[PATCH 1/4] i2c: Add bmp085 pressure driver.
Stefan Schmidt
stefan at datenfreihafen.org
Mon Apr 26 09:25:03 CEST 2010
The driver was developed by Christoph Mair <christoph.mair at gmail.com> out of
tree so far.
Signed-off-by: Stefan Schmidt <stefan at datenfreihafen.org>
---
arch/arm/mach-s3c2440/mach-gta02.c | 3 +
drivers/i2c/chips/Kconfig | 11 ++
drivers/i2c/chips/Makefile | 1 +
drivers/i2c/chips/bmp085.c | 345 ++++++++++++++++++++++++++++++++++++
4 files changed, 360 insertions(+), 0 deletions(-)
create mode 100644 drivers/i2c/chips/bmp085.c
diff --git a/arch/arm/mach-s3c2440/mach-gta02.c b/arch/arm/mach-s3c2440/mach-gta02.c
index 4520d7b..153549e 100644
--- a/arch/arm/mach-s3c2440/mach-gta02.c
+++ b/arch/arm/mach-s3c2440/mach-gta02.c
@@ -928,6 +928,9 @@ static struct i2c_board_info gta02_i2c_devs[] __initdata = {
.irq = GTA02_IRQ_PCF50633,
.platform_data = >a02_pcf_pdata,
},
+ {
+ I2C_BOARD_INFO("bmp085", 0x77),
+ },
};
static struct s3c2410_nand_set gta02_nand_sets[] = {
diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index a84179a..e59c8cb 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -224,4 +224,15 @@ config PCA9632
This driver can also be built as a module. If so, the module
will be called pca9632.
+
+config SENSORS_BMP085
+ tristate "Bosch Sensortec BMP085 pressure driver"
+ depends on I2C
+ help
+ If you say yes here you get support for the Bosch Sensortec BMP085
+ pressure driver.
+
+ This driver can also be built as a module. If so, the module
+ will be called bmp085.
+
endmenu
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index b0dc12e..17c3107 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_SENSORS_TSL2550) += tsl2550.o
obj-$(CONFIG_MCU_MPC8349EMITX) += mcu_mpc8349emitx.o
obj-$(CONFIG_SENSORS_TSL256X) += tsl256x.o
obj-$(CONFIG_PCA9632) += pca9632.o
+obj-$(CONFIG_SENSORS_BMP085) += bmp085.o
ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/i2c/chips/bmp085.c b/drivers/i2c/chips/bmp085.c
new file mode 100644
index 0000000..d4523ce
--- /dev/null
+++ b/drivers/i2c/chips/bmp085.c
@@ -0,0 +1,345 @@
+/* Copyright (c) 2009 Christoph Mair <christoph.mair at gmail.com>
+
+ 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/init.h>
+#include <linux/i2c.h>
+#include <linux/delay.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 /* 85 */
+
+
+/* Addresses to scan: 0x77 */
+static const unsigned short normal_i2c[] = { 0x77, I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD_1(bmp085);
+
+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 {
+ unsigned char version;
+ struct bmp085_calibration_data calibration;
+ unsigned char oversampling_setting;
+ unsigned long next_temp_measurement;
+ long 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)
+{
+ struct bmp085_data *data = i2c_get_clientdata(client);
+ u16 temperature = 0x00;
+ u8 tmp[2];
+ s32 status = i2c_smbus_write_byte_data(client, 0xF4, 0x2E);
+ if (status != 0) {
+ printk(KERN_INFO "bmp085: Error while requesting temperature measurement.\n");
+ return status;
+ }
+ msleep(5);
+
+ i2c_smbus_read_i2c_block_data(client, 0xF6, 2, tmp);
+ data->next_temp_measurement = jiffies + 1;/**HZ;*/ /* next temperature measurement is needed in one second */
+ temperature = (tmp[0] << 8) + tmp[1];
+ printk(KERN_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 = 0;
+ *pressure = 0;
+
+ status = i2c_smbus_write_byte_data(client, 0xF4, 0x34 + (data->oversampling_setting<<6));
+ if (status != 0) {
+ return status;
+ }
+ msleep(2+(3 << data->oversampling_setting<<1)); /* wait for the end of conversion */
+
+ status = i2c_smbus_read_i2c_block_data(client, 0xF6, 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);
+ printk(KERN_INFO "pressure: %u\n", *pressure);
+ 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 ssize_t show_temperature(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);
+ struct bmp085_calibration_data *cali = &data->calibration;
+
+ long raw_temp = bmp085_get_temperature(client);
+ long x1 = ((raw_temp - cali->AC6) * cali->AC5) >> 15;
+ long x2 = (cali->MC << 11) / (x1 + cali->MD);
+ data->b6 = x1 + x2 - 4000;
+// printk(KERN_INFO "got raw temp: %ld; AC5: %d, AC6: %d, MC: %d, MD: %d\n", raw_temp, cali->AC5, cali->AC6, cali->MC, cali->MD);
+ return sprintf(buf, "%ld\n", (x1+x2+8) >> 4);
+}
+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 *data = i2c_get_clientdata(client);
+ struct bmp085_calibration_data *cali = &data->calibration;
+ long x1, x2, x3, b3;
+ unsigned long b4, b7;
+ long p;
+ unsigned int raw_pressure;
+ if (time_after(jiffies, data->next_temp_measurement)) {
+ printk(KERN_INFO "new temp required: %lu v.s. %lu\n", jiffies, data->next_temp_measurement);
+ show_temperature(dev, attr, buf); /* read temperature and calculate coefficients */
+ }
+
+ bmp085_read_pressure(client, &raw_pressure);
+// printk(KERN_INFO "raw_pressure: %ud, B6: %ld\n", raw_pressure, data->b6);
+
+ x1 = (data->b6 * data->b6) >> 12;
+ x1 *= cali->B2;
+ x1 >>= 11;
+
+ x2 = cali->AC2 * data->b6;
+ x2 >>= 11;
+
+ x3 = x1 + x2;
+
+ b3 = (((((long)cali->AC1) * 4 + x3) << data->oversampling_setting) + 2) >> 2;
+
+// printk(KERN_INFO "x1: %ld, x2: %ld, x3: %ld, b3: %ld\n", x1, x2, x3, b3);
+ x1 = (cali->AC3 * data->b6) >> 13;
+ x2 = (cali->B1 * ((data->b6 * data->b6) >> 12)) >> 16;
+ x3 = (x1 + x2 + 2) >> 2;
+ b4 = (cali->AC4 * (unsigned long)(x3 + 32768)) >> 15;
+
+// printk(KERN_INFO "x1: %ld, x2: %ld, x3: %ld, b4: %ld\n", x1, x2, x3, b4);
+ b7 = ((unsigned long)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;
+ return sprintf(buf, "%ld\n", p);
+}
+static DEVICE_ATTR(pressure, S_IRUGO, show_pressure, NULL);
+
+
+static struct attribute *bmp085_attributes[] = {
+ &dev_attr_temperature.attr,
+ &dev_attr_pressure.attr,
+ &dev_attr_oversampling.attr,
+ NULL
+};
+
+static const struct attribute_group bmp085_attr_group = {
+ .attrs = bmp085_attributes,
+};
+
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int bmp085_detect(struct i2c_client *client, int kind, struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter = client->adapter;
+ const char *client_name;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
+ return -ENODEV;
+
+ if (client->addr == BMP085_I2C_ADDRESS) {
+ if (i2c_smbus_read_byte_data(client, BMP085_CHIP_ID_REG) != BMP085_CHIP_ID) {
+ goto exit;
+ }
+
+ /* Chip identified */
+ client_name = "bmp085";
+ strlcpy(info->type, client_name, I2C_NAME_SIZE);
+ printk(KERN_INFO "BMP085 found!\n");
+ return 0;
+ }
+
+ exit:
+ printk(KERN_INFO "BMP085 not found at address %x!\n", client->addr);
+ return -ENODEV;
+}
+
+static int bmp085_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct bmp085_data *data;
+ int err;
+
+ printk(KERN_INFO "bmp085 probe!\n");
+
+ 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 */
+ bmp085_init_client(client);
+
+ /* Register sysfs hooks */
+ err = sysfs_create_group(&client->dev.kobj, &bmp085_attr_group);
+ if (err)
+ goto exit_free;
+
+ printk(KERN_INFO "bmp085 probe succeeded!\n");
+ return 0;
+
+ exit_free:
+ kfree(data);
+ exit:
+ return err;
+}
+
+static int bmp085_remove(struct i2c_client *client)
+{
+ printk(KERN_INFO "bmp085 remove!\n");
+ sysfs_remove_group(&client->dev.kobj, &bmp085_attr_group);
+ kfree(i2c_get_clientdata(client));
+ return 0;
+}
+
+/* Called when we have found a new HMC5843. */
+static void bmp085_init_client(struct i2c_client *client)
+{
+ struct bmp085_data *data = i2c_get_clientdata(client);
+ bmp085_get_calibration_data(client);
+ data->version = i2c_smbus_read_byte_data(client, BMP085_VERSION_REG);
+ data->next_temp_measurement = 0;
+ data->oversampling_setting = 3;
+ printk(KERN_INFO "BMP085 ver. %d.%d initialized\n", (data->version & 0x0F), (data->version & 0xF0) >> 4);
+}
+
+static const struct i2c_device_id bmp085_id[] = {
+ { "bmp085", 0 },
+ { }
+};
+
+static struct i2c_driver bmp085_driver = {
+ .driver = {
+ .name = "bmp085",
+ },
+ .probe = bmp085_probe,
+ .remove = bmp085_remove,
+ .id_table = bmp085_id,
+
+ .detect = bmp085_detect,
+ .address_data = &addr_data,
+};
+
+static int __init bmp085_init(void)
+{
+ printk(KERN_INFO "init!\n");
+ return i2c_add_driver(&bmp085_driver);
+}
+
+static void __exit bmp085_exit(void)
+{
+ printk(KERN_INFO "exit!\n");
+ i2c_del_driver(&bmp085_driver);
+}
+
+
+MODULE_AUTHOR("Christoph Mair <christoph.mair at gmail.com");
+MODULE_DESCRIPTION("BMP085 driver");
+MODULE_LICENSE("GPL");
+
+module_init(bmp085_init);
+module_exit(bmp085_exit);
--
1.7.0.5
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