> -----Original Message----- > From: Stefan Schmidt [mailto:stefan@xxxxxxxxxxxxxxxxxx] > Sent: Monday, June 14, 2010 4:06 PM > To: Datta, Shubhrajyoti > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-input@xxxxxxxxxxxxxxx; > christoph.mair@xxxxxxxxx > Subject: Re: [RFC] [PATCH] Adding support for BMP085 pressure sensor. > > Hello. > > On Mon, 2010-06-14 at 15:43, Datta, Shubhrajyoti wrote: > > 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. > > Did you coordinate with Christoph on this driver? I used it myself and the > last > time I talked to Christoph he was planning to brining it mainline himself. > Added > him to cc to keep him in the loop. I modified the initial version to use it as an input device an a few bug fixes and sent him the patch for his signoff. Also I have kept the copyright banner that he had. However since it is not really a human input device I thought of making it an misc as it doesn't really justify a hwmon. > > regards > Stefan Schmidt > > > Signed-off-by: Shubhrajyoti D <shubhrajyoti@xxxxxx> > > --- > > drivers/misc/bmp085.c | 333 > +++++++++++++++++++++++++++++++++++++++++++++++++ > > 1 files changed, 333 insertions(+), 0 deletions(-) > > create mode 100755 drivers/misc/bmp085.c > > > > diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c > > new file mode 100755 > > index 0000000..fab2480 > > --- /dev/null > > +++ b/drivers/misc/bmp085.c > > @@ -0,0 +1,333 @@ > > +/* Copyright (c) 2009 Christoph Mair <christoph.mair@xxxxxxxxx> > > + > > + 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/i2c.h> > > +#include <linux/slab.h> > > +#include <linux/delay.h> > > +#include <linux/jiffies.h> > > + > > +#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 */ > > +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(temperature, 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(pressure, S_IRUGO, show_pressure, NULL); > > + > > +static struct attribute *bmp085_attributes[] = { > > + &dev_attr_oversampling.attr, > > + &dev_attr_pressure.attr, > > + &dev_attr_temperature.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@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
