Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753646Ab0FUGqc (ORCPT ); Mon, 21 Jun 2010 02:46:32 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:34141 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751751Ab0FUGqa convert rfc822-to-8bit (ORCPT ); Mon, 21 Jun 2010 02:46:30 -0400 From: "Datta, Shubhrajyoti" To: Christoph Mair , Jonathan Cameron CC: "linux-kernel@vger.kernel.org" , Andrew Morton , Stefan Schmidt Date: Mon, 21 Jun 2010 12:15:02 +0530 Subject: RE: [PATCH] Support for the pressure sensor BMP085 from Bosch Sensortec. Thread-Topic: [PATCH] Support for the pressure sensor BMP085 from Bosch Sensortec. Thread-Index: AcsQutjsx+Lxk+AIRrugCnrvCgKSeAASjUXg Message-ID: <0680EC522D0CC943BC586913CF3768C003B34A6CDF@dbde02.ent.ti.com> References: <4C1DF4DE.5090403@jic23.retrosnub.co.uk> <1277067058-6929-1-git-send-email-christoph.mair@gmail.com> In-Reply-To: <1277067058-6929-1-git-send-email-christoph.mair@gmail.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 17719 Lines: 536 > -----Original Message----- > From: Christoph Mair [mailto:christoph.mair@gmail.com] > Sent: Monday, June 21, 2010 2:21 AM > To: Jonathan Cameron > Cc: linux-kernel@vger.kernel.org; Andrew Morton; Stefan Schmidt; Datta, > Shubhrajyoti; Christoph Mair > Subject: [PATCH] Support for the pressure sensor BMP085 from Bosch > Sensortec. > > This driver adds support for the BMP085 digital pressure sensor > from Bosch Sensortec. It exposes a sysfs api to userspace where > pressure and temperature measurement results can be read from the > pressure0_input and temp0_input file. The chip is able to calculate > the average of up to eight samples to increase the accuracy. > This feature can be controlled by writing to the oversampling file. > > Signed-off-by: Christoph Mair > Acked-by: Jonathan Cameron > --- > drivers/misc/Kconfig | 10 + > drivers/misc/Makefile | 1 + > drivers/misc/bmp085.c | 455 > +++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 466 insertions(+), 0 deletions(-) > create mode 100644 drivers/misc/bmp085.c > > diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig > index 26386a9..9df8d3e 100644 > --- a/drivers/misc/Kconfig > +++ b/drivers/misc/Kconfig > @@ -353,6 +353,16 @@ config VMWARE_BALLOON > To compile this driver as a module, choose M here: the > module will be called vmware_balloon. > > +config BMP085 > + tristate "BMP085 digital pressure sensor" > + depends on I2C && SYSFS > + help > + If you say yes here you get support for the Bosch Sensortec > + BMP086 digital pressure sensor. > + > + To compile this driver as a module, choose M here: the > + module will be called bmp085. > + > source "drivers/misc/c2port/Kconfig" > source "drivers/misc/eeprom/Kconfig" > source "drivers/misc/cb710/Kconfig" > diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile > index 6ed06a1..5623c54 100644 > --- a/drivers/misc/Makefile > +++ b/drivers/misc/Makefile > @@ -31,3 +31,4 @@ obj-$(CONFIG_IWMC3200TOP) += iwmc3200top/ > obj-y += eeprom/ > obj-y += cb710/ > obj-$(CONFIG_VMWARE_BALLOON) += vmware_balloon.o > +obj-$(CONFIG_BMP085) += bmp085.o > diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c > new file mode 100644 > index 0000000..16a2b2c > --- /dev/null > +++ b/drivers/misc/bmp085.c > @@ -0,0 +1,455 @@ > +/* Copyright (c) 2010 Christoph Mair > + > + 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 > +#include > +#include > +#include > +#include > + > + > +#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 > +#define BMP085_CONVERSION_REGISTER_MSB 0xF6 > +#define BMP085_CONVERSION_REGISTER_LSB 0xF7 > +#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 }; > + > +struct bmp085_calibration_data { > + s16 AC1, AC2, AC3; > + u16 AC4, AC5, AC6; > + s16 B1, B2; > + 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; > + unsigned long last_temp_measurement; The size of long is arch dependent so using something like s32 etc may be used. > + s32 b6; /* calculated temperature correction coefficient */ > +}; > + > + > +static s32 bmp085_read_calibration_data(struct i2c_client *client) > +{ > + u16 tmp[BMP085_CALIBRATION_DATA_LENGTH]; > + struct bmp085_data *data = i2c_get_clientdata(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), > + (u8 *)tmp); > + if (status < 0) > + return status; > + > + if (status != BMP085_CALIBRATION_DATA_LENGTH*sizeof(u16)) > + return -EIO; > + > + 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); > + status = i2c_smbus_write_byte_data(data->client, BMP085_CTRL_REG, > + BMP085_TEMP_MEASUREMENT); > + if (status != 0) { > + dev_err(&data->client->dev, > + "Error while requesting temperature measurement.