提交 e939ca0a 编写于 作者: E Eric Andersson 提交者: Greg Kroah-Hartman

misc: clean up bmp085 driver

This patch includes various cleaning of the bmp085 driver including:
- Whitespaces and alignment fixes
- Minor typos
- Consistency fixes
Reviewed-by: NStefan Nilsson <stefan.nilsson@unixphere.com>
Signed-off-by: NEric Andersson <eric.andersson@unixphere.com>
Reviewed-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
上级 0ed0d579
/* Copyright (c) 2010 Christoph Mair <christoph.mair@gmail.com>
This driver supports the bmp085 digital barometric pressure
and temperature sensor from Bosch Sensortec. The datasheet
is available from their website:
http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP085-DS000-05.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.
*/
* Copyright (c) 2012 Bosch Sensortec GmbH
* Copyright (c) 2012 Unixphere AB
*
* This driver supports the bmp085 digital barometric pressure
* and temperature sensor from Bosch Sensortec. The datasheet
* is available from their website:
* http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP085-DS000-05.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/init.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/delay.h>
#define BMP085_NAME "bmp085"
#define BMP085_I2C_ADDRESS 0x77
#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_VERSION_REG 0xD1
#define BMP085_CTRL_REG 0xF4
#define BMP085_TEMP_MEASUREMENT 0x2E
#define BMP085_PRESSURE_MEASUREMENT 0x34
......@@ -65,9 +66,6 @@
#define BMP085_CONVERSION_REGISTER_XLSB 0xF8
#define BMP085_TEMP_CONVERSION_TIME 5
#define BMP085_CLIENT_NAME "bmp085"
static const unsigned short normal_i2c[] = { BMP085_I2C_ADDRESS,
I2C_CLIENT_END };
......@@ -78,20 +76,18 @@ struct bmp085_calibration_data {
s16 MB, MC, MD;
};
/* Each client has this additional data */
struct bmp085_data {
struct i2c_client *client;
struct mutex lock;
struct bmp085_calibration_data calibration;
u32 raw_temperature;
u32 raw_pressure;
unsigned char oversampling_setting;
struct i2c_client *client;
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;
s32 b6; /* calculated temperature correction coefficient */
s32 b6; /* calculated temperature correction coefficient */
};
static s32 bmp085_read_calibration_data(struct i2c_client *client)
{
u16 tmp[BMP085_CALIBRATION_DATA_LENGTH];
......@@ -99,12 +95,12 @@ static s32 bmp085_read_calibration_data(struct i2c_client *client)
struct bmp085_calibration_data *cali = &(data->calibration);
s32 status = i2c_smbus_read_i2c_block_data(client,
BMP085_CALIBRATION_DATA_START,
BMP085_CALIBRATION_DATA_LENGTH*sizeof(u16),
(BMP085_CALIBRATION_DATA_LENGTH << 1),
(u8 *)tmp);
if (status < 0)
return status;
if (status != BMP085_CALIBRATION_DATA_LENGTH*sizeof(u16))
if (status != (BMP085_CALIBRATION_DATA_LENGTH << 1))
return -EIO;
cali->AC1 = be16_to_cpu(tmp[0]);
......@@ -121,7 +117,6 @@ static s32 bmp085_read_calibration_data(struct i2c_client *client)
return 0;
}
static s32 bmp085_update_raw_temperature(struct bmp085_data *data)
{
u16 tmp;
......@@ -130,7 +125,7 @@ static s32 bmp085_update_raw_temperature(struct bmp085_data *data)
mutex_lock(&data->lock);
status = i2c_smbus_write_byte_data(data->client, BMP085_CTRL_REG,
BMP085_TEMP_MEASUREMENT);
if (status != 0) {
if (status < 0) {
dev_err(&data->client->dev,
"Error while requesting temperature measurement.\n");
goto exit;
......@@ -163,8 +158,9 @@ static s32 bmp085_update_raw_pressure(struct bmp085_data *data)
mutex_lock(&data->lock);
status = i2c_smbus_write_byte_data(data->client, BMP085_CTRL_REG,
BMP085_PRESSURE_MEASUREMENT + (data->oversampling_setting<<6));
if (status != 0) {
BMP085_PRESSURE_MEASUREMENT +
(data->oversampling_setting << 6));
if (status < 0) {
dev_err(&data->client->dev,
"Error while requesting pressure measurement.\n");
goto exit;
......@@ -193,7 +189,6 @@ static s32 bmp085_update_raw_pressure(struct bmp085_data *data)
return status;
}
/*
* This function starts the temperature measurement and returns the value
* in tenth of a degree celsius.
......@@ -205,7 +200,7 @@ static s32 bmp085_get_temperature(struct bmp085_data *data, int *temperature)
int status;
status = bmp085_update_raw_temperature(data);
if (status != 0)
if (status < 0)
goto exit;
x1 = ((data->raw_temperature - cali->AC6) * cali->AC5) >> 15;
......@@ -222,8 +217,10 @@ static s32 bmp085_get_temperature(struct bmp085_data *data, int *temperature)
/*
* 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 if the last known value is older
* than one second.
* 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)
{
......@@ -234,16 +231,16 @@ static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure)
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)) {
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)
goto exit;
if (status < 0)
return status;
}
status = bmp085_update_raw_pressure(data);
if (status != 0)
goto exit;
if (status < 0)
return status;
x1 = (data->b6 * data->b6) >> 12;
x1 *= cali->B2;
......@@ -274,15 +271,14 @@ static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure)
*pressure = p;
exit:
return status;
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 on overview on how measurement time,
* increase both. The datasheet gives an overview on how measurement time,
* accuracy and noise correlate.
*/
static void bmp085_set_oversampling(struct bmp085_data *data,
......@@ -309,12 +305,16 @@ static ssize_t set_oversampling(struct device *dev,
struct i2c_client *client = to_i2c_client(dev);
struct bmp085_data *data = i2c_get_clientdata(client);
unsigned long oversampling;
int success = strict_strtoul(buf, 10, &oversampling);
if (success == 0) {
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 success;
return err;
}
static ssize_t show_oversampling(struct device *dev,
......@@ -322,6 +322,7 @@ static ssize_t show_oversampling(struct device *dev,
{
struct i2c_client *client = to_i2c_client(dev);
struct bmp085_data *data = i2c_get_clientdata(client);
return sprintf(buf, "%u\n", bmp085_get_oversampling(data));
}
static DEVICE_ATTR(oversampling, S_IWUSR | S_IRUGO,
......@@ -337,7 +338,7 @@ static ssize_t show_temperature(struct device *dev,
struct bmp085_data *data = i2c_get_clientdata(client);
status = bmp085_get_temperature(data, &temperature);
if (status != 0)
if (status < 0)
return status;
else
return sprintf(buf, "%d\n", temperature);
......@@ -354,7 +355,7 @@ static ssize_t show_pressure(struct device *dev,
struct bmp085_data *data = i2c_get_clientdata(client);
status = bmp085_get_pressure(data, &pressure);
if (status != 0)
if (status < 0)
return status;
else
return sprintf(buf, "%d\n", pressure);
......@@ -386,25 +387,23 @@ static int bmp085_detect(struct i2c_client *client, struct i2c_board_info *info)
static int bmp085_init_client(struct i2c_client *client)
{
unsigned char version;
int status;
struct bmp085_data *data = i2c_get_clientdata(client);
int status = bmp085_read_calibration_data(client);
if (status < 0)
return status;
data->client = client;
status = bmp085_read_calibration_data(client);
if (status != 0)
goto exit;
version = i2c_smbus_read_byte_data(client, BMP085_VERSION_REG);
data->last_temp_measurement = 0;
data->temp_measurement_period = 1*HZ;
data->oversampling_setting = 3;
mutex_init(&data->lock);
dev_info(&data->client->dev, "BMP085 ver. %d.%d found.\n",
(version & 0x0F), (version & 0xF0) >> 4);
exit:
return status;
return 0;
}
static int __devinit bmp085_probe(struct i2c_client *client,
const struct i2c_device_id *id)
const struct i2c_device_id *id)
{
struct bmp085_data *data;
int err = 0;
......@@ -415,14 +414,11 @@ static int __devinit bmp085_probe(struct i2c_client *client,
goto exit;
}
/* default settings after POR */
data->oversampling_setting = 0x00;
i2c_set_clientdata(client, data);
/* Initialize the BMP085 chip */
err = bmp085_init_client(client);
if (err != 0)
if (err < 0)
goto exit_free;
/* Register sysfs hooks */
......@@ -430,8 +426,9 @@ static int __devinit bmp085_probe(struct i2c_client *client,
if (err)
goto exit_free;
dev_info(&data->client->dev, "Successfully initialized bmp085!\n");
goto exit;
dev_info(&client->dev, "Successfully initialized %s!\n", BMP085_NAME);
return 0;
exit_free:
kfree(data);
......@@ -441,13 +438,16 @@ static int __devinit bmp085_probe(struct i2c_client *client,
static int __devexit bmp085_remove(struct i2c_client *client)
{
struct bmp085_data *data = i2c_get_clientdata(client);
sysfs_remove_group(&client->dev.kobj, &bmp085_attr_group);
kfree(i2c_get_clientdata(client));
kfree(data);
return 0;
}
static const struct i2c_device_id bmp085_id[] = {
{ "bmp085", 0 },
{ BMP085_NAME, 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, bmp085_id);
......@@ -455,7 +455,7 @@ MODULE_DEVICE_TABLE(i2c, bmp085_id);
static struct i2c_driver bmp085_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "bmp085"
.name = BMP085_NAME
},
.id_table = bmp085_id,
.probe = bmp085_probe,
......@@ -467,6 +467,6 @@ static struct i2c_driver bmp085_driver = {
module_i2c_driver(bmp085_driver);
MODULE_AUTHOR("Christoph Mair <christoph.mair@gmail.com");
MODULE_AUTHOR("Christoph Mair <christoph.mair@gmail.com>");
MODULE_DESCRIPTION("BMP085 driver");
MODULE_LICENSE("GPL");
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