Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754703Ab0FNOTJ (ORCPT ); Mon, 14 Jun 2010 10:19:09 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:53811 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754303Ab0FNOTF convert rfc822-to-8bit (ORCPT ); Mon, 14 Jun 2010 10:19:05 -0400 From: "Datta, Shubhrajyoti" To: "linux-kernel@vger.kernel.org" Date: Mon, 14 Jun 2010 19:49:00 +0530 Subject: [RFC] [PATCH] Adding support for BMP085 pressure sensor. Thread-Topic: [RFC] [PATCH] Adding support for BMP085 pressure sensor. Thread-Index: AcsLx9ajrMUfmYL5Rf6bj45lmUHl3QAABVVg Message-ID: <0680EC522D0CC943BC586913CF3768C003B34A6178@dbde02.ent.ti.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: 10438 Lines: 369 Adding support for BMP085 pressure sensor. The interface of the device is I2C. The driver is based on a version initially written by Christoph Mair. Signed-off-by: Shubhrajyoti Datta --- drivers/misc/bmp085.c | 342 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 342 insertions(+), 0 deletions(-) create mode 100644 drivers/misc/bmp085.c diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c new file mode 100644 index 0000000..73edf1b --- /dev/null +++ b/drivers/misc/bmp085.c @@ -0,0 +1,342 @@ +/* Copyright (c) 2009 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 + +#define BMP085_I2C_ADDRESS 0x77 +#define BMP085_CALIBRATION_DATA_START 0xAA +#define BMP085_CALIBRATION_DATA_LENGTH 22 +#define BMP085_CHIP_ID_REG 0xD0 +#define BMP085_VERSION_REG 0xD1 +#define BMP085_CHIP_ID 0x55 +#define BMP085_CTRL_REG 0xF4 +#define BMP085_TEMP_REG 0x2E +#define BMP085_PRESSURE_OSRS0 0x34 +#define BMP085_MSB 0xF6 +#define BMP085_LSB 0xF7 +#define BMP085_XLSB 0xF8 +#define BMP085_TEMP_CONV_TIME 5 + +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; + unsigned char oversampling_setting; + s32 b6; /* calculated temperature correction coefficient */ +}; + +static void bmp085_init_client(struct i2c_client *client); + +static s32 bmp085_get_calibration_data(struct i2c_client *client) +{ + u8 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, tmp); + + cali->AC1 = (tmp[0] << 8) | tmp[1]; + cali->AC2 = (tmp[2] << 8) | tmp[3]; + cali->AC3 = (tmp[4] << 8) | tmp[5]; + cali->AC4 = (tmp[6] << 8) | tmp[7]; + cali->AC5 = (tmp[8] << 8) | tmp[9]; + cali->AC6 = (tmp[10] << 8) | tmp[11]; + + /*parameters B1,B2*/ + cali->B1 = (tmp[12] << 8) | tmp[13]; + cali->B2 = (tmp[14] << 8) | tmp[15]; + + /*parameters MB,MC,MD*/ + cali->MB = (tmp[16] << 8) | tmp[17]; + cali->MC = (tmp[18] << 8) | tmp[19]; + cali->MD = (tmp[20] << 8) | tmp[21]; + return status; +} + +static s32 bmp085_get_temperature(struct i2c_client *client) +{ + u16 temperature = 0x00; + u8 tmp[2]; + s32 status = i2c_smbus_write_byte_data(client, BMP085_CTRL_REG, + BMP085_TEMP_REG); + if (status != 0) { + dev_err(&client->dev, "bmp085: Error requesting\ + temperature measurement.\n"); + return status; + } + msleep(BMP085_TEMP_CONV_TIME); + + i2c_smbus_read_i2c_block_data(client, BMP085_MSB, 2, tmp); + /* next temperature measurement is needed in one second */ + temperature = (tmp[0] << 8) + tmp[1]; + pr_info("temperature: %u\n", temperature); + return temperature; +} + +static s32 bmp085_read_pressure(struct i2c_client *client, u32 *pressure) +{ + struct bmp085_data *data = i2c_get_clientdata(client); + u8 tmp[3]; + s32 status; + + status = i2c_smbus_write_byte_data(client, BMP085_CTRL_REG, + BMP085_PRESSURE_OSRS0 + (data->oversampling_setting<<6)); + if (status != 0) + return status; + + /* wait for the end of conversion */ + msleep(2+(3 << data->oversampling_setting)); + + status = i2c_smbus_read_i2c_block_data(client, BMP085_MSB, 0x03, tmp); + /* swap positions to correct the MSB/LSB positions*/ + *pressure = (tmp[0] << 16) | (tmp[1] << 8) | tmp[2]; + *pressure = *pressure >> (8-data->oversampling_setting); + return status; +} + +/* sysfs callbacks */ +/* +* From the Datasheet +* Oversampling (osrs) +* Measurement | Control register | conversion time[ms] +* Pressure (osrs 0 ) |0x34 |4.5 +* Pressure (osrs 0 ) |0x74 |7.5 +* Pressure (osrs 0 ) |0xB4 |13.5 +* Pressure (osrs 0 ) |0xF4 |25.5 +*/ +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); + data->oversampling_setting = simple_strtoul(buf, NULL, 10); + if (data->oversampling_setting > 3) + data->oversampling_setting = 3; + return count; +} + +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", data->oversampling_setting); +} +static DEVICE_ATTR(oversampling, S_IWUSR | S_IRUGO, + show_oversampling, set_oversampling); + +static void bmp085_read_temperature(struct i2c_client *client, s32 *buf) +{ + s32 raw_temp, x1 , x2; + struct bmp085_data *data = i2c_get_clientdata(client); + struct bmp085_calibration_data *cali = &data->calibration; + + raw_temp = bmp085_get_temperature(client); + x1 = ((raw_temp - cali->AC6) * cali->AC5) >> 15; + x2 = (cali->MC << 11) / (x1 + cali->MD); + data->b6 = x1 + x2 - 4000; + *buf = ((x1+x2+8) >> 4) ; +} + +static int bmp085_read_sensor(struct bmp085_data *bmp085, + s32 *pressure, + s32 *temp) +{ + + struct i2c_client *client = bmp085->client; + struct bmp085_data *data = i2c_get_clientdata(client); + struct bmp085_calibration_data *cali = &data->calibration; + s32 x1, x2, x3, b3; + u32 b4, b7; + s32 p; + unsigned int raw_pressure = 0; + s32 raw_temp; + + bmp085_read_temperature(client, &raw_temp); + *temp = raw_temp ; + bmp085_read_pressure(client, &raw_pressure); + + 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) >> 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)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; +} +static ssize_t show_temperature(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + return sprintf(buf, "%d\n", bmp085_get_temperature(client)); +} +static DEVICE_ATTR(temp0_input, S_IRUGO, show_temperature, NULL); + +static ssize_t show_pressure(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + struct bmp085_data *bmp085 = i2c_get_clientdata(client); + s32 pressure_read, temperature; + + bmp085_read_sensor(bmp085, &pressure_read, &temperature); + + return sprintf(buf, "%d\n", pressure_read); +} +static DEVICE_ATTR(pressure0_input, S_IRUGO, show_pressure, NULL); + +static struct attribute *bmp085_attributes[] = { + &dev_attr_oversampling.attr, + &dev_attr_pressure0_input.attr, + &dev_attr_temp0_input.attr, + NULL +}; + +static const struct attribute_group bmp085_attr_group = { + .attrs = bmp085_attributes, +}; + +static int bmp085_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct bmp085_data *bmp085_data; + int err; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { + dev_dbg(&client->dev, "adapter doesn't support I2C\n"); + return -ENODEV; + } + + bmp085_data = kzalloc(sizeof(struct bmp085_data), GFP_KERNEL); + if (!bmp085_data) { + err = -ENOMEM; + goto exit; + } + bmp085_data->client = client; + + /* default settings after POR */ + bmp085_data->oversampling_setting = 0x00; + + i2c_set_clientdata(client, bmp085_data); + + /* Initialize the BMP085 chip */ + bmp085_init_client(client); + + /* Register sysfs hooks */ + err = sysfs_create_group(&client->dev.kobj, &bmp085_attr_group); + if (err) + dev_err(&client->dev, + "failed to create sysfs entries\n"); + + return 0; + +exit: + return err; +} + +static int bmp085_remove(struct i2c_client *client) +{ + struct bmp085_data *bmp085 = i2c_get_clientdata(client); + + pr_info("bmp085 remove\n"); + sysfs_remove_group(&client->dev.kobj, &bmp085_attr_group); + kfree(bmp085); + return 0; +} + +static void bmp085_init_client(struct i2c_client *client) +{ + u8 version; + struct bmp085_data *data = i2c_get_clientdata(client); + + bmp085_get_calibration_data(client); + version = i2c_smbus_read_byte_data(client, BMP085_VERSION_REG); + data->oversampling_setting = 3; + mutex_init(&data->lock); + pr_info("BMP085 ver. %d.%d initialized\n", + (version & 0x0F), (version & 0xF0) >> 4); +} + +static const struct i2c_device_id bmp085_id[] = { + { "bmp085", 0 }, + { } +}; + +static struct i2c_driver bmp085_driver = { + .driver = { + .name = "bmp085", + .owner = THIS_MODULE, + }, + .probe = bmp085_probe, + .remove = bmp085_remove, + .id_table = bmp085_id, +}; + +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, Shubhrajyoti"); +MODULE_DESCRIPTION("BMP085 driver"); +MODULE_LICENSE("GPL"); + +module_init(bmp085_init); +module_exit(bmp085_exit); + + -- 1.5.4.7 -- 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/