\n"); > + goto exit; > + } > + msleep(BMP085_TEMP_CONVERSION_TIME); > + > + status = i2c_smbus_read_i2c_block_data(data->client, > + BMP085_CONVERSION_REGISTER_MSB, sizeof(tmp), (u8 *)&tmp); > + if (status < 0) > + goto exit; > + if (status != sizeof(tmp)) { > + dev_err(&data->client->dev, > + "Error while reading temperature measurement result\n"); > + status = -EIO; > + 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); > + status = i2c_smbus_write_byte_data(data->client, BMP085_CTRL_REG, > + BMP085_PRESSURE_MEASUREMENT + (data- > >oversampling_setting<<6)); > + if (status != 0) { > + dev_err(&data->client->dev, > + "Error while requesting pressure measurement.\n"); > + goto exit; > + } > + > + /* wait for the end of conversion */ > + msleep(2+(3 << data->oversampling_setting<<1)); > + > + /* copy data into a u32 (4 bytes), but skip the first byte. */ > + status = i2c_smbus_read_i2c_block_data(data->client, > + BMP085_CONVERSION_REGISTER_MSB, 3, ((u8 *)&tmp)+1); > + if (status < 0) > + goto exit; > + if (status != 3) { > + dev_err(&data->client->dev, > + "Error while reading pressure measurement results\n"); > + status = -EIO; > + 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 if the last known value is older > + * than one second. > + */ > +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 + 1*HZ < jiffies) { > + status = bmp085_get_temperature(data, NULL); > + if (status != 0) > + goto exit; > + } > + > + status = bmp085_update_raw_pressure(data); > + if (status != 0) > + goto exit; > + > + 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; > + > +exit: > + return status; > +} > + > +/* > + * This function sets the chip-internal oversampling. Valid values are > 0..3. > + * The chip will use 2^oversampling samples for interlan averaging. > + * This influences the measurement time and the accuracy; larger values > + * increase both. The datasheet gives on 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 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) { > + bmp085_set_oversampling(data, oversampling); > + return count; > + } > + return success; > +} > + > +static ssize_t show_oversampling(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + 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, > + show_oversampling, set_oversampling); > + > + > +static ssize_t show_temperature(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + int temperature; > + int status; > + struct i2c_client *client = to_i2c_client(dev); > + struct bmp085_data *data = i2c_get_clientdata(client); > + > + 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 i2c_client *client = to_i2c_client(dev); > + struct bmp085_data *data = i2c_get_clientdata(client); > + > + 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, > +}; > + > +static int bmp085_detect(struct i2c_client *client, struct i2c_board_info > *info) > +{ > + if (client->addr != BMP085_I2C_ADDRESS) > + return -ENODEV; > + > + if (i2c_smbus_read_byte_data(client, BMP085_CHIP_ID_REG) != > BMP085_CHIP_ID) > + return -ENODEV; > + > + return 0; > +} > + > +static int bmp085_init_client(struct i2c_client *client) > +{ > + unsigned char version; > + int status; > + struct bmp085_data *data = i2c_get_clientdata(client); > + 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->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; > +} > + > +static int bmp085_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct bmp085_data *data; > + int err = 0; > + > + data = kzalloc(sizeof(struct bmp085_data), GFP_KERNEL); > + if (!data) { > + err = -ENOMEM; > + 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) > + goto exit_free; > + > + /* Register sysfs hooks */ > + err = sysfs_create_group(&client->dev.kobj, &bmp085_attr_group); > + if (err) > + goto exit_free; > + > + dev_info(&data->client->dev, "Succesfully initialized bmp085!\n"); > + goto exit; > + > +exit_free: > + kfree(data); > +exit: > + return err; > +} > + > +static int bmp085_remove(struct i2c_client *client) > +{ > + sysfs_remove_group(&client->dev.kobj, &bmp085_attr_group); > + kfree(i2c_get_clientdata(client)); > + return 0; > +} > + > +static const struct i2c_device_id bmp085_id[] = { > + { "bmp085", 0 }, > + { } > +}; > + > +static struct i2c_driver bmp085_driver = { > + .driver = { > + .owner = THIS_MODULE, > + .name = "bmp085" > + }, > + .id_table = bmp085_id, > + .probe = bmp085_probe, > + .remove = bmp085_remove, > + > + .detect = bmp085_detect, > + .address_list = normal_i2c > +}; > + > +static int __init bmp085_init(void) > +{ > + return i2c_add_driver(&bmp085_driver); > +} > + > +static void __exit bmp085_exit(void) > +{ > + i2c_del_driver(&bmp085_driver); > +} > + > + > +MODULE_AUTHOR("Christoph Mair +MODULE_DESCRIPTION("BMP085 driver"); > +MODULE_LICENSE("GPL"); > + > +module_init(bmp085_init); > +module_exit(bmp085_exit); > -- > 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/