->AC2 * data->b6;
- x2 >>= 11;
-
- x3 = x1 + x2;
-
- b3 = (((((s32)cali->AC1) * 4 + x3) << data->oversampling_setting) + 2);
- b3 >>= 2;
-
- x1 = (cali->AC3 * data->b6) >> 13;
- x2 = (cali->B1 * ((data->b6 * data->b6) >> 12)) >> 16;
- x3 = (x1 + x2 + 2) >> 2;
- b4 = (cali->AC4 * (u32)(x3 + 32768)) >> 15;
-
- b7 = ((u32)data->raw_pressure - b3) *
- (50000 >> data->oversampling_setting);
- p = ((b7 < 0x80000000) ? ((b7 << 1) / b4) : ((b7 / b4) * 2));
-
- x1 = p >> 8;
- x1 *= x1;
- x1 = (x1 * 3038) >> 16;
- x2 = (-7357 * p) >> 16;
- p += (x1 + x2 + 3791) >> 4;
-
- *pressure = p;
-
- return 0;
-}
-
-/*
- * This function sets the chip-internal oversampling. Valid values are 0..3.
- * The chip will use 2^oversampling samples for internal averaging.
- * This influences the measurement time and the accuracy; larger values
- * increase both. The datasheet gives an overview on how measurement time,
- * accuracy and noise correlate.
- */
-static void bmp085_set_oversampling(struct bmp085_data *data,
- unsigned char oversampling)
-{
- if (oversampling > 3)
- oversampling = 3;
- data->oversampling_setting = oversampling;
-}
-
-/*
- * Returns the currently selected oversampling. Range: 0..3
- */
-static unsigned char bmp085_get_oversampling(struct bmp085_data *data)
-{
- return data->oversampling_setting;
-}
-
-/* sysfs callbacks */
-static ssize_t set_oversampling(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct bmp085_data *data = dev_get_drvdata(dev);
- unsigned long oversampling;
- int err = kstrtoul(buf, 10, &oversampling);
-
- if (err == 0) {
- mutex_lock(&data->lock);
- bmp085_set_oversampling(data, oversampling);
- mutex_unlock(&data->lock);
- return count;
- }
-
- return err;
-}
-
-static ssize_t show_oversampling(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct bmp085_data *data = dev_get_drvdata(dev);
-
- return sprintf(buf, "%u\n", bmp085_get_oversampling(data));
-}
-static DEVICE_ATTR(oversampling, S_IWUSR | S_IRUGO,
- show_oversampling, set_oversampling);
-
-
-static ssize_t show_temperature(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- int temperature;
- int status;
- struct bmp085_data *data = dev_get_drvdata(dev);
-
- status = bmp085_get_temperature(data, &temperature);
- if (status < 0)
- return status;
- else
- return sprintf(buf, "%d\n", temperature);
-}
-static DEVICE_ATTR(temp0_input, S_IRUGO, show_temperature, NULL);
-
-
-static ssize_t show_pressure(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- int pressure;
- int status;
- struct bmp085_data *data = dev_get_drvdata(dev);
-
- status = bmp085_get_pressure(data, &pressure);
- if (status < 0)
- return status;
- else
- return sprintf(buf, "%d\n", pressure);
-}
-static DEVICE_ATTR(pressure0_input, S_IRUGO, show_pressure, NULL);
-
-
-static struct attribute *bmp085_attributes[] = {
- &dev_attr_temp0_input.attr,
- &dev_attr_pressure0_input.attr,
- &dev_attr_oversampling.attr,
- NULL
-};
-
-static const struct attribute_group bmp085_attr_group = {
- .attrs = bmp085_attributes,
-};
-
-int bmp085_detect(struct device *dev)
-{
- struct bmp085_data *data = dev_get_drvdata(dev);
- unsigned int id;
- int ret;
-
- ret = regmap_read(data->regmap, BMP085_CHIP_ID_REG, &id);
- if (ret < 0)
- return ret;
-
- if (id != data->chip_id)
- return -ENODEV;
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(bmp085_detect);
-
-static void bmp085_get_of_properties(struct bmp085_data *data)
-{
-#ifdef CONFIG_OF
- struct device_node *np = data->dev->of_node;
- u32 prop;
-
- if (!np)
- return;
-
- if (!of_property_read_u32(np, "chip-id", &prop))
- data->chip_id = prop & 0xff;
-
- if (!of_property_read_u32(np, "temp-measurement-period", &prop))
- data->temp_measurement_period = (prop/100)*HZ;
-
- if (!of_property_read_u32(np, "default-oversampling", &prop))
- data->oversampling_setting = prop & 0xff;
-#endif
-}
-
-static int bmp085_init_client(struct bmp085_data *data)
-{
- int status = bmp085_read_calibration_data(data);
-
- if (status < 0)
- return status;
-
- /* default settings */
- data->chip_id = BMP085_CHIP_ID;
- data->last_temp_measurement = 0;
- data->temp_measurement_period = 1*HZ;
- data->oversampling_setting = 3;
-
- bmp085_get_of_properties(data);
-
- mutex_init(&data->lock);
-
- return 0;
-}
-
-struct regmap_config bmp085_regmap_config = {
- .reg_bits = 8,
- .val_bits = 8
-};
-EXPORT_SYMBOL_GPL(bmp085_regmap_config);
-
-int bmp085_probe(struct device *dev, struct regmap *regmap, int irq)
-{
- struct bmp085_data *data;
- int err = 0;
-
- data = kzalloc(sizeof(struct bmp085_data), GFP_KERNEL);
- if (!data) {
- err = -ENOMEM;
- goto exit;
- }
-
- dev_set_drvdata(dev, data);
- data->dev = dev;
- data->regmap = regmap;
- data->irq = irq;
-
- if (data->irq > 0) {
- err = devm_request_irq(dev, data->irq, bmp085_eoc_isr,
- IRQF_TRIGGER_RISING, "bmp085",
- data);
- if (err < 0)
- goto exit_free;
- }
-
- /* Initialize the BMP085 chip */
- err = bmp085_init_client(data);
- if (err < 0)
- goto exit_free;
-
- err = bmp085_detect(dev);
- if (err < 0) {
- dev_err(dev, "%s: chip_id failed!\n", BMP085_NAME);
- goto exit_free;
- }
-
- /* Register sysfs hooks */
- err = sysfs_create_group(&dev->kobj, &bmp085_attr_group);
- if (err)
- goto exit_free;
-
- dev_info(dev, "Successfully initialized %s!\n", BMP085_NAME);
-
- return 0;
-
-exit_free:
- kfree(data);
-exit:
- return err;
-}
-EXPORT_SYMBOL_GPL(bmp085_probe);
-
-int bmp085_remove(struct device *dev)
-{
- struct bmp085_data *data = dev_get_drvdata(dev);
-
- sysfs_remove_group(&data->dev->kobj, &bmp085_attr_group);
- kfree(data);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(bmp085_remove);
-
-MODULE_AUTHOR("Christoph Mair <christoph.mair@gmail.com>");
-MODULE_DESCRIPTION("BMP085 driver");
-MODULE_LICENSE("GPL");
projects / deliverable / linux.git / commitdiff